Distance to the Sun

The mean Earth-Sun distance is very important in astronomy. It is called 1 Astronomical Unit or 1 AU.

It is rather easy to determine distances within the Solar System if you measure them in AU's.

Methods like this give 1 AU = 150 x 106 km.

Later, we will want to know distances to stars. Getting the distance from the Earth to the Sun right is the first step.

Davison E. Soper, Institute of Theoretical Science, University of Oregon, Eugene OR 97403 USA soper@bovine.uoregon.edu