Dictionary of Space Concepts

Source:

Short Definition:
A Comet is a small object orbiting the star (e.g. the Sun) composed of dust, rock and ices. Comets appear in our solar system and have mostly origin in Kuiper belt or Oort Cloud.

Detailed Definition:
Comets show up periodically, orbiting a star on the ecliptic orbit with different span from several to thousands of years. The comet appearance changes depending on the distance from the source of heat. If the comet is far away from the star, it only consists of the nucleus. After approaching the source of a heat, the surface of the icy heart of the comet starts heating up and slowly transforms into gas, creating a coma (fuzzy cloud of gas and dust) around the nucleus. When the coma appears, two tails spread behind the nucleus. Due to the ion tail's electric charge, it always points away from the star. The dust tail indicates the path of the nucleus, which is wide, curved and spread behind the nucleus for millions of miles. The most popular comet is Halley's Comet (1P/Halley) which is visible from Earth every 75–79 years.

Sample Sentence(s):
There are likely billions of comets orbiting our Sun in the Kuiper Belt and even more distant Oort Cloud.

French:
La comète

German:
der Komet

Polish:
kometa

Swedish:
Komet

Spanish
El cometa

Links to Videos/Articles:
https://solarsystem.nasa.gov/asteroids-comets-and-meteors/comets/overview/
https://spaceplace.nasa.gov/comets/en/
https://en.wikipedia.org/wiki/Comet#Etymology
https://en.wikipedia.org/wiki/Comet_Encke
https://en.wikipedia.org/wiki/Halley%27s_Comet