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A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or coma surrounding the nucleus, and sometimes a tail of gas and dust gas blown out from the coma.
Jun 13, 2024 · Comets, such as the comet ISON pictured here, are thought to hold material from the time when the Sun and planets were forming. They are like giant, frozen time capsules in our solar system. Credit: NASA/MSFC/Aaron Kingery
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.
Feb 1, 2023 · If astronomers discover an incoming object that Comet Interceptor can get to with enough notice—ideally a pristine comet that’s nearing the sun for the very first time—scientists will ...
Jul 31, 2023 · Comets. Comets: Everything you need to know about the 'dirty snowballs' of space. References. By Charles Q. Choi, Daisy Dobrijevic. last updated 31 July 2023. Comets are our cosmic time capsules...
May 25, 2024 · Comet, a small body orbiting the Sun with a substantial fraction of its composition made up of volatile ices. Comets are among the most-spectacular objects in the sky, with their bright glowing comae and their long tails. Comets can appear at random from any direction as they move in eccentric orbits around the Sun.
Comets actually have two tails―a dust tail and an ion (gas) tail. Most comets travel a safe distance from the Sun―comet Halley comes no closer than 89 million kilometers (55 million miles). However, some comets, called sungrazers, crash straight into the Sun or get so close that they break up and evaporate.
Comets. Comets are a wondrous sight for amateur astronomers. As one approaches it often reveals a tail, slowly unfurling a long ghostly banner of light. Often marked by a distinct greenish-blue haze, they are not to be missed.
Jun 7, 2000 · Comets Are Important Because They . . . * May be the oldest, most primitive bodies in the solar system preserving the earliest record of material from the nebula which formed the sun and the planets. * Bring volatile light elements to the planets, playing a role in forming oceans and atmospheres.
Comet Halley moves backward (opposite to Earth's motion) around the Sun in a plane tilted 18 degrees to that of the Earth's orbit. Halley's backward, or retrograde, motion is unusual among short-period comets, as its greatest distance from the Sun (aphelion) is beyond the orbit of Neptune.
