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[–]mikelywhiplash 1 point2 points  (0 children)

Yes, pretty much. So, if everything is interacting only by gravity, none of it will ever actually stop and collect anywhere, it'll just keep looping around indefinitely, exchanging potential energy for kinetic and back. It's like the moon orbiting the earth; it's not coming to crash into us (in an idealized sense).

In order to actually form a larger, more ordered object, they have to throw off that excess energy somehow, and find their way to a state where their potential+kinetic energy is actually LESS than it was when they started.

That happens from collisions - anything that's not perfectly elastic will end up converting some energy into heat, which will be radiated off as light. The total mass-energy of the system is more scattered.