What would happen if Ceres collided with Earth?
The Chicxulub asteroid that collided with earth 66 million years ago and killed off the dinosaurs is estimated to have been 15 kilometers in diameter. By comparison Ceres is 945 kilometers in diameter - with a mass 200,000 times greater than the Chicxlub asteroid. The asteroid that hit the earth 4.4 billion years ago and resulted in the creation of the moon was even bigger and is estimated to have had a diameter of about 3000 kilometers. So Ceres would do damage somewhere in between. Depending whether it was a glancing blow or a head on and the collission speed, it is likely that it would kill all life on earth by heating the surface to over 2,000 degrees C. Possibly it would create a ring of debris which eventually would form a new rather smaller moon. It would certainly disrupt plate tectonics for a long time.In the picture the Earth, Moon and Ceres are all to scale.