Today Phil talks about distances, going back to early astronomy. Ancient Greeks were able to find the size of the Earth, and from that the distance to and the sizes of the Moon and Sun.

Astronomy is weird. Everything we study is really, really far away. So far away really, that for most of history we didn’t know how far away they were.

Along with Crash Course Astronomy, there’s going to be a new U.S. government series hosted by Craig Benzine (aka WheezyWaiter).