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Comet

A chunk of ice and rock that orbits a star. In our solar system, the majority of comets orbit well beyond Pluto, in regions known as the Kuiper Belt and the Oort Cloud. Most comets are no more than a few miles in diameter. Upon close encounters with the Sun, comet ices vaporize, creating a coma, or cloud, around the comet, and a long tail that always points away from the Sun.

Resources

Craters and Extinctions February 19, 2016
Comet

Comets February 19, 2016

Remnants from the Beginning June 10, 2010

Featured Images

Encke's Comet in mid-February

Evening Comet February 16, 2017
A comet in the February pre-dawn sky

Green Visitor February 8, 2017
Artist's concept of 2016 WF9

Heading In January 1, 2017
SOHO view of a Kreutz Sun-grazing comet

Racing Toward Its Doom August 3, 2016
Giotto view of Halley's Comet, March 1986

Assault on a Comet March 5, 2016
View of a doomed comet approaching the Sun

Doomed Comet January 20, 2016
Comet ISON has disintegrated

Comet Fizzles? September 14, 2015
Comet ISON streaks ever-closer to the Sun in this November 19 image

Breaking Up? September 14, 2015

Comet Crawl September 14, 2015
Images of Comet Churyumov-Gerasimenko on August 12

Busy Comet August 15, 2015
Rosetta view of Comet Churyumov-Gerasimenko on March 22, 2015

Messy Comet April 2, 2015
Rosetta view of Comet Churyumov-Gerasimenko on February 14, 2015

Imhotep February 21, 2015
Philae lander view of its landing site

Stuck? November 14, 2014
Artist's concept of Philae lander on Comet 67P/Churyumov–Gerasimenko

Touchdown! November 12, 2014
View of Philae lander and its target comet

Headed for a Comet November 12, 2014
Artist's concept of Comet Siding Spring approaching Mars

Martian Encounter October 16, 2014
October 7 view of Rosetta spacecraft and its target comet

Neighbors October 14, 2014
August 6, 2014, view of Comet Churyumov-Gerasimenko by Rosetta

Getting Closer August 7, 2014
August 3, 2014, image of Comet Churyumov-Gerasimenko from Rosetta

Arrival August 6, 2014
Artist's concept of comet impact on Jupiter

Strike One! July 16, 2014
Artist's concept of Rosetta contacting Earth

Back to Work January 20, 2014
Three views of Comet Kohoutek

Comet Flop December 26, 2013
Space station view of Comet ISON and other celestial objects

Doomed Comet December 4, 2013
View of Comets ISON and Encke from a Sun-watching spacecraft

Sizzling Comets November 27, 2013
Hubble Space Telescope view of Comet ISON in October 2013

Getting Closer October 18, 2013
Hubble Space Telescope view of Comet ISON, May 2013

Closing In July 2, 2013
Hubble Space Telescope image of Comet ISON, April 2013

Closing In April 24, 2013
Comet C/2011 L4 Panstarrs in the western evening sky in March

Sneaky Comet March 10, 2013
Comet McNaught, 2007

Bright Interlopers January 2, 2013
Orionid Meteor Shower

Orionid Meteors October 20, 2012
False-color view of Comet Swift-Tuttle, 1992

Swift Comet July 16, 2012
View of Comet Lovejoy from the International Space Station

Christmas Comet December 23, 2011
A comet plunges toward the Sun

Survivor: Comet December 16, 2011
Illustration showing the Great Comet of 1861

Great Comet June 30, 2011
Giotto spacecraft view of Halley's Comet, March 1986

Halley's Armada March 5, 2011
Comet Tempel 1 as seen by the Stardust spacecraft, February 14, 2011

Close Cometary Encounter February 17, 2011
Comet Tempel-1 from the Stardust spacecraft, February 14, 2011

Second Glance February 15, 2011
Comet Hartley-2 from Deep Impact Spacecraft

Fowl Comet? November 5, 2010
Deep Impact view of Comet Hartley-2

Closing In November 4, 2010
Comet Hartley-2 from McDonald Observatory

Jolly Green Comet October 21, 2010
Infrared view of Comet Hartley 2 from WISE

Heading for a Rendezvous October 6, 2010
Halley's Comet streaks across the sky

Look! It's Halley's Comet! May 11, 2010

Impact! February 3, 2010

Radio Programs

Encke’s Comet A faint comet in the evening sky February 16, 2017

End of Rosetta Final rendezvous with a comet September 5, 2016

Perseid Meteors Finding the cause of meteor showers August 10, 2016

Moon and Jupiter Vacuuming up some trouble August 5, 2016

Close Visitor Keeping an eye on a close visitor March 12, 2016

Assault on a Comet A fleet takes aim at a comet March 5, 2016

Doomed Comets Tracking doomed comets — after this. January 20, 2016

Stardust Catching bits of stardust January 15, 2016

Orionid Meteors Reminders of a distant comet October 18, 2015

Morning Mercury A dark planet in the dawn sky October 9, 2015

Fomalhaut Grinding up some “dusty” comets September 20, 2015

Oceans Gained Filling up Earth’s oceans June 4, 2015

Floating Comet Bobbing along with a rubber duckie March 12, 2015

Ready for Landing Getting ready to land on a comet November 1, 2014

Meteor Showers Meteor showers on two planets October 17, 2014

Close to Mars II Hiding behind the Red Planet October 16, 2014

Close to Mars An icy relic takes aim at Mars October 15, 2014

Perseid Meteors Looking for sparks through the moonlight August 9, 2014

Impact! Cosmic missiles slam into Jupiter July 15, 2014

Surprise Shower? Looking for a new meteor shower May 21, 2014

Eta Aquarid Meteors Naming a meteor shower May 3, 2014

Watery Asteroid Water vapor from a big ball of rock May 1, 2014

Stardust Catching bits of comet dust December 31, 2013

Comet Flop A good view of a cometary dud December 25, 2013

Geminid Meteors Feeding a meteor shower December 11, 2013

Sunward Bound A comet blazes toward the Sun November 26, 2013

Getting Closer A comet streaks toward the Sun October 31, 2013

Orionid Meteors Moonlight and meteors October 19, 2013

Getting Closer Climbing high to see a comet September 5, 2013

Comet PanStarrs A comet gets ready to shine March 3, 2013

Bright Interlopers Disorderly visitors head inward January 2, 2013

Comets Icy remnants from the birth of the planets January 1, 2013

Orionid Meteors A trail of lights from a messy comet October 19, 2012

Comet Swift-Tuttle A famous comet changes its image July 17, 2012

Tuttle Comets War, embezzlement, and comets July 16, 2012

Swift Comets From hardware-store owner to cosmic celebrity July 15, 2012

Comet Exchange Stars exchange frozen leftovers June 14, 2012

Watery Earth Raining on the young planet Earth January 8, 2012