Calculating Galactic Distances
Name: Katy T.
Date: February 23, 2003
How are distances from the Earth to specific galaxies
calculated? I know it is determined employing the speed of light in a
year. But how can the time it takes to leave the source galaxy be
The light coming from the galaxy or a star experiences a shift in
frequency spectrum towards longer wavelengths, commonly called the "red
shift". The greater the shift the greater the distance away the galaxy is.
Search the Internet for the term "red shift" and you will find more
David R. Cook
Atmospheric Research Section
Environmental Research Division
Argonne National Laboratory
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Update: June 2012