Thank you for the response. I thought the Milky Way was born as a result of collisions within a Nebula (I may be wrong). If so, both the sun and thereafter, the Earth (with its core) should have also originated from this Nebula?
Thus, this doesn't make sense: "almost every atom the Earth is...
I've recently been told by my mentor that the source for all energy is the Sun, which makes sense if were talking about chemical energy in photosynthesis, solar energy, etc. However, if we think about a meteorite which is due to hit the earth, surely we cannot say it got its energy from the Sun...