CREDIT: AlpenGlow
Almost all galaxies are moving away from us.
Edwin Hubble found that galaxies are constantly moving away from us. According to his observations with the Hubble Space Telescope, galaxies are moving at different speeds. This shows that the universe is expanding.
The farther away a galaxy is, the faster it is moving away.
Based on the redshift that was calculated, Hubble noticed that the galaxies further away were moving faster. When light moves further away, it shifts towards the end of the spectrum (which happens to be red), thus it is called redshift.