Origin of Asteroids

Good ol' Walt!My favorite parts of his "theory" are:
1) Asteroids would of necessity have chemical and isotopic compositions like Earth's crust - and they don't.
2) Asteroids launched from the cannon of the midocean ridges would all be on earth-intersecting orbits - all of them don't seem likely to have gotton promoted to new orbits on the first time around. Noah would have needed to dodge a lot.
3) Launched by superheated steam.....how did that cool before falling back to earth, again? Radiation into a vacuum, with no heat directed arkwards?

Not membership, just free registration: everything from '96 to a year before today is open access. PNAS is even a better deal - they're free from 1915.

Back to the OP, it just occurred to me: the Main Belt asteroids all orbit direct - in the same direction as the Earth. In Walt's scenario, they were "launched" by a huge explosion along the earth-girdling mid-oceanic ridge. How did they all end up in similar orbits with differences of at least 50,000 miles per hour of orbital velocity at launch? The ones that took off at 6 AM local time would be going at earth's orbital velocity plus escape velocity (25,000 mph), while the ones leaving the opposite side of the earth at the same time would be going orbital minus escape.'Course, this is mighty like worrying about how many invisible pink unicorns can stage their own Kentucky Derby around the edge of a pore on the butt of a manticore.....

I'm sure you're correct - the ones launched "backwards" could have all fallen into the sun, for instance. And yup, the rest would pretty much all fall back to earth after an orbit or so, just when ol' Noah was sending out ravens and such. They'd fall hard, too.