by Phil Plait, SYFY Wire
Hey, some good news: The impending colossal cosmic train wreck of the Andromeda galaxy smashing into our Milky Way and causing massive havoc and chaos on a literally galactic scale has been postponed. According to new measurements and calculations it’ll happen 4.6 billion years from now, not 3.9 billion.
Our Sun is one of several hundred billion stars in the Milky Way galaxy, a sprawling flat spiral-armed disk of gas, stars, dust, and dark matter about 100,000 light years across. The Andromeda galaxy (aka M31) is roughly the same size, though more massive, and about 2.5 million light years away. Together our two spiral galaxies dominate the Local Group, a small cluster of a few dozen mostly dwarf galaxies. An exception is the Triangulum galaxy (aka M33, also a spiral), about a third the size of the Milky Way — bigger than most dwarfs but far smaller than us and Andromeda — and roughly 2.9 million light years away.