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

Artist's illustration of a meteor shower.

A meteor shower outburst from a shattered comet may spawn new tau Herculids display on May 30

By Joe Rao last updated

The tau Herculids from comet 73P/Schwassman-Wachmann which began to fragment in 1995 may make an appearance on the night of May 30-31.

The moon sets after a partial lunar eclipse in November 2021.

May's lunar eclipse and a wild-card meteor shower may offer double spectacle

By Joe Rao last updated

May offers an unusual skywatching bounty: the possibility of two major celestial highlights occurring within the span of a single month.

An artist's impression of comets hurtling towards Beta Pictoris.

Largest treasure trove of exocomets to date found in alien solar system

By Keith Cooper published

Thirty alien comets have been spotted transiting the young star Beta Pictoris, their long tails lighting up the skies of the fledgling planets forming there.

These images from the Hubble Space Telescope show the comet C/2014 UN271 (Bernardinelli-Berstein), the biggest comet ever seen, NASA says.

'Megacomet' Bernardinelli-Berstein is largest ever seen, Hubble telescope confirms

By Chelsea Gohd published

A gigantic comet is actually the largest ever seen, new observations by the Hubble Space Telescope confirm.

Returning comets fade even when they don't approach the sun, a new study found.

Comets fade even as deep in space as Saturn's orbit, scientists find

By Elizabeth Howell last updated

When comets first appear near Earth, their bright tails of ionized gas stun observers, but on every subsequent return, they become dimmer.

A comet known as C/2021 O3 (Pan-STARRS) may be visible in the night sky in April 2022.

Recently discovered Comet Pan-STARRS could be visible in April's night sky (maybe)

By Joe Rao published

Recently discovered comet Pan-STARRS is heading towards the sun in late April, but will we be able to see it?

The asteroid Ryugu, as seen by Japan's Hayabusa2 spacecraft on June 30, 2018.

Asteroid Ryugu may be a remnant of an extinct comet

By Samantha Mathewson published

Observations from the Hayabusa2 mission have astronomers questioning the true origin of asteroid Ryugu, a new study shows.

Astrophotographer Chris Schur captured this stunning photo of Comet Leonard on Dec. 4, 2021 from Payson, Arizona using a 10-inch Newtonian telescope and 60-minute camera exposure.

Comet Leonard has broken into pieces as it rounds the sun: report

By Elizabeth Howell published

Comet Leonard, the brightest comet of 2021 has disintegrated, according to EarthSky.

Comet 67P/Churyumov-Gerasimenko, like the solar system's other small bodies, is shaped by geological processes rather than by gravity.

Why are asteroids and comets such weird shapes?

By JoAnna Wendel published

While planets and some moons are almost perfectly spherical, the smaller bits of the solar system, such as asteroids and comets, come in all different shapes. But why is that?

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

Largest comet ever observed bumps Hale-Bopp from pedestal

By Stephanie Pappas published

The Bernardinelli-Bernstein comet is officially the largest ever observed, according to new measurements.

Hale-Bopp comet is regarded as one of the most viewed comets in history.

Comet Hale-Bopp: Facts about the bright and tragic comet

By Elizabeth Howell, Daisy Dobrijevic last updated

Reference Hale-Bopp was an unusually bright comet that flew close to Earth in 1997. Tragically, Hale-Bopp also influenced the Heaven's Gate cult's mass suicide.

Comet ISON, as photographed by the TRAPPIST national telescope at ESO's La Silla Observatory on Nov. 15, 2013.

Comet impact may have triggered decline of Ohio's Hopewell people 1,600 years ago

By Doris Elin Urrutia published

Researchers think that comet fragments may have exploded over Ohio 1,600 years ago, triggering a violent airburst and starting wildfires that devastated the Hopewell people's crops and the landscape.

A set of superimposed images captured by the Solar Orbiter show Comet Leonard and its two tails in visible light.

European sun probe flew through the tail of Comet Leonard

By Meghan Bartels last updated

As Comet Leonard bid farewell to Earth and flew past Venus, a sun-studying spacecraft flew through the comet's long tail, giving humans a new perspective on the icy wanderer.

An artist's illustration of the evolution of the interstellar object 'Oumuamua, whose weird, elongated shape may have come from tidal forces.

Could a spacecraft 'catch up' to interstellar visitor 'Oumuamua in just 26 years?

By Chelsea Gohd published

Could we send a spacecraft to the giant, cigar-shaped interstellar interloper 'Oumuamua? Should we?

Astrophotographer Chris Schur captured this stunning photo of Comet Leonard on Dec. 4, 2021 from Payson, Arizona using a 10-inch Newtonian telescope and 60-minute camera exposure.

Amazing photos of Comet Leonard in the night sky

By Elizabeth Howell published

Astrophotographers captured incredible views of the celestial visitor.

Leonardo DiCaprio (left) and Jennifer Lawrence portray ignored astronomers in Netflix's "Don't Look Up," a comet impact movie that doubles as a climate change warning.

Climate scientist and Netflix 'Don't Look Up' director talk comet metaphors and global warming (exclusive)

By Elizabeth Howell last updated

Adam McKay, creator of Netflix's popular satire-comedy movie "Don't Look Up," and climate scientist Kate Marvel talk why the world needs more films like the comet metaphor movie.

An image of Halley's Comet taken in 1986.

Halley's Comet: Facts about history's most famous comet

By Elizabeth Howell published

The comet's frequent recurrence has played a part in historical events for millennia.

A view of Comet Leonard as seen over Australia.

Comet Leonard puts on a final, spectacular display with ion tail in solar wind

By Meghan Bartels last updated

Comet Leonard is slipping out of view, but not without putting on one last show.

The newfound comet C/2021 A1 (Leonard) will reach perihelion, its closest point to the sun, on Jan. 3, 2022.

Comet Leonard makes its closest approach to the sun today, one year after its discovery

By Elizabeth Howell published

Comet Leonard shines brightly in images captured by a small Chinese satellite on the backdrop of aurora and passing meteors.

An image of Comet ISON shows a greenish tinge to the head, but not the tail.

Comets' heads may be green, but never their tails, study finds

By Samantha Mathewson published

Comets heat up very quickly as they approach the sun, causing the icy bodies to glow green, but never in the tails trailing behind them. A new study may finally reveal why.