Seeing a galaxy in different lights

2015-09-16 - This side-by-side comparison of a neighbouring galaxy known as Messier 81, which is similar to our own Milky Way, in both visible (left) and ultraviolet light (right). While visible-light images of galaxies reveal the distribution of stars, ultraviolet-light images highlight the most active, young stars. The ultraviolet image of Messier 81 shows that the galaxy’s spiral arms are dotted with pockets of violent star-forming activity.

The visible-light image is from the National Optical Astronomy Observatory. The ultraviolet-light image was taken by the Galaxy Evolution Explorer. (Credits: NASA, JPL-Caltech, NOAO)