Comets Archives

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.

October 14, 2021October 14, 2021 by Nancy Atkinson

The Biggest Comet Ever Seen Will get as Close as Saturn in 2031

A graphic comparing the size of Comet 2014 UN271 (Bernardinelli-Bernstein) to other solar system objects. Credit and copyright: Will Gater. Used by permission.

A mega-comet – potentially the largest ever discovered – is heading from the Oort Cloud towards our direction. Estimated to be 100–200 kilometers across, the unusual celestial wanderer will make its closest approach to the Sun in 2031. However, the closest it will come to Earth is to the orbit of Saturn.

June 24, 2021June 24, 2021 by Andy Tomaswick

A Newly-Discovered (Almost) Dwarf Planet Will Come Surprisingly Close in 2031

It’s good to remember how little we know about the outer solar system. Humans only really began observing it within the past 100 years, and given the constraints on that observations there are still plenty of things we don’t know about. For example, researchers recently found an object almost the size of a dwarf planet that is inbound to the inner solar system, with an estimated orbital period of over 2 million years, more than six the lifetime of the modern human species.

May 21, 2021May 21, 2021 by Andy Tomaswick

Comets Have Tails of gas, Dust… and Metal?

In outer space, an object’s location has a huge impact on its temperature. The closer the object is to its star, the hotter it most likely is. Heat then plays a major role in what materials are present in that object’s atmosphere, if it has one. Lighter elements such as hydrogen and helium and much easier to take a gaseous state and create an atmosphere. So it came as a surprise when two different teams found much heavier elements in the atmosphere of comets that were relatively far away from the Sun. And one of those comets happened to be from another solar system.