The Galilean Cannon experiment supposedly models how supernovas work. Could someone possibly explain how the concepts correlate in simple terms?
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The [Galilean Cannon](https://en.wikipedia.org/wiki/Galilean_cannon) is basically a demonstration of the conservation of momentum. Create a stack of increasing size balls, then drop them from a height. The small ball shoots up a lot higher because the momentum of the entire stack is conserved and transferred to the small ball.
Stars have two competing actions: fusion, which wants to push things out, and gravity, which wants to pull things in. For most of the life of a star, fusion is enough to keep gravity at bay, but the price for that is turning hydrogen into heavier elements that don’t want to fuse. At the end of a star’s life, there’s not enough fusion going on to resist gravity wanting to crush things. Once the tipping point is reached and gravity wins, things happen *very* quickly. Like the stack of balls in the Galilean Cannon, all the layers of the star go rushing to the star’s core and compacting. Once things can’t compact anymore, they explode outward, resulting in a supernova, and when you consider the sheer amount of mass in a star, that results in a huge momentum transfer. That means that the outer layers gets blasted out at near light speed.
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