These galaxies are much smaller than typical ones like our Milky Way. In this galaxy, the population of stars is more strongly segregated by age. The picture at right shows a cosmic collision between two galaxies, UGC 06471 and UGC 06472. These collisions occurred frequently in the early universe, producing galaxies of unusual shapes. The Hubble telescope has spied many such galaxies in the deep field surveys.
Galaxies emit all kinds of light, from visible to infrared.
From this light, astronomers get a clear picture of what these galaxies look like. But distant galaxies pose a special problem. As a result, the light is no longer visible, but has been shifted to the infrared where present instruments are less sensitive. About the only light astronomers can see comes from regions where hot, young stars reside. These stars emit mostly ultraviolet light.