Also, a recent paper shed some doubt on the impact theory (apparently Earth and Moon isotopes are too similar), so the impact might not have happened or it might have been different than previously thought (glancing and causing the proto-Earth to spin itself apart, or strong enough to completely melt and mix both objects).

In any case, though, yeah, Mars has the wrong composition, size, and orbit for it to have been involved in any impact with Earth. The mistake probably came from Theia often being described as ‘Mars sized’.

[–] notfromhere@lemmy.ml 3 points 3 weeks ago (1 children)

I think they mean Mars could be Theia.

[–] Zron@lemmy.world 1 points 3 weeks ago (1 children)

I think the fact that it’s really far away, in a circular orbit, and doesn’t have a big chunk missing is still a good sign that mars isn’t theia

[–] notfromhere@lemmy.ml 1 points 3 weeks ago* (last edited 3 weeks ago)

Why would it have a chunk missing after all this time? If it did could we even tell? Whatever it was isn’t still in the area so being far away may not mean much. Circular orbit is probably biggest reason it’s likely not Mars, although it could have evened out relatively recently.

This simulation shows the Mars sized object merging with Earth so there goes that theory.