Galaxies are created from dust clouds that are floating random in space and as they come near each other, they ‘clump’ together. As they continue to clump together, they build up ‘matter’ and as this matter builds, gravity is created.
When gravity builds, it attracts more dust and matter to the point that stars and planets are created, resulting in solar systems. All staying in place by an invisible force in the center of the galaxy, called a black hole, where the creation of the galaxy all began.
Our Milky Way galaxy is over 100,000 light years long, so to put this in perspective, if you traveled at the speed of light it would take you 100,000 years to go from one end to the other.
There are over 100,000,000 galaxies in the universe. All consisting of hundreds of millions of stars and solar systems. Some are over 13 billion light years from Earth, so if you were to see microbes (early life) on a planet in a solar system that is in a galaxy that is 13 billion light years from here, you are looking at them 13 billion years ago.
No doubt that civilization has advanced way beyond anything we can imagine. What’s more, that galaxy may not even be in existence anymore, along with the intelligent life that was on it. The galaxy could have collided with another galaxy forming a new larger galaxy or could have simply reached its life cycle and dispersed back into dust and random matter due to other universal forces at work.
It is estimated that our Milky Way galaxy will collide with our neighboring Andromeda galaxy in about 4.5 billion years. Are you ready?