Explore Alliance Presents: How Do You KNOW? – Episode #17: 'Measuring the Earth’s Rotation'

There is a misconception that ‘doing real astronomy’ is difficult and expensive, only highly trained and generously funded people can do it; the entire How Do You Know? series is designed to show that both of these ideas are false. Measuring the length of Earth's day is simple enough that a seven year old can do it in their own backyard with a little parental help.