One of the most amazing things about astronomy is simply the fact that we understand so much about it. That wasn't true at first, of course. Our minds were curious, our telescopes got better, and then our ability to program computers with equations really helped us leap-frog ahead. Now we can observe objects, feed their parameters into computers programmed with the physics, and see what happens.
Because of this, we understand star formation.
Stars form in clouds of gas. The cloud is sitting there, its gravity balanced by pressure, until something happens to upset that balance. The cloud collapses, and stars form in various parts of it. But what are those "somethings" that happen? Well, clouds can collide with each other, for one, or a nearby supernova can slam them with high speed ejecta that can also trigger collapse.
And even cooler? Now you can see this for yourself with The Star Formation Game! In this game, commissioned byThe Hive Overmind Discover Magazine, you start with a gas cloud, and click where you want to detonate supernovae, corralling the gas. Do it right, form stars, and you move to the next level. Do it wrong, and the cloud dissipates, and you fail in your godlike powers of birth and death.
The game was crafted with the help of astronomer Adam Frank, who also wrote a companion piece to it. It's actually a fun game, and just to let you know, I suck at it. I can't seem to break 1000, but clearly there are ways to rack up lots more points. Give it a try and find out!