What is the scientific explanation for comets?

Answer 1

Comets are small bodies of rock and ice which are in highly eccentric orbits around the Sun. They spend most of their time far from the Sun, some beyond the outer planets. When a comet's orbit eventually comes close to the Sun, the surface is heated and partly vaporized. This ejects the gas molecules that give the comet its tails.

Comets are thought to be objects from the Kuiper belt beyond Neptune, or from even farther out. The Oort Cloud is a region many billions of miles past Pluto, where it is theorized that millions of widely scattered icy objects exist. Gravitational disturbances can eventually pull them inward into cometary paths. If they achieve a regular orbit, they can become comets seen again and again.

Answer 2

Comets are icy bodies composed of dust, rock, and frozen gases like water, ammonia, methane, and carbon dioxide. As a comet orbits the Sun, the heat causes these materials to vaporize and create a glowing coma and tails of gas and dust. The dust and gas released from comets provide valuable information about the early solar system.