Four galaxies are colliding, divided by the Spitzer Space Telescope of NASA and the MMT and WIYN telescopes, will join each other in the future in a unique and monstrous galaxy 10 times the mass of our own, the Milky Way. This rare sighting provides an unusual and valuable window into how they form the most massive galaxies in the universe.

 
 

The new quadruple merger was discovered during a study of a distant cluster of galaxies, called CL 0958 + 4702, located nearly five billion light-years away. The four galaxies are elliptical. Three of them are about the size of the Milky Way, while the fourth is three times higher. Many of the stars of these galaxies are old. Further analysis of an unusual light in the plume revealed it is composed of billions of old stars.