Are We Weird or Typical?

One of the really fun things about modern astronomy is that we are now able to use our telescopes to study planets around other stars. This gives us this amazing window into the question of whether our solar system is weird or typical. It's an interesting question because it could be that maybe other solar systems out there in the universe are totally different than ours, right? If you were an astronomer in a far away solar system studying hours and you could measure the density of Earth and the density of Jupiter, that would tell you, oh, one of those is probably a gas planet," he says.