New Source of Comets - the Asteroid Belt ?
Found on the Planetary Society Blog:
So far, it has generally been assumed that all comets originate from the other two known reservoir regions: the Oort cloud and Kuiper belt. The main asteroid belt is home to, well, asteroids, not comets. But Hsieh and Jewitt have proven that there are comets in the main asteroid belt, and that they almost certainly formed there.
Pretty interesting given that the current assumption is that all water on Earth arrived via cometary bombardment early on in the life of the solar system.
You can read more on Henry Hsieh’s website and peruse the abstract of their paper “A Population of Comets in the Main Asteroid Belt” from Science Magazine.
April 30th, 2006 at 1:27 am
It seems that comets don’t exactly follow their action scripts too assiduously, either.
For example, (http://www.seds.org/sl9/sl9.html) the 22-ish fragments of Shoemaker/Levy-9 blew up BEFORE they [brightly, against predictions] hit Jupiter (and this is in addition to the big disassembly into those 22-ish dusty chunks some time before the main set of — for lack of a more precise word) impacts on the big planet, and Deep Impact mission’s noisy cometary impact (http://www.nasa.gov/mission_pages/deepimpact/main/) on Tempel-1 was a little, er, different as well.
That’s only a couple of the more famous cases. Dear old Hubble is one of scores of other scriptophobes also recorded (http://www.space.com/scienceastronomy/solarsystem/ds1_rendezvous_010916.html). That mission also took snapshots of both SM/L-9 and Tempel-1 comets, although these were not primary mission goals.