Space Mystery | Where did Galaxies come from?

We live in a galaxy called, the Milky Way, and when we use telescopic eyes to look into space, we see galaxies everywhere. We see big ones, small ones, richly detailed spirals, and bulbous ellipticals, loner galaxies, galaxies about to collide. There are about millions of galaxies containing billions of stars containing trillions planets in them.



Science has only recently been able to explain where the stars and planets came from that is formed by the galactic dust and gases. Now the heads are thinking of a much bigger mystery, where did galaxies come from? We know galaxies are not scattered randomly throughout space like stars rather they are found in clusters. There are two main theory regarding this.



First, the gas left over from the big bang clustered together to form galaxies, in which stars and planets were born.
Second is that gas from the big bang created stars and planets all over the universe, and they migrated through gravity into galaxies.

However, none of the theory has been universally accepted yet and scientists are still struggling to answer it.



Second theory is more baseless since universe is expanding at a very high rate and it's not possible for planets and stars to come around and form a galaxy while the universe expands.



The question is how after the big bang galaxies comes to exist.


In short how are solar system was added in Milky way galaxy and why it didn't went to any other galaxy?


What If ever earth was situated in a lunar galaxy?