The globular star cluster Terzan 12 is an excellent example of how the dust in space affects starlight coming from background objects. The location of this globular cluster, deep in the Milky Way in the constellation Sagittarius about 15,000 light-years away, means that it is shrouded in gas and dust which absorb its starlight. Intervening dust particles between Earth and the cluster to scatter blue light, so mostly the redder wavelengths make it to Earth, and interstellar dust clouds are inconsistent causing parts of the cluster look redder than others.

Image Credit: NASA / ESA