Comet: Difference between revisions
imported>Mark Widmer ("elliptical" now links to "ellipse" page, rather than nonexistent "elliptical orbit") |
imported>Mark Widmer (Added short-period vs. long-period classification info.) |
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A '''comet''' is composed of [[ice]], [[gas]] and dust, and has a highly eccentric, [[ellipse|elliptical]] orbit around the [[Sun]]. Comets become visible as they approach the Sun and can be much larger than they seem - the tails of some comets are over 1,000,000 km long. Examples include [[Halley's Comet]] and the [[Tago-Sato-Kosaka Comet]]. | A '''comet''' is composed of [[ice]], [[gas]] and dust, and has a highly eccentric, [[ellipse|elliptical]] orbit around the [[Sun]]. Comets become visible as they approach the Sun and can be much larger than they seem - the tails of some comets are over 1,000,000 km long. Examples include [[Halley's Comet]] and the [[Tago-Sato-Kosaka Comet]]. | ||
Comets typically have orbital periods much longer than 1 Earth year, and are classified as either short-period or long-period comets, depending on whether the orbital period is less than or greater than 200 years. | |||
In November 2014, the [[European Space Agency]] successfully landed a probe on a [[comet nucleus]], the first time in history that this had been achieved. ''[[Philae (comet lander)|Philae]]'' sent back data for three days as it probed the surface of [[67P/Churyumov–Gerasimenko]]. | In November 2014, the [[European Space Agency]] successfully landed a probe on a [[comet nucleus]], the first time in history that this had been achieved. ''[[Philae (comet lander)|Philae]]'' sent back data for three days as it probed the surface of [[67P/Churyumov–Gerasimenko]]. | ||
Revision as of 14:36, 18 August 2020
A comet is composed of ice, gas and dust, and has a highly eccentric, elliptical orbit around the Sun. Comets become visible as they approach the Sun and can be much larger than they seem - the tails of some comets are over 1,000,000 km long. Examples include Halley's Comet and the Tago-Sato-Kosaka Comet.
Comets typically have orbital periods much longer than 1 Earth year, and are classified as either short-period or long-period comets, depending on whether the orbital period is less than or greater than 200 years.
In November 2014, the European Space Agency successfully landed a probe on a comet nucleus, the first time in history that this had been achieved. Philae sent back data for three days as it probed the surface of 67P/Churyumov–Gerasimenko.