Every a billion years. the black holes will be collided. that is our fate. This is called Andromeda-Milky Way collision. 2 galaxies collide. supermassive black holes will orbit and merge. This is called Milkomeda. a proposed merged galaxy. This collision occurs 2.5 billion years and merger is 5 billion years. 400,000,000 years before the red giant expansion of our sun is 5,400,000,000 years.