dougettinger wrote:Is the oxygen isotope ratio considered uniquely different for each orbital distance from the Sun as you hinted?
It is different for materials that appear to have been created under different conditions. The most common assumption is that it is related to differences in the presolar and parasolar nebula, which probably means differences in radial position. But there are a lot of unknowns. I'd say nobody is very confident what it all really means.
Is this ratio linear between the Earth-Moon, Mars, and the Asteroidal orbital regions?
I don't think so. One problem is that there isn't enough material to test to get good statistics. Very little material is associated with bodies which have a known position of formation (none, in fact, but some can at least have reasonable guesses applied).
Is there any chance that the Later Heavy Bombardment was caused by ejecta from the Earth-Moon collision scenario 3.9 bya?
I've not heard it suggested. Something like the Nice scenario or some other perturbation induced scenario seems to be much more likely. Most debris from the collision that created the Moon would probably be ejected from the Solar System completely, or end up in the inner System where it would have been cleared long before the LHB.
[quote="dougettinger"]Is the oxygen isotope ratio considered uniquely different for each orbital distance from the Sun as you hinted?[/quote]
It is different for materials that appear to have been created under different conditions. The most common assumption is that it is related to differences in the presolar and parasolar nebula, which probably means differences in radial position. But there are a lot of unknowns. I'd say nobody is very confident what it all really means.
[quote]Is this ratio linear between the Earth-Moon, Mars, and the Asteroidal orbital regions?[/quote]
I don't think so. One problem is that there isn't enough material to test to get good statistics. Very little material is associated with bodies which have a known position of formation (none, in fact, but some can at least have reasonable guesses applied).
[quote]Is there any chance that the Later Heavy Bombardment was caused by ejecta from the Earth-Moon collision scenario 3.9 bya?[/quote]
I've not heard it suggested. Something like the Nice scenario or some other perturbation induced scenario seems to be much more likely. Most debris from the collision that created the Moon would probably be ejected from the Solar System completely, or end up in the inner System where it would have been cleared long before the LHB.