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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 

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Comet C/2012 S1 (ISON) imaged by the TRAPPIST-South national telescope at the European Southern Observatory's (ESOs) La Silla Observatory on November 15, 2013.

Comets: Facts about the 'dirty snowballs' of space

By Charles Q. Choi, Daisy Dobrijevic

Learn about the composition and orbit of comets, as well as the history of their discovery, famous comets and space missions to analyze them.

don't look up"Don't Look Up", starring Jennifer Lawrence (left) and Leonardo DiCaprio, portrays a fictional comet threat to Earth.

Watch the first trailer for 'Don't Look Up,' Netflix's dark comedy about a comet headed for Earth

By Elizabeth Howell

The first teaser trailer for "Don't Look Up" has Jennifer Lawrence and Leonardo DiCaprio as astronomers hoping to warn Earth of a comet impact.

An image taken by the Dark Energy Survey shows Comet Bernardinelli-Bernstein in October 2017.

The 'megacomet' Bernardinelli-Bernstein is the find of a decade. Here's the discovery explained.

By Meghan Bartels

Comet Bernardinelli-Bernstein will be a spectacle for more than a decade to come, even though its discovery was a matter of luck.

planets comets round shape

I've always wondered: Why are the stars, planets and moons round, when comets and asteroids aren’t?

By Jonti Horner

This is a fantastic question Lionel, and a really good observation!

The outer solar system might be full of comets from other stars.

Interstellar comets visit our solar system more frequently than thought

By Tereza Pultarova

Comets from other star systems, such as 2019 Borisov, visit the sun's neighborhood more frequently than scientists had thought, a new study suggests.

An artist's depiction of a meteor shower on Venus.

Venus and a newly discovered comet will cross paths in December. Will sparks fly?

By Meghan Bartels

Venus is Earth's twisted twin in so many ways, what about on the skywatching front?

Images of Comet ATLAS taken on April 20 and April 23, 2020, show the comet breaking up into as many as 30 pieces.

The Comet ATLAS was a cosmic flop last year and scientists may finally know why

By Elizabeth Howell

When scientists first spotted Comet ATLAS last year, they hoped it would be the brightest comet of the decade. Then, the icy hunk unexpectedly fell to pieces.

Comet C/2014 UN271 (Bernardinelli-Bernstein), as seen in a synthetic color composite image made with the Las Cumbres Observatory 1-meter telescope at Sutherland, South Africa, on 22 June 2021. The diffuse cloud is the comet’s coma.

Astronomers spot first activity on giant megacomet beyond Saturn

By Elizabeth Howell

Spotting the first signs of activity on a record-setting megacomet came down to a time-zone advantage.

This artist's illustration shows the distant Comet Bernardinelli-Bernstein as it might look in the outer solar system. Comet Bernardinelli-Bernstein is estimated to be about 1000 times more massive than a typical comet, making it arguably the largest comet discovered in modern times. It has an extremely elongated orbit, journeying inward from the distant Oort Cloud over millions of years. It is the most distant comet to be discovered on its incoming path.

Newly found mega comet may be the largest seen in recorded history

By Elizabeth Howell

A giant comet found far out in the solar system may be 1,000 times more massive than a typical comet, making it potentially the largest ever found in modern times.

The Bernardinelli-Bernstein comet takes 5.5 million years to complete its orbit.

Never-before-seen colossal comet on a trek toward the sun

By Stephanie Pappas

A new visitor is swinging by the solar system: a never-before-observed comet that hails from the Oort Cloud.

This archaeological site in Arizona in the U.S. shows evidence of an impact from a comet.

Did a comet strike 13,000 years ago change human civilization as we know it?

By Chelsea Gohd

Could a devastating comet impact in Earth's distant past have forever changed human civilization?

The meteoroid stream of Comet Thatcher.

Scientists track meteor shower to unusual comet seen every 4,000 years

By Meghan Bartels

Meteor showers are the dazzling result of cometary debris building up along well-worn paths through the solar system, then burning up in Earth's atmosphere as our planet crosses that dust trail.

This image of comet C/2016 R2 (PANSTARRS) was captured from ESO's SPECULOOS telescope at the Paranal Observatory in Chile.

Metals found in the atmospheres of comets in and beyond our solar system surprise scientists

By Charles Q. Choi

Metal atoms have surprisingly been discovered in the frigid atmosphere of the first known interstellar comet to visit our solar system, a new study finds.

Astrophotographer Sébastien Joly sent in a photo of a Taurid meteor captured over Lake Cerknica in Slovenia, on Nov. 10, 2015.

Surprise meteor shower! 'Finlay-id' 'shooting stars' will appear for the first time in 2021.

By Doris Elin Urrutia

A never-before-seen meteor shower will sprinkle tiny pieces of comet dust over Earth's southernmost regions later this year.

Justin Ng of Singapore captured this view of a bright Eta Aquarid meteor hurtling across the night sky over Mount Bromo, on the Indonesian island of Java.

The Eta Aquarid meteor shower of 2021 peaks this week. Here's how to see it.

By Joe Rao

The asteroid 2016 HO3 has an orbit around the sun that keeps it as a constant companion of Earth.

Russia joins China's mission to sample an asteroid and study a comet

By Andrew Jones

China has selected a Russian science payload to fly on an upcoming mission to sample a near-Earth asteroid and later visit a main-belt comet.

An artist's impression of what the surface of the interstellar comet 2I/Borisov might look like.

Interstellar interloper 2I/Borisov may be the most pristine comet ever observed

By Charles Q. Choi

The first known interstellar comet to visit our solar system may be the most pristine ever found, never passing near a star until visiting our own, researchers say.

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

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

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

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.