The Doppler Effect in Astronomy

The Doppler Effect in Astronomy

Astronomers may use the information in the shift in frequency of electromagnetic waves produced by moving stars in our galaxy and beyond in order to derive correct information about those stars. The theory that the universe is expanding is actually based on the electromagnetic waves emitted by stars beyond our galaxy. Specific information about these stars can be determined by applying the Doppler effect. Since galaxies are ususally clusters of stars moving around a central point, electromagnetic radiation emitted by such stars in a distant galaxy would appear to be shifted down in frequency if a star in its cluster is moving away from Earth. If the star would be moving towards Earth, it would result in an upward shift of frequency.