Why do galaxies have different colours?

Why are galaxies the colors that they are, like when we see them through telescopes they are blue, white, red, sometimes purple or a mixture of colors. Would those be their ... When a proton captures an electron, it can give off light of various wavelengths as the electron hops down through energy levels. read more

Large elliptical galaxies have a yellowish color. The small ellipticals, called dwarfs, have a shade tending towards blue. Spiral galaxies have a triple coloration. The arms are clearly blue, while the core tends in a clear way to yellow. Finally, the regions between the spiral arms appear white or slightly yellowish at the limit. read more

The color of a few galaxies is affected by distance; an extremely distant galaxy has a high recessional velocity due to the expansion of the universe, which causes its light to be shifted toward the red (google "relativistic Doppler shift"). Most galaxies distant enough for this to have a noticable effect on the color of an image are very faint. read more

Galaxies come in a range of colours, but more distant galaxies appear redder than nearby galaxies. First, a bit of background on how galaxy colours are measured. We take a picture of the galaxy through a filter that only allows a specific colour of light through. read more