On 01/02/2016 5:27 PM, Steve Willner wrote:
In article ,
Yousuf Khan writes:
My question is, if the isotopic evidence which was used to create the
Theia Hypothesis in the first place, due to a previously perceived
difference in isotopic abundances,

The isotope ratios are _at least_ very similar, now seemingly
identical within measurement accuracy. This tends to support the
Theia hypothesis. If the Moon formed on its own and was somehow
captured by the Earth, it would be expected to have very different
isotope ratios.

The Moon capture hypothesis was only one such hypothesis. That one would
still be excluded by this recent finding.

Other ones that would still be viable are the Fission hypothesis, where
the Moon was once a part of the Earth, but due to an imbalance it
pinched itself off of the Earth. This would certainly maintain identical
isotope levels between the Earth and Moon.

Another one is the Condensation Hypothesis, which suggested that the
Earth and Moon formed from the same section of the original solar system
nebula. So basically the two worlds evolved together as a twin planet
system. This would also pretty much maintain identical isotope levels.

This site even says that if the isotope levels are different, then the
above theories would be unlikely, but now that the isotope levels are
similar, those theories come back into play.

Theories of Formation for the Moon
http://csep10.phys.utk.edu/astr161/l...formation.html

Yousuf Khan