This is not breaking news, but rather a brief breakdown of information gleaned from David Shiga’s great New Scientist article last week regarding the findings of the recently launched WISE infrared space telescope. The information from the article, though unattributed, is presumably from the mission scientists themselves:
In its first six weeks of observations, it has discovered 16 previously unknown asteroids [comets ed.] with orbits close to Earth’s. Of these, 55 per cent reflect less than one-tenth of the sunlight that falls on them, which makes them difficult to spot with visible-light telescopes. One of these objects is as dark as fresh asphalt, reflecting less than 5 per cent of the light it receives.
If I read the information correctly, half the comets WISE is findng are extraordinarily dark — and one is damn near black. Presumably (again) these objects are not easily identified with commonly employed asteroid search methods; search methods (and data) upon which asteroid impact frequency science is largely based. Therefore, 55% of the objects found — in six weeks — are not objects we can expect to have been included in current calculations of impact hazards.
I’d like to hear from JPL or David Morrsion on this subject. I’m getting a lot of cool international hits lately — perhaps I will.