#428 – Sean Carroll: General Relativity, Quantum Mechanics, Black Holes & Aliens

4280.257 - 4300.41 Sean Carroll

You found that you could explain that motion by positing something very simple. One more planet. In a very, very particular place. And you went and looked for it, and there it was, right? That was the first successful example of finding dark matter in the universe. It's a matter that we can't see. Neptune was dark. Yeah. There's a difference between dark matter and dark energy, right?