Science in a Can is one of my favorite blogs: one paragraph articles explaining the universe. What more could a girl ask for? Stunning photographs and a great paragraph from them today, plus a link to simulations of the collision from NASA:
Most galaxies are hurtling away from each other as the universe expands, but some were formed so close together that gravity is actually pulling them together. The Hubble Space Telescope has observed that our Milky Way galaxy and its closest neighbour, Andromeda (2.5 million lightyears away), are being pulled towards each other at speeds of 100–140 kilometres per second—or 400 lightyears every million years. Only recently have we confidently been able to estimate when they’ll crash head-on: in 4 billion years. Our sun will be flung into a new galactic region, along with one hundred billion other stars that will scatter and occasionally be ripped away and driven into interstellar space. Earth and our solar system, however, aren’t in much danger of being destroyed—there’s so much empty space between each star that the likelihood of stars actually crashing into each other is pretty slim. Rather, their gravitational forces will cause them to swirl around each other in a gravitational maelstrom, slowly merging to form the core of a new galaxy around 6 billion years from now. Andromeda’s close companion, the Triangulum galaxy, might merge with them later too. A suggested name for the new galaxy? Milkomeda.
(Source: Science in a Can)