One development which throws the recent 'Big Splat' giant impact theory into doubt is the recent detailed analysis of moon rocks carried out by cosmochemist Junjun Zhang from the University of Chicago in 2012.

This analysis shows that many of the isotopes found are identical to that of the Earth. If the giant impact scenario was correct the composition of terrestrial and lunar rocks would differ, with different amounts of isotopes of the same element, as they did not all come from the Earth.