Looking Back In Time to the Big Bang Theory

 

Looking Back In Time

The Big Bang theory says that the universe started out as a tiny point of concentrated energy about 13.5 billion years ago. The energy expanded and the universe has been expanding from this point ever since. Astronomers use telescopes to look at distant galaxies and the spectra of light from stars to look for evidence for the Big Bang theory. Astronomers have observed that almost all of the galaxies are moving away from each other.