Bolide Shockwave Injures 1000+ in Russia: Black Swan — or I Told You So?

 

 

 

 

The Bos!

Slow feed but great vids

Plugged!: Younger Dryas Impact Event

Feb Fireball Season

San Fran

Cuba and video

Japan

Miami

Brazil 2012

Iowa 1875 and here

1913

Fireball Hush-Up?

NASA Urges Vigilance for Weird Fireballs

NASA 2012 Press Release “The Fireballs of February”

Year of the Snake?

Black Swan

As readers know, the Tusk is generally uninterested in current events related to our subject. We stick to the past unless we simply cannot ignore the present. But, in the end, we study the past so that we may be more prepared for what happened this morning in Russia.

This humble blog has some of the most informed and open-minded readers in fields related to this event of any source on the internet. I hope our regular commentors and others will develop an informative thread of observations.

 

  • Hermann Burchard

    From some of the pictures, this was a grazing impact, the trail begins and ends in the upper atmosphere.

    This French newspaper report has a few additional infos. Newly updated, it reports 950 injured persons.

    http://www.lefigaro.fr/international/2013/02/15/01003-20130215ARTFIG00312-de-nombreux-blesses-apres-la-pluie-de-meteorites-en-russie.php

    On one of the videos explosions are heard.

  • Steve Garcia

    I don’t think I will be saying anything important that others here don’t already know or think:

    Why anyone’s first real reaction would be that the two are not connected flummoxes me. They were on parallel orbits only a day apart. It is not like it is a population of objects like the Taurids. What are the chances that two objects on the same path, separated only by time and a very slight side-to-side would be crossing Earth’s orbit within a day?

    My own 1st reaction is: Are there more?

    This was such a wonderful, basically benign, warning shot across the bow. It is great that no one was killed. But 950 injured – wow. 3000 buildings actually damaged – wow.

    2nd thought: A bit deeper into the atmosphere and it might nearly have been another Tunguska, more or less (probably less). Hermann notes that it grazed and mostly kept on going.

    3rd thought: No one had a CLUE this was coming.

    4th thought: Jonny and others here may be able to estimate its size and compare it to Tunguska.

    5th thought: Yeah, 3000 buildings damaged (Le Figaro) as easily as 3. The explosion shock wave doesn’t discriminate.

    6th thought: If it had impacted, what damage?

    7th thought: That hole in the ice was about the same size as the impact in Peru a couple of years ago. (Yes, water/ice vs ground…) And that was only one of many fragments.

    8th thought: Half the pieces went essentially down, half up. The pieces that went up may be strewn downfield a long way. It should be a great time for meteor hunters north of there. Damage on a much smaller scale is possible there, too.

    9th thought: WOW! The blast was terrific! MUCH greater than sonic booms I’ve heard, which also broke windows in the 1950s. I wondered if it was the sonic boom or the shock wave of the blast. One link on Le Figaro (no text) attributed the damage to the sonic boom. Yes? No?

    10th thought: The one video shows plywood getting blown inward. From that the force there could be estimated pretty closely.

    11th thought: The brightness – it to some degree substantiates reports in 1908 of Tunguska lighting up the sky all the way to western Europe.

    12th thought: Is this pairing of the two objects an anomaly? Or will we find out that this is the norm? How many other companions of this one flew by (or will fly by) without being even seen?

    13th thought? Not intending to be alarmist, but are more pieces coming? We never saw this one coming, and often where there is smoke, there is fire. How many other pieces are accompanying this asteroid 2012 DA14? Legitimate questions – and ones we can’t do a darned thing about.

    ‘Nuff for now. I will let others throw in more scientific thoughts…

  • Hermann Burchard

    Steve,
    6th thought: If it had impacted, what damage?

    One of the links leads to this thought (& more, but silly):

    GoldMorg Com writes ; very very very very coincidental, Chelyabinsk, where huge radioactive stockpiles are. A direct full hit would have caused a nuclear disaster for Eurasia that is thousand times worse than Chernobyl.

  • Jonny

    They are not on parallel orbits Steve, very much opposite in that one could describe them as anti-parallel. The russian meteorite is seen moving left to right in front of the rising sun, and thus must be travelling north to south. 2012 DA14 is moving south to north. This is as about as dynamically unrelated as you can get. This is cosmic coincidence, nothing more.

    The Russian meteorite is thought to be about 10 tonnes in mass. That puts it in the 2-5 meter class of object. Travelling at 15 km/sec it would have had an energy of around 270 tonnes of TNT. A big explosion certainly, but if had made it through to ground (and being the size it is its unlikely), it would have caused local destruction and serious loss of life if it was in an urbanised area. The thing to bear in mind is that we can expect an event of this size to occur approximately once per year somewhere in the world.

  • Steve Garcia

    Thanks on that, Jonny. I had evidently misread that.

    Once per year? Since I can’t recall any quite like this, the question would be where have they been exploding (besides over oceans)? This one is by far the largest one I’ve heard of in my time.

    If they are that common, then no big deal, right? What’s 270 tonnes of TNT (35 Hiroshimas) among friends, after all?

    The big thing to take away, then, is that we are at their mercy. We don’t see them coming, so we are ducks in a shooting gallery – if they happen to come our way. The operative term there is “happen to”. We have no control, no detection, no plan, no preparation. Just sit and wait for the lightning to strike. And hope it “happens to” happen in someone else’s back yard. Thanks, David Morrison, et al.

    This being the first time (that we know of) that we’ve had the possible ability to protect ourselves from such things, the biggest problem is coming to realize that it has happened before and will happen again. Without adequate funding, neither our realization can happen, nor any plan will ever happen.

    I know, that makes me sound like an alarmist. But, this isn’t like global warming where the Kyoto Protocols would only have reduced the 2100 global temperature by ~0.12°C, so wrong or right, it didn’t make a hill of beans difference. With NEOs and comets, if we screw it up we get to wear rabbit skins and shiver in rock overhangs for a millennium.or ten. That is, those few who survive the impact and the real environmental disaster that follows.

  • Jonny

    From here http://www.nature.com/news/russian-meteor-largest-in-a-century-1.12438 the size was about 15 meters and about 7000 tonnes as measured from infrasound stations(I was going by a precious BBC news report). This sounds more probably given its effects than a sub 5 meter object. If travelling at 15 km/sec this gives it an energy of 188 Kilotonnes of TNT, which is about 12-13 hiroshima bombs. This is the lower end of the energy estimate of the 13 August 1930 airburst over the neighbourhood of the River Curuça in the Brazilian Amazon (estimated to be between 0.2 and 2 MegaTonnes). Of course the nature article seems to ignore the 1930 and the 1935 airburst over British Guiana the later of which has an uncertain energy but is likely bigger than the Russian meteor in size due to it levelling an elongated area of forest 32 kilometers across.

  • Jonny

    Steve,

    Hirohsima was about 15 Kilotonnes (but, not 7 Tonnes). Given the energy estimate measured from the infrasound stations I would be more inclined to go with the second post of mine. You might be interested to see these videos here http://say26.com/meteorite-in-russia-all-videos-in-one-place, particularly the office based videos, where it looks like the overpressure from the sonic boom blows those close to teh window away from it.

    Jonny

  • Jonny

    Approximate path of the Russian meteor in comparison to 2012 DA14 from the Daily Telegraph http://s.telegraph.co.uk/graphics/html/Years/2013/February/images/Meteor5.png

  • Hermann Burchard

    Jonny,

    A big explosion certainly, but if had made it through to ground (and being the size it is its unlikely), it would have caused local destruction . . .

    This rock would not have reached the grround as it was grazing the upper atmosphere, as Steve noted, . . . it grazed and mostly kept on going. “”. . It kept going,” meaning a remnant left the atmosphere and the body did not completely burn up.

    The brilliant light indicates explosions from heating the outer layers upon contact with dense air, and probably caused repeated ablation or spalling of outer layers without complete destruction. This should be considered when estimating the size.

    The delay of the sound of the blasts of three minutes translates into an altitude of 60 km (speed of sound may not have been standard). It should be possible to measure the trail from photos and confirm entry into and departure from air density levels sufficient to cause incandescent heating.

  • Steve Garcia

    Jonny –

    I can’t believe I did math in my head that mad. Yep, 270/20 is not 35. I am embarrassed. I was using 20 as Hiroshima as what was reported. It’s what is listed in Wiki, among others. So it was about 9 Hiroshimas. But I sure did the math wrong. Can I blame it on cobwebs? I guess not…

    It is O/T a bit, but for U.S. A-Bombs tests from 1945 to 1963, 270 kt would be more powerful than any fission-only bomb tested, and is more powerful than a handful of H-Bomb tests. Other tests in this range were relatively small fission-fusion bombs. Generally, anything at or above about 100 kt was fusion of some sort. (They were tests, after all, and the aim was toward various designs of fusion bombs.)

    The Nature article said it was about 15 meters across, about 50 feet – about half the width of the Tunguska object’s estimated size. Given 2 of these in 105 years, what does that do to the astronomers’ estimated rates?

  • Jonny

    Hermann,

    I dont think this was an object that skipped in and out of our atmosphere. Given that there are reports of at least two fragments hitting the ground. Also from Spaceweather.com quoting Bill Cooke, head of NASA’s Meteoroid Environment Office.

    “The asteroid was about 15 meters in diameter and weighed approximately 7000 metric tons. It struck Earth’s atmosphere at 40,000 mph (18 km/s) and broke apart about 12 to 15 miles (20 to 25 km) above Earth’s surface. The energy of the resulting explosion was in the vicinity of 300 kilotons of TNT.”

    Penetrating that deep into the atmosphere usually means that the object wont be leaving it again, usually it sheds too much energy to its surroundings.

  • Jonny

    Steve,

    The average frequency of events for this energy size is typically about 1 every 60-100 years (according to conventional impact assessment). Tunguska class is considered to be 1 every thousand years (give or take), though Duncan Steel and others suggest the more sobering figure of 1 in 300 years for Tunguska like impacts.

    Alas though, it may not likely change astronomers estimated frequency rates, since those rates are based upon size distributions of near earth objects, and with most statistics, a single event will not upset those statistics, particularly since the interval from the last biggish event (either 1930 or 1935) is of the order of timescale one would expect for objects of this size.

  • Hermann Burchard

    Johnny,
    thank you very much for your reply! Am working on a deadline job for a paper to be submitted, so am awake at this time.

    Ok, you can easily check this out by looking at the videos that George has linked to this blog above, under Slow feed but great vids. The entire trail took about ten (10) seconds and has an explosive widening in the central part in the densest part altitude ~60 km of the atmospher, as confirmed on numerous videos including one from about 730 (?) km away with the trail just above the horizon. The formula for the horizon is d=113*sqrt(h), with d=distance and h=altitude both in km.

    The succession of about five or six explosions after the initial main one can be heard on several of the videos and can only be due to spalling of overheated layers of a potentially large rock (larger than NASA estimate) as layer after layer breaks off until the rock leaves the atmosphere still in one, but a little smaller, piece!

    Gotta look at the vidies!

  • Trent Telenko

    FWIW, There are now new videos this morning from San Francisco of a new (smaller) meteor event

  • Jonny

    Hi Hermann,

    While the entry into atmosphere was shallow it was not shallow enough to pass back out, and it does seem as if it penetrated into the lower atmosphere before disintegrating. The shallow entry would have given the bolide a better chance of survival and reaching these lower altitudes by virtue of decelerating the body significantly before it reached the denser lower atmosphere (this is the reason why it is thought the Tunguska object was able to survive to its detonation altitude). The final and brightest “flare” we see on the videos (a nice animated gif is here http://i.imgur.com/SnVvLv8.gif is followed by rapidly cooling fragments. This marks the destruction of the bolide, and I would hazard a guess that this is the source of the shock wave that injured so many people through debris, and not a sonic boom.

    Also see this new release of data from infrasound stations (http://www.nasa.gov/mission_pages/asteroids/news/asteroid20130215.html) which has revised the estimate of its size and energy.

    “The estimated size of the object, prior to entering Earth’s atmosphere, has been revised upward from 49 feet (15 meters) to 55 feet (17 meters), and its estimated mass has increased from 7,000 to 10,000 tons. Also, the estimate for energy released during the event has increased by 30 kilotons to nearly 500 kilotons of energy released. These new estimates were generated using new data that had been collected by five additional infrasound stations located around the world – the first recording of the event being in Alaska, over 6,500 kilometers away from Chelyabinsk. The infrasound data indicates that the event, from atmospheric entry to the meteor’s airborne disintegration took 32.5 seconds. The calculations using the infrasound data were performed by Peter Brown at the University of Western Ontario, Canada”

    Note there is no statement telling us that it skipped back out. We would expect some sort of infrasound “tail” in the Energy-time domain indicating that after the main detonation, a remnant leaving the atmosphere. If this were the case, I would fully expect an announcement to the effect that this was skipping asteroid. This was a true impact event, in that all of the energy of the bolide was dumped into our atmosphere (through ablation and disintegration) having penetrated down to about 20-25 kilometers.

  • George Howard

    Thanks, Trent.

  • Hermann Burchard

    Jonny,
    this video from George’s post shows the whole trail, no sign not a smidgeon of entering lower atmosphere.

    http://www.youtube.com/v/iCawTYPtehk?hl=en_US&version=3

    The fact that the trail is visible from Orenburg, 770 km from Chelyabink (same post) proves it was at the 60 km altitude for the ten seconds the trail appeared in the skies of Russia.

    Sadly, NASA doesn’t comment on the need to revise the 25 km altitude, nor on the five or six minor explosions after the main blast, enough to explain debris picked up by police.

    Why the irrelevant remark there is no statement telling us that it skipped back out
    when you could viddy the viddies yourself?

  • The dash cam video I looked at clearly showed a fairly abrupt terminal parabolic arc with burnout of the pieces. It didn’t skip.

  • Hermann Burchard

    TLE,

    no sign of such an arc on the dash cam video posted in my comment preceding:

    http://www.youtube.com/v/iCawTYPtehk?hl=en_US&version=3

    What you think is burnout of the pieces, in reality is the tail end of the trail where the rock is leaving our sad and lonely planet’s happy atmosphere, as you can tell when you compare the entry segment with the tail.

  • Jonny

    Permit me to ask you a few questions Hermann.

    1) What did you use to calibrate your distances and angular scale from the videos to arrive at your conclusion?

    2) how did you take into consideration the projection effect to allow for the fact that the meteor may have had some forward or away from you component of velocity even though it could look from the videos that it was simply moving perpendicular to you? Hence the flaring point could be substantially closer or further from the camera than you think

    3) Did you take into consideration any slope in the terrain which could make the horizon appear lower than it is?

    4) you have stated a formula for calculating the the height, namely d = 113 sqrt(h) where d is the distance, and h is the height. can you explain how you got this, and what the co-efficient of 113 represents, since it looks to me that this equation is not dimensionally balanced given that you have dimensions of length on the one side, and dimensions of length to the power of a half on the other. The only way this would balance is if the 113 had dimensions of length to the power of half. If we reduce this to dimensions we get L = k L^(1/2), implying that k should have a dimensionality of L^(1/2) for the equation to balance. If this is not the case then you formula is not physically correct.

    As for the so called irrelevant remark, it is not irrelevant. Asteroids that skip in and out of the atmosphere are interesting, and if this were the case, then it is likely that in the “press releases” and updates, some mention would be made of it. The general consensus amongst academia is that it deposited teh bulk of its energy at teh 20 to 25 kilometer mark, meaning it did not escape back out again.

  • That’s just about the best video of a distant capture of the entire event and it has already been turned into a .gif. However that is a very distant shot of it, but even so you can see it is following a convex trajectory. The known observed skipper spent a lot more time in the atmosphere and traveled much longer through the sky before departing. Even the Thomas Jefferson skipper behaved quite a bit differently. If you look here you can see the very end of the luminous event at 4:40 to 4:47. It didn’t skip. That’s the end of my discussion at least of the meteor skipping phenomenon. Platinum iridium ratios I might talk about. Also, if anyone wishes to discuss deep space and lunar space architectures that facilitate asteroid derotation and capture I could talk about that as well. But it didn’t skip.

  • Hermann Burchard

    Jonny,

    are you not simply trying to ignore that events in Chelyabinsk at altitude 25 km cannot possibly be above the horizon when viewed from 770 km in Orenburg?

    You are asking me for a tutorial on
    what the co-efficient of 113 represents?

    Sorry that I did not include the proof of the horizon formula, thinking you would do it yourself, as presumably you are in command of basic high school math, up to Pythagoras’s Theorem?

    Here, the value of the co-efficient c is valid for an ideal spherical Earth of exact circumference 40,000 km:

    c = 112.838…
    = 200/sqrt(pi)

    Even more precisely, the co-efficient c in the horizon formula depends on h very slightly for moderate size h, and the exact formula is

    c = [200/sqrt(pi)] * sqrt(1+pi*h/40,000).

    You are right, about dimensions I was being sloppy. For the sake of discussion, let us set
    1 km = 1.
    Then the circumference of Earth is just 40,000.

    TLE,
    the path in that video looks much more curved in the tail than the one from George’s list. But if you consider possible trouble with the optics of viewing through the windahield in your case at its very edge vs in the center of the windshield done from a great distance in the one that I have posted, you will appreciate that I cannot give much credence to the one your evidence.

    End of Discussion?

    Oh baby baby, the world is so much more deep and complicated than you can possibly imagine!

  • Hermann Burchard
  • Trent Telenko

    Havana reported a fireball.

    See —

    http://www.havanatimes.org/?p=87801

    Cuba Town Also Rocked by Celestial Body
    February 15, 2013 | | Print Print | 14 65 590

    HAVANA TIMES — Homes in the central Cuban town of Rodas, Cienfuegos shook on Wednesday evening after an explosion overhead, reported ANSA news service.

    Witnesses reported the fall of a celestial phenomenon that ended with a huge explosion with a very bright light in the sky that shook their homes, said ANSA citing the Cuban morning TV news program as its source.

    Experts are scouring the area in search of any remains that fell to Earth. No reports of injuries or damage to property has come in.

    Meanwhile in Russia on Friday, a piece of a meteorite caused extensive material damage and nearly a thousand injures were reported in the Ural region of the country. See report. (http://www.havanatimes.org/?p=87761)

  • This from Alan Boyle’s Cosmic Log

    Estimates raised for nuclear-sized asteroid blast that hit Russia

    I note that he makes no mention of the thing skipping back out of the atmosphere.

  • Hermann Burchard

    Dennis,
    the 770 km from Chelyabinsk to Orenburg mentioned in the Russian blog posted on Tusk is the long route, by Google maps, best roads.

    A shorter round is only 715 km, very curvy.

    Hence, I took the trouble to use spherical geometry & determined the distance of the two cities is 558.74 km as the crow flies. For this horizon distance my formula requires an altitude of only 24.45 km, in agreement with NASA.

    Hence my crude estimate of reported 3 minutes for blast sound wave = 60 km to source was vastly incorrect, Jonny.

    The edge of windshield argument remains valid, as the center windshield shows almost no terminal curvature, I still believe it skipped, maybe NASA guys can look into it.

  • Jonny

    Hermann,

    My apologies, i did not realize that you were using the “distance to the horizon” formula in that original post, and was confused by the horizon formula, and hence was in a completely different mind set than yourself, hence the questions. Thanks for explaining, its clearer now what you were doing.

  • Hermann Burchard

    Jonny,
    thanks for your kind sentiment.

    Of course Tuskers all know, you are one of George’s best/ favorite commentors, for your expert contributions.

  • George Howard

    What an enjoyable dialogue, thanks folks.

  • Trent Telenko

    Another FYI, Feb 15, 2009 there was a fireball over Texas and fragments were later found near the city of West, Texas.

    See:

    Houston Chronicle

    http://www.chron.com/disp/story.mpl/ap/tx/6270243.html

    A reporter from Austin Texas captured the meteor on his video:

    ttp://www.news8austin.com/content/top_stories/default.asp?ArID=232127

    Meteorite hunter suspects meteor landed near Waco:

    http://www.news8austin.com/content/top_stories/default.asp?ArID=232127

    Meteorite hunters descend upon West, Texas:

    http://www.wacotrib.com/blogs/content/shared-gen/blogs/communities/breakingnews/entries/2009/02/18/meteorite_hunters_searching_ne.html

    http://www.wacotrib.com/news/content/multimedia/players/brightcove.html?bcpid=1475275870&bclid=1493222307&bctid=13607945001

  • Hello for all

    Last year on fev/2012 a news about a possible earthquake in Pernambuco call my attencion, yes they do exist in my home state, even in small intesidade and frequency. But the story that was published I think something else about it! Earthquake in Brazil? It can be! But this story was poorly told!

    What do You think about it? It is worth checking the phenomenon in Flores. See below. Unfortunately the news is not echoed and faded into oblivion.

    http://www.florespe.net/c.php?id=2945&d=Abalo-sismico-de-media-proporcao-atinge-comunidade-rural-no-municipio-de-Flores%20&cat=Paginas

    ” Last Tuesday (21/feb/2012) at about 10.40 am, the ground shook in the town of Saco dos Caldeirões, rural region of Flores in Pernambuco, distant 385 km from Recife.

    According to reports from farmers, Paulo Henrique and his brother Gerard, a flame of fire that looked like a rocket ascended with great speed occupying the space of the sky. The brothers Paul and Gerald worked on their property when they were surprised by a great shot that hit the ground heavily.

    At that moment they ran toward their residences for shelter, leaving behind farming tools they used in replanting. All this caused panic in the community, who never witnessed such an event.

    Our onsite team found a small crater caused natural phenomenon, forming a hole about one meter wide and half a meter deep.

    The farmer Anália, mother of Paul and Geraldo says that at the time of the blast was about 800 meters from the site, and who worked with her husband, and he heard a roar that shook the ground.

    “All I saw was a list of fire that went up to heaven, leaving behind a lot of smoke, it seemed fires of St. John, this happened in broad day,” said lady Analia.

    This is just a curiosity! will the meteors are falling increasingly in populated areas?

    regards
    pierson

  • chicken little

    wow all those mega tons ;P

    and it didn’t kill off all OR any animals.

    it didn’t even create a black mat with 4 or 5 inches of ash at least

    then it didn’t deposit 4 feet at least of sterile sand in the process of washing all those dead animals into the newly formed Atlantic void .

    it didn’t deposit thorium or any other minerals on the earth either .

    it didn’t move any islands that we got here on nor create new continents in that process .

    it didn’t drop the sea level by someplace in the 1500 to 2000 ft .

    mostly It also didn’t stop the world from turning for 24 hours or move it some degrees.

    it isn’t in anyway going to alter any kind of Radioactive isotopes or effect IN ANYWAY THE current AGREED UPON dating systems .

    THAT LITTLE FLAMING SPIT BALL WILL NOT GIVE ANYONE THE ANSWERS THAT CHANGED THE FACE OF OUR WORLD !

  • Trent Telenko

    Chicken Little needs to go and read this link, as it is more his speed than the Tusk —

    http://www.bibliotecapleyades.net/ciencia/esp_ciencia_tunguska13.htm

  • To CL: It sure showed 1000+ Russians how painful flying glass can be. Also interesting are the reports that the blast was 3 minutes after (!) the flash. It’s important to understand that any blast induced shock wave loses energy with time as it propagates. This means the shock imparted energy that reached the ground was far less energy than was released in the fireball. This agrees with the intense luminosity, duration and very white color of the prolonged ” flash”, all pointing to substantial energy release. How high up is the question.
    The relatively shallow angle approach of the Russian incident gives a slower heating rate (still astronomical energy) compared to steep angle cosmic visitor, which may distribute the delivered energy over longer time and over a longer distance, all of which may have given mercy to the Russian victims.
    Weird things can also happen with atmospherics in terms of dispersion or focusing of shock wave energy, making hot spots and protected regions at the surface
    TimH

  • Dr. B –

    My interpretation of the NASA speak is that the trajectory was grazing (shallow angle high altitude) and that the bolide disintegrated or fragmented upon “fireballing” (if that word is OK to use)….

    500 ktons – that will wake the neighbors even in the roughest hood

    Brighter than the sun. Good lessons here. Don’t look at it. and stay clear of glass windows or shock wave sensitive structure for several minutes after the flash. Naturally I trust our government so we won’t likely have another one of these for another 100 yrs or so. Unless one hits sooner.

    TimH

  • Steve Garcia

    Hermann and all –

    Word imprecision:

    The phrase “ .. . so it was grazing through the atmosphere” is almost ridiculously imprecise. It has two words that each could have two meanings.

    The term “through” along with “grazing” appear to mean that it grazed and then eventually exited the atmosphere.

    “Grazing” could mean that the path was a non-ground-impact quasi-tangential path.

    And “through” could mean that it exited, but it can also mean that it was simply moving along IN the atmosphere, like, “The airplane was flying through the sky,” in which of course the airplane never left the atmosphere.

    Does anyone have any idea if the term “grazing” has a technical definition? It might.

    As to the word “through” I believe the writer/speaker was just being careless, in which case who knows WHAT he meant?

  • Hermann Burchard

    Steve,
    thanks for your comment: The fact you noted, that NASA’s

    phrase . . . is almost ridiculously imprecise

    had not escaped my attention!

    To my “completely unbiased” POV, the fact merely was proof certain that NASA got the term “grazing” from CosmicTusk, my comment:


    February 15, 2013 at 10:12 am

    From some of the pictures, this was a grazing impact, the trail begins and ends in the upper atmosphere.

    They were embarrassed to rely on the Tusk and hid their feelings under vague, “ridiculously imprecise” language, d’accord?

  • Jonny

    Grazing does have a precise terminology in some branches of physics. In Grazing angle X-ray diffraction for example, it means that the incident x-ray beam is nearly parallel plane defined by the surface the sample under scrutiny. In other words, it describes the angle of incidence as being low with respect to a specific plane.

    In impact terminology, grazing impacts also have a degree of precision of language, and refer to low angles of incidence with respect to the plane of the ground (compared to oblique impacts, which are high angled impacts, where the angle of incidence is closer to the normal of the plane of the ground).

    So for the term “so it was a grazing impact through the atmosphere” in impact lexicography means that the angle of incidence of the impactor as it moved through the atmosphere was very low with respect to the plane of the ground. While this does not forbid an object skipping out of the atmosphere (since a high altitude object travelling at a fast enough speed at low incidence angle will do so), it is not implicit that this should be the case, since the exact angle of incidence is important as well as the objects velocity and cross section, the latter two of which effects its aerodynamic drag (since drag scales with area and with the square of its velocity). The quicker it slows down the quicker its angle of incidence increases, as its horizontal component of velocity is retarded.

  • Steve Garcia

    Questions…

    1. The updated 500 kt blast would put this event squarely in the middle range of H-bombs tested by the USA in the 1940s through 1963.

    That makes Chelyabinsk lucky it was no lower. (Though had it been on a lower trajectory, the burst would have happened earlier in its path…)

    * * * *

    2. Speaking of which, does anyone care to comment on what damage would have been done if the path were a ground impact path? Everyone at NASA seems to make sure such questions aren’t addressed, and none of the science writers seems to want to ask them.

    3. The Figaro article shows a path map coming from somewhere around the Bering Strait. This is supported by the mention of the first infrasound detection being in Alaska.
    (See http://tiny.cc/iezrsw) But Jonny corrected me on the path vs the flyby asteroid, saying one was gong N-S and one was going S-N.

    For me that brings up the question of its direction. What have they determined it to be?

    4. Curiosity: What plane does this put the orbit relative to the ecliptic? Was it high inclination?

  • Has anyone considered the posibility that the lower end of the contrails simply mark the point along the Russian meteor’s path where the fragments had slowed enough to go into ‘dark flight’, and not a point of departure as it skipped back out of the atmosphere?

  • Steve Garcia

    Actually, Dennis, that seems to be what I hear Jonny saying. But I may be wrong on that. My own first impression was that they /it had skipped back out to space, but for now I am accepting the dark flight explanation which (I think) Jonny says happened.

    Change points:

    Okay, NASA saw asteroid 2012 DA14 coming, but they missed the Chelyabinsk meteor, which was only 2/3 smaller.

    Am I the only one who wonders if a Tunguska object – reckoned at 1/3 less than 2012 DA14 – could have also been missed by NASA?

    And if a second Tunguska had blown up that high over Chelyabinsk, what would have been the damage?

    And one more:

    Tunguska did not blow down trees with its sonic boom. Why is everyone attributing the damage in Chelyabinsk to the sonic boom and not the big airburst?

    And even one more:

    Tunguska is always reckoned as one big blast, and the blast pattern seems to support that. The Chelyabinsk meteor had one big one and about 3 or 4 smaller ones. Tunguska has been reckoned to have been a comet (because nothing was found), and other reasons, too. But comets are supposed to be so much more friable than meteors or asteroids – so should Tunguska be given another look? If the Feb 15th meteor had at least 4 air bursts, why would Tunguska not have had multiple bursts, too? Secondary ones might have been too weak to show up in the on-the-ground evidence (perhaps).

    And finally:

    Any number of pieces of the Feb 15th meteor have been found downfield. Why would not Tunguska have such pieces downfield also? Ones that might be found even now?

    And is it not now in the realm of possibility that Tunguska was a “grazing” meteor?

  • Jonny

    Steve,

    The original North to south was based on an estimate of direction travel seen in videos, since it appeared to move from left to right across the region of sky where the sun was rising. Since then a more accurate determination of its trajectory does seem to have it coming North East to the south west. This was probably done through triangulation of infra-sound data, and/or from triangulation of eyewitnesses and locations of the video footage. This still means that the DA14 and the meteor are unrelated, and indeed looking at the two orbits of the objects they do indeed seem to unrelated.

    I have not been able to find “official” figures for the meteor’s pre impact orbital elements, but some figures I have seen place its inclination at about 4 degrees to the ecliptic, with a semimajor axis of about 1.66 AU, eccentricity about 0.52 and aphelion of 2.5 au, making this an asteroidal belt object. These were admitted to be preliminary based upon the videos and weather satellite images, so they may have changed with more accurate determined data.

    I didnt saying anything about dark flight but rather the point of complete disruption so i cannot claim recognition for that, but dark flight would be consistent with the contrail. When a meteor enters dark flight it no longer ablates, meaning it is not “dusting” the atmosphere, meaning that it is no longer seeding the air with small dust particles which act as nucleation centres for water droplet condensation. So the end of the contrail would likely indicate the point at which any surviving fragments enter dark flight.

    The tunguska object is determined to be between 45 and 100 meters in size, depending upon its composition (smaller for asteroidal material, larger for more comet like material). Therefore the Tunguska object would be comparable to DA14 for the lower estimate of size, not 1/3 its size. Explosive energy falls off with the square of distance (i.e. it is a 1/r^2 relation), so if a Tunguska class object detonated above Chelyabisnk, at the height of the recent meteor (about 25 kilomters), the ground energy would have been about 10% that of the ground energy of the Tunguska event. This is back of the envelope stuff though, and of course there are always other factors such as blast wave focusing etc to consider.

    The continued of attribution of the damage being caused by teh sonic boom may be a throw back to the old 10 tonne mass estimate. Other than this I cannot say why this should be. The tunguska object did though effect trees by its passage. Alexey Zolotov was able to find traces of the ballistic shockwave in the levelled trees around the epicentre of the tunguska site.

    With regards tunguska, eyewitness accounts do report secondary explosions before the main impact, however the problem with this is that the timing is a little off, as the reports tend to indicate that the explosions were heard first, then the object seen, before the object explodes, and then the big explosion occurred. For an object travelling far faster than the speed of sound this should not be the case. For example K. A. Kokorin of Kezhma told the interviewer that he heard sounds like cannon fire, and when he went outside to look seen the object in the sky. He reported the sounds continued until it disappeared behind the trees at which point it stopped. this could of course be strong electrophonic phenomena from the plasma sheath of the bolide. Also see this which seems to imply there was explosions heard BEFORE the impact

    “…At that time I was ploughing my land at Narodima (6 km to the west of Kezhma). When I sat down to have my breakfast beside my plough, I heard sudden bangs, as if from gun-fire. My horse fell on its knees. From the north side above the forest a flame shot up. I thought the enemy was firing, since at that time there was talk of war. Then I saw that the fir forest had been bent over by the wind and I thought of a hurricane. I seized hold of my plough with both hands, so that it would not be carried off. The wind was so strong that it carried off some of the soil from the surface of the ground, and then the hurricane drove a wall of water up the Angara. I saw it all quite clearly, because my land was on a hillside”

    “Letter to A. V. Voznesenskii, 25 July 1908:

    On the 17th of June, at approximately 7:15 in the morning, the workers building a bell tower saw a fiery block, flying, it seems, from the southeast to the northwest. At first, two bangs resounded (not unlike gunfire), then an extremely strong bang accompanied by shaking. More bangs were heard. They noticed a shaking of the earth. One girl (the priest’s maid-servant) fell off a bench. The populace became frightened. They saw that fiery sphere in Karapchanskii, and heard the bangs. The day was clear, and for that reason the thunder put the public in a state of bewilderment. In Nizhne-Ilimsk two Tunguses recounted that the meteor had, in falling, formed a lake which boiled for two full days. The Tunguses were prepared to show people that lake, but no one believed their story.”

    Which brings us to the idea of fragments being found of the Tunguska object. Lake Cheko is a conical lake downrange from the tunguska airburst site, and some believe could be a crater caused by a large fragment from the impactor hitting teh earth, which would tie in with the above “tunguses” statement that a lake was made by the event.

    By all accounts, the Tunguska object is thought to have been a low angled impact (of course it does depend upon the exact definition of grazing!). V.A. Bronshten has estimated that the initial angle of incidence would be no more than about 15 degrees with the final angle of impact being as much as 40 degrees at the end of its trajectory. Experiments have shown that impact would have had to be at 30 degrees. Its shallow trajectory would have ensured that a large fragment (even if made of low density material) could survive to lower altitudes, since low inclinations mean there is more time to slow the object before it reaches higher density of air.

  • Lets also remember that these incomprehensibly ancient objects may not be of uniform composition at all, having complex and convoluted histories of formation in various regions of space over a huge range of epochs. A good example may be a rocky core which then collects a far greater amount of ice over hundreds of millions or even billions of years, during which time other chunks of rock may also become embedded.

    Now our ancient object arrives at Earth going tens of times the speed of sound in our atmosphere. It’s astronomical kinetic energy is converted to heat through frictional heating. Quickly. The steeper the approach angle the greater the rate of heating. The ablation (burn) rate is as non-uniform as the density distribution within the object, likely with no two objects the same, like snow flakes. Cosmic snowflakes. The high temp (hotter than surface of the Sun) and resultant rapid pressurization suddenly applied to our long sleeping visitor wakes it up in the form of explosive fragmentation. So what does that leave us with?

    Chaos.

    Irregular ablation rate and irregular shock wave. The shock wave (same as sonic boom) is an over-pressure discontinuity which travels faster than the speed of sound by a factor dependent on the degree of over-pressure. An over-pressure (shock strength) of just 1 or 2 psi can cause fatal internal injury. That isn’t much since atmospheric pressure is nearly 15 psi and a nuke can generate over-pressure of a few to several ATMOSPHERES, which will cover long distance before disappating to non-lethal levels.

    During propagation, a shock wave may be slightly or highly focused or reflected (extreme cases) by normal/natural atmospheric gradients and surface morphology. All of these factors make any exact prediction or even reconstruction after an event a very complex task, since it depends on so many variables including irregularities in the object itself which are lost in the destructive process.

    Blah blah blah….

  • Steve Garcia

    Jonny –

    Great responses to my questions. Much appreciated. And its much appreciated that you have all of this information in your head (or know where to find it).

    For Tunguska size, I had 150 feet in my head, 3 times as wide as this meteor. 45 meters comes to about 145 feet, so I must have had that smaller size stuck in my head. I don’t confuse width with mass, but width is convenient. Mass increases as a factor of r^3.

    In reading the accounts of bangs (none of which I had run across before) it occurs to me that people up field of the burst point could certainly have heard the sonic boom before the burst, then have time to go outside or whatever. Also, from memory as a kid, I do seem to recall multiple booms from single aircraft, but I am probably wrong on that. I am glad to hear there were multiple bangs heard at Tunguska. It seems to render the two events more similar to each other.

    However, I do still wonder if this will change minds about Tunguska being a comet vs meteor. Tunguska was deeper into the atmosphere, suggesting its friability was more toward the meteor end than comet. As you say, larger objects will be able to get lower before bursting, so some combination of size and cohesion ties the two together. And while that lake had a nice round hole in its ice, no impact crater on the ground will ever exist from this event. Again, similarities.

    While I’d like that there exist downfield craters from fragments of Tunguska, the area around the burst is so littered with bogs that finding and identifying one of them as from a fragment seems worse then needle-and-haystack stuff. And it was the dead of summer, so all those bogs were likely to have thawed by then. That latter is not necessarily true, though. I know of one lake in southern Maine that doesn’t thaw till the 1st of June; in Siberia the end of June may or may not have a full thaw yet. That one guy was still plowing, after all, at the end of June, so for that locale it was early in the planting season.

    Thomas mentioned reflection of the shock wave off ground topology. Good point in one way – perhaps those multiple sonic booms I heard as a kid were echoes off of buildings (I lived quite close to downtown St Louis then).

    T.H. pointed to one of my points about the non-uniformity of aggregated bodies. He is thinking the same way, that non-uniform bodies will heat up irregularly, which would lead to pieces breaking off in some irregular sequence – and that no two objects would be the same. Yep.

    I think that in time T.H.’s “snowflake” realization will be recognized, and those who try to predict what future objects will do based on past ones will continually be proven in error. It is just too early in the observation period to have seen all the classes of possibilities. Astronomers even now are very often caught unawares by what objects do. It’s not yet a good science for making successful predictions on such things as bursts. Actual ground impacts, perhaps, but air bursts seem to be able to do all sorts of things.

  • Hermann Burchard

    Since it seems to matter, an authoritative site (JPL?) had Chelyabinsk (Ch.)meteoroid come from “East by South” which I think means ESE. This agrees with the Orenburg video. That city is to the SSW by 559 km or 347 miles. The meteor is low over the horizon and descends toward the left (W), skims the horizon, then the bright flash of the explosion from below the horizon, difficult to reconcile with a NE approach. — Steve, yes, “sonic boom” must be replaced by “airburst, explosive blast shock” or whatever, an initial one 42 km E of Ch., & four or five smaller ones of them from successive ablations or spalling. — The size is still uncertain and may be larger than now stated if it the trail end’s dimming means it left the atmosphere, so that Ch. was spared the Tunguska type downward momentum torch (Boslough).

  • The reason you remember a double sonic boom off supersonic aircraft is that one is attached to the leading edge of the vehicle and one to the trailing edge. Both are equally powerful. They are physically close together, so you hear the ba-boom sound at passage. The high speed aerodynamics guys use Schlieren photography to see the attached shockwaves. An example is at the link:

    http://www.nasa.gov/centers/dryden/news/FactSheets/FS-033-DFRC.html

    When things are exploding or you get a stream of supersonic objects, the sounds get more complex. For example, on a military gunnery range, it is possible to get 3 noises when you hear an aircraft like an A-10 strafe a controlled target. The first noise is the shockwave of the bullets in flight; second is the bullet stream coming out of the gun; final are the impacts on the other side of the target.

    With a supersonic object exploding overhead, you should get several sounds (shock waves) including but not limited to the shock waves attached to the supersonic body itself, the noise of the structural failure of the body itself, and reflected sound waves off nearby structures / clouds / other shockwaves. It should be complex and noisy for a while. Cheers –

  • Hermann Burchard

    agimarc:
    excellent expert explaining! Would you listen to this YouTube video with Chelyabinsk meteor noises,
    and give your interpretation, please:

    http://www.youtube.com/watch?v=vXpTxCH6HIE

    There seem to be 5 or so ba-booms after initial main at 40 km S of city (Wikipedia) which helps explain a 3 minute delay after the flash.

    View from Orenburg:
    http://www.youtube.com/watch?v=1EWD5mRkyow

    Bright flash still above horizon, trail end as well upon repeated viewing explained by site being 40 km South of city center.

    BTW, “South of East” approach by Wikipedia, and stands for 101.25 degrees off N, what one might call EESE, ESE being 112.5 degrees off N.

  • One problem I have with the idea of the thing skipping back out of the atmosphere is the assumption that it had the structural itegrity to do so after surviving a 500 kiloton detonation. Nah…

  • Hermann Burchard

    Dennis,
    good point! But if you examine trail end, thinning and dimming at the end, almost constant speed, well after main debris cloud is emplaced, what else can one conclude?

    http://www.youtube.com/watch?v=iCawTYPtehk&feature=player_embedded

    The fairly tame debris cloud too suggests a body staying intact, perhaps because much larger than school bus size?

  • George Howard

    First time I have seen this particular vid: http://www.youtube.com/watch?v=b6J2iniSGKI

  • That 500 kilotons of explosive energy had to come from somewhere. The meteor either lost a considerable portion of its mass in that detonation, or it gave up a lot of momentum, or a goodly amount of both. Either way its difficult to imagine there being enough remaining mass with enough remaining momentum to account for an escape velocity, and/or trajecory.

  • Steve Garcia

    Hermann –

    Direction:
    It isn’t exactly scientific, but this video at
    http://www.youtube.com/watch?v=DKAvPxujA8E
    shows the meteor as it approaches.

    At the 0:48 mark the dashcam is pointing right at the Sun, and the meteor is first visible, and it is coming from just to the left of the rising Sun, on a diagonal path toward and to the right of the camera. The video’s clock shows 09:26. An online sunrise calculator at http://www.sunearthtools.com gives the sunrise at Ch. as 09:21 and the azimuth as 112.49°.

    That is 22.49° south of due east, and only five minutes before the dashcam clock time.

    If you look at the glow “dome” of the rising sun, the meteor is JUST to the left of the peak of the dome, which peak I interpret as directly over the Sun. So I’d say the meteor is coming from – basically – 111-112°, or 21-22° south of east. Someone on another site said it was “coming out of the Sun”, and pretty much that is true. Though that is the point at which it is first seen, that is NOT its direction.

    The direction of travel is not straight toward the dashcam. It is skewed off at some diagonal toward the right. The next 9 seconds show it traveling at an angle that I would estimate as about 20° off of directly at the camera. (Then the car turns and we can’t see anything undistorted through the windshield.) Hahaha – and on what do I base that angle? you might ask. As an engineer I have had to deal with a LOT of angles over the years, specific angles. 15° and 30° I have dealt with so much I can see them in my sleep, and I have seen them at all angles of above and below. I can tell you that the angle is NOT as great as 30°, which would be 1/3 of that quadrant of sky. It might be as small as 15°, but certainly not much smaller than that.

    So, I would say the angle would be 112° minus about 20°, or about 92° +/-5°. It is essentially coming out of the east and traveling almost due west.

    That is my estimate, based on as solid and specific information as I can find.

  • Steve Garcia

    Dennis –

    I am mostly with you about it escaping the atmosphere. Certainly most of it didn’t. I am open to some of it having escaped, but I wouldn’t be surprised if none did.

    The 500kt explosion – which is what they reported at Nature – HAS to indicate that some of the bangs – that the biggest one – were not sonic booms. If there was a 500kt explosion above the city, the pressure froma sonic boom could not be as big. I think the biggest bang one was the burst.

    In one video I believe I counted SIX visual flares. I counted on one video, but now I can’t find it again. But another had at least four.

    agimarc –

    Thanks for the info on the sonic booms. With ~4 flares and 2 or more sonic booms, that should be about 6 peaks in the sound. I tried to find a video with sound and no background sound, so I could look at spikes, but I couldn’t find any.

    LOL – Personally, I think this was a very instructive meteor, and I think people will be learning from it for some time to come.

  • Hermann Burchard

    Steve,
    great stuff! We are all engineers here, can follow you, and easily see what you are doing.

    Some additional details which may confirm your data further, I believe:

    The video you are using exists somewhere in isolation, saw it in compilations, & it may be from near te city of Ufa, Bashkortostan, which is South of West, almost due West, of, and about 200 miles from, Chelyabinsk — both cities are near 55 degrees North latitude.

    Map coordinates:

    Ch.: 55.15, 61.378

    Ufa: 54.75, 55.97

    (I haven’t done the spherical geom here.)

    Dennis, I’m with you as well, with a caution to the effect that the trajectory is very smooth to the bitter end, no sign of any discontinuity in the function and derivatives. My experience with curves, computing trajectories, is vast, as Steve’s is with angles, and if the thing went bust, there ought to be a few kinks, which just don’t show.

  • Steve Garcia

    Hermann –

    In reference to trajectories, I want to ask the simple and basic question:

    Why are there TWO trails through most of the “biggest” part of the trajectory?

    I have speculations. I’d rather someone who knows tells me.

  • Steve Garcia

    Hermann –

    Hold your praise…

    One confusing issue for me on the path is that I looked at the angle from 0:48 to about 0:56, while the vehicle was on a straight road (heading just to the right of the rising sun, which would be about azimuth 130-135°) . At about 0:58 or so the vehicle takes a 90° right turn. (Based on the square building, it is not a >90° turn). That should put that road bearing at about 220-225°. But then after the turn, the object’s trajectory is going to the LEFT of the roadway and just about parallel to that road.

    Because of the curvature of the windshield, the trajectory during the turn appears to be curving (which I know it isn’t doing). Then, coming out of the turn the trajectory is more or less parallel to the 90° road.

    Trough the entire turn, the object is still in the camera view. VERY ODD.

    That part has me flummoxed. I know from other videos that the trajectory is straight as an arrow.

    After ten viewings, I still can’t make out what it is showing. Even in stop frame I can’t process what the video shows then. If it was coming at the dashcam at an angle of even 30° it should have gone on overhead and past the right-angle street – but it sure doesn’t seem to do that in that video.. It seems to be making a curved trajectory, and it isn’t just the distortion of the windshield that is making it look that way. But what else it could be, I don’t know. Optical illusion? I was fine when the car was going straight. Why the trajectory seemed to be going at (92°-to-) 272° and then seems to be going at about 230°, I can’t compute.

    . . .Unless my original calcs were just dead wrong.

    That is my guess right now.

  • Hermann Burchard

    Stevo,
    [by George, this is how to address you!?!]

    YOUR QUESTIONS HAVE AN EASY ANSWER: THE THEORY OF NEWTONIAN/ LEIBNIZIAN RELATIVITY:
    Because of the curvature of the windshield, the trajectory during the turn appears to be curving (which I know it isn’t doing). Then, coming out of the turn the trajectory is more or less parallel to the 90° road.

    Trough the entire turn, the object is still in the camera view. VERY ODD.

    That part has me flummoxed. I know from other videos that the trajectory is straight as an arrow.

    The dash cam is recording a straight trajectory [almost, Earth’s gravity is bending it slightly] on a rotating platform, the curvature is RELATIVE to the platform, not due to the curve but reflecting the car.

    If this is Ufa, Bashkortostan, 200 miles East of Chelyabinsk, then it should be near the end of the luminous path. And Google maps should allow finding the exact point where the auto is making that right turn,
    < 90 degrees.

    Is this not almost the same car track as your posted video?

    http://www.youtube.com/watch?v=itnLK3902RI&feature=player_embedded

    BTW, Wikipedia has the epicenter 40 km South of Chelyabinsk, in Korkino. This explains why the meteor came from South of East.

    Your double trail question:

    Why are there TWO trails through most of the “biggest” part of the trajectory?

    I have speculations. I’d rather someone who knows tells me.

    This is my question as well. Must be something about how the ablations do occur in their detail.

    Dennis is a blast expert, I wish he would give it a thought.

  • Hermann Burchard

    [cont’d] . . . where the auto is making that right turn < 90 degrees,and, second, the edge-of-windshield effect seems to bend the trajectory again, although in reality it is straight as an arrow. A third factor is your focus on the moving end-point, all three combine to an optical illusion.

  • The twin contrails can be explained simply by recognizing that the meteor began to break up into smaller fragments almost immediately after hitting the upper atmosphere, and well before any of the fragments had slowed enough to go into dark flight. That fact alone tells us the folks in Chelyabinsk got lucky this time. There was enough mass and kinetic energy in the thing to take out a good sized city. If it had possessed the structural integrity to remain intact just a little longer, and detonated in a single more powerful low altitude blast, or even worse, impact the ground without detonating first, and with all kinetic energy intact, then the intensity of the blast wave reaching the ground, and the resulting devastation could have been many orders of magnitude worse. I can take a half pound of ordinary black powder and put it into a bunch of firecrackers that don’t do much more than make a lot of noise, even if a light all the fuses at the same time.  But if I pack the same amount of powder into a single charge I’ve got enough concentrated energy to instantly accelerate a small cannon ball to supersonic speeds and blow a great big hole in a steel reinforced concrete wall.

    Beyond all that I’m waiting for fragments of the thing to make it into someone’s lab so we can have a better idea of it’s composition and better data on it’s velocity and exact trajectory before I turn my imagination loose. I also want to see some detailed infrasound data from NASA that’s synchronized with some of the more detailed dash cam videos with it  if they don’t get too stingy with it. The trouble for the curious folks like us is that NASA will probably be reluctant to release much of that data. Not because the data itself should be withheld, but because it will be difficult for them too release it without revealing too much about what their remote sensing technology is actually capable of.

  • P.S. The “curved windshield effect” and the object remaining in the camera’s view for so long, begins to make more sense when you recognize that it has nothing to do with the the curvature of the windshield. The simple explanation is that the dash cam was shooting through a wide angle fish-eye lens.

  • I’m starting to think Dr. B may be right, although completely not at first. Dennis you are the one making my mind change, because truely nothing’s so small would survive 0.5 Megaton shot and be cold a second later, especially if its spitting out the back end at speed.

    But the real tell tale heart here is what is left before our eyes as Dr. B beautifully reminds us. Lame debris cloud! Not fairly lame at all here people – COMPLETELY LAME! There was almost no plume or vapor trail at all.

    And as for the spalling, I kind of like that word to hint at the chaotic fragmentation concept, but clearly that whisker thin whisp of a debris cloud, or “effluent” cloud, doesn’t look like a Boslough-simulated total bolide consumption plume AT ALL. Hello? Especially not with stuff flying out the back end. What the heck was that thing anyway!?!

    I think Dr. Boslough still needs to model the “grazer” that sheds whimpy whisps of plume to figure this one out. If he hasn’t yet my guess is that he may be about too….

    Shock waves can echo off of objects like normal sonic oscillation (sound) can. The mathematical solution follows a different convolution but the effect is comparable in many ways. Thunder echoes off of clouds weakly I believe because of the weak variation of impedance of the cloud boundary, and fireworks sounds echo off of buildings all the time with high efficiency due to the typically high impedance of the building’s surface(s). These are not shock waves, however once the initial over pressure has disapated. Anyone who has ever survived a close call with lightning can tell you the “POP” before the boom hurts the ears the most. Usually we only hear boob-ba-boom etc of the thunder.

    Another thing, shock waves travel faster in lower temp since there is less thermal vibration and therefore less space between particles inthe medium of propagation. That area of the world is known for its insanely cold high pressure winter air masses. I learned this while trying to navigate spacecraft above the region with albeto (sp?) limb sensors. Looking at the videos the entire region was clearly under a high pressure cold air mass (from piloting and Metieorology) evidenced by the uniform clear blue sky. So the shock would have disapated more gradually (propagated more efficiently) and delivered more energy over a longer distance.

    So Dennis, what degree of over pressure will blow out that garage door and knock in that brick wall at the metals factory? If we start with an estimate of what it takes to do that we can make a guess at strength 3 minutes earlier when the shock wave was formed… What we’ll likely find is that it was a large grazer. The reason I’m very sure of this now is the cold air dome again. The same cold air mass and clear sky mentioned above tend to refract light through a very high angle, which when you combine it with the trajectory in the imagery, means those Russians (and plenty more of their neighbors and countrymen) were exceedingly lucky that day. That was larger (or more dense) bolide that only partially burned during a grazing incident before flying back away from the surface after close approach (brightest flash or just before) over the horizon.

    I just don’t think there is any way it got very low. I think the shock raced a long way down very quickly in cold conditions because whatever it was essentially maintained speed for the entire passage (!!!) and barely got dusted off in the process. Clearly – from the whisper thin trail and from the departing, rapidly re-cooled bolide. Finding the chunk in the lake will be a milestone in this case.

  • Steve Garcia

    Hremann – Thsnks dor your feedback. I’m still not clear yet, but IO will get there. I agree that the car was near – but past – the end of the the luminous path. It was high in the windshield’s frame, but still on view.

    Dennis – Yes, it makes some good sense that it had already fragmented in order to make two trails..

    Dennis – “Beyond all that I’m waiting for fragments of the thing to make it into someone’s lab so we can have a better idea of it’s composition and better data on it’s velocity and exact trajectory before I turn my imagination loose.”

    I wonder if there is ANY possibility someone got the burning on a spectrograph. I doubt it, but it may have happened somewhere by accident. I think the small samples I’ve seen photos of could be unrepresentative and give the wrong impression of what the bulk of the object was.

    I also wonder f there was any water/ice. I still wonder that a meteor was coming at us from so close to the Sun. I thought NEOs tend to have orbits in which they more or less parallel the Earth. Since comets have thrown some curves at people about the “dirty ice ball” concept, is it also allowed that some meteors might have ice? I am open to the possibility that this object may have come from “out of the Sun” because it wasn’t a meteor at all. Ergo my question about ice.

  • Jonny

    Steve,

    You are probably thinking of the class of NEO’s whose orbits are similar to the Earth’s, but even in this case there are earth asteroid geometries in which the object can come from the sunward side. Generally NEO’s can have many different orbital elements, with their only prerequisite that they approach the orbit of the earth. As such you can have different degrees of eccentricity, which allows for a whole gamut of different earth approaches since high eccentricity objects will tend to be earth crossers and so can approach the earth from the solar or anti-solar directions. With the orbit determination of the Russian meteor, the Earth encountered the meteor when the latter had passed its perihelion and was moving away from the sun.

  • I’m still considering the bolide impact plume particle collection and sampling by high altitude aircraft. Obviously we can’t wait another couple of decades for another large bolide to drill it’s way down to 50,000 feet and explode, but in conjunction with the existing optical detection network something might he able to be done with more precise sampling of well tracked trails. They are detectable optically, they show up on weather radar and they also ionize the atmosphere for radio wave reflection (meteor trail UHF DX. I’m not sure how an actual sample collection device might work since it’s not in a vacuum and it would be traveling quite fast through the air.

    Once the impact ellipse is determined from this impact and any consistent macroscopic particle distribution is determined it may indeed be possible to get some surface ice and snow samples and then take a look for any spherules and melt quenched impact plume byproducts. That would help immensely to establish a baseline that might help legitimize the field of microscopic impact proxies.

  • Steve Garcia

    Jonny –

    Thanks for the lowdown on NEOs. I am not totally surprised some are high eccentricity, but if the graze the Sun like that, does it make them more like comets than asteroids or meteors? I know, NEO does not mean only meteors and asteroids. I would consider filing this one as a cometary NEO, I think.

  • Hmmmm… Ok Tim, Since they’re reporting the 500 kt kabooom  originated at 20 km altitude, (The shock that bashed in all those windows was a detonation shockwave, not a mere sonic boom. But since it was expanding outward from the blast at the speed of sound we can easily confirm the distance to the blast in videos that show both the flash, and the windows getting blasted in. We can also get a pretty good confirmation of the power of the blast if we work backwards from the structural strength of the bashed in window frames, and knocked down walls.) and the low end of the contrails is about that height, then if it barely got dusted off in the process as you say, and rapidly began to to cool as it began skipping back out, how do you account for the assumed rapid cooling of the object and shutting down of the contrails at only 20 km if it hadn’t lost any velocity?

    Also, if it “barely got dusted off” then where do we get the energy to produce a 500 kt detonation without sacrificing a considerable amount of mass and/or velocity?

  • Trent Telenko

    NASA has a “numbers problem” with it’s ‘once in 100 years’ blather about the Chelyabinsk Meteor Event.

    From a brief web search and limiting the data to Hiroshima size or larger events from Tunguska on —

    Tunguska, Russia, 1908 — 10-to-15 MT ?
    Rio Curuca Impact, Brazil, 1930 — 100 KT-to-5 MT ?
    Arroyomolinos de León, Spain, 1932 — 190 KT
    Benghazi, Libya 2009 — 12–to-20 KT
    South Sulawesi, Indonesia, 2009 — 31–to-50 KT
    Chelyabinsk, Russia, 2013 — 500 KT

    http://en.wikipedia.org/wiki/List_of_meteor_air_bursts *

    (* Yes, use wikipedia with care)

  • Excellent Dennis, thank you –

    That’s what I mean. It couldn’t have been so low as to cool immediately after the bright flash if it were still moving fast. That quick darkening to me is implying it was much higher up, which could be explained by faster moving shock due to the cold conditions.

    (D. Cox) “The shock that bashed in all those windows was a detonation shockwave, not a mere sonic boom”

    Exactly.

    So tell me what the overpressure is on a 500kt shot.

    The shock wave doesn’t travel at the speed of sound, as I mentioned in the Feb 22nd post above. It travels faster than the speed of sound by a factor dependent on the degree of overpressure. That’s why its a shock wave and not just normal sound (proverbial “sonic boom”), and likewise why it is able to deliver damaging energy. So when you start multiplying those 3 minutes of delay by speed faster than the speed of sound, and even faster due to cold, you start getting (from the first speed of sound URL of my google search):

    http://hyperphysics.phy-astr.gsu.edu/hbase/sound/souspe.html

    just a W.A.G. ~= 675 mph at -50C
    so you get more like 33 miles, not 20 km (!) or 178,000 feet in altitude.

    One hundred seventy eight thousand feet in altitude. (about 54 km) But that is speed of sound, not SHOCK which travels faster, so farther in a given time.

    That’s the Ionosphere (~70 km and up) we’re talking about. Now its important to note that shock wave speed will be lower as height increases, but three minutes of transit time combined with damaging effects upon arrival are telling us that this was a significant blast. Very significant.

    Temp and therefore shock speed vary plenty through that range of altitude, and there is the question of how much energy the wave could carry from thin air into thick air, but remember the high pressure dome over that area this time of year and the energy transport becomes more likely possible.

    The bolide wouldn’t have to sacrifice much mass or velocity for 500Kt worth of detonation energy because its energy is in the form of Kinetic which goes 1/2*m*v^2 or
    1/2 times (mass) times (velocity SQUARED)

    Now square the velocity of 15 miles per second, and you get the idea. A tiny bit of mass at that speed has plenty of punch

    The video evidence is about optics and heat transfer.

    Looking at the (darkened) object departing the scene after the flash(es), already many miles away and moving farther away at that point, the relative motion in the wide angle video frame implies it was still traveling at many miles per second when it “went dark” AFTER the flashes and contrail were created. It seems to fly down to the horizon, but very rapidly, because it is actually flying off a great distance beyond the horizon back into space.

    Simply the fact that ANY object at a distance of 20 or more kilometers was visible from the ground in a wide angle video frame is telling us that this was a very large object. A single pixel, even from the HD dash cams that are common today, translates to a very large object at that distance, and that fly-away object was more than a single pixel. What is that telling us? The pixel count of object size and lens F.O.V. along with an estimate of distance to the dark object after the flash (ground distance and altitude) will reveal the object was at least the size of a large building, but I’m guessing more like 50 to 150 meters in diameter.

    I’ve spent many years studying wide angle imagery, both stills and video, and it can play some serious tricks. The simple angular resolution and relative motion within the frame, combined with the great distance of the dark object after the flashes tell the tale clearly. The dark object was plenty fast and plenty far off, still at astronomical speed by all means, most likely very close to approach speed.

    Heat transfer is the other key here….

    Think about rapid onset hypersonic ablation for a minute. Think about the meaning of ablation to begin with. Burning surface material leaves the heated/ing surface and carries off the heat with it in the process. Rapid onset means heat never has a chance to penetrate the deeply frozen ancient bolide. So how do you turn off the switch of a fireball hotter than the surface of the sun and immediately get a cold object? Simple.

    It never got hot to begin with. Most of it didn’t anyway. Only a small fraction.

    As the outer layer of the bolide was vaporized and ablated away, it carried heat with it. This happens at extremely high altitude, with ionic stripping as a driving mechanism in the very rarified upper atmosphere (ionosphere). As the heat is applied momentarily, the outer layer launches off of the bolide carrying heat with it, and radiating like crazy because of the extreme temperature. Irradiative heat transfer rate is a function of the 4th (fourth) power of delta temperature. So the hotter something gets, the brighter the color and more joules per second get carried away from it in the form of IR radiation.

    The ionic heating doesn’t reach deep below the surface, however, which is why the Apollo astronauts survived the ride back in the tiny capsules.

    The amazing thing is that heat transfer is time dependent, so this also means that the bolide doesn’t have time to absorb much heat at all because all of the “hot” leaves with the ablated surface particles. I always tell my kids – “heat transfer is a time dependent process”.

    Remove the forcing function (ionic bombardment) and the process is quickly terminated.

    Also, I don’t think it was a double trail. I think it was a low density thermal plume that was shock-driven outward very briefly and then rose convectively as it cooled.

    Three (3) points of interest, and these are the most important of all:

    1) “Departing from atmospheric encounter” means, by definition, “still Earth crossing”. This means bad news some time in the future, although it could be a long time, because this thing will come back and eventually impact Earth’s surface or atmosphere more directly (see 2012 post from T.L.E about computer study of asteroid simulation stating that initial close or grazing encounters almost always result in object eventually being absorbed by the body encountered)

    2) The government is not giving you the whole story. Think about it. If the government knows this thing is coming but it isn’t clear if it is going to kill tens or hundreds of thousands or miss completely, what are they going to tell you? If its going to come back and they aren’t sure when or where yet, what will they tell you? They will either tell you nothing, or they will tell you it was small and burned up in the encounter. But they can’t change the dozens of independently posted pieces of video evidence, or the damage or the injuries sustained on the ground, or the physical laws that dictate what is in the videos.

    3) Use your brain. Call your congress-folk and tell them to identify and cover the threat. That is why this web site exists and that is why you are reading this right now. No joke.

    TH

  • Reviewing some imagery again, it looks like the Russian job did indeed split into two main fragments during the critical exposure (rapid heating and brightening – the flashes)), quite fortuitously, as the southern or lower one of the two fragments is absorbed by the atmosphere and its plume comes to a swollen stop in that process (terminal plume) while the Northern or upper plume generating chunk continues at high speed and may be seen (relatively) gradually dimming and getting dark as it flies away. That is the typical signature of a grazer.

    Then there are a few fragments (?) just behind that larger leading chunk, and a slightly discontinuous ‘dash’ of plume along the fly-away chunk path.

    In the videos where the shock impact is “caught on tape”, the camera is at a steep angle underneath the swollen endpoint of the terminal plume. This terminal plume is likely the cause of the majority of the shock that damaged the surface.

    It looks like we get a sample of each type of behavior in this fantastic event!

    TH

  • Hermann Burchard

    These videos are really tricky to interpret, Tim. On some, the two “halves” of the vapor trail look asymmetric, one coming to a swollen stop, as you write, the other proceeding on a longer track ultimately departing from the planet.

    That apparent asymmetry most likely is caused by parallax. On this video it’s not there, the two sides, left & right seem completely symmetric in detail to an amazing degree, probably because it is shot from a better angle.
    http://www.youtube.com/watch?v=Mwieex7gFAs

  • Tom Holsinger

    Mr. Harris,

    I have some issues with a 500 kt yield detonation at the optiumum burst height to maximize the 5 psi overpressure zone, producing the demonstrated results here at 33 miles distance, particularly on the factory. The same yield detonation at the same distance in altitude (33 miles above the surface) runs into even more issues due to the atmosphere at such an altitude being to thin to convey significant amounts of blast energy, and particularly so in conveying it to lower altitudes whose greater density would tend to absorb some of the blast energy.

    Basically a detonation at 33 miles altitute needs to be of far larger yield than 500kt to produce the surface blast effects shown in photos.

  • Here’s an interesting piece from MIT’s Technology Review: Astronomers Calculate Orbit of Chelyabinsk Meteorite

  • Steve Garcia

    Dennis –

    My first reaction to the astronomers’ calcs is that they are on drugs.

    The orbit diagram at https://www.technologyreview.com/sites/default/files/images/Chelyabinsk%20meteorite_0.png
    shows the object coming essentially tangential to the Earth’s orbit. . .

    1. I assume the Earth’s position is at the time of the encounter.
    2. The object’s inclination seems to jibe with what Jonny said – about 4° off the ecliptic.

    That means it is essentially at a right angle to the Sun.

    At 0:15 of the Hermann’s last video, look at the shadows of the trail. . .

    A. It is quite interesting that the UNDERSIDE of the trail is lit up well by sunlight.

    B. The image apparently is of the point at which the big blast occurred.

    B. Mostly the near side of the trail is lit up – but not all. Some of it is in shadow.

    C. SOME of the shadow appears to be toward the downfield end of the “clouds”.

    D. [Not from the video] The Sun rise 5 minutes earlier was at heading 112.49°, according to an online sunrise calculator.

    I submit that if the object was traveling as shown in the diagram – passing the Earth nearly tangential to its orbit – that:

    a. The path would be either in the midnight region of the Earth’s night side or

    b. The path would be in the noontime region of Earth’s day side

    c. a. and b. clearly could not be farther from what is seen in the videos, where the object is coming out of the dawn – meaning from the general direction of the Sun.

    d. I conclude based on obvious video images that the astronomers have got it wrong.

    Look at this video – a copy of the one I tried to calculate a bit from) and see if it is coming from that a direction tangential to the Earth’s orbit (i.e., at nearly 90° from the Sun):
    youtube.com / Watch? sEH0T_NvF V =- U

    When it first comes into view, the object is CLEARLY in view ABOVE the arc of the Sun’s glare and a bit to the left. The center of that glare’s arc is, of course, the Sun. The object cannot be more than 2 or 3 apparent solar diameters to the left of the Sun.

    There can be no doubt: As the video begins the dashcam is heading almost straight at the Sun. The right edge of the glare is directly in line with the straight roadway.

    If the object were on a path nearly tangential to the Earth’s orbit the object would be FAR to the left and not visible in the car’s windshield or in the camera’s view.

    How can an object “coming out of the Sun” ALSO be at right angles to the Sun?

    I look at that diagram and wonder “Where did they get their numbers?”

    Hey, guys, if I am dead wrong, can someone point at my error?

  • Steve Garcia

    Yes. a. and b. are not the only possibilities. I forgot to include those. I got ahead of myself.

    But the object could not possibly be coming out of the Sun, given the path shown in the astronomers’ diagram.

  • Steve Garcia

    Okay, something I typed didn’t get in that last one. (???)

    It should have read:

    Yes. a. and b. are not the only possibilities. The object could have gone over the top of the Earth or below it. I forgot to include those. I got ahead of myself.

    But the object seen in the videos could not possibly be coming out of the Sun, given the path shown in the astronomers’ diagram. Since the object WAS coming out of the Sun… QED

  • Hermann Burchard

    Steve,

    let me try to figure this out (from scratch). On my Desktop I have your 3-D orbit diagram and also the 2-D orbit diagram from the Wikipedia article “2013 Russian meteor event,” both magnified. Both diagrams show the orbit of CM (the Chebarkul meteoroid) crossing Earth’s orbit from inside to out, moving away from the Sun. The 3-D has it going down, from above the Ecliptic plane to underneath where “up” is North. Orbits are counterclockwise, E to W.

    Region of events has map coordinates about 55 N, 61 E. The event time is stated as 3:20 UTC, local time should be about four (4) hours later than Greenwich or 7:20 am, but because of a weird Ch (Chelyabinsk) time zone is 9:20 am, officially. I will use local time, 7:20. From your comment, the Sun rises five minutes earlier, 7:15 local time, late by 1:15 hrs because it is February and 55 N is fairly far North (S Hudson Bay).

    The Earth axis is tilted away from the Sun, around it the Ch meridian turns counterclockwise. Put the Sun at the center of a circle (rim of clock dial) and Earth in the six o’clock position. Ch is on the right side of Earth (a smaller circle in the six o’clock position), rotated about 19 degrees upward (toward the sun) to account for the late sunrise.

    Now picture the meteor CM coming from the left inside the rim crossing the clock rim near the six o’clock position. It is descending from above the clock dial at a gentle angle to below while it exits the rim passing tangentially over a part of the surface of Earth that is facing up on the right of the Earth.

    I wish the Tusk would function like a sketch pad or white board, so that I could draw this arrangement for you right on the Tusk!

  • Hermann Burchard

    (cont’d)

    To complete the solution, consider the location of sunrise on the horizon. Steve Garcia (on Feb 20) calculated the sunrise to be 22.5 deg S of E, and as the season progresses it keeps moving N, as long as we stay S of the arctic circle. The effect this has is difficult to put in words w/o drawing a picture, but it changes the angle made by the meteor orbit and the line of sight to the sun at sunrise. At Chelyabinsk on Feb 15. the result was what we see in some of the videos showing the sun glow with the meteor appearing above it: The orbit is deflected westward (toward the right side from the sun). Steve estimated the angle to about 20 deg. Now imagine the sun and meteor coming up due East, then the orbit would be aimed slightly N of because the meteoroid is crossing outward over Earth’s orbit. That angle is the difference 2.5 = 22.5 – 20 between Steve’s two angles, so that should be the anomaly of the meteoroid, the angle of its orbital plane with the ecliptic, kapeesh?

  • Steve Garcia

    Hermann –

    This part I don’t think I will agree with:

    On my Desktop I have your 3-D orbit diagram and also the 2-D orbit diagram from the Wikipedia article “2013 Russian meteor event,” both magnified. Both diagrams show the orbit of CM (the Chebarkul meteoroid) crossing Earth’s orbit from inside to out, moving away from the Sun.

    I am 100% certain those both are wrong.

    The intersection of the two orbits shown on those diagrams appears to be about 10° or 15°. Yes, technically, you would be right (as far as the diagrams are concerned) that the CM is crossing the Earth’s orbit from inside to out. But look at the view from the Earth, looking at CM. Which was is the SUN? WAY to the left – in those diagrams. Basically 90° to the left. No object can come at us only 15° off OUR orbit and still look the way it does in the videos. 15° more and it would be coming at us right straight tangent to our orbit. And THAT is looking out into space, not at the Sun. In ALL the videos I’ve seen of its first appearance CM is almost directly in line with the Sun.

    Go look at the videos. The Sun is in the same direction as CM. NOT 90° to one side.

    George’s at http://www.youtube.com/watch?v=itnLK3902RI&feature=player_embedded shows CM appearing to the RIGHT of the glow of the rising Sun. And in the same direction.

    The one I’ve been working with mostly shows CM just barely to the left of the Sun, and above it. I will concede that it could pass from below to above before entering the atmosphere. After all, its orbit was (as we have been told) only 4° tilted.

    I agree with the diagram in The Telegraph at http://s.telegraph.co.uk/graphics/html/Years/2013/February/images/Meteor5.png
    that George has at the beginning of this post, and that Jonny linked to on Feb 15, 5:38pm.

    Look at where the Sun is! CM is “coming out of the Sun”.

    This one: http://www.youtube.com/watch?feature=player_embedded&v=zJ-Y7vhS1JE#!

    Can anyone tell me that isn’t coming from the direction of the Sun?

    http://www.youtube.com/watch?v=b0cRHsApzt8

    Look at the direction of the trail at the beginning of the video. The rising Sun is to the RIGHT, but just a little bit. [The astronomers show the Sun 90° to the LEFT. How wrong can they BE?]

    http://www.youtube.com/watch?v=aMygG4F0hk8

    The car is on a curve to the right. Because the cam sweeps from left to right, you can see where the Sun is. You can SEE where the brightest glow of the Sun is. CM is coming FROM that direction. There is no doubt.

    No go look at the astronomers’ diagram and description. I just can’t believe they could get this so wrong. Basically they are 90° wrong.

    Guys help me out here. What am I seeing wrong? Either the videos are wrong or the astronomers are wrong. They can’t both be right.

    They aren’t both right. The astronomers diagram and text are incompatible with the evidence in the videos.

  • Hermann Burchard

    Oops, wrong orbital element: The 2.5 deg angle would be the inclination (not the anomaly).

  • George Howard

    Come on guys. Give me some orbital analysis love over at the lede Mars post!

  • Jonny

    George, There’s nothing much to go on at the moment with C/2013 A1, and not much to talk about its orbit that hasn’t already been said in the links.

  • Trent Telenko

    So, if the the Chebarkul meteoroid is not an Apollo asteroid family object.

    Then what is it?

  • Steve Garcia

    Trent –

    It seems to me that if the early take on it was that it came from the direction of the Sun (which is in agreement with basically every video I’ve seen), then it was either:

    – An NEO with a Sun-grazing orbit, more or less (which means highly elliptical)

    or

    – It was a comet.

    It definitely was crossing the Earth’s orbit at nearly a right angle.

    I’d mentioned in one earlier comment that comets are not necessarily “dirty iceballs” anymore; they can be just about any configuration. The delineation between meteor and comet isn’t as clear as we all used to think. I’d bring up my Oort cloud cometary origins doubts here, but that is for another day.

    That this one air burst so high in the atmosphere suggests (to me, anyway) that it was awfully friable – though to give it credit it WAS in the atmosphere a long distance before the air bursts. Friable tends toward it being a comet, I would think.

    So my semi-illiterate guess right now is that it was a small dark short-period comet. What else goes close to the Sun?

    I know, that puts me out there in left field, but it sure as heck didn’t come from a near-parallel orbit. There is not ONE video that shows that. They astronomers based their assessment upon ONE video from some square. All the videos I’ve found from that square so far aren’t looking at buildings. Why they have not used others I don’t know. Maybe they did, but if they did they didn’t say so in what I read.

  • Jonny

    Steve, They used the security cameras since they are stationary/fixed and would have had the most reliable time keeping. You are forgetting though that the results that they obtained match the image taken of the objects entry by a weather satellite http://phys.org/news/2013-02-astronomers-orbit-russian-fireball.html. And actually they used two videos (they needed a second one fro triangulation), and the “impact crater” in the ice. they are continuing their analysis (trying to exclude the ice crater as it may have nothing to do with the event, and may even have been faked).

    Also the data from the infra-sound stations confirm the trajectory http://phys.org/news/2013-02-russia.html, and that preliminary reports indicate that the object consisted of stone and iron (which is not typically associated with comets). Also see the images of recovered fragments here http://astrobob.areavoices.com/2013/02/26/update-on-the-fireball-that-exploded-over-russia/

  • Hermann Burchard

    Steve,
    this video

    http://www.youtube.com/watch?v=Mwieex7gFAs

    shows vapor trail illuminated from the South, shadows on the North side of cloud portions. So the trail’s angle to sun rays is at nearly 90 degrees, the asteroid orbit making a shallow angle with Earth’s orbit.

  • Steve Garcia

    For (probably) the few among those here that don’t already know much of this, I found this about the Apollo asteroids:

    Per http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1983LPI….14..853W&data_type=PDF_HIGH&whole_paper=YES&type=PRINTER&filetype=.pdf

    Article Name: Searching for Comet Cores Among Apollo/Amor Asteroids – by C.A. Wood, SN4/NASA Johnson Space Center

    ASSOCIATED METEOR STREAMS: Sekanina (4) discovered that the orbits of the Apollo asteroid Adonis and the Sigma Capricornids meteror stream are so similar as to imply “a likely evolutionary relatinoship.” Because meteor stream are known to be derived from comets, Sekanina’s discovery strongly implies a cometary origin for A/A’s with associated meteor streams. Indeed, the Apollo object Hephaistos has an orbit similar to that of comet Encke! Sekanina (4) and Drummond (5) have ound that ten Apollos and three Amors can be associated with meteor showers; since most Amors do not cross Earth’s orbit, detection of Amor-related meteor streams is difficult.

    GEOCENTRIC VELOCITY: Anders and Arnold (6), noting that Apollo asteroids fell into two groups differing in geocentric velocity, proposed that the low-velocity group was asteroidal and the high-velocity group was cometary. With more that three times as many Apollos no known compared to 1965, the bimodal grouping still exists; based on a minimum in the velocity histogram I propose that a geocentric velocity of 0.8 marks the division.

    HIGH e, i, Q: Because most main belt asteroids have low to moderate values of orbital eccentricty (e) and inclination (i), higher values are often considered (eg., 14) to imply a cometary object. I consider i > 20° or e > 0.5 to suggest a cometary origin. Similarly, Marsden (7) believes that the single most important factor for distinguishing asteroidal and cometary orbits is the a[ehelion distance (Q). Only 95 asteroids (out of 2500) have Q > 3.9 AU, and no known comet has Q 3.9 is taken to indicate a possible cometary object. . .

    CONSTANT ECCENTRICITY: Taking into account secular perturbations of orbital elements, Kozai found that of all the asteroids only 11 (all A/A’s) have nearly constant values of e, and hence their apehelian [sic] and perihelion distances vary. This is also a property of short period comets andhence Kozai proposes that these 11 are the remains of cometary nuclei. . .

    DISCUSSION: … A remarkable result of this simple study is that 51 of the 64 known A/A objects have one or more cometary characteristics, and 17 (26%) are cometary in half or more of their properties. The spectral types of the most comet-like A/A’s (=>50% CC in Tabel 1) are not definite but include one possible ordinary chondrite, three S types, two C’s, a diogenite, three U’s, and eleven unknowns. If all of these objects are derived from comets, then traditional concepts of comets as core-less dirty snowball are incorrect. Likewise, it would seem impossible for such a diverse group of inferred chemical compositions to have formed in the outer solar system, reinforcing ideas (10,11,12) that many small bodies which formed in the solar system. . .

    …If so, derivation of Apollos from the asteroid belt by way of the Amor orbits may be very inefficient and perhaps the majority of Apollos are extinct comets.

    QUESTION: Do we know what KIND of Apollo they are saying that Chelyabinsk (Korkino) was? And its characteristics?

    (I am not done with the path – I have some interesting additions… but it is taking a while.)

  • Trent Telenko

    I have a real problem with the blast energy budget for this Chelyabinsk event.

    When I plugged 500 KT yield into the nuclear effects generator, which is based upon “The Effects of Nuclear Weapons”, 3rd Edition, by Samuel Glasstone and Philip J. Dolan, at this link —

    http://meyerweb.com/eric/tools/gmap/hydesim.html

    The damage at Chelyabinsk was mainly consistent with a 0.25 psi blast line, see —

    0.25 psi — Most glass surfaces, such as windows, will shatter within this ring, some with enough force to cause injury.

    (The collapsed factory could either be the result of either or both poor construction and multiple blast reflections adding up at that one location.)

    Plugging 500 KT yield into the hydesim calculator gives _8.63 miles_ (13.887 km) for the 0.25 psi line.

    Hydesim blast effect key below —

    Overpressure Key

    15 psi Complete destruction of reinforced concrete structures, such as skyscrapers, will occur within this ring. Between 7 psi and 15 psi, there will be severe to total damage to these types of structures.

    7 psi Severe damage to complete destruction of reinforced concrete structures, such as skyscrapers, will occur within this ring.

    5 psi Complete destruction of ordinary houses, and moderate to severe damage to reinforced concrete structures, will occur within this ring.

    2 psi Severe damage to ordinary houses, and light to moderate damage to reinforced concrete structures, will occur within this ring.

    1 psi Light damage to all structures, and light to moderate damage to ordinary houses, will occur within this ring.

    0.25 psi Most glass surfaces, such as windows, will shatter within this ring, some with enough force to cause injury.

    When I go to http://nuclearweaponarchive.org/Nwfaq/Nfaq5.html, they give the following table —

    These many different effects make it difficult to provide a simple rule of thumb for assessing the magnitude of harm produced by different blast intensities. A general guide is given below:

    1 psi Window glass shatters
    Light injuries from fragments occur.
    3 psi Residential structures collapse.
    Serious injuries are common, fatalities may occur.
    5 psi Most buildings collapse.
    Injuries are universal, fatalities are widespread.
    10 psi Reinforced concrete buildings are severely damaged or demolished.
    Most people are killed.
    20 psi Heavily built concrete buildings are severely damaged or demolished.
    Fatalities approach 100%.

    Suitable scaling constants for the equation r_blast = Y^0.33 * constant_bl
    are:

    constant_bl_1_psi = 2.2
    constant_bl_3_psi = 1.0
    constant_bl_5_psi = 0.71
    constant_bl_10_psi = 0.45
    constant_bl_20_psi = 0.28

    where Y is in kilotons and range is in km.

    Blast effects need air to work on and there was not much air at 33 miles altitude. And this is leaving out density effects with the sonic/blast wave energy wave.

    Active sonar pulse waves run into layer effects as its transmission medium gets thicker, which bend and attenuate sonar pulses in colder, saltier & denser sea water.

    Short story — either the Chelyabinsk blast was a whole lot bigger, or it was a whole lot lower.

    I think there is a problem with the the nuclear infrasound detectors people keep quoting as being definitive because the detectors are calculating yields for either hidden nuclear testing or optimum altitude blast yield nuclear detonations.

    They cannot cope with really high altitude meteor bursts because there is not a data base of real world data to calculate with.

    Others have noticed this problem as well, see this blog post —

    http://up-ship.com/blog/?p=18904

  • Trent Telenko

    Here is another point on the infrasound detectors.

    Their calculating software models assume;
    a) An instantaneous energy release,
    b) A point source, and
    c) An energy release inside the sensible atmosphere,
    as those are the characteristic’s of a nuclear detonation.

    The Chelyabinsk event was none of the above.

    It wasn’t a nuke. So it was not an instantaneous event.

    It was hypersonic AND thus the energy of the extended event was smeared across tens of kilometers of upper atmosphere.

    The 500 kt infrasound number can’t help but be pure GiGo — garbage in and garbage out.

  • Steve Garcia

    Okay, I don’t think this YT video has been posted here. It took me a while to find a good one with some really good views.

    https://www.youtube.com/watch?v=Ee49ZIu_dH0

    15 minutes. 10 minutes of direct video views – lots and lots. And lots. From all sorts of POVs.

    I was going to post all my disagreements, with the astronomers, but I figured out how to rectify their findings with the observations.

    Let’s just number things:

    1. NOT ONE video showed a parallel, grazing trajectory. The only ones that did not show a downward trajectory were the ones directly underneath. Scores of angles from the N, S, SE, SW, NW, NE, E – all showed what looked like the later end of the trail was lower than the start. If ANY of them showed

    2. The astronomers determined that the object entered the atmosphere on a 20° downward slope. I am of a mind to agree with that.

    3. The first thing that tells us is that this was no grazing, skipping-off-the-atmosphere impact. This one was doomed to hit or blow up before it reached the ground.

    4. One view, in Korkino (about 30km S of Chelyabinsk), appeared to not only be directly under the path, but was apparently directly under the big blast, too. Conclusion: It should be called the Korkino meteor.

    5. All the views from the towns S of Korkino showed the meteor N.

    6. All the views from the towns N of Korkino showed the meteor S.

    7. ALL of the videos that also show the rising Sun also show that the object appears to come from very near the direction of the rising Sun. Ergo, my impressions from before were not incorrect. But I now think this does not refute the astronomers.

    8. The azimuth of the sunrise was about 111°, 21° S of due E.

    9. In all the videos wher it could be seen well enough, the object was coming from the left of thee Sun. Therefore it is reasonable to say that the object was traveling more or less due west across the Chelyabinskaya province.

    10. The astronomers’ claim that the object became visible at one height and exploded at a lesser height appear to be correct.

    11. Meteor fragments were found at Lake Chebarkul, the one with the round hole.

    12. The heading from Korkino to Lake Chebarkul is 276.5°, about 6.5° N of due west.

    13. With its downward slope of 20°, the object would have impacted somewhere about as far west as Lake Chebarkul, perhaps a bit farther.

    14. The geometry of the Earth vis-a-vis the Sun at the moment of the blast was this:

    14a. Korkino was high on the surface of the Earth, relative to the ecliptic.

    14b. Korkino was facing at almost a right angle to the Sun. I.e., UP at Korkino was at right angles to the Sun. Also I.e., Korkon was facing along the Earth’s orbit in the direction of the Earth’s travel. Figuratively speaking, if the Earthe were a bus, Korkino was high on the windshield, and pretty much halfway across the windshield.

    14c. The object was traveling in the same direction as the Earth, but coming up from below the ecliptic at an angle of about 4°, and was coming from slightly inside the Earth’s orbit. So, it was coming from behind, slightly from the lower left. The sideways angle was about 20° as it caught up with the Earth.

    15. The astronomers determined that the object was closing on the Earth at about 13-19 km/sec. That is pretty fast. The Earth travels about 30 km/sec and so do most objects in this region of the Solar System. The gross velocity of the object was about 43-40 km/sec. Wow.

    16. The Earth was leading the object, so the gravity of the Earth was accelerating the object, right till it entered the atmosphere. Thus, the high velocity has some reasonableness to it.

    17. The question arises: HOW did the object coming from behind blow up just in front of a spot high on the centerline of the windshield?

    17a. It seems the Earth’s gravity well had to have captured the object as it was passing the Earth on a slightly upward path. This veered the object into a semi-slingshot orbit – but one which failed to succeed. (Again, this is consistent with the high velocity of the object.)

    17b. The object did not have the proper trajectory around to slingshot and keep on going. Its path became a spiral down to the Earth’s center of gravity.

    17c. As the object “caught up with” the Earth, I am certain that it came in slightly below the center (slightly below the ecliptic).

    17d. The object seems to have passed the Earth on its left side – the side facing the Sun.

    17e. Just as it caught up with the Earth, the object went into a tight right turn (which was really a spiral).

    17f. In looking at it, it is my impression that the object could not have taken the path in the atmosphere that it did – coming from where it did – unless it orbited the Earth at least one time. I say this just by looking at the final path vs the incoming path – I can’t see how it could have done that on the first pass.

    18. More than 50% of Apollo asteroids exhibit some characteristics of comets.

    19. Main Belt Comets are members of the main asteroid belt that exhibit some cometary characteristics, including outgassing/forming of a tails/comas. Some objects in the main belt were originally thought to be comets, but later were given the designation of asteroids. And vice versa.

    20. Calling the Korkino object an Apollo asteroid, then, does not necessarily end the story.

    – – – I have probably figured something wrong here, but I gave it the old college try. I didn’t see originally how the scientists could have been correct, but if we consider that the object did not come down on a direct line to the Korkino area, we can rectify the videos with the astronomers likely path. If the Earth captured the object on a very close pass-by, it COULD go into a tight spiral around the Earth before entering the atmosphere – and then hit or air burst on the “hidden” side of the Earth.

    I would VERY much like to see what kind of detail the astronomers show for the last part of the object’s path. Did it turn and nosedive right away? Or did it loop around a few times before its orbit decayed enough to enter the atmosphere?

  • Steve Garcia

    BTW, the Korkino part of the video starts at 1:13.

    You can hardly see the “tail” for a while, it is coming so much straight over.

  • Jonny

    Here is a Google Earth .kml file which shows the trajectory of the bolide as supplied by Alan Fitzsimmons of Queen’s University Belfast https://dl.dropbox.com/u/15286514/Trajectory.kml. It denotes the 16 seconds of luminous flight, and ranges from an altitude of 91 Km down to about 15 Km. Vertical lines mark disintegration points.

    You can see that its angle of incidence is about 20 degrees, and has a heading of about 282 degrees. So it is coming from slightly south of east (Not northish to southish as initially reported).

  • Hello for all

    Russian meteorite fragments…………..

    http://english.ruvr.ru/2013_02_28/Scientists-end-search-for-meteorite-fragments/

    regards
    pierson

  • Steve Garcia

    Jonny –

    Thanks. I’d say that was pretty darned close. And like I said, it should be called the Korkino meteor.

    When I twist and turn Google Earth for the one best video view I found, the angle from there is just about perfect. I like that angle of incidence and heading.

    But I also am hoping to find about it’s transition from the low-to-high orbit behind the Earth into that final approach. It cannot be a very simple transition. (If it is, I will have learned something.) That final approach is like at a right angle to its orbit around the Sun.

    That is a really good look at the downward angle. That angle made all the videos tough to figure out the angle. I’m glad someone could do it better than me.

    But that angle should also dispel ideas that part of the object skipped out of the atmosphere. That object was well and truly captured. And the amount of velocity lost was huge – it couldn’t have had the velocity to escape. Especially with the geocentric velocity being only 13-19 km/sec.

    I’d also point out that Lake Chebarkul, where the fragments have been found, was directly on that line and only 18 km downfield.

  • Steve Garcia

    A few more bits:

    The town of Belonosovo was actually closer than Korkino. It passed 6 km south of Korkino, and the big burst was 8.25 km away. Belonosovo was only 3 km away from both the path and the big air burst.

    So, I correct myself. It was the Belonosovo meteor. . . 🙂

    The sunrise azimuth was at 111° for Chelyabinsk/Korkino. The first appearance was on a heading of 104.25° from Korkino (just to the left of the Sun). It was 113° from the center of Chelyabinsk, just to the right of the Sun. But I have not seen any video from the center looking back at the object; the views are from cars I know not where. So, very literally, someone saying it “came out of the Sun” was not wrong.

    It is rather amazing that the Sun was rising right then, to give such a great reference.

    One can better understand ancient accounts of “the Sun was breaking up” or the story of Phaëton.

    When Phaeton [“shining”, the son of Helios] obtains his father’s promise to drive the sun chariot as proof, he fails to control it and the Earth is in danger of burning up when Phaeton is killed by a thunderbolt from Zeus to prevent further disaster.

    Son of Helios and the thunderbolt destroying the object = “coming out of the Sun” and then the air bursts – a better ancient, un-scientific description of the Korkino meteor would have been difficult to find. Can you imagine the reaction to the shock wave while watching the fiery object careening across the sky, just after bursting before their eyes? Thunderbolts, indeed! And then, at the end, it just fades to nothing (is killed, certainly). In the language and paradigm of the day, what could be more obvious?

    /////

    This would be a strong argument against Velikovsky interpreting Phaëton being Venus – when a “simple” meteor burning up in the atmosphere is a match item for item of the Phaëton story. Venus is not required at all.

  • Maybe this’ll help. There’s new paper in arXiv regarding the orbit of the Russian meteor.

    A preliminary reconstruction of the orbit of the Chelyabinsk Meteoroid

    Jorge I. Zuluaga, Ignacio Ferrin

    Abstract

    In February 15 2013 a medium-sized meteoroid impacted the atmosphere in the region of Chelyabinsk, Russia. After its entrance to the atmosphere and after travel by several hundred of kilometers the body exploded in a powerful event responsible for physical damages and injured people spread over a region enclosing several large cities. We present in this letter the results of a preliminary reconstruction of the orbit of the Chelyabinsk meteoroid. Using evidence gathered by one camera at the Revolution Square in the city of Chelyabinsk and other videos recorded by witnesses in the close city of Korkino, we calculate the trajectory of the body in the atmosphere and use it to reconstruct the orbit in space of the meteoroid previous to the violent encounter with our planet. In order to account for the uncertainties implicit in the determination of the trajectory of the body in the atmosphere we use Monte Carlo methods to calculate the most probable orbital parameters and their dispersion. Although the orbital elements are affected by uncertainties the orbit has been successfully reconstructed. We use it to classify the meteoroid among the near Earth asteroid families finding that the parent body belonged to the Apollo asteroids.

  • Jonny

    Dennis,

    I thought I had already posted that paper, but looking over the thread, I obviously hadnt. I had posted it a few places, so I think I just got confused. Have had a sinus infection and a 4 day headache, so that may have had something to do with it too!

    Its a good paper.

  • The term “impacted the atmosphere” is one we don’t hear enough. Too manny people forget that we live on the bottom of a sea of air. Or that slamming into the atmosphere at 18,000 miles per hour is more violent than slamming into a stone wall at hundreds.

  • Trent Telenko

    The 0.25 psi damage line for a 500 KT explosion is a straight line radius distance of 13.887 km from a point source, instantaneous, detonation.

    The pathway and demonstrated damage effects the Chelyabinsk boloid don’t work for a 500kt energy budget.

    See from the article:

    In table 1 we present the properties of the trajectories defined by the extreme values of
    the independent parameter d.
    Property Symbol d = 50 km d = 72 km Units
    Height at BP HBP 32.47 46.75 km
    Elevation BP h 16.32 19.73 degree
    Azimut BP A 91.60 96.48 degree
    Latitude below BP  54.92 54.81 degree
    Longitude below BP  62.06 62.35 degree
    Height at FP HFP 20.31 25.04 km
    Radiant declination  12.38 12.39 degree
    Radiant right ascension RA 22.44 22.07 hour
    Meteoroid velocity v 13.43 19.65 km/s

    According to our estimations, the Chelyabinski meteor started to brighten up when it
    was between 32 and 47 km up in the atmosphere.
    The radiant of the meteoroid was located
    in the constellation of Pegasus (northern hemisphere). At the time of the event the radiant
    was close to the East horizon where the sun was starting to rise (this is confirmed by many
    videos showing the first appearance of the meteor during the twilight, see an example at ).
    The velocity of the body predicted by our analysis was between 13 and 19 km/s (relative
    to the Earth) which encloses the preferred figure of 18 km/s assumed by other researchers.
    The relatively large range of velocities compatible with our uncertainties in the direction of
    the trajectory, represent the largest source of dispersion in the reconstruction of the orbit.

    They are talking 32-to-47 km with an energy budget that can deliver damage only to 0.25 psi damage to 13.887 km!

    We are looking at a whole lot more kinetic energy, spread over a larger atmospheric volume & land area foot print (from 16 to 30 km or so of trajectory cone?), over a several second time period.

    This was an impact event and not a _detonation_.

    The energy release curve for an atmospheric impact event is far different, far longer, and spread over a much larger, differential density, fluid volume and land foot print than for a point source nuclear detonation.

    Bolids have such different energy release curve characteristics that using a nuclear detonation energy release model — with an instant sharp peak and trailing right hand curve — for the Chelyabinsk bolid energy budget is simply poor science.

    The peak energy release for a boloid may be as high as a nuclear detonation, but area under the boloid impact release curve is much, much, bigger!!!

  • George Howard

    Yep, Dennis. I often bring up that you don’t find craters from “jumpers” on the floor of San Fran Bay below the Golden Gate bridge.

  • Steve Garcia

    Yeah, Jonny, I had thought you posted the abstract link, too.

    Thanks, Dennis, for putting it up.

    The full paper is at http://arxiv.org/pdf/1302.5377v1.pdf.

    I’d gone to a link for the abstract right after it was submitted, and I did not find the entire paper then. (Not sure why not.)

  • Another thing to keep in mind as we grapple with understanding way the event unfolded is that since the velocity of the meteorite was roughly equal to the speed at which it detonated, then the energy of its detonation was distributed along a line. It was not a point source detonation by any stretch of the imagination. So if your math is founded on the point source approximations that came out of the nuclear tests of the cold war years, there’s an additional wrinkle you need to take into consideration.

  • Steve Garcia

    Another thing is its velocity. If it overtook the Earth from behind, and the Earth’s velocity is 30 km/sec, then they need to account for why the final in-atmosphere velocity was 13-19 km/sec. The normal velocity of Apollos is what? about 20-30 km/sec? Why was this one going so fast?

    No one has even asked this question.

  • Jonny

    Steve, if you use the vis viva equation, you can work out that an object with a semi-major axis of 1.6 AU, will have a velocity of around 35 km/sec at 1 AU. Earths orbital velocity at 1 AU is about 30 km/sec, so the difference is 5 km/sec at this point. Now add in the acceleration effect of the earth’s gravity, which could increase the velocity of the object by 11 km/sec (i.e. an “initially stationary” object “falling to earth” from a far distance will be accelerated to escape velocity), and you now have a potential encounter speed of 16 km/sec. In fact, if teh earth is moving away from the object, we end up with a form of “sling shot” effect, and the object could be accelerated by more than 11 km/sec. If we want we can even add in the minor addition of the rotation of the earth under the objet, which could add up to another 0.5 km/sec to the apparent velocity of the bolide, since the earth turns west to east, and teh object was moving east to west.

    The specifics are probably a little more involved than this, but it gives an explanation for the objects observed encounter speed.

  • Steve Garcia

    Jonny –

    Thanks! I knew if I asked enough times someone would explain all that. I knew the Earth would be accelerating it, but didn’t have a good idea how much. After looking at a celestial mechanics book, I decided I am too old to get into it all.. Maybe not over my head, but my brain doesn’t want to work THAT hard. . . LOL

    But I had not been informed of the vis viva equation before. Thanks.

  • Steve Garcia

    http://www.youtube.com/watch?feature=player_embedded&v=ZzwB7FeJRgA

    Cool! Fragments falling. Location unknown and source refuses to give location (possibly a secure location). But definitely downfield of Korkino/Chelyabinsk area.

  • Steve Garcia

    I have nailed the meteor’s path in the atmosphere.

    I found a video with REALLY good landmarks for directly arriving at the heading of the meteor. The video is at http://www.youtube.com/watch?feature=player_embedded&v=3kc274wZgMg

    This is the single best video for this I’ve found. The Korkino video that I also liked the most turned out to be one of the two used by the Columbian scientists. But THIS video is far superior to their Revolution Square video. The Revolution Square video was also used by the guys at ogleearth.com, and is referred to below as “the first calcs.”

    Getting on with it:

    . . .At 0:02 the view clearly shows the path of the object’s trail is very slightly to the left. The angle is not vertical, but slightly skewed. Ergo, this camera is NOT exactly under the trail.

    …At 0:09 this is repeated, so I can safely say that the trail – as observed – is again very slightly to the south of the camera.

    …At 0:25 the cameraman stops. He immediately points the camera at the building on the west side of the street. The trail is aligned with the center of the roof eave’s southern end. Almost.

    Still standing in that spot, he swings the camera overhead, along the trail, and stops at 0:26 (you have to be quick with the ) when he has the eastern end of the trail in view. Also in view is the roof of the house on the east side. The trail aligns about a foot to the left of the southern edge.

    . . .At 0:27 the east end of the trail aligns about 1 foot from the southern edge of the blue roof. The western end is about 1 meter east of the center of the southern edge of the roof of the long apt. building on the west side.

    The blue roof is 14 meters wide. The white roof is also 14 meters wide.

    So now we have a camera in one spot, underneath the trail, and it has both ends of the trail. Bingo!

    Lining up those two points on those roofs, we draw a line. The E-W heading is 279.46°. I’d give that a +/- of 0.5° with a 75% certainty it is within 0.25°.

    Now we just have to determine where he is. He is at 54°49’19.02″N 61°35’3.50″E. That is only a couple of meters from being exactly ON the line between the two endpoints of the line. He is about 0.5 meter off the edge of the road. That part can be determined by the views as he is walking. How far along the road he is can be determined pretty closely by the buildings on the other side of the road, s noted above.

    . . .Now, that heading worked back from Lake Chebarkul, using the end of the 2nd trajectory calcs at http://ogleearth.com/2013/02/reconstructing-the-chelyabinsk-meteors-path-with-google-earth-youtube-and-high-school-math/ (the 1st set of calcs doesn’t show an impact point), passes only 70 meters north of the cameraman. Pretty good, I’d say.

    . . .But north isn’t south. Why do the 0:02 and 0:09 views look like the trail is to the south a little bit?

    Issues:
    1. Time – We don’t know how soon afterward the cameraman got out there.
    2. Accuracy – I estimated the distances from the center of one roof and from the edge of the other. The two are less than 45 meters from each other, so extrapolating up to over 70 km will multiply any error by about 1500-fold.
    3. Wind – was the wind blowing out of the north, pushing the trail southward? If not, then I don’t know how to rectify these observations. So I have to posit that the wind WAS blowing that way.

    This heading is only 0.25° below the value of the first calcs done on http://ogleearth.com/2013/02/reconstructing-the-chelyabinsk-meteors-path-with-google-earth-youtube-and-high-school-math/. So I am pretty confident of it. (Yeah, ,I know, it does say “and high school math.”…LOL)

    / / / /

    But I am still not pleased that no one has addressed the transition path from before Earth capture and the final atmospheric flight.

  • Steve Garcia

    I observed something in one of the meteor videos. Two somethings, actually.

    See my blog post from today at http://www.feet2thefire.wordpress.com. I may have to edit it for typos, but it says what I want to say.

    I would only add that the “smoke” of the trail is almost certainly incomplete combustion – which is amazing, considering how much oxygen is getting ram-jetted onto ever molecule of the meteor. I suppose there are also some simple particulates that got blown off before being oxygenized.

    The two trails? The co-pilot of the airliner up there said he saw three separate meteors.

    And it isn’t about the heading or the transitional period as it tried to enter Earth orbit.

  • Trent Telenko

    Dennis cox said —

    >Another thing to keep in mind as we grapple with understanding way the event unfolded is that
    >since the velocity of the meteorite was roughly equal to the speed at which it detonated, then
    >the energy of its detonation was distributed along a line. It was not a point source detonation
    >by any stretch of the imagination.

    The closest you are going to find to atmosheric/boloid impacts are something like the penetration of armor by armor piercing projectiles.

    See this Canadian National Defence article titled “DEPLETED URANIUM ON THE BATTLEFIELD PART 1 – BALLISTIC CONSIDERATIONS”

    at the link —

    http://www.journal.forces.gc.ca/vo4/no1/research-recherch-eng.asp

    The diagram of depleted uranium vice tungsten projectiles going through armor [The (a) versus (b) diagram] gives you some idea of what a boloid going through the atmposphere is like until boloid failure & break up.

    The discussion of plastic failure and how increased tareget density reduces projectile penetration are also useful in understanding the material forces involved.

    The boloid energy release curve is going to look more like a failed armor penetration (AKA projectile break up in armor) than a nuke.

  • Hermann Burchard

    Trent, Dennis, Steve,
    the plume to me looks a lot like the Boslough blowtorch effect: Forward momentum flame thrower, in view of the lateral symmetry of the plume, meaning the vapor trail. Except, here it’s not vertical as at Tunguska, but at the 20 degree incidence angle.

    Also note the forward ejection of fragments on some of Steve Garcia’s remarkable videos!

    BTW, the Orenburg video at 550 km shows the 20 degree angle very clearly. But I still rejected it to the last because I was so sure it was a grazer!

    http://www.youtube.com/watch?v=1EWD5mRkyow

    Almost all of the trail is above the horizon, except for where the trail goes down to 15 km altitude at its termination a few km East of Lake Chebarkul.

    Can I get away with calling this an almost grazer?

  • Thanks Hermann. Some day we might have a scale that we can compare events like this to. While many of the downed trees at Tunguska were scorched by the IR pulse, there is no evidence that the fireball reached the ground. And any fires started by the heat of that IR pulse seams to have been extinguished by the shockwave. But if there is a threshold in airburst events where anything larger can produce temps at ground level capable of melting silicate rocks the Tunguska event can probably be thought of as an example of that threshold point. Many of Boslough’s SIMs at Sandia were based on data gleaned from studying the Libyan Desert Glass. Those Simulations give us a picture of what to expect from a 120 meter stony asteroid. And they very strongly suggest powerful thermal effects at ground level for an object that size.

    The real scientific value of the Chelyabinsk event is that it give us a very well documented calibration point for the low end of our impact scale. We’ll be happily studying it for a good long time to come.

  • Guys,

    Remember that the fireball portion of the Chelyabinsk event kept moving horizontally due to entrained momentum delivered with that portion of the bolide even after the fireball finished burning. This “momentum current” (like density current) effect is less constrained at higher altitude where the air is very thin, offering less retarding drag or impedance to that motion. Such motion or drift is also less obvious when there is no surface morphology near by (in the high altitude case) to give any kind of stationary reference.

    Vertical motion of the post-fireball portion of the plume is perhaps even more significant. I think the 20 kiloton Hiroshima blast mushroom cloud rose something like 60k ft in 60 one minute, starting nearly at the surface in thick, warmer, low altitude air. (granted it reflected off the surface as an airburst, but I’m talking generalities here) Chelyabinsk was 25 times more energy released than Hiroshima (per estimates of the 500 kiloton Chelyabinsk yield) into the thin, cold upper atmosphere. This tells us that the plume can rise very far and very fast. This is the problem with not knowing how long after passage the video was acquired. One solution here would be to compare all videos of the plume including the ones that captured the passage, and then to derive timeline estimates for those videos starting after the passage.

    Incomplete combustion is possible at hypersonic speeds because the meteor has a plasma envelop between it and the bow shock. Although super heated, this envelop is relatively low density and deflects a large fraction of the “ram air” radially outward from the velocity axis. The stuff cooking off the meteor surface is generally not due directly to the hypersonic ram air flow. Because of the extreme heating and photon radiation going on (IR heat transmission) the high pressure envelop staves off the bow shock from direct contact with the meteor. Thats the simplified form, with regular surface and no spin, etc., which well never know about for this case. It also gets more complex as the meteor fragments and exposes more surface at odd angles to the existing shock tube/sheath, a process largely dependent on bolide composition and entry conditions, blah blah blah.

    What is amazing about this event is that it seems like both results, atmospheric absorption as well as grazing contact, are possible from the same entry conditions. We assume this is because of the separation of components during initial fragmentation (early bifurcation event), leaving the low density (low ballistic coefficient) ripe for further geometric fragmentation and resultant fireball fate, while the more dense component remains in tact on nearly the same trajectory as its approach, minus a bit of frictional loss. I’m guessing the initial bifurcation event to separate the components largely by density is evidenced by the ‘kink’ in the trail of the approaching meteor, near the beginning of the visible plume.

    The ‘kink’ in the plume happens at great altitude, and I see it as evidence of 2 possible conditions:

    1) a shear or turbulence layer in the atmosphere (unlikely at that altitude/temp/pressure where atmospheric flow tends to be laminar, not turbulent), or

    2) violent ‘activity’ within the meteor itself as the rapidly ramping-up shock heating and pressure apply a large torque on the vastly non-homogeneous and randomly aligned structure of the intruder, causing mechanical loads within that structure to exceed its material strength. As the shock heating begins, area applied deceleration force causes the dense end to want to swing forward, like a badminton shuttlecock.

    But this ancient and very cold object is brittle in the face of such violent applied force. The applied forces exceed its strength, so the draggy low density hunk and the dense chunk come apart. This is a clue that at least one phase of the formative process of the thing was likely in low gravity, being cold accretionary vs. it being a single solid chunk-o-rock that was formed in gravity (from planet or large asteroid?) at higher pressure and temp.

    It is an amazing volume of information! What is the origin of the Apollo class (or whatever the Chelyabinsk object family is) and how can these subtle yet well recorded hints tell us more about the life history of this class of object?

    If I had to guess based on the duality of structure and peculiar orbit of Apollo-class object, maybe there was a comet which collided with an asteroid to yield that combination of characteristics. Either way, these dark, small, plentiful nearby neighbors of ours need much closer attention as our planet continues to build population and infrastructure while they “float around gently” overhead.

    Bottom line:
    Part of the sky is always falling. Sometimes Earth get in the way of that part. It has happened. It keeps happening. To deny it is akin to forgoing Fall harvest in denial of approaching Winter. Big mistake. Only questions – how many megatons, when and where? I know I’ll always be on the lookout on or about 15 Feb now that I know of that particular Earth crossing object.

    Acknowledge the threat. Characterize the threat. Defend against the threat. Survive the threat.

    To do otherwise is like mortgages without insurance. Unrecoverable loss is the result in some percentage of homes. Earth is our home. Take a chance on the percentage.

  • Steve Garcia

    Wow – I was typing here and all of a sudden it blipped out and I lost what I typed.

    Hermann –

    Yeah, the Orenburg video is pretty clear about the downward slope of the path.

    I don’t see how any object with a 20° downward slope could ever bounce back out to space. I think 20° is a sure sign it is captured and is doomed.

    An almost grazer? Actually, I’ve been working on something that argues that it not only isn’t a grazer, but that it orbited the Earth at least once, spiraling downward the whole time. If it was going to fast to do that, then Houston, we have a problem.

    See this diagram on my Facebook page: http://tiny.cc/27ujtw

    The object both makes a right turn at Earth that seems impossible, actually an upward jog as it is turning right. What I call the Phase 1 orbit (the Columbians’) and the Phase 3 final approach are incompatible with each other, as I see it. Going 16 km/sec is 5 km/sec above escape velocity, so it seems unlikely (tending to the impossible) that the Earth’s mass could have made the object make the abrupt right turn it did and then capture it. If it made a direct entry into the atmosphere, then the resulting final approach could not have been on the heading it was on. Chelyabinsk was essentially on top of the world, as viewed from the ecliptic. If the object came in above center and got captured it would have had a N-S heading, more or less. It HAS to follow a path centered around the Earth’s center of gravity (CG). If it came in underneath, it’s final heading would have been S-N.

    From a Phase 1 orbit nearly parallel to the Ecliptic, if it somehow got to Chelyabinsk, its path could not possibly have been from the east. With Chelyabinsk nearly at 90º vertical from the Ecliptic AND almost directly above the Earth’s CG, a single wrap around path could not have ended up from the east.

    Every way I look at it, the Columbians’ orbit for the object doesn’t work.

    Damn, it is hard to explain an impossibility. I know what I am saying, but I can’t get the geometry in my head down in black and white.

  • Steve Garcia

    Thomas –

    On the Apollos and their origins, I had posted a 1983 article by D.A. Wood of NASA, entitled “Searching for Comet Cores Among Apollo/Amor Asteroids” that might inform you of some of what you are looking for. I had trouble finding much on them online. The article is at http://adsabs.harvard.edu/full/1983LPI….14..853W.

    I see that the previous link didn’t work.

    The Discussion section of the paper reads:

    DISCUSSION: … A remarkable result of this simple study is that 51 of the 64 known A/A objects have one or more cometary characteristics, and 17 (26%) are cometary in half or more of their properties. The spectral types of the most comet-like A/A’s (=>50% CC in Tabel 1) are not definite but include one possible ordinary chondrite, three S types, two C’s, a diogenite, three U’s, and eleven unknowns. If all of these objects are derived from comets, then traditional concepts of comets as core-less dirty snowball are incorrect. Likewise, it would seem impossible for such a diverse group of inferred chemical compositions to have formed in the outer solar system, reinforcing ideas (10,11,12) that many small bodies which formed in the solar system. . .

    …If so, derivation of Apollos from the asteroid belt by way of the Amor orbits may be very inefficient and perhaps the majority of Apollos are extinct comets.

    That is 30 years ago now, and more recent papers are likely to amend those comments.

    This Google Scholar page should give you some good articles to peruse:
    http://scholar.google.com.mx/scholar?q=Apollo%2FAmor+Asteroids&btnG=&hl=en&as_sdt=1%2C5

    I thought some of them are promising.

  • E.P. Grondine

    Hi Tom –

    The reason why part of this impactor survived the bolide event and was not converted to plasma is most likely due to the fact that this meteoroid was fractured by an inter asteroid impact long ago.

    At least that is what has been seen in the images and data from every asteroid probe so far.

  • E.P. Grondine

    Hi Dennis –

    Note that Boslough’s sims do not take into account the real data on Libyan Desert Glass. There may have been other mechanisms at work, other than the preservation of momentum through the bolide (plasma) event.

    Certainly the complete lack of other glass features in all of the world’s deserts would indicate this.

    Did it ever occur to you that perhaps a better explanation of Boslough’s sims result is that his physics is as bad as his work on the Holocene Start Impact event?

  • When did you become qualified to pass judgement on the work of a physicist? I note that Boslough went to Libya to collect the specimens, and data he used for his work on the LDG personally. Perhaps you should tell us what the “real” data is that you think he missed, and who collected it.

  • Steve Garcia

    FYI, folks –

    I just found out last week that the basically identical Rio Cuarto features I’ve talked about in the past here are tied to large glass fields.

    There is some really interesting confluences there, SSW of the Rio Cuarto craters that are accepted now on the impact database as true impact craters. Not only are those accepted ones aligned with the ones further SSW (which are interpeted as aeolian), but they area also essentially the same ellipticity. And those ones SSW are laying right where an airburst is supposed to have created impact glass at some other time in geological history.

    That is a lot of coincidence going on in a pretty small region.

    Some of the ones further SSW are even bigger than the accepted ones close by Rio Cuarto – same features, same alignments. But with glass.

    Michael Davias might be interested to know that the sand THERE is also used for making glass. Hmmm – Rio Cuarto elliptical craters and glass, Carolina Bays elliptical craters and glass.

    Nothing to see here; move along now and don’t make no trouble.

  • Steve Garcia

    Ed –

    I have to agree with you on that about Boslough.

    His models look nice and pretty. So do the ones in climate science that can’t replicate the recent past climate but are supposed to predict the climate 100 years from now.

    The climate models are diverging from the near future now, too. At least the near future from 10-20 years ago. I won’t go into that anymore, but just to point out that when one does models against something that can’t be compared to experience in the real world, one can get away with a lot of who knows what.

    Boslough’s mendacity to George – with his time travel excuse – made me lose respect for the man. Especially since he dropped in, made his “Sci-Fi Alibi” and then split the scene, daddy-o? What kind of un-hip hipster with any cred does that kind of split scene?

    I lost enough respect to wonder just what you asked. Now, my wondering and $4.00 will by you some sort of meager latte these days. I am sure The Bos is really crying when he reads that.

    But then the Russian meteor has me questioning quite a bit of the accepted “knowledge” about impactors, especially air bursts.

    Thomas above talks about Tunguska being a near-threshold air burst, that studies are showing 120 m ones will do this and that, like melt materials on the ground but that Tunguska at 100 m didn’t. Hey, guys, declaring 20% at one particular point in this field to be definitive is pretty much a balderdash speculation.

    I am very MUCH questioning the 500kt number, too. Looking at the negatives of one of the “burts” it wasn’t even a burst – it was just pieces ablating and being shucked off. The flare seemed to be new volatiles being exposed, outgassing, and then igniting. I don’t see an ablation event on the object itself as being an airburst. Yes, perhaps the big one was.

    Maybe I should see if I can create a negative of that burst and see what I can see. I fully expect to see something of the same family.

    It is almost like the old joke: Opinions in this field are kind of like rectums – everybody’s got one.

  • Steve Garcia

    Thomas –

    Dammit, that Harvard link didn’t work, either. They put “….” and “..” in the middle of the URLs, and it screws them all up for linking.

    See? http://adsabs.harvard.edu/full/1983LPI….14..853W

    Go to Google Scholar and enter this:

    Searching for Comet Cores among Apollo/amor Asteroids CA Wood. Then pick on the GS link.

    Sorry.

  • E.P. Grondine

    Dennis –

    Boslough’s “work” on the Holocene Start Impact Event has been witnessed and commented on by everyone here.

    Now either Boslough is incompetent, or he is intentionally being corrupt. Which one is it?

    As far as your expectation of me wasting my time providing you with anything for free, they are misplaced.

  • Hermann Burchard

    Steve,

    trying to answer your question about the orbit,

    . . . makes a right turn at Earth that seems impossible . . .

    It not only seems impossible, it is! The meteor first appears above the rising Sun, then veers off to one side, the South. The trajectory crosses the Earth’s radius vector (from Sun to Earth) near Chelyabinsk departing from inside the ecliptic outward. So you see it in front of the Sun’s apparent position in the sky only for seconds.

    Everything is foreshortened which makes it really hard to visualize without a sketch. I made a sketch for myself, which I cannot scan into the Tusk, but I will describe my sketch:

    Earth drawn as a circle for its circumference seen from above the ecliptic, as you describe it yourself. I drew the ecliptic as a shallow arc (more like a straight line) along which Earth travels from right to left, the Sun at the bottom, far away. The top half of Earth is dark in the shadow, the North Pole (NP) and Earth axis in the upper half tilted slightly toward the right because it is Feb 15, after winter solstice. The city of Chelyabinsk (Ch) on the ecliptic ‘line,’ more or less, near the center of Earth’s circle [I did not try to be very accurate on this point, and put Ch in the exact center in my rough sketch!]. (Actually, the entry point East of Korkino should be drawn on the ecliptic, & Ch a short distance above.) The meridian of Ch projects into the plane of sketch as a straight line through Ch and NP aslant from upper right to lower left. Now the orbit of the meteoroid is nearly a line (in this scale), at a shallow angle to the ecliptic with the meteor passing from lower right to upper left, just like Earth, overtaking her, through the ecliptic just South of the Ch point.

    So, at the moment the meteor first appears in the skies over Russia, it is still miles East of Korkino, and if you draw the sketch carelfully, between Ch and the Sun.

    Oh dear, pheww, this is really tricky. I hope I did not make too many mistakes. Perhaps some of the commenters can correct me and do a better job! At any rate, I hope this helps.

  • E.P. Grondine

    Hi Steve –

    Everyone may have an opinion, and we are all free to be stupid, as Secretary of State Kerry put it.

    There are skilled and brilliant professionals working on this one. They have access to information and facilities, and have talents that you are completely unaware of.

    That does not mean that you are not free to speculate. But do not expect them to participate in your reveries, and do not expect them to teach you impact fundamentals.

    That said, you need to remember that Rio Cuarto was a tangential impact which left impact scars instead of craters.

  • I should have known you’d lack the intelectual integrity to back up what you say with an honest reference to actual science I see we’re back to childish barbs and personal ad hominem insults from you. Typical behavior, no suprise there. But it was you made the claim of “real” data that was missed. I don’t expect anything for free. But then again, I don’t expect you’ll ever produce the “real” data you speak of, or cite a real paper, or even provide a compelling description of it, only empty and childish ad hominems, because the “real” data that was missed only exists in your imagination.

  • Hermann Burchard

    Off center meridians are not straight lines, but elliptical arcs through NP. This would be the case in a sketch where Ch is not in the center of the circle (as required for a more accurate sketch than mine).

  • E.P. Grondine

    Hi Hermann, Steve, Tom:

    http://www.skyandtelescope.com/news/Update-on-the-Russian-Mega-Meteor-195553631.html

    compare these estimates with Jonny’s note here.

    The professional meteorite hunters have their own estimates, which they do not share with the public at this point in time.

  • E.P. Grondine

    Hi Dennis –

    Yes, Boslough missed real data about Libyan Desert Glass. But his incompetence in regards to the Holocene Start Impact Event is well known.

    Why you expect me to provide you with anything to you for free is beyond me. Perhaps it is indicative of other problems.

  • I just expect the truth Ed; something you always have a hard time providing when called into question. My only problem in this conversation is your own complete lack of intellectual integrity when challenged. But to fall back on childish personal ad hominem insults is very typical of you. It’s the very same behavior that got you kicked off the Tusk for a few months last year. I do expect that people here should have the integrity to back up what they say with actual science. But since in the years that George has been doing this blog there has not a single thread where you can be shown to have provided a valid peer reviewed reference when challenged by anyone, not just me. So it comes as no surprise to me that you haven’t changed a bit.

  • George Howard

    I just scanned the conversation and it seemed you became pointed first, Dennis. Please tone it down guys or I will clean house again.

  • E.P. Grondine

    Dennis –

    Glass, whether impact as in the case of LDG, or volcanic, is useful for tool making. If there were any other deposits in all of the Earth’s deserts they would have been exploited by ancient man.

    There is a large community of impactite collectors, and another of artifact collectors. If there were any other deposits of impact glass, or artifacts created from it, they would have been found, and by now would be on the market.

    If you had managed to locate any deposits of impact glass, samples would be on the market.

    Given even Morrison’s estimate of the asteroid impact rate, you would expect to find other impact glass deposits in the Earth’s deserts if Boslough’s model held.

    There are none.

    Dennis, you have no idea who my peers are.

  • E.P. Grondine

    Hi Dennis –

    It is strange. In 1996 Boslough was proposing interacting bolide plumes, which he now says are impossible for the HSIE:

    http://www.df.unibo.it/ricerca/proceed.htm

    One of the problems with Boslough’s current work is that he gives no distribution of LDG, and further presents no distribution mapping of chondritic products within the LDG field.

    That is the real data Boslough left out, and it is crucial to any demonstration of his hypothesis of the preservation of momentum in the plasma from the bolide for large air bursts, as well the validity of his computer model.

    Boslough also provides no discussion of water content of LDG.

    Note carefully that Boslough is not the only person knowledgeable about LDG.

    Dennis, I went through my crater wrong days in 1997. But I had sense enough to listen to the experts when they told me I was wrong.

    Boslough reminds me of some of the cranks who visit the Pyramids and then quite vocally proclaim an expertise in Egyptology.

    Now you stated earlier that you expected nothing for free, so when can I expect the arrival of an envelop full of cash?

    Ones will be fine, as long as the bank will take them.

  • Actually I expect nothing at all from you. There is simply nothing you have to say Ed that I would spend more than two cents on.

  • E.P. Grondine

    Fair enough, and pretty much what I expected.

    But the errors in Boslough’s work remain, whether you want to acknowledge them or not. Since you won’t pay for my time and expertise, please don’t demand any of it in the future.

    And please stop using the Tusk to vent your confusion and frustrations, in a futile attempt to bring me down to your level.

  • Now this is my last post.

    I believe Dr. Boslough may have been onto something with his fragmentation model and the exponential atmosphere model, because it does seem to be useful to explain a family of possible causes for Tunguska. And is also seems to capture the generic fireball fate of atmospheric detonation as observed in part of the object over Chelyabinsk, Russia on 15 Feb of this year.

    The fact that his numerically derived solution for Tunguska points to a smaller (50 to 90 m diameter) object being able to deliver 20 to 30 megatons to very close to the surface was actually in favor of our belief that the ET bolide threat has been mischaracterized. We have only got essentially all 8,000 or so Earth-crossers of 1 km or larger diameter characterized. The estimated EIGHTY MILLION or so smaller ones down through the size of Dr. Boslough’s Tunguska solution are not yet mapped in terms of their orbits.

    Realize that what Dr. Boslough works on is mostly classified as far as I can tell. The LDG deal was also perfect for his work in terms of good publicity (Sandia science solves Pharaoh’s chest plate mystery), and low scientific risk. All he had to do was explain how an ET fireball may have formed glass from desert sand 29 million (?) yrs ago, more than anyone else had explained, by using such a powerful tool as hydrocode. Transport of that glass since then, or any other bit of data, wasn’t necessary in the LDG explanation, so why risk it.

    Dr. Boslough is an expert at thermodynamics and the complex math involved with expanding the equation of state of matter in detail and tracking changes in that matter through the entire range of temperature of a thermonuclear bomb. Not just a plain old nuclear bomb. Thermonuclear (fusion) is even hotter than nuclear (fission). He has expertise in the math and computer science which it takes to simulate such physics. I don’t think we should expect anything else from him. And any other technical subjects he claims authority in I would view with caution.

    YDLB impact hypothesis is one of those “other subjects”, one that has been associated with climate science, and has as a result become politically tainted by bunk from both corporate interest and scientific infighting regarding its validity. Now I notice Dr. Boslough makes the mistake of saying the Tunguska fireball DID make contact with the ground, which is in direct conflict with his results from that work back in the 2000’s. Clearly he is not thinking about this topic, much less not even reading about it. This should come as no surprise from a guy who doesn’t work in this area of science.

    So that puts things into perspective. Clearly.

    Dr. Boslough is a nuclear detonation physicist. Not a climatologist. Not an archeologist. Not a geologist. He is a good mathematician with a license to operate a very high tech, expensive and often classified family of tools. One that few people in the world will ever have a chance to drive: the hydrocode. Bow down. The funniest part is that he is also a tree hugger, very ironic. I just don’t know how long he can survive the dual lifestyle, bomb scientist and pro-environmentalist, without going completely nutzo. Gotta keep an eye on that….

    Yep.

    And his classified work is for the D.O.E. and D.O.E., because that’s who commissions that work (directly or indirectly). The US government. Think about that, and think about the time scale of the problem we’er facing with Comet Catastrophism (for lack of a better single title). Now, what possible reason would any elected official ever have for actually taking the risk of facing this threat publicly during a congressional term, or for that matter during an entire congressional career? And what President is ever going to come at this problem to favorable public opinion in today’s economic situation around the world?

    Not likely. It would take profound leadership. Something like Kennedy’s Lunar mandate. “Not because its easy, but because there are EIGHTY MILLION of those pesky bolide critters lurking overhead….”

    “… and that stuff makes nasty visitors…”

    “…doesn’t play nice with others….”

    More likely a President in today’s political and economic climate would simply funnel some cash to the DOD and encourage them to use some classified technologies such as computational and remote sensing program already existing or already in development. That way the issue may be kept below the RADAR of public opinion, and more importantly, of public panic.

    Because really, how is the general public going to react to news of such an uncharacterized and potentially devastating and deadly threat? They no like. Mortgage troubles are bad enough without property values further plummeting or insurance rates skyrocketing. Remember insurance after 9/11?

    TLE is right. Impact proxies lack validity right now, still, in the greater field of science. The amazing people like Ted Bunch and every collaborator including George Howard and many, many others all over the world are changing that with their careers on the line. New tools, new science, new field techniques, new remote sensing, ever evolving insights into various diverse oral histories, tree ring and ice core and ocean core sciences are going to make it happen. All of the carefully measured records will be correlated and the periodic doses to Earths atmosphere and surface will become chronicled to ever increasing detail.

    The question is how long will it take. I believe the pendulum has begun to swing clearly toward impact proxy validity, but there is far more work to go. And it seems that the resistance to these newer ideas and this newer science gains fortitude as as fast or faster than the new science grows itself.

    It also seems clear to me that the folks that resist the new ideas are not typically working in the same areas of physical sciences where the advances are being made, where the proxies themselves are being characterized. By physical sciences, I’m talking about making detailed measurements with highly accurate, highly calibrated tools to get repeatable, indisputable quantitative results. And no offense to Geologists, but even those Geoscience folks using the same machines and techniques are typically not dealing with the same temperature scales of these proxies being uncovered, so typically not even the Geo folk can refute with authority. It seems to be a relatively small body of scientists at the moment who have actually looked at and understand these otherwise subtile differences.

    And that’s what so frustrating. Lots of times its the high profile scientist with a career’s worth of reputation to throw around who doesn’t bother to look at or read about the subtile differences, but who instead assumes their own ego is all they need to guide their judgments and actions. They are too quick to judge, too quick to naysay, instead of looking more closely and quietly like a good scientist always SHOULD, or anyone with wisdom ALWAYS does. And those silly high profile scientist naysayers (super-scientists, like super-models, looking good in the spotlight but not always so sharp as we might hope) hurt our efforts the most.

    There are scientists banding together to petition congress for funding for an orbital telescope to catch darker, smaller Earth crossers. The request falls on deaf ears. This is most unfortunate, but again, not a surprise. The government doesn’t want to risk looking bad by public admission that the bolide threat is relatively uncharacterized and according to the best new data, very largely underestimated. So anything they do they are more likely to do quietly. Lets just hope they are doing something, because this is obviously not a good situation. I can give you EIGHTY MILLION reasons, one of which was 500 kilotons equivalent TNT on 15 Feb 2013.

    And now I’m going to give up posting here.

    Again.

    TH

  • Steve Garcia

    Hermann –

    Sorry I didn’t get back to this earlier. Was out of town o a day trip.

    Your sketch is okay up to this point:

    “The city of Chelyabinsk (Ch) on the ecliptic ‘line,’ more or less, near the center of Earth’s circle [I did not try to be very accurate on this point, and put Ch in the exact center in my rough sketch!].

    The city of Chelyabinsk is not on the ecliptic line. Because it was dawn, it is on the orbit line, on the “leading side” of the Earth. It is not on the Ecliptic. That runs through the center of the Earth, it’s Center of gravity (CG) Because of the til of the axis, Chelyabinsk’s 55° latitude is higher than the 55° by about 18° (due to what you mentioned about Feb 15). So Chelyabinsk is up at about 73° up from the ecliptic, only 17° from being on top of the world.

    “(Actually, the entry point East of Korkino should be drawn on the ecliptic, & Ch a short distance above.)”

    No.

    “The meridian of Ch projects into the plane of sketch as a straight line through Ch and NP aslant from upper right to lower left.”

    No again. Chelyasbinsk’s meridian is the orbit line/arc (actually tangent to it). remember, it is dawn. The Sun being just visible on the horizon, Chelyabinsk is at the day-night boundary. THAT is always on (tangent to) the orbit line/arc – by definition.

    On your sketch, put Chelyabinsk there and then put the object on a path coming straight at that point from the Sun. (It is a little of that, but for simplifying the mentally imaging all of it).

    Note that the path you just drew is not tangent to the Earth. Since it’s interesection with the orbit line/arc is 73° up from the CG, it’s path around the CG will be an ellipse viewed from the top. The object’s path is really tangemt to that ellipse, but still coming out of the Sun.

    What does that tell us? That the object’s pth may be ON that ellipse for some duration. If it comes from below, then if is on the ellipse for a longer duration. If it is on that ellipse for a short duration, then its orbital path around the Sun is VERY different from what the Columbians came up with.

    If the last did NOT happen, then the path was ON the ellipse for a long duration, coming from down below (from below the ecliptic).. But that – on a single wrap-around of Earth – also is incompatible with the Columbians’ orbit around the Earth.

    Since both of those cannot fit with the Columbians’ orbit, and since I am still trying to find a way to connect their orbit with the final apporoach, I can only assume that the transition (Phase 2) came in off-center, and as it spiraled in it wrapped around twice of more, in a convoluted path around the CG.

    But even THAT is going to be impossible, because if the object came by at higher than escape velocity (which they say it did), then it would not have gotten captured unless it had already entered the atmosphere. (It would have needed something to slow it down to less than escape velocity.) But we all know that once it entered the atmosphere it was already headed “out of the Sun” toward Yeklut, as was seen on the videos.. Those videos saw it’s entry as the first visible sign it was here.

    Escape velocity is escape velocity. If it was going fast enough to escape, it would have veered because of the Earth;’s gravity, but kept on going after it passed the CG.

    I thus retract my suggestion that it had to have taken several loops around the Earth. It’s stated velocity as it entered the atmosphere is simply to high toi have been captured and whirled around a few times while its orbit decayed. Unless I am mistaken, an orbit can only decay when it has dropped below escape velocity. Multiple looping orbits are thus incompatible with their stated entry velocity.

    For the life of me, I cannot rectify the Columbians’ orbit at all with the geometry of the final approach. Every attempt I’ve made to bend over and work with what they have, it turns into an absurdity.

    At this point I simply think they got it wrong – which was my first take on it, but I thought I saw a way to rectify the two paths. I was wrong – such rectification is impossible.. “Coming out of the Sun” (which is absolute fact) means a final path at essentially right angle’s to their orbit. AND out of any possible plane that could PUT it on that final path. And every attempt to fit the two together ends up not connecting.

    NO approach from the Earth – on any plane – can deliver the object to that atmospheric entry point AND ALSO make it come from “out of the Sun.”

    If I am wrong, someone refute that statement.

  • Steve Garcia

    Boslough.

    In reading some of his papers last night, I was aghast that he could blithely talk about quartz melt – only ONE proxy – as being an indicator of air bursts, while siding with those who argue that the entire YD suite of proxies are invalid as such.

    I am also amazed that no one has worked on the statistical probability that all those proxies could point at anything BUT an impact. That sounds like a no-brainer paper to write up.

  • Hermann Burchard

    Steve,
    all your “No”s should be “aye”s! My rough drawing of Earth projects the planet on a plane “2D” circle, and its orbit = ecliptic reduces to a straight line for the short duration.

    Wikipedia: The ecliptic is the apparent path of the Sun on the celestial sphere as seen from the Earth’s center, and also the plane of this path, which is essentially coplanar with the orbit of the Earth around the Sun.

    See also my added post, a few minutes later:

    Hermann Burchard

    March 6, 2013 at 11:38 pm

    Off center meridians are not straight lines, but elliptical arcs through NP. This would be the case in a sketch where Ch is not in the center of the circle (as required for a more accurate sketch than mine).

    This line — really a great circle in 3D — is called `terminator’ I think, recalling the term from when we had guys fly to the moon, as it bounds the sunlit side of Earth (no, not Arnold Schwarzenegger). All cities where the Sun rises or sets at the instant the meteoroid hits project vertically onto the ecliptic, including Ch. Etc, etc.

    Perhaps George has an astronomer friend who could make an accurate version of my sketch for posting? Accompanied by an expert legend?

  • E.P. Grondine

    Hi Tom –

    What you refer to as “proxies” are impactites.
    But you are right that the impactities alone will not be persuasive. We are talking about real money here, and the vested inteerests will do everything in their power to keep that part of the federal money which they view as “theirs”.

    What the distribution of impactites can be used for is locating impact craters with shocked quartz. Generally, the impactites appear to be denser the nearer to a crater you are.

  • E.P. Grondine

    I am posting this note on Boslough seperately.
    IMO, he is not that good, or he would be working at Los Alamos or Berkeley, or else at a location other than Sanida.

    In my opinion, from what I know, his motive for his recent statements has been to secure the data processing segment of the Atlas system for the University of New Mexico.

    If you want a first order approximation, the impact data seems to indicate that 30 meter cometissimals explode with 5 kilotons of energy at 5 kilometers altitude, while 60 meter cometissimals explode with 15 megatons of energy at 5 kilometers altitude.

  • Steve Garcia

    Hermann, –

    I am not taking exception to the ecliptic. I am saying that Chelyabinsk was on the “dawn line” – the edge of darkness/lightness. That it perpendicular to the ecliptic – and for all intents and purposes it is on the orbit line, as viewed from above the orbit looking straight down.

  • George Howard

    Thats a damn good point Steve. The Bos’ whole Libyan Desert Glass schtick is based on a single proxy. Stay tuned..

  • Hermann Burchard

    Steve,

    your words here agree with mine:

    I am saying that Chelyabinsk was on the “dawn line” – the edge of darkness/lightness.

    Your “dawn line” is my “terminator.” In 3D it is a great circle, “perpendicular, to the ecliptic plane” but in the 2D sketch it projects onto the line of the ecliptic which I tak to be identical to the Earth’s orbit.

    George,

    to me, the simulation by the Bos of his blowtorch downward momentum flame thrower is still valuable, and was cited by me in the earlier comment above to explain the Chelyabinsk vapor trail with its North and South halves being so amazingly symmetrical, thus exhibiting an internal coherence based on their common genetic origin in the blowtorch event, which otherwise would be inexplicable, — even though his behavior is hard to swallow, not to say despicable. Personally, I had run into the Boslough buzz saw years ago discussing a book with a Russian theory that more CO2 would actually cool the atmosphere (somehow due to the high molecular weight, same for methane). My physics was no match to his as I tried to fill in the gaps in the book. He won.

  • George Howard

    Oh, don’t get me wrong, Herm. I appreciate many of The Bos’ qualities and the vast majority of his work. But the Libyan Desert Glass is a great example of the double-standard he applies when others have their own ideas and evidence. If a relatively uncredentialed Allen West had published precisely the Bos’ work and data on the LDG (limited though it is) — The Bos would have scoffed! And attacked Allen privately.

  • Hermann Burchard

    Yeah, good to hear that, George, about LDG, which I know nothing about . . ..

    His career: indoor science, office desk, and computer programming, might explain why he is not competent to judge your work with the Firestone group on things where kneeling in the wet soil, true talent for observation, and native sense of understanding are required. Similarly he would not be able to publish well on LDG, where you actually need to dig in the sands of the Sahara desert and come up with something new — but I don’t know his paper.

    BTW, sci observation was needed to recognize the amazing vapor trail symmetry
    in the skies above Chelyabinsk Oblast. Besides myself, no one on Tusk has commented on the symmetry, even though I mentioned it several times as here:


    Hermann Burchard

    March 5, 2013 at 9:13 pm

    . . . the plume to me looks a lot like the Boslough blowtorch effect . . . .

  • George Howard

    I know, I know, Herm — and I am dying to post something regarding the “forked tongue.”

    I keep waiting, as I suppose others are, for some analysis of the two twin and merged and morphed dragon tails. But for some reason our discussion here has focused on whether it skipped back out into space???

  • Hermann Burchard

    Sorry about my stubborn error claiming a “grazing” impact, which I had conceded in the same comment, March 5 9:13 pm.

    Perhaps I hid that concession so well that you may have overlooked it? Here it is again, I wish I had made it more emphatic, it’s all about the 20 degree angle of incidence of course:


    BTW, the Orenburg video at 550 km shows the 20 degree angle very clearly. But I still rejected it to the last because I was so sure it was a grazer!

    http://www.youtube.com/watch?v=1EWD5mRkyow

    Almost all of the trail is above the horizon, except for where the trail goes down to 15 km altitude at its termination a few km East of Lake Chebarkul.

    Can I get away with calling this an almost grazer?

  • George Howard

    Were there (mostly) two bodies for most of the film(s)?

  • Hermann Burchard

    Yeah, two downward plumes, tiny, at the start. Perhaps indication of a small jolt upward, then gradually broadening till the big flash point. At the speed it developped there are no videos from that time, only the tail end. As I wrote, this is a coherence signature. Perhaps a small gradient of density explains the lateral, not vertical, symmetry — guess what we need to ask the Bos to sim it for us.

  • E.P. Grondine

    Hi George, Hermann –

    Current debate is between those who think the “plumes” were the result of the diffraction of sunlight by the ablation dust, and the old theory that the “contrails” are the result of the diffraction of sunlight by water vapor condensed around particles of ablation dust.

    (Where ablation dust is the condensate of ablation plasma. You can collect these spherules from gutters, but it looks like they don’t use gutters in Chelyabinsk, so they will probably be dragging plastic wrap covered magnets through the snow.)

    Another possibility is that the ablation plasma’s cooling causes some reaction in the atmosphere.

    In your analyses, remember that the videos were of sunlight and taken on the ground.

    As far as the relationship between Chelyabinsk and DA14, it is possible that some small outlying piece of DA14 hit a part of the February meteoroid stream, leading to a combination shot with a lot of rubber.

  • Steve Garcia

    George –

    The co-pilot of the jetliner it went past said he saw THREE objects.

    The end of the double trail – what was it that kept going? Were there two big ones that took each other out at that big burst, with the third one continuing on?

    Was the third one in there where we couldn’t see its trail?

  • E.P. Grondine

    George, Steve –

    “proxy” is used for the HSIE impactites, that data being a “proxy” for proved surface impacts.

    LDG is not a “proxy”. It is impact glass, data, and contains elements from the impactor which created it.

    Just to clear up some further confusion, at Chelybinsk you had the plumes from surface ablation, and then you had the bright IR release and blast wave from the bolide. Two separate energy conversions.

    Some large fragments of the meteoroid survived the bolide and traveled on at lower speed, but none of the plasma of the bolide did. Most likely this was because of earlier fractures of the meteoroid.

  • E.P. Grondine

    Finally and separately, Boslough’s model. Boslough maintains based solely on ONE data point that the plasma from the bolide conserves momentum.

    The two problems: there are not second data points. And his first and only data point has limited study as to the meteoroid plasma/heat energy distributions within the entire field of it.

    This data is what Boslough would need to verify his computer model.

    Like I said, IMO, he’s not that good.

  • Barry Weathersby
  • Barry Weathersby

    Oops… Delete my name from the end of that URL.

  • Trent Telenko

    >>If you want a first order approximation, the impact data seems to indicate that 30 meter
    >>cometissimals explode with 5 kilotons of energy at 5 kilometers altitude, while 60 meter
    >>cometissimals explode with 15 megatons of energy at 5 kilometers altitude.

    Ed,

    That is an extremely useful set of numbers for FEMA types.

    If you could get some sort of ground foot print based on angle of entry to go with it, you have a 1st responder planning tool.

  • Steve Garcia

    Hermann –

    I found this photo from the airliner (it might possibly have been a second one – not sure):
    http://tiny.cc/w3dptw

    It shows the steep down slope pretty well.

  • Steve Garcia

    http://www.youtube.com/watch?v=R99zvcrqXo8

    Location: Cement plant at Pervomaisky, about 8 km SW of Korkino. From the video – Definitely right under it AND right under the big burst. From other sources Pervomaisky was directly under the path. One burst was

    From my other sources, one burst was 20 km east, and one was 15 km west – and one burst was freaking right over it, exactly.

    A new video to me. People looking at the trail from directly below, when loud bangs are heard. I counted at least seven nearby and three more at some distance, maybe four.

    This implies that they were NOT noises from only the “explosions” above, but suggests to me that fragments were landing nearby.

    I had seen another video that definitely was impacts on the ground. Don’t know why I didn’t posit it here.

  • Steve Garcia

    Ed –

    First of all, did you really mean to say “diffraction of SUNLIGHT”? By the ATMOSPHERE? I am shaking my head if that is what THEY are saying. If you typo-ed that, no problem.

    1. How is SUNLIGHT going to be diffracting when the Sun is behind the tail?

    2. How is sunlight going to be diffracting when there is a more intense light right there to diffract?

    3. How is the atmosphere diffracting on an angle like that – and just HAPPENS to be following along with the meteor?

    At the same time, I am prepared to agree that it IS diffraction, but it IS either the camera lens or windshield.

    In this other “negative” video at http://www.youtube.com/watch?v=h0yUdDjWhLs , the same types of apparent ejecta occurs.

    Note that there is a 180° opposed streamer each time. ONE shoots out straight ahead of the path, and no opposite one appears, but I think it is hidden in the tail.

    Later on the NW-SE opposing rays change angle. That bothered me until I re-ran it, and I could see that the angle to the camera changed: The meteor was farther to the right in the field of view.

    The rays extend down past the tree line, so it can’t be an atmospheric thing.

    To prove my point here that it cannot be the atmosphere, the second part of the video is another dashcam SW of the object. In this video, after the big flare-up, the rays continue – and one of the vertical rays extends down in FRONT of an oncoming car.

    Case closed. I was wrong. There was no ejecta visible – except for the ablation vapors.

    It IS amazing if a 10 meter object can disintegrate without throwing off pieces.

    Let’s consider that for a moment…

    When CO2-bearing magma comes out of a volcanic vent, the magma is pulverized by the escaping high pressure gases. Can we relate that to this? When this flared did the escaping gasses pulverize almost the entire body(ies)?

    Maybe so.

  • Steve Garcia

    Ed –

    I can’t find which post it is on, but you commented something about Peter Brown in the last couple of days or so.

    At something called Tomsastroblog.com, on March 29, Tom quoted the following from ESA:

    At 03:20 GMT on 15 February, a natural object entered the atmosphere and disintegrated in the skies over Chelyabinsk, Russia.

    Extensive video records indicate a northeast to southwest path at a shallow angle of 20* above the horizontal. The entry speed is estimated at around 18 km/s – more than 64 000 km/h.

    According to calculations by Peter Brown at the University of Western Ontario, Canada, drawing on extremely low-frequency sound waves detected by a global network,

    WTF? NE to SW? No no no no no. The bearing was around 279°. The Sun was rising at about 111° – 21° south of due east, and the object’s radiant was to its left (east, as some phrase it). At Ogleearth.com they calculated and came within an eyelash of matching the Columbians’ path – and it had a bearing of over 282°.

    What is with ESA – or is it Peter Brown? – saying the “Extensive video records indicate a northeast to southwest path” six weeks after the event?

  • Steve Garcia

    Guys, I am beating a dead horse of a different color here:

    From Russia Beyond The Headlines (Rossiyskaya Gazeta). Interfax. 5 March 2013:

    “By 5 March 2013 Interfax had reported that the number of damaged buildings had risen to over 7,200, which included some 6,040 apartment blocks, 293 medical facilities, 718 schools and universities, 100 cultural organizations, and 43 sport facilities, of which only about one and a half percent had not yet been repaired.

    The “damage” was almost entirely broken windows breaking and window trim being blown in. Yes, that one video had a garage door being blown in. And one poorly constructed building had its roof (almost certainly with some snow load on it already) cave in.

    We here never did seem to come to a conclusion whether the big boom was a sonic boom or the burst.

    But that does leave the question: If a large supersonic jet had come in low over Chelyabkinsk what kind of damage would it have done?

    My point eventually gets to this: The damage certainly wasn’t a LOT more than what a sonic boom might have caused. Ergo, the burst shock wave was a WHOLE LOT less than the 500 kts or 524 kts we keep being told. NO sonic boom could be mistaken for a 500kt explosion.

  • Hermann Burchard

    Obviously, the missing disaster that you remark on, is due to the long trail at a shallow angle of 20 degrees, as was discussed earlier on this BBS.

    The blow torch/ blast furnace/ flame thrower/ produced .44 Mt spread out over the length of a 100 km trail, or so.

    However, the main airburst with EM energy flash radiation was near Chelyabinsk or Korkino, but at altitude ~20 km (a .44 Mt nuke at 20 km horizontally would be survivable, I am guessing).

    As posted earlier, .44 Mt is the exact kinetic energy of an 11,000 ton rock at 18 km/sec.

  • Steve Garcia

    I have no disagreement that energy that might have approached .44 Mt was dissipated over the length of the trail between the radiant and the big burst.

    I will also agree that at 20 km the remaining kilotonnage was easily survivable.
    From http://blog.modernmechanix.com/untold-facts-about-the-h-bomb/ :

    [Modern Mechanix 1954] “In Hiroshima, more than one-half of the people a mile from ground zero survived the bombing. In Nagasaki, 69 out of every 100 persons at that same distance lived…”

    My latest info is that the height of the big burst was ~23 km. And ground distance was about 35 km from Chelyabinsk. That is line-of-sight about 42 km.

    Korkino was only 7km ground and 24 km line-of-sight, and no real damage.

  • E.P. Grondine

    Hi Steve –

    If you search youtube for “NOVA russian meteor strike” it will likely lead you to copies of the NOVA special on Chelysbinsk.

    It is well worth watching.

  • The Earth’s atmosphere really does protect us from lots of stuff….

    Cool stuff up at Space Daily dot com including:

    Comet to Make Close Flyby of Red Planet in October 2014
    http://www.spacedaily.com/reports/Comet_to_Make_Close_Flyby_of_Red_Planet_in_October_2014_999.html

    and one you should love Steve G about simulation and modeling of early solar system (I’m just kidding man, take a deep breath…)

    The mathematical method for simulating the evolution of the solar system has been improved
    http://www.spacedaily.com/reports/The_mathematical_method_for_simulating_the_evolution_of_the_solar_system_has_been_improved_999.html

    If either of these are reposts I’m sorry without much time to read Tusk while second child shattered elbow and I had long business travel. My usual browsing routine is Space Daily first, to troll for good links to post here. When time is very limited, I don’t review Tusk first to avoid redundant coverage….

    TimH

  • For those who haven’t seen it yet the full PBS NOVA episode is on the PBS video website. See ‘Meteor Strike’

  • George Howard

    Thanks, D.

  • Hermann Burchard

    The 3/27/2013 NOVA video outdated a bit. Pretty much the same story as told on Tusk.

    The trail is a moving mushroom cloud, says the Bos man. Ergo, the longitudinal center split is hollow stem of mushroom, stretched out.

    Most interesting part, infra sound frequency f tells energy E. Least f –> largest E. Needs formula:

    E = c * 1/ f^a, c,a=const ???

    Wikipedia has latest: Main air burst lasted 5 sec, visible spectrum radiant energy alone was .09 Mt. At 18 km/sec the main burst is spread over 90 km.

    Garage door blow down all from pressure wave of powerful blast, no sonic boom to speak off IMHO: Is there even a clear distinction?

  • E.P. Grondine

    Hermann,

    B. does not know what he is talking about, and dealing with his nonsense is a waste of time.

    Peter Brown is presenting (has presented) his latest analysis at the current conference in Arizona. Holsapple and Lawrence Livermore are at the conference as well, as well as DoD.

    The only people not there are those known to be from the “comets and comet fragments do hit” school. But that is the kind of petty BS I learned to expect from Morrison years ago.

    Despite M.’s efforts, there are people at thix conference from the comets and comet5 fragments do hit and have hit school; its simply that M. does not know who they are, and I want to keep it that way.

    This conference is being streamed.

  • E.P. Grondine

    PS –

    The current division between impact geologists and the obervor community is entirely M.’s doing, though he’s had help in doing this.

    For me, there is nothing more contemptable than preventing data from interfering with your theories.

  • More goodies at Space Daily dot com:

    Supernova may have left biological ‘signature’ in ancient Earth
    http://www.spacedaily.com/reports/Supernova_may_have_left_biological_signature_in_ancient_Earth_999.html

    Shocking. Unless you read Tusk.

    TH

  • Dennis that PBS video link to Meteor Strike is a gold mine.

    Good shock modeling of the cook-off and subsequent propagation down to surface. In that sim you can see the convection on the order of 5k meters or so upward of the plume in the time it takes the (faster) shock to reach the surface much further beneath. Of course its only a model.

    The vertical version of the similar impact model shows the convective plume reversing direction and traveling back up the entry “tube”, and larger overpressure at surface. Those hydrocode guys, I think they may be onto something with that “equation-of-state” business….

    Also interesting that a stony asteroid would still drop scorched pebbles out of the fireball. At some level the process eventually loses speed, and so thermal consumption of some portion of mass never happens, however relatively small that remaining portion is. Bunch of little pieces.

    This to me implies signature of impactor to everywhere within the full volumetric limits of the fireball envelop and even beyond, during the fireball process and short time subsequent. There will be a test on this material.

    Still the best line from above linked article:

    “The sediment core contained the isotope iron-60, which does not form on Earth, and scientists said the source was likely a supernova in our cosmic neighborhood, the journal Nature reported Monday.”

    That’s WAY out there. Really. That places the Tusk firmly in the mainstream, getting down to pure statistical probability of supernova dust vs. impact tweaking of everything from continental bio speciation, to hemispheric climate and possibly longer term (1400 yr) global climate. I’m just sayin’.

    Yes it would have to be a big old bunch of barge loads of brew haa raining down. Tough to imagine no surface signature at all, though, even if in secondary proxies only, due to mixing of the (albeit extremely faint) impactor signature with that of the atmosphere/surface during production of effluent from whatever the impact process. Thats the thing, we’re not sure of the process, other than it involves unEarthly high temperatures. Proxy ID then becomes the pursuit…..

    WHen I hear about Iron 60 in concentration, I wonder if Earth may not have produced it one time? Or could our own Sun have belched some out (I know Iron is the death nell for a star so ours not yet near that phase)

    TH

  • Steve Garcia

    Hermann –

    The garage door thing – you find out early on in real world mechanical engineering that it takes very little pressure on an entire large area like a garage door to be able to push it in. Especially when the force is delivered as a quick impulse. That can multiply the effect of the force by a magnitude or more. The shorter the impulse, the greater the magnification of the force.

  • E.P. Grondine

    It looks to me like several people here do not understand the difference between a fireball and a bolide.

  • George Howard

    Ed, quit the smartest guy in the room schtick.

  • Steve Garcia

    Oy vey.

    Ed, thanks for the YouTube suggestion. I was able to watch the NOVA meteor episode.

    However, I learned basically nothing from watching it that I didn’t already know, except that Boslough did his precise mapping of the path. That was basically sound science. (But why weren’t other scientists also doing that? We should have at least a handful of such studies to compare to each other, narrowing down the final path even more.)

    But I saw some GLARING errors and inconsistencies.

    Peter Brown [08:25] was pulling numbers out of his head (“My first estimate was about 40 or 50 kilotons, based on just sort of an estimate”) – all that proved to be terrifically wrong – even before he had gotten any evidence upon which to base anything on. BAD science. Good honesty to admit it on camera, but bad science. It should have been edited out – by Brown himself if given a chance to review what he had said. It shows how when even “those in the know” jump to conclusions without evidence, they can be so far off as to be no better than guesses by people off the street using their wet thumbs up in the air. So the next time you hear a scientist pontificate on some phenomenon without looking into it, remember Peter Brown and his hip shooting on this event. Pulling numbers out of one’s butt is exactly that – no matter HOW “in the know” a person is. When he could be off by an ENTIRE MAGNITUDE, Mother of God, that is bad.

    He then had the balls to actually say “We wanted to give people an informed idea” from “those with past experience,” when he and everyone involved say over and over again, “this was unprecedented” and “this is a once in a lifetime” and “this was the biggest in one hundred years.” How exactly does any of that translate into past experience?

    More later. I was VERY underwhelmed by the scientists on the show. Typical NOVA – aiming for the 4th graders.

  • E.P. Grondine

    Hi George –

    “Fireball” and “bolide” are fundamental terms in impact science. While I am no longer the smartest guy in the room, understanding those words is essential in this field of science.

  • Trent Telenko

    This link gives a working definition of “Fireball” versus “Bolide.”

    http://en.wikipedia.org/wiki/Meteoroid

    I broke up the wall o’ text for easier reading.

    Fireball

    — A ‘fireball’ is a brighter-than-usual meteor. The International Astronomical Union defines a fireball as “a meteor brighter than any of the planets” (magnitude −4 or greater).[21]

    The International Meteor Organization (an amateur organization that studies meteors) has a more rigid definition.

    — It defines a fireball as a meteor that would have a magnitude of −3 or brighter if seen at zenith. This definition corrects for the greater distance between an observer and a meteor near the horizon. For example, a meteor of magnitude −1 at 5 degrees above the horizon would be classified as a fireball because if the observer had been directly below the meteor it would have appeared as magnitude −6.[22] For 2012 there were 2126 fireballs recorded at the American Meteor Society.[23] There are probably more than 500,000 fireballs a year,[24] but most will go unnoticed because most will occur over the ocean and half will occur during the daytime.

    — Fireballs reaching magnitude −14 or brighter are called bolides.[25] The IAU has no official definition of “bolide”, and generally considers the term synonymous with “fireball”. Astronomers often use “bolide” to identify an exceptionally bright fireball, particularly one that explodes (sometimes called a detonating fireball). It may also be used to mean a fireball which creates audible sounds.

    — In the late twentieth century, bolide has also come to mean any object that hits the Earth and explodes, with no regard to its composition (asteroid or comet).[26] The word bolide comes from the Greek βολίς (bolis) [27] which can mean a missile or to flash. If the magnitude of a bolide reaches −17 or brighter it is known as a superbolide.[25][28]

    What I found interesting at the same text-link was the following table

    Reported Fireballs[20]
    Year #Fireballs
    2012 2126
    2011 1631
    2010 951
    2009 694
    2008 726

    …which confirms my observation that more of these events are being reported, for whatever reason.

  • Steve Garcia

    Trent –

    Good stuff.

    There is a glossary tab at the top of the page. Right nmow it has only one comment/glossary definition.

    It might actually be a good idea here to take your comment and paste in into a comment there.

    I’d never gone to that link. Perhaps we should all add items to that when we run across definitive stuff. (duh…)

  • E.P. Grondine

    Hi TT –

    http://www.theonion.com/articles/wikipedia-celebrates-750-years-of-american-indepen,2007/

    You may want to check the meteorite list archive for the discussions of those definitions.

    The Chelyabinsk videos have pretty much brought those discussions and the confusion to an end.

    Note carefully the light output levels.

  • Steve Garcia

    Ed –

    Which meteor list archive and discussion are you talking about. You keep tossing out references without giving links, so it is impossible to follow up on.

  • E.P. Grondine

    Hi Steve –

    Google “meteorite list archive” “bolide” and “fireball”.

    I get so many questions that I casn not provide you personally with more than that right now. I may have archived those discussions myself on my home machine, but if so it will only be possible to send them to you later, if you are real nice and polite between now and then, and I have time to retrieve them later.

    If your income and livelyhood depend on the knowing the difference between a bolide and a fireball, then you know it. Strewn fields are not a matter of recreation or “simple” curiousity for some people.

  • Trent Telenko

    This is another quick link to go too —

    http://www.amsmeteors.org/fireballs/

  • Trent Telenko

    Here is another important link —

    http://www.purdue.edu/impactearth

    It is the University of Purdue’s >Impact Earth!< Impact calcualtor.

    Now anyone can play at bolide yield what ifs.

  • Trent Telenko

    I saw this over on Instapundit:

    http://www.abc.net.au/news/2013-08-27/meteor-russia-sun-earth-crater-space-aliens/4914156

    The meteor that injured more than 1,500 people when it exploded and showered debris over Russia in February may have had a close shave with the Sun earlier, researchers said.

    A study of its composition showed the space rock had undergone “intensive melting” before entering Earth’s atmosphere and streaking over the central Russia’s Chelyabinsk region in a blinding fireball, they said in a statement.

    This “almost certainly” points to a near-miss with the Sun, or a collision with another body in the solar system, possibly a planet or asteroid, study co-author Victor Sharygin from the Russian Academy of Sciences’ Institute of Geology and Mineralogy said.

    The findings were presented at the Goldschmidt geochemistry conference in Florence, Italy.

    Does this affect any of the earlier findings on the trajectory of the Russian fireball?

  • Steve Garcia

    Like I said:

    The orbit they told the world was on not so far different from the Earth’s, one that the Apollos have. Those orbits are nearly circular. If it grazed the Sun, then by definition it had to have a highly elliptical orbit. You can’t have both.

    Such an orbit could not hit the Earth on its leading side “on its windshield, near the top” – which the Chebarkul object did. It was impossible to match the final path and the earlier orbit.

    It is, of course, possible that they are misreading the evidence now. But I am certain that they would know that the physical evidence they are presenting contradicts the earlier orbit, so they would have known they needed to be extra sure of their evidence before they published.

    This evidence trumps that orbit.

  • I have to research the Apollos, but I can tell you that orbits can be changed radically over time by resonances with planets and long term perturbation.

    The key to remember with sun or iting objects is the immense time over which these objects are exposed to the effects in question – small forces but huge integration times add to significant dynamic change. Tough to comprehend the time scales over which these bodies are exposed.

    Secular perturbation can evolve an orbit into resosnance with a planet (2:1 w Jupiter being a common example), at which point crazy things can happen very quickly in terms of orbit transformation, with energy transfer happening over an extremely short period, even one or just a few orbits.

    That can throw a heliocentric orbit straight out of the solar system, or drop it straight at the sun by giving it or taking away from it the right quantity of orbital mechanical energy.

    So circular orbits can end up highly eccentric. It’s nuts but its been studied for a long time, and even has analogs in stability of matter, particle physics.

    Also remember that it could have encountered the Sun many times and/or an immensely long time ago.

    and

    When it appeared to come nearly out of the Sun’s direction, that observation was an apparent direction, a combined result of both the bolide’s motion in space and of Earth’s. Earth alone moves about 10 of its own diameters through space every hour. This always confuses the observation. Lots of relative motion and a lack of local inertial reference.

    I’m not trying to say anyone’s right or wrong, just throwing out tidbits of my own experirnce from my Comsat fleet ops days as an or it analyst and from my work with the mission planners on the Mars Observer interplanetary mapping spacecraft.

    TimH

  • Steve Garcia

    Thanks, TH –

    Yeah, the Sun grazing could have been a long, long time ago. Are there any tests to gauge that by?

    The bit about “appearing” to come out of the Sun’s direction – there really was not “appearing” about it. It did. I think your point was that even though its final approach came from Sun-ward, its previous orbit could have been far different. No argument there. But for its final flight path to be coming from where it did, the center of gravity of the Earth had to have put it on a Great Circle path or damned near it – meaning the landing point, the initial sighting and the center of Earth had to define a plane. And that plane ain’t NOWHERE near coming from the Apollos, from behind the Earth’s track.

    NO ONE that I’ve seen has yet tied the intitial orbit given by the S American guys to the final path. I don’t remember all the details now (they are posted here somewhere), but I’ve said this since day one, and no one has listened to me. I don’t give a crap anymore, but the orbits given to the world are wrong. Period.

  • Trent Telenko

    Physicist Mark Boslough of the Sandia National Laboratories is revising and extending is remarks on Chelyabinsk.

    See:

    http://www.wired.com/wiredscience/2013/10/chelyabinsk-frequent-impact/

    But meteors explode in a very different way than a typical nuclear bomb, says physicist Mark Boslough of the Sandia National Laboratories, who studies asteroid impacts and is presenting a talk today about the Chelyabinsk event at the American Astronomical Society’s 2013 Division for Planetary Science meeting in Denver.

    “When an asteroid explodes, its momentum is conserved and that explosion continues down toward the Earth,” Boslough said.

    For that reason, the people who live in Chelyabinsk explosion are very lucky to be alive, he added. If the bollide had come into the atmosphere at a less steep angle, its blast would have been aimed right at the ground, likely doing much more damage.

    That an airburst continues traveling in the same direction as a meteorite was only appreciated starting in the 1990s, particularly after the impact of Shoemaker-Levy 9 on Jupiter.

  • Steve Garcia

    The Russian meteor wsa in the news again recently.

    On October 16, divers found the biggest piece of the meteor, weighing 670kg, at the bottom of Lake Chebarkul. Strange how long it took…

    And four days ago there was this:

    http://www.space.com/23487-asteroid-threat-earth-russian-meteor-explosion.html

    “It deposited much less material than expected,” [Peter] Jenniskens [NASA Ames] told SPACE.com. “That’s similar to what was seen with Tunguska, where nothing from the impactor survived.”

    A question I have not heard is:

    If the Chelyabinsk meteor fell about 74km away from the big explosion, had anyone ever looked downfield that far for a remnant of Tunguska? Yes, in 2013 it blew up much higher, so the distance was more. But it should be some sort of guide for possibly finding a Tunguska remnant, after all these years.

  • Trent Telenko

    Found via Instapundit:

    Russian Meteor, from Birth to Fiery Death: An Asteroid’s Story
    By Mike Wall, Senior Writer |
    December 10, 2013 07:20pm ET

    http://www.space.com/23915-russian-meteor-asteroid-history.html?cmpid=514648

    SAN FRANCISCO — The asteroid that exploded over Russia earlier this year died as it had lived — in a welter of chaos and violence.

    Scientists have pieced together the history of the space rock that slammed into the atmosphere over the Russian city of Chelyabinsk on Feb. 15, creating a shock wave that injured 1,200 people. It’s a long, convoluted tale that picks up just after the solar system started coming together 4.56 billion years ago.

    Molten droplets that found their way into the Chelyabinsk object formed within the first four million years of solar system history, David Kring of the Lunar and Planetary Institute in Houston said here Monday (Dec. 9) at the annual meeting of the American Geophysical Union. [Photos: Russian Meteor Explosion of Feb. 15, 2013]

    Over the next 10 million years, these tiny pieces, along with generous helpings of dust, coalesced into an asteroid on the order of 60 miles (100 kilometers) wide. Textures spotted within pieces of the Chelyabinsk asteroid recovered here on Earth reveal that the rock was likely once buried several kilometers beneath the surface of this larger object, which scientists call the LL chondrite parent body, Kring added.

    Further, analysis of “shock veins” within Chelyabinsk meteorites indicate that the parent body suffered a major impact about 125 million years after the solar system started forming.

    And the hits kept on coming, with the parent body absorbing strike after strike between 4.3 billion and 3.8 billion years ago, Kring said. (Earth and other planets in the inner solar system were also pummeled during this period, which is known as the “late heavy bombardment.”)

    The LL chondrite parent body apparently then got a break, and was left alone to lick its wounds for a few billion years. But meteorite fragments record evidence of two more large impacts in the last 500 million years, with one of them coming between 30 million and 25 million years ago.

    The next big event for the parent body had consequences for people on Earth as well.

    “The meteoroid then encountered a gravitational resonance in the asteroid belt, and that altered its orbit,” Kring said. “So at that point, it moved from being a main-belt asteroid to being a near-Earth asteroid.”

    Work published just a few months ago indicates that the Chelyabinsk asteroid was exposed to space just 1.2 million years ago, suggesting that yet another impact occurred around that time, Kring added.

    This collision perhaps finalized the size of the space rock, which is thought to have measured about 65 feet (20 meters) wide when it entered Earth’s atmosphere.

    “And finally, of course, we have one more collisional event, on Feb. 15, 2013,” Kring said.

    While the Chelyabinsk asteroid met its end that day, other fragments of the LL chondrite still exist out in the depths of space. One such chunk is the 1,770-foot-long (540 m) asteroid Itokawa, which Japan’s Hayabusa spacecraft visited in 2005, gathering samples that were returned to Earth five years later.