NGC 520, seen here in this photograph that was just released by the European Southern Observatory, a research facility and intergovernmental astronomy organization, is made up of two giant galaxies that are slowly merging together. "This happens slowly, over millions of years -- the whole process started some 300 million years ago," the Observatory explained. "The objects, about 100,000 light-years across, is now in the middle stage of the merging process, as the two nuclei haven't merged yet, but the two discs have."
Once the process is complete, the resulting galaxy will be about the size of the Milky Way. It is believed that mergers like this one resulted in the formation of our own galaxy. It's possible that this image resembles the Milky Way at a moment in the distant past.
This photograph was taken by the ESO's Faint Object Spectrograph and Camera attached to a telescope in Chile.
Image: European Southern Observatory.
View more Pictures of the Day.