The universe is a huge, complex, beautiful-yet-terrifying place, and we've spent a lot of time studying it. While some of the more complex models of the universe call for super-computers and tons of processor power, MinutePhysics has one you can run on your laptop.
Sure it's not the most accurate model of the universe there ever was, but for something that you can whip up in After Effects and run on a laptop, it's not a bad substitute. And there's nothing quite like having your own pet universe (model). [YouTube]