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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.


Craters and Extinctions February 19, 2016


Comets February 19, 2016

Radio Programs

Comet Wirtanen A special visitor for the bull December 13, 2018

Comet Wirtanen A hyperactive comet gets close November 28, 2018

Comet Tails Making a comet a comet November 27, 2018

The ‘Angry Star’ Words about an “angry star” November 18, 2018

Leonid Meteors A quiet but steady meteor shower November 16, 2018

Draconid Meteors Sparks or misfires from the dragon? October 8, 2018

Catching Dust Catching dust in the stratosphere June 19, 2018

Great Comet A comet that overperformed February 5, 2018

Orionid Meteor Shower Sparks from a distant comet October 20, 2017

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

Featured Images

Comet Wirtanen's path across the December sky

Passing the Bull December 9, 2018

Space-dust collecting aircraft

Dust Collector June 19, 2018