Asteroids and comets — and the meteors that sometimes come from them—are leftovers from the formation of our solar system 4.6 billion years ago. While the planets and moons have changed over the millennia, many of these small chunks of ice, rock and metal have not. They are a lot like a fossil record of planetary evolution. There are currently 1,016,501 known asteroids and 3,683 known comets.
(Credit: https://solarsystem.nasa.gov/asteroids-comets-and-meteors/)
Comets, Asteroids, and Meteors
Meteor Facts for Kids
How Asteroids Really Killed The Dinosaurs
NASA’s plan to save Earth from a giant asteroid
