We've discussed at great lengths what would happen if two black holes—objects so dense, nothing, not even light, can escape their pull—wandered too close and collided. Bar extreme outbursts and a bevy of gravitational waves, the merger itself wouldn't be all that extraordinary from the outside. That, of course, only relates to black holes that are made of the same stuff.
For the sake of argument, let's say that only one of our supermassive black holes is composed of normal matter--the backbone of our physical world, and everything in it—and the other is made entirely of something else, like antimatter. Things would get interesting because matter and its antimatter counterpart—which are believed to have been thrust into the universe in almost equal proportions after the big bang—are pretty much opposites in every way.
And their feud will inevitably lead to mutually assured destruction, as not only do the two not get along, but they can't even come in contact without destroying one another (and to think, many believe family reunions are awful).
So, if you combined one of the most complex objects in the universe with the antithesis of matter, what would happen? Fraser Cain (UniverseToday) explains:
WATCH: "What If A Black Hole Met An Antimatter Black Hole?"