Coma (comet) - Wikipedia
The coma is the nebulous envelope around the nucleus of a comet, formed when the comet passes near the Sun in its highly elliptical orbit. As the comet warms, parts of it sublimate; [1] this gives a comet a diffuse appearance when viewed through telescopes and distinguishes it …
Comets: Facts - Science@NASA
A comet warms up as it nears the Sun and develops an atmosphere, or coma. The Sun's heat causes the comet's ices to change to gases so the coma gets larger. The coma may extend hundreds of thousands of kilometers.
Comets: Everything you need to know | Space
2023年7月31日 · A comet primarily consists of a nucleus, coma, hydrogen envelope, dust and plasma tails. Scientists analyze these components to learn about the size and location of these icy bodies, according...
Comet - Wikipedia
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.
Coma | comet | Britannica
Such a cloud, termed a coma, is a distinguishing feature of comets and consists of gases and entrained dust escaping from the cometary nucleus when sunlight causes its ices to sublimate. Given Chiron’s large distance from the Sun, the sublimating ices are likely far more volatile substances than water ice,…
Comet | Definition, Composition, & Facts | Britannica
2024年10月28日 · 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.
Why Comets Are Important - NASA Solar System Exploration
2000年6月7日 · * Comet structures are diverse and very dynamic, but they all develop a surrounding cloud of diffuse material, called a coma, that usually grows in size and brightness as the comet approaches the Sun. A small, bright nucleus (less than 10 km in diameter) is sometimes visible in the middle of the coma.
Parts of a Comet - Science Notes and Projects
2022年1月30日 · The main parts of a comet are the nucleus, coma, hydrogen envelope, dust tail, and ion tail. A comet is a small icy body that orbits the Sun and has a visible atmosphere (coma) and sometimes one or more tails.
What Is a Comet? | NASA Space Place – NASA Science for Kids
2024年11月8日 · Comets are large objects made of dust and ice that orbit the Sun. Best known for their long, streaming tails, these ancient objects are leftovers from the formation of the solar system 4.6 billion years ago. Comets, such as the comet ISON pictured here, are thought to hold material from the time when the Sun and planets were forming.
ESA Science & Technology - Catching up with the comet's coma
2014年7月31日 · When the comet moves away from the Sun and returns to the outer Solar System again, the activity and the resulting coma and tails all fade away. Today, comet 67P/C-G and Rosetta are between the orbits of Jupiter and Mars, about 544 …