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: -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.

Detailed explanation-3: -Coma. As a comet gets closer to the sun, the ice on the surface of the nucleus begins turning into a gas via a process called sublimation, forming a cloud around the comet known as the coma.

Detailed explanation-4: -The streams of dust and gas thus released form a huge, extremely tenuous atmosphere around the comet called the coma, and the force exerted on the coma by the Sun’s radiation pressure and solar wind cause an enormous tail to form, which points away from the Sun.

Detailed explanation-5: -When far from the sun, a comet is like a stone rolling around the universe. But when it approaches the sun, the heat evaporates the comet’s gases, causing it to emit dust and microparticles (electrons and ions). These materials form a tail whose flow is affected by the sun’s radiation pressure.