At the centers of some galaxies (including our Milky Way) there are super massive black holes.

Do you see the big cloud of gas in the center?  Behind that is a black hole!  But how did it get there?  Well, early in the universe’s life, there were many black holes, which collided, making bigger black holes.  Those black holes pulled in gas, making stars.  Start watching at 26:22 and stop at 29:03.

https://www.youtube.com/watch?v=cKSncLxC9lc

Now this raises a question.  If we’re orbiting a black hole, why aren’t we sucked in?  Well, it’s for the same reasons that the Earth isn’t sucked into the sun: there’s no friction in space and we’re far enough away.  Our solar system isn’t rubbing against anything so it’s not going to lose energy, and it’s far enough away from the black hole that it isn’t pulling super hard on us.  In fact, we’re this far away ——————————->