myrmepropagandistJan 12, 2023

The moon formed when Theia hit the earth. The surface of the moon is mostly material from the #earth with the same isotopes... but if we could drill into the moon... we could find some of #Theia according to some models of the collision.

Theia is still here! Just covered in a super thick earthy sweater.

I don't know why I find this so exciting-- it's probably not going to be anything shocking...

I guess Theia always seemed... vanished into the deep past. But Theia remains. #musings #moon

Show threadberndandewegJan 12, 2023
@futurebird but it remains a mystery still why the moon in chemistry and isotopes resembles so much our mantle. If you want to cover Theia with earth material, the moon should be more dense than it is. So the only possibility is that Theia (if it existed) should have had nearly the same composition as Earth.
Show threadSam Adams
@berndandeweg The Moon's gravity could account for the lower density, couldn't it?
Jan 12, 2023 at 12:21pmWeb
Show threadberndandewegJan 12, 2023
@Sameagle Theia would still have a higher density than Earth mantle in thar case. Isn't it?
Show threadSam AdamsJan 12, 2023
@berndandeweg I don't know. I think any meteorite has a higher density or it wouldn't survive the trip through our atmosphere, but I'm by no means an expert. My question about the density of the moon had more to do with material from Earth ejected into space and collecting around remains of Theia. Since smaller mass equates to lower gravity, I was asking whether that would cause a lower density of the material compacted around the core. I don't know the answer, but it seems logical to me.