Comets TOP STORY
Large, Distant Comets More Common Than Previously Thought 
© NASA
Comet structure
Comets that take more than 200 years to make one revolution around the Sun are notoriously difficult to study.
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Comets TOP STORIES
Strange Comet Challenging Researchers
© University of Central Florida
comet 174P/Echeclus
Scientists pursue research through observation, experimentation and modeling. They strive for all of these pieces to fit together, but sometimes finding the unexpected is even more exciting.
Explaining An Oxygen Mystery on Comets
A Caltech chemical engineer who normally develops new ways to fabricate microprocessors in computers has figured out how to explain a nagging mystery in space -- why comets expel oxygen gas, the same gas we humans breathe.
Watching Landslides On A Comet
Sudden and short-lived outbursts were observed frequently during Rosetta's two-year mission at Comet 67P/Churyumov-Gerasimenko.
NASA Study Hints at Possible Change in Water 'Fingerprint' of Comet
A trip past the sun may have selectively altered the production of one form of water in a comet - an effect not seen by astronomers before, a new NASA study suggests.
Arecibo Observatory Images Comet 45P/Honda-Mrkos-Pajdusakova
Though not visible to the naked eye or even with binoculars, the green-tailed Comet 45P/Honda-Mrkos-Pajdusakova (HMP) did not escape the gaze of the world-renowned Arecibo Observatory.
Comet Destruction Observed Around Another Star
Scientists using the NASA/ESA Hubble Space Telescope have observed, for the first time, a massive, comet-like object that has been ripped apart and scattered in the atmosphere of a white dwarf.
Micro Spacecraft Investigates Cometary Water Mystery
In September 2015, a team of astronomers from the National Astronomical Observatory of Japan, University of Michigan, Kyoto Sangyo University, Rikkyo University and the University of Tokyo successfully observed the entire hydrogen coma of the comet 67P/Churyumov-Gerasimenko, using the LAICA telescope onboard the PROCYON spacecraft.
NEOWISE Discovers One, Maybe Two Comets
NASA's NEOWISE mission has recently discovered some celestial objects traveling through our neighborhood, including one on the blurry line between asteroid and comet. Another--definitely a comet--might be seen with binoculars through next week.
The Relationships Between Chemicals on Comets
A new study has revealed similarities and relationships between certain types of chemicals found on 30 different comets, which vary widely in their overall composition compared to one another.
Rosetta Ends Its Mission By Slowly Crash Landing On A Comet
ESA's historic Rosetta mission has concluded as planned, with the controlled impact onto the comet it had been investigating for more than two years
Video: Rosetta Mission Comes to an End and Science Highlights 
The Rosetta mission came to an end today with the orbiter purposefully "crash" landing (softly) on the Comet 67P/Churyumov-Gerasimenko just as the Philae lander had done previously.
Astronomers Capture Best View Ever of Disintegrating Comet
Astronomers have captured the sharpest, most detailed observations of a comet breaking apart 67 million miles from Earth, using NASA's Hubble Space Telescope.
Rosetta's Comet Offered Brief and Powerful Summer Fireworks
Brief but powerful outbursts seen from Comet 67P/Churyumov-Gerasimenko during its most active period last year have been traced back to their origins on the surface.
Rosetta's Descent Towards Active Pits on Comet 67P
Squeezing out unique scientific observations until the very end, Rosetta's thrilling mission will culminate with a descent on 30 September towards a region of active pits on the comet's 'head'.
Philae Lander Found on Comet 67P
Less than a month before the end of the mission, Rosetta's high-resolution camera has revealed the Philae lander wedged into a dark crack on Comet 67P/Churyumov-Gerasimenko.
Rosetta Captures Comet Outburst
In unprecedented observations made earlier this year, Rosetta unexpectedly captured a dramatic comet outburst that may have been triggered by a landslide.
How Comets Are Born
Understanding how and when objects like Comet 67P/Churyumov-Gerasimenko took shape is of utmost importance in determining how exactly they can be used to interpret the formation and early evolution of our Solar System.
More top stories from August.
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Video: Rosetta Mission Comes to an End and Science Highlights
Rosetta's Comet Offered Brief and Powerful Summer Fireworks
Philae Comet Lander Faces Eternal Hibernation
Philae Lander: One Year On A Comet
Philae's Descent on Comet 67P/Churyumov-Gerasimenko: The Director's Cut
ESA: The Organic Comet 67P/Churyumov-Gerasimenko
Rosetta Reveals Surprises in Comet 67P's Coma
Video and Image: Rosetta Mission Results from Philae 14 November 2014
Video and Images: Rosetta Mission Philae Lander Media Briefing 13 November 2014
Artist's Impression of Exocomets Orbiting the Star Beta Pictoris
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