comet

[kom-it]

noun

Astronomy.

1. a celestial body moving about the sun, usually in a highly eccentric orbit, consisting of a central mass surrounded by an envelope of dust and gas that may form a tail that streams away from the sun.

comet

/ ˈkɒmɪt, kɒˈmɛtɪk /

noun

1. a celestial body that travels around the sun, usually in a highly elliptical orbit: thought to consist of a solid frozen nucleus part of which vaporizes on approaching the sun to form a gaseous luminous coma and a long luminous tail

comet

1. A celestial object that orbits the Sun along an elongated path. A comet that is not near the Sun consists only of a nucleus—a solid core of frozen water, frozen gases, and dust. When a comet comes close to the Sun, its nucleus heats up and releases a gaseous coma that surrounds the nucleus. A comet forms a tail when solar heat or wind forces dust or gas off its coma, with the tail always streaming away from the Sun.

2. ◆ Short-period comets have orbital periods of less than 200 years and come from the region known as the Kuiper belt. Long-period comets have periods greater than 200 years and come from the Oort cloud.

3. See more at Kuiper belt Oort cloud See Note at solar system

comet

1. An object that enters the inner solar system, typically in a very elongated orbit around the sun. Material is boiled off from the comet by the heat of the sun, so that a characteristic tail is formed. The path of a comet can be in the form of an ellipse or a hyperbola. If it follows a hyperbolic path, it enters the solar system once and then leaves forever. If its path is an ellipse, it stays in orbit around the sun.

Comets were once believed to be omens, and their appearances in the sky were greatly feared or welcomed.

The most famous comet, Comet Halley (or Halley's comet), passes close to the Earth roughly every seventy-six years, most recently in 1986.

Other Word Forms

• cometary adjective
• cometic adjective
• cometical adjective
• cometlike adjective

Word History and Origins

Origin of comet¹

1150–1200; Middle English comete < Anglo-French, Old French < Latin comētēs, comēta < Greek komḗtēs wearing long hair, equivalent to komē-, variant stem of komân to let one's hair grow (derivative of kómē hair) + -tēs agent suffix

Word History and Origins

Origin of comet¹

C13: from Old French comète, from Latin comēta, from Greek komētēs long-haired, from komē hair

Example Sentences

He will be remembered as the actor who blazed like a comet at the height of the 1960s, surrounded by the decade's most beautiful women.

From BBC

Meteor showers occur when Earth passes through trails of dust and debris left behind by comets or asteroids.

From BBC

“Just because you find something in a comet doesn’t mean that it can’t be a biosignature on a planetary atmosphere, because those are two very different environments.”

From Salon

The annual shower hits its peak on warm, laid-back August nights as the Earth crosses paths with the dust cloud left by comet Swift-Tuttle on its every-133-years swing past our planet.

From Los Angeles Times

Meteorites are the remains of rock left after an asteroid or comet passes through Earth's atmosphere.

From BBC