Comets

Overview

Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices. They range from a few miles to tens of miles wide, but as they orbit closer to the Sun, they heat up and spew gases and dust into a glowing head that can be larger than a planet. This material forms a tail that stretches millions of miles.

Comets are cosmic snowballs of frozen gases, rock, and dust that orbit the Sun. When frozen, they are the size of a small town. When a comet's orbit brings it close to the Sun, it heats up and spews dust and gases into a giant glowing head larger than most planets. The dust and gases form a tail that stretches away from the Sun for millions of miles. There are likely billions of comets orbiting our Sun in the Kuiper Belt and even more distant Oort Cloud.

Featured Story

NASA Researchers Discover More Dark Comets

These celestial objects look like asteroids but act like comets now come in two flavors. The first dark comet —…

Read the Story

Experience Earth, our solar system, nearby asteroids, the universe, and the spacecraft exploring them with immersive real-time 3D web-based apps for Mac, PC and mobile devices. No download or sign up necessary.

NASA/JPL-Caltech/VTAD