The solar system, let alone the universe, is too big to measure by any conventional means. So how the hell did early astronomers manage to do it without all the fancy kit scientists now have at their disposal?
In this video, Crash Course describes how the universe got measured -- from the Ancient Greeks figuring out the size of the Earth, to using the distance between the Earth and sun as a means of measuring how far away nearby stars are. It's enough to make you feel a little small.
Picture: Joe Plocki/Flickr