Comets Archives

December 9, 2022December 9, 2022 by Carolyn Collins Petersen

Comets Leave Dusty Trails That Surround the Solar System

Could the solar system be enveloped in a shell of faintly glowing dust from comets? Courtesy NASA/ESA/STSci

Comets are messy things. They scatter bits of dust as they travel through the solar system. If Earth happens to encounter one of those cometary dust trails, we get to see a meteor shower.

June 20, 2022June 20, 2022 by Nancy Atkinson

Astronomers Watched a “Near-Sun” Comet Disintegrate as it Flew too Close to the Sun

Near-Sun object 323P/SOHO observed by the Subaru Telescope on December 21, 2020 (left) and CFHT on February 11, 2021 (right). 323P/SOHO on its way to perihelion is seen as a point source in the center of the left image; after the perihelion, the comet has developed a long narrow tail as seen in the right image. (Credit: Subaru Telescope/CFHT/Man-To Hui/David Tholen)

Comets that venture close to the Sun can transform into something beautiful, but sometimes they encounter incineration if they get too close. Of the various types of comets that orbit close to the Sun, astronomers had never seen the destruction of the type classified as “near-Sun” comets. But thanks to a variety of telescopes on summit of Mauna Kea in Hawai?i, scientists have now captured images of a periodic rocky near-Sun comet breaking apart. They say the disintegration of this comet could help explain the scarcity of such periodic near-Sun comets.

June 14, 2022June 14, 2022 by Laurence Tognetti

ESA Gives Green Light on its Comet Interceptor Mission

Comets, with their long, beautiful, bright tails of ice, are some of the most spectacular sightings in the night sky. This was most apparent when Comet NEOWISE passed by Earth in the summer of 2020, dazzling viewers from all over the planet while being mainly visible in the northern hemisphere. Even though the sky might look the same night after night, comets are a humble reminder that the universe is a very active and beautiful place.

April 14, 2022April 14, 2022 by Nancy Atkinson

Hubble Confirms Comet C/2014 UN271 is an Absolute Unit, Astronomically Speaking

This diagram compares the size of the icy, solid nucleus of comet C/2014 UN271 (Bernardinelli-Bernstein) to several other comets. The majority of comet nuclei observed are smaller than Halley’s comet. They are typically a mile across or less. Comet C/2014 UN271 is currently the record-holder for big comets. And, it may be just the tip of the iceberg. There could be many more monsters out there for astronomers to identify as sky surveys improve in sensitivity. Though astronomers know this comet must be big to be detected so far out to a distance of over 2 billion miles from Earth, only the Hubble Space Telescope has the sharpness and sensitivity to make a definitive estimate of nucleus size. Credits: Illustration: NASA, ESA, Zena Levy (STScI)

It’s official. Comet C/2014 UN271 (Bernardinelli-Bernstein) has the largest nucleus ever seen in a comet. The gargantuan comet was discovered in the fall of 2021, and in January 2022, astronomers turned the Hubble Space Telescope to ascertain more details and determine the exact size.

NASA said a team of scientists has now estimated the diameter is approximately 129 km (80 miles) across, making it larger than the state of Rhode Island. The nucleus is about 50 times larger than other known comets. Its mass is estimated to be a staggering 500 trillion tons, a hundred thousand times greater than the mass of a typical comet found much closer to the Sun.

March 24, 2022March 24, 2022 by Evan Gough

Asteroid Ryugu Might Actually Be a Dead Comet

egion of the highest resolution image. Yellow boxes correspond to the region in Figure 1. (Left) The region is shown on the ONC-T global image of Ryugu. (Right) ONC-W1 image, taken at 70 m height. 2018-09-21 13:02(JST). Credit: JAXA

In 2014, the Japanese Space Agency JAXA launched the Hayabusa 2 spacecraft to visit asteroid Ryugu. It arrived at the asteroid in June 2018 and studied it from orbit for over a year. Hayabusa 2 even dispatched four rovers to the asteroid’s surface. After departing, it flew past Earth in December 2020, dropping off a sample of Ryugu.

Of all the scientific results from that impressive mission, the most interesting one might be this: Asteroid Ryugu might not be an asteroid. It might be the remnant of a comet.

March 11, 2022March 11, 2022 by Evan Gough

The Sun is Slowly Tearing This Comet Apart

A fine sungrazer nears its doom as seen via SOHOs LASCO C2 camera. Image credit: NASA/ESA/SOHO/NRLSungrazers

Using ground-based and space-based observations, a team of researchers has been monitoring a difficult-to-see comet carefully. It’s called Comet 323P/SOHO, and it was discovered over 20 years ago in 1999. But it’s difficult to observe due to its proximity to the Sun.

They’ve found that the Sun is slowly tearing the comet to pieces.

January 28, 2022January 30, 2022 by Nancy Atkinson

We Already Have the Technology to Save Earth From a “Don’t Look Up” Comet or Asteroid

DON'T LOOK UP (L to R) LEONARDO DICAPRIO as DR. RANDALL MINDY, JENNIFER LAWRENCE as KATE DIBIASKY. Cr. NIKO TAVERNISE/NETFLIX © 2021

What if a 10 km (6.5 mile)-wide asteroid was on a bee-line towards Earth, with an impending, calamitous impact just six months away? This was the scenario in the recent Netflix film, “Don’t Look Up.” The movie has led many to wonder if we have the resources and technology ready and available today to avert such a disaster.

A new paper looking at the technical aspects of such an endeavor says yes. Yes, we do.

January 6, 2022January 6, 2022 by Brian Koberlein

Why don’t Green Comets Have Green Tails?

Comet C/2014 Q2 Lovejoy photographed overnight December 28-29, 2014 remotely from Siding Spring, Australia as passed within 1/6 degree of the globular cluster M79. The coma glows green from fluorescing carbon molecules while the narrow ion tail is carbon monoxide gas fluorescing in UV sunlight. Credit: Rolando Ligustri

Green is an unusual color in astronomy. It is the color to which our eyes are most sensitive, and yet few things in the night sky actually appear green. There are, for example, no green stars, only yellow-white, red, and blue ones. But there can be green comets, and we are still learning why.

December 28, 2021December 28, 2021 by Nancy Atkinson

The Real Science Behind the Movie “Don’t Look Up”

The new movie “Don’t Look Up” — now available on Netflix — is not your usual sci-fi disaster film. Instead, it is a biting parody on the general public’s dismissal and indifference to science. While the movie is about a comet on a collision course with Earth, filmmakers originally meant “Don’t Look Up” to be a commentary on climate change denial. But it also is reflective of the current COVID denial and mask/vaccine resistance, as well as our existing political polarization. It also lays bare our preoccupation with social media. While the movie is sometimes funny, it can also be depressing and frustrating.

December 22, 2021December 23, 2021 by Nancy Atkinson

This Video of Comet Leonard (with Venus and Mercury) will Blow Your Mind

Comet Leonard seen by two spacecraft: The image at right was captured by NASA’s Solar Terrestrial Relations Observatory-A spacecraft's SECCHI/HI-2 telescope. Image on left is from the ESA/NASA Solar Orbiter spacecraft. Credit: NASA/ESA.

Since early this year, skywatchers on Earth have been tracking Comet Leonard, a kilometer-wide dirty snowball made of ice, rock and dust. Now, as it heads towards a close encounter with the Sun on January 3, 2022, several spacecraft – with the distinct advantage of having an unobstructed front-row seat to the action – have been keeping an eye on how the comet is changing and evolving as it heats up.