#5. Black Hole
We don’t know when the black hole will come. There are millions of black holes in the universe. Someday one could join our galaxy. The black hole is so hard to see. Black hole will suck everything in its path, even the sun. This might or might not happen, after all we don’t know much about black holes and the few things we know are just theories, so it’s a bit unlikely to die because of it.