One day, when I was a teenager, some friends and I had several boxes of those snaps that you throw on the ground during fireworks season. For some reason, we decided to come up with a creative way to use them. In the end, one of us (possibly me; I have largely repressed my memory of the incident) suggested that we unwrap them all and combine their minuscule amounts of gunpowder to make a super snap. So, we got a paper towel and sat on my friend Krista’s porch, unwrapping the snaps and pouring their contents onto the paper towel. Star formation is very interesting, aside from all the math. It turns out that one way a star ignites is through gravitational collapse , which occurs when the mass of a dust cloud becomes so great that it collapses in on itself, heating up to the point that the fusion reaction begins. So anyway, there we were, sitting on the semi-enclosed porch, with our heads close together over the ever-growing pile of explosives . And then the pile reached the Jeans mass , ...