The European Southern Observatory just released this lovely picture of NGC 520, two galaxies in the middle of the long, long process of colliding:
[Click to galactinate.] NGC 520 is pretty far away, about 100 million light years. Still, even at a glance you can tell something is fishy* about it. Colliding galaxies like NGC 520 are relatively common; hundreds of examples are known. These galactic train wrecks can take billions of years to unfold, and in this case the two galaxies have probably been at it for 300 million years or so. They're well on their way to merging to become one much bigger galaxy, probably the size of the Milky Way: 100,000 light years across. We think our own galaxy grew over time in this way.
And if NGC 520 looks familiar to you, that may be because you've been reading this blog for more than a week. ...
