How do you measure something that is so mind-bogglingly vast that we have barely begun to explore it? Astronomers do it every day, and it turns out that they have some pretty nifty (and surprisingly simple) secrets. This short film from the Royal Observatory Greenwich explains some of the tools astronomers use to figure out how far distant stars are from us.

Thankfully, the cute animation uses simple terms, so even those unfamiliar with space studies will be able to follow along. If you take a moment to really consider the centuries of study, work and sometimes dangerous discoveries that have gone into these measurements – well, it’s nearly as mind-boggling as the vast universe itself.