What Happens When Black Hole Collide?

"Pop quiz": What happens when black holes collide? Is it A, it explodes, B the universe ends, C you get one big black hole or D nobody knows. The correct answer is C nothing can destroy a black hole. They just get bigger when they eat other things including other black holes. "Biggest in terms of like impact right like how it can affect us here on earth"? Well the earth is getting hit by this stuff all the time we can't deflect all of it but in our history we have been smacked by some pretty big asteroids Like the dinosaurs were not as on point as NASA is in terms of planetary defense so they got smacked by a pretty big rock