New Evidence Supports Impact Theory of Moon’s Creation
It’s long been theorized that the moon was created when a Mars-sized proto-planet slammed into the Earth. Unfortunately, though, the chemistry of the two bodies has stubbornly failed to bear this out. Now, though, two very different models of such a collision have been developed, both explaining satisfactorily – but incompatibly – how the Earth-moon system ended up as it did.
The big problem with current models is that they predict that the Earth and moon should have different oxygen isotope compositions, as much of ther material for the moon would have come from the impacting body, sometimes known as Theia. Observations, though, have shown that they don’t. But a new model developed by the Southwest Research Institute matches reality rather better, by assuming that the impactor was much bigger than previously believed.