How Far Away Is The Sun?

The angular size of an object does not provide us with enough information to determine its distance. This is illustrated by our view of the Moon and the Sun. To the naked eye, they appear to be the same size. But in reality, the Sun is about 400 times larger than the Moon and 400 times further away.

Determining solar distance was a major scientific challenge for the 18th century. In this talk Professor Don Kurtz will explain how astronomers were finally able to determine the distance of the Sun.