What happens when two black holes are smashed together?

We've never seen it happen, but a collision with two black holes would be one of the most dramatic events in the entire universe, releasing so much energy that we could detect it clear across the cosmos.

The question of colliding black holes is tackled in this video made by the University of Nottingham's Sixty Symbols project, which is a series of awesome videos in which professors explain lots of different scientific topics. This particular video looks at two very different questions: not only what happens when two black holes become one, but also how the beauty of a sunset is affected by knowing the science behind it:

You can check out Sixty Symbols for more great videos.