SOLAR SYSTEM

Detailed explanation-1: -The coma is a cloud of gases that surrounds the nucleus of a comet. In some comets, a cloud of hydrogen gas surrounds the coma. This hydrogen cloud may be as big as 3 million kilometers (about 2 million miles) across.

Detailed explanation-2: -Surrounding the coma is an invisible layer of hydrogen called the hydrogen envelope; the hydrogen may come from water molecules. It usually has an irregular shape because it is distorted by the solar wind. The hydrogen envelope gets bigger as the comet approaches the sun.

Detailed explanation-3: -A hazy cloud called a coma surrounds the nucleus. The coma and the nucleus together form the comet’s head. Comets follow a regular orbit around the Sun. If the comet nucleus is pulled into an orbit which carries it close to the Sun, the solar heat will cause the outer layers of the icy nucleus to evaporate.

Detailed explanation-4: -The gas (water vapor, carbon monoxide, carbon dioxide, and traces of other substances) and dust forms an “atmosphere” around the nucleus called a “coma.” Material from the coma gets swept into the tail. As comets move close to the Sun, they develop tails of dust and ionized gas.