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True. So was it likely that it was this Jupiter incursion that sent the "Mars-size planet" to the Earth, creating the Moon? Also, I read somewhere, a few year

True. So was it likely that it was this Jupiter incursion that sent the "Mars-size planet" to the Earth, creating the Moon? Also, I read somewhere, a few years ago, that the core of said "Mars-size planet" survived the collision, and ended up as Mercury. As I recall, part of the argument was that by composition, Mercury looks like a core, not a planet (not even a near-solar planet). And there perhaps was some isotopic evidence. Maybe also some compositional mass-balance argument like "'proto Earth' + 'Mars-size planet' <> Earth + Moon". There being missing iron etc.

kijin 7y ago
The jumping Jupiter scenario is usually associated with the Late Heavy Bombardment, which is half a billion years too late for the age of the Moon estimated by OP. But of course there are disagreements about when Jupiter did its thing. There's a lot of variance in "Mars-sized", so I wouldn't count on an easily noticeable mass-balance match. Mars, Mercury, and the Moon are all very small compared to Earth. Earth is more massive than all of the other rocky planets and the Moon combined, and yes, that includes Venus.