Wednesday, September 9, 2015
Today's Astronomy Picture of the Day shows NGC 1316 and NGC 13176, two galaxies post-collision. What happens when galaxies collide? As "Doc" Smith said, they mostly just pass through each other, but the interacting forces and clouds of matter can distort (or completely "tear") a galaxy. Some galaxies swallow other galaxies (our own may have swallowed three or more).