6 ms·
I still don't think anyone would think 2.5 billion years ago would be recent, on a body that is only 4.5 billion years old. 2.5 billion in the past is less than
by spfzero 5y ago
I still don't think anyone would think 2.5 billion years ago would be recent, on a body that is only 4.5 billion years old. 2.5 billion in the past is less than mid-point in the moon's age, closer to the beginning than the end.
- garmaine 5y agoTo a planetary scientist who is familiar with lunar geology, yes that is recent. It was widely believed after Apollo that the lunar core shut off and plate tectonics stopped soon after formation. 2Gya is a long time from now, but it is also almost equidistant from lunar formation. So the title here ought to be “the Moon was geologically active for almost 2 billion years after formation” which IS surprising.
- spfzero 5y agoThanks for the insight.