Astronomers are keeping a close eye on 2 very large black holes that are on a crash course for one another. The only difference is that when they collide they won’t break apart or evaporate. What will happen is one of the black holes will “eat” the other and grow to a super massive hole.

Right now each hole is releasing oppositely directed jets of plasma will moving though space.  "The jets are similar to the contrails produced by planes as they fly through the air on Earth," Sarazin said. "From the contrails, we can determine where the planes have been, and in which direction they are going. What we see is that the jets are bent together and intertwined, which indicates that the pair of super massive black holes are bound and moving together."

Although black holes cannot be seen they can be located by the effects they have on their surroundings and the radiation it emits.

The black holes will not merge for millions of years but when they do they will emit a series of gravitational waves just as Einstein’s theory of relativity predicts.