Massive galaxies collide

Fraser Cain over at Universe Today has a story on the merger of four galaxies to form one of the universe's largest galaxies. There also more on the story on the BBC News site and in the original NASA press release.

clipped from www.universetoday.com Galaxies aren't born, they evolve, getting built up through a succession of mergers over billions of years. In most cases, this process is slow and steady, with galaxies tearing apart their satellite neighbours and gaining mass. But in one cosmic collision seen by NASA's Spitzer Space Telescope, 4 extremely massive galaxies are coming together at the same time in a cosmic pileup. "Most of the galaxy mergers we already knew about are like compact cars crashing together," said Kenneth Rines of the Harvard-Smithsonian Center for Astrophysics, Cambridge, Mass. "What we have here is like four sand trucks smashing together, flinging sand everywhere."