Comets

Comets are remnants from the early days of the solar system, billions of years ago. Primarily made of ice and dust, these "dirty snowballs" orbit the sun and in habit the Oort cloud, an area in the outskirts of the solar system beyond Pluto. As comets approach the inner solar system, solar wind from the sun can sweep dust back into a long tail. When these comets are close enough to Earth, they can appear as dazzling objects in the night sky. Space probes from Earth have visited several comets to learn more about their composition. Learn more about comets, icy wanderers in the solar system.

Related Topics: Asteroids, Meteors, Shooting Stars and Fireballs, Rosetta Spacecraft, Stargazer Photos 

Latest Updates

The newfound comet C/2021 A1 (Leonard) will make its closest approach to Earth on Dec. 12, 2021.

Newfound Comet Leonard will blaze into view this year

By Joe Rao published

A new comet is on its way in toward the sun, with prospects that it may become bright enough to see with the unaided eye by year's end.

This image, captured by the Hubble Space Telescope, shows the comet P/2019 LD2 as it swoops closely to the Trojans, the ancient asteroids trapped near Jupiter by the planet's gravitational pull. This is the first comet that astronomers have observed near these ancient asteroids and the image reveals the comet's dust and gas tail trailing away from its glowing center (or nucleus). The comet was discovered in June 2019 and is likely among the comets journeying towards the Sun after escaping the Kuiper belt.

Future interstellar comet? Gas-spewing object spotted in asteroid group near Jupiter

By Elizabeth Howell last updated

Researchers spotted an object strangely outgassing far from the sun — like a comet — during a long road trip through our solar system that could conclude in interstellar space, NASA says.

Artist's rendering of a comet headed toward Earth.

Dinosaur-killing space rock may have originated at the edge of the solar system

By Stephanie Pappas published

The chunk of space rock that killed the nonavian dinosaurs may have been a piece of a comet that Jupiter's gravity kicked onto a collision course with Earth.

(Left) The SOHO observatory spotted comet C/2020 X3, seen in the bottom left-hand corner. (Right) A composite image shows the sun's corona as seen during the total solar eclipse on Dec. 14, 2020.

This tiny comet photobombed the total solar eclipse of 2020

By Kasandra Brabaw published

Looking closely at eclipse images, stargazers can spot a newfound Kreutz sungrazer comet that zoomed by the Sun during Chile and Argentina's solar eclipse.

In 2020, scientists announced the potential discovery of phosphine in in the clouds of Venus, sparking speculation on its implications for life.

The 10 biggest space discoveries and stories of 2020

By Doris Elin Urrutia published

This year saw a new age of sample-retrieval missions, protests against a telescope, an incredible visit from a dazzling comet and the ''great conjunction'' of Saturn and Jupiter.

This image shows the outline of Skull-Top Ridge, the second landing site on Comet 67P/Churyumov-Gerasimenko for the Rosetta spacecraft's Philae lander, which set down on Nov. 12, 2014.

Europe's Philae comet lander made a 2nd touchdown in a spooky spot: 'Skull-Top Ridge'

By Mike Wall last updated

Scientists have found the second place where a bouncing European lander touched down on Comet 67P six years ago, and the discovery is shedding light on the icy wanderer's composition.

Orionid meteors streak through the starry sky over Big Bend National Park in Texas, in this composite of four shots taken by astrophotographer Sergio Garcia Rill in October 2017.

The Orionid meteor shower peaks this week! Here's what to expect.

By Joe Rao published

It's an excellent year to view the Orionids, which peak before dawn on Wednesday (Oct. 21).

This series of images of Comet 67P/Churyumov-Gerasimenko was captured by the Rosetta spacecraft's OSIRIS narrow-angle camera on Aug. 12, 2015, a few hours before the comet reached perihelion, or the closest point to the sun along its 6.5-year orbit.

Rosetta's 'rubber ducky' comet has ultraviolet auroras

By Hanneke Weitering published

Planets aren't the only things in the solar system with auroras. Comets can have them too, data from the European Space Agency's Rosetta mission has revealed.

An artist's depiction of the first identified interstellar object, 'Oumuamua.

Interstellar visitor 'Oumuamua could actually be a cosmic dust bunny

By Chelsea Gohd published

A new theory has emerged that the cigar-shaped space rock 'Oumuamua might actually be a dust bunny.

The Hubble Space Telescope captured this image of Comet NEOWISE on Aug. 8, 2020, after the object's close approach to the sun.

Hubble telescope catches stunning view of Comet NEOWISE after its spectacular summer sky show

By Elizabeth Howell published

The Hubble Space Telescope turned its powerful eyes to a celestial visitor to our skies — Comet NEOWISE, which put on a stunning show in the United States earlier this summer.

On July 18, 2020, astrophotographer Evan Zucker and his wife, Paula, drove three hours to the Mojave Desert north of Desert Center, California, to see Comet NEOWISE. "The comet itself was an very obvious naked eye object, even all the way down to the horizon, but the ion tail was a challenge to perceive naked eye," Zucker said. They used a Sony a7iii camera with a Sony 85mm f/1.4 GM lens, set to f/1.4 and ISO 800, mounted on a 6-in. Celestron telescope to provide tracking. The single 13-second exposure was processed in Adobe Lightroom and Topaz AI De-Noise.

The curtain is about to come down on Comet NEOWISE

By Joe Rao last updated

The brightest comet to appear in Northern Hemisphere skies in nearly a quarter of a century will soon be ending its run as a naked-eye object.

Astrophysicist Gianluca Masi of the Virtual Telescope Project captured this view of Comet C/2020 F3 (NEOWISE) on July 18, 2020.

Comet NEOWISE is making its closest approach to Earth. Here's how to see it live online.

By Hanneke Weitering last updated

After dusk during July, comet C/2020 F3 (NEOWISE) will be visible low in the northwestern sky as it travels northwest in the sky below the constellation of Ursa Major. Mobile apps can help you find it. This chart shows the comet's path through the sky until mid-August, at 11 p.m. local time. Each night the comet will diminish in brightness — so look for it as soon as possible.

How to spot the bright Comet NEOWISE using mobile apps

By Chris Vaughan last updated

Skywatchers the world over are buzzing about Comet NEOWISE, the first easily-visible comet to appear in years. Your favorite mobile astronomy app can tell you when, where and how to look for it.

Comet NEOWISE shines above a SpaceX Falcon 9 rocket on the pad at Cape Canaveral Air Force Station in Florida. SpaceX posted this photo on Twitter on July 20, 2020.

Comet NEOWISE shines over SpaceX Falcon 9 rocket (photo)

By Mike Wall published

The gorgeous image shows Comet NEOWISE blazing above a Falcon 9 rocket that's poised to launch South Korea's first military satellite today (July 20).

Comet NEOWISE, as photographed by Joy Ng, a multimedia producer at NASA's Goddard Space Flight Center.

Comet NEOWISE: 10 big questions (and answers) about the icy wanderer

By Chelsea Gohd last updated

Comet NEOWISE has returned to the skies and is delighting skywatchers. So what makes this comet so special?

Comet NEOWISE is seen by NASA’s Parker Solar Probe, which captured the comet's twin tail on July 5, 2020. The lower, broader tail is the comet’s dust tail, while the thinner, upper tail is the comet’s ion tail.

Replay: See Comet NEOWISE online tonight in a Slooh webcast

By Tariq Malik last updated

You can see Comet NEOWISE online tonight (July 18) in a lvie webcast from Slooh.

Astrophotographer Bill Dunford, a NASA social media specialist at the Jet Propulsion Laboratory in Pasadena, California, captured this view of Comet NEOWISE when it was visible in the predawn sky in early July 2020.

How to photograph Comet NEOWISE: NASA tips for stargazers

By Chelsea Gohd published

Are you excited to spot Comet NEOWISE as it pops into view in the night sky? Do you want to try your hand at photographing the cosmic snowball?

How to see Comet NEOWISE in the evening sky now. It won't be back for 6,800 years.

By Tariq Malik last updated

Comet NEOWISE is now visible in the evening sky for stargazers. It won't be back for 6,800 years.

Processed data from the WISPR instrument on NASA’s Parker Solar Probe shows great detail in the twin tails of Comet NEOWISE, as seen on July 5, 2020. The lower, broader tail is the comet’s dust tail, while the thinner, upper tail is the comet’s ion tail.

Dazzling Comet NEOWISE could be an astronomical bonanza

By Mike Wall published

Astronomers are buzzing about Comet NEOWISE, which observers under clear, dark skies in the Northern Hemisphere can currently see with the naked eye.

These false-color images of Comet NEOWISE show the concentration of sodium atoms in the comet's dusty ion tail. Astronomers created the images using the Planetary Science Institute's Input/Output facility near Tucson, Arizona. The image on the left shows light reflected off of cometary dust, while the image on the right shows light emitted by sodium atoms.

Comet NEOWISE has a sodium tail. Here's what it looks like.

By Elizabeth Howell last updated

Images of bright comet C/2020 F3 (NEOWISE) show signs of a sodium tail, giving scientists fresh insight on what's happening on the surface.