Earth occasionally goes through ‘meteor clouds’ that are left behind by comets. This creates meteor showers. What are the chances that Earth will collide with the comet itself?

EarthSky asked planetary scientist Dr. Richard Binzel of MIT. He said that comet collisions are a real potential hazard to the Earth – but probably not from a comet that spawns an annual meteor shower. Space is very big, and comets are very small in contrast to the streams of debris they leave behind.

In fact, a meteor stream moving in space is millions of times larger than the small solid part of the comet – the nucleus – often not much bigger than a kilometer across. So it’s millions of times more likely that we’ll enjoy many future years of a particular meteor shower than suffer a collision with that shower’s parent comet.

What’s more, the orbits of comets are constantly being perturbed by the gravitational pull of the planets. So any meteor stream the Earth passes through this year is likely to miss the Earth completely within the next millennium. And as if that isn’t enough, Dr. Binzel adds that orbital calculations of all of the known meteor showers show no future collision between Earth and their parent comets.