The hypothesis is that a planet called Theia smashed into the Earth and parts of Theia and the resulting debris eventually clumped back together into a separate celestial object that we now know as the moon. If that’s the case then parts of Theia ended up in Earth and parts of Earth and Theia ended up forming the moon.
With an impact like this, it’s probably more correct to say that the impact of Thea and Earth formed two bodies, that we now call Earth and Luna (the moon). Earth has a lot fo Thea and the thing formerly known as Thea has a lot of Earth. They basically become two liquids impacting and swirling around. The cores are largely the same, but the sarfaces are a bit of a mix.
The hypothesis is that a planet called Theia smashed into the Earth and parts of Theia and the resulting debris eventually clumped back together into a separate celestial object that we now know as the moon. If that’s the case then parts of Theia ended up in Earth and parts of Earth and Theia ended up forming the moon.
With an impact like this, it’s probably more correct to say that the impact of Thea and Earth formed two bodies, that we now call Earth and Luna (the moon). Earth has a lot fo Thea and the thing formerly known as Thea has a lot of Earth. They basically become two liquids impacting and swirling around. The cores are largely the same, but the sarfaces are a bit of a mix.