The Origin of the Universe
A survey of the evidence
Introduction
Measurement Overview
Parallax Distances
Star Sizes and Absolute Magnitudes
Cepheid Distances
Type 1a Supernovae Distances
Redshift Velocities and Distances
Age of the Stars in Globular Clusters
The Oldest White Dwarfs
The Cosmic Microwave Background
Conclusion
The positions of nearby stars change as the Earth orbits the Sun. The movement is called parallax. If a star's parallax is known, the distance to it can be calculated. Astronomers have used the technique to measure the distance to more than a million stars out to about 3,000 light years, beyond which parallax shifts become too small to yield accurate measurements.