Comets Archives

August 13, 2023August 13, 2023 by Brian Koberlein

Vera Rubin Will Find Many More Interstellar Objects

Illustration of an interstellar object approaching our solar system. Credit: Rubin Observatory/NOIRLab/NSF/AURA/J. daSilva

Most of the comets we see in the sky were born in our solar system. They may have formed deep within the Oort cloud, and for some, it is their first visit to the inner solar system, but they are distinctly children of the Sun. We know of only two objects that came from beyond our solar system, Omuamua and Borisov. There are likely other interstellar objects visiting our solar system, we just haven’t found them. But that’s likely to change when Rubin Observatory comes online.

April 24, 2023April 24, 2023 by Nancy Atkinson

Here's How NASA is Planning to Protect Earth From Asteroids and Comets

This diagram shows the orbits of 2,200 potentially hazardous objects as calculated by JPL’s Center for Near Earth Object Studies (CNEOS). Highlighted is the orbit of the double asteroid Didymos, the target of NASA’s Double Asteroid Redirect Test (DART) mission. Credit: NASA/JPL-Caltech

The large impact craters dotting our planet are powerful reminders that asteroids and comets strike the Earth from time to time. As often said, it’s not a question of “if”; it’s a matter of “when” our planet will face an impending strike from space. But an impact is one existential threat humanity is finally starting to take seriously and wrap its head around.

Seemingly spurred by the success of the Double Asteroid Redirection Test (DART), NASA just released a new planetary defense strategy and action plan, describing its efforts to find and identify potentially hazardous objects to provide an advanced warning, and then even push them off an impact trajectory.

This 10-year strategy looks to advance efforts to protect the Earth from a devastating encounter with a Near Earth asteroid or comet.

March 10, 2023March 10, 2023 by Evan Gough

Water’s Epic Journey to Earth Began Before the Sun Formed

This artist’s impression shows the planet-forming disc around the star V883 Orionis. New research shows how water starts its journey in the gas cloud that forms the star, and eventually ends its journey on Earth. Image Credit: ESO/L. Calçada

The origins of Earth’s water is a complicated mystery that scientists have been untangling for decades. Life is impossible without water, so the origin of Earth’s life-giving water is a foundational question. As the power of our telescopes grows, researchers have made meaningful headway on the question.

Previous research uncovered links between Earth’s water and the Solar System’s comets and icy planetesimals. But newer research follows the chain back even further in time to when the Sun itself had yet to form.

December 20, 2022December 20, 2022 by Evan Gough

We Could Spread Life to the Milky Way With Comets. But Should We?

Gerald Rhemann captured this incredible image of Comet Leonard when a piece of the comet's tail was disconnected and carried away. Rhemann won Astronomy Photographer of the Year 2022 for the image. Image Credit: Gerald Rhemann

Here’s a thorny problem: What if life doesn’t always appear on planets that can support it? What if we find more and more exoplanets and determine that some of them are habitable? What if we also determine that life hasn’t appeared on them yet?

Could we send life-bringing comets to those planets and seed them with terrestrial life? And if we could do that, should we?

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.