What are comets and how do they differ from other objects in the solar system?

Comets are small, icy solar system objects that orbit the sun. They are different from other objects in the solar system in several ways. For one, comets are made up of ice, dust, and small rocky particles, whereas many other objects in the solar system are made up mostly of rock and/or gas. Secondly, comets have highly elliptical orbits that take them far from the sun and then back again, whereas most other objects in the solar system have relatively circular orbits.

When a comet gets close to the sun, its icy nucleus begins to heat up and release gas and dust in a process called sublimation. This creates a glowing coma (the fuzzy part around the nucleus) and sometimes a tail that can be seen from Earth.

Comets are believed to be pristine remnants from the early solar system, and astronomers study them to learn about the conditions and materials present in the early solar system. Many comets come from the Kuiper Belt, a region beyond the orbit of Neptune that is believed to contain many icy objects like comets. Others come from the Oort Cloud, a hypothetical region of the solar system far beyond the orbits of the planets that is believed to contain trillions of comets.