Comet
A comet was a planetary body, usually orbiting a star, composed of rock and ice. If a comet approaches close enough to a star, the increased heat causes it to shed mass away from the star, creating a coma and/or "tail".

One of the best known comets in the Sol system was Halley's Comet. (; )

When Sub-commander T'Pol analyzed an impact crater on the northern hemisphere of Terra Nova, Captain Jonathan Archer asked her if it was from an asteroid or a comet to which T'Pol responds it was a large asteroid. ()

In 2151, the Earth starship   the largest comet yet observed by Humans or Vulcans, with a diameter of 82.6 kilometers. It was named Archer's Comet for Enterprises captain, Jonathan Archer. ()

Later that year,  asked if anyone on an Enterprise landing party had heard the story of the haunted comet. ()

In the 22nd century, many comets in the Sol system were diverted to Mars by the verteron array for the Martian terraforming project. At one point, fourteen comets were scheduled to impact with Mars in a thirty-month span, starting with the arrival of  in January 2155. ()

In 2259, xenoanthropologist Sam Kirk stated that he knew of no civilizations that developed on the surface of a comet. ()

The comet Icarus IV in the Romulan Neutral Zone was the locus for part of a battle between the  and a Romulan Bird-of-Prey in 2266. ()

The  tracked a rogue comet through Sector 1156 in 2370. Its core, composed largely of fortanium, proved to be a D'Arsay cultural archive, built over eighty-seven million years previous. ()

While under the influence of Saltah'na energy spheres, Commander Benjamin Sisko compared his name with a comet who would blaze across the stars long after Kira's petty treacheries would be forgotten. ()

In 2371, the wormhole relay station experiment, conducted by the  in the Gamma Quadrant, diverted a comet laden with silithium towards the Bajoran wormhole. Some interpreted this comet as the "Sword of Stars", an element in Trakor's Third Prophecy. ()

In 2373, the  detected a class-2 comet while on patrol in the Romulan Neutral Zone. ()

In late 2374, Jadzia Dax ran a spectral scan on a comet that was passing through the Denorios belt. She had waited three weeks for it to enter the belt. ()

When Chakotay tried to erase a comet which had forced the  to enter Krenim territory several months beforehand, he altered the timeline by wiping out almost 8,000 civilizations, as life within fifty-thousand kilometers around the comet would have never existed. Four billion years ago, hydrocarbon fragments of this comet erased plant life on a planet. ()

Around this time, the Silver Blood USS Voyager collected silicates from a comet in the Podaris sector. ()

In 2377, Harry Kim, Seven of Nine, and The Doctor undertook a mission to collect cometary bio-matter, so that The Doctor could create new medicines. ()

See also 
 List of comets
 Dark matter proto-comet
 Rogue comet

External links 
 
 

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Celestial objects
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