{"id":796937,"date":"2025-06-26T11:59:07","date_gmt":"2025-06-26T16:59:07","guid":{"rendered":"https:\/\/spaceweekly.com\/?p=796937"},"modified":"2025-06-26T11:59:07","modified_gmt":"2025-06-26T16:59:07","slug":"mega-comet-bernardinelli-bernstein-is-erupting-with-jets","status":"publish","type":"post","link":"https:\/\/spaceweekly.com\/?p=796937","title":{"rendered":"Mega comet Bernardinelli-Bernstein is erupting with jets"},"content":{"rendered":"
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\nArtist\u2019s concept of Comet Bernardinelli-Bernstein. Astronomers have spotted the mega comet shooting out jets of carbon monoxide as it barrels toward the sun. Image via NSF\/ AUI\/ NSF NRAO\/ M. Weiss.<\/figcaption><\/figure>\n
Mega comet Bernardinelli-Bernstein is erupting with jets<\/h3>\n
An enormous comet, named Bernardinelli-Bernstein, is headed toward the sun. We first told you about this mega comet in 2021. But don\u2019t worry, it\u2019s not coming anywhere near Earth. On January 29, 2031, it will come closest to the sun at a comfortable 1 billion miles away, or slightly farther than Saturn\u2019s orbit. But on June 16, 2025, NSF\u2019s National Radio Astronomy Observatory said jets are erupting from the comet\u2019s nucleus as it barrels inward in our solar system.<\/p>\n
The 85-mile-wide (140-km-wide) comet is about 10 times the size of a typical comet. At the moment, Comet Bernardinelli-Bernstein is still more than halfway to Neptune. That\u2019s 16.6 astronomical units (AU) away, or more than 16 times the distance from Earth to the sun. Though it\u2019s still far away, astronomers used the Atacama Large Millimeter\/submillimeter Array (ALMA) in Chile to get a better look at it.<\/p>\n
The new observations confirm that this is the largest comet from the Oort Cloud we\u2019ve ever found. And they also showed carbon monoxide gas erupting in complex and evolving jets coming from the comet\u2019s nucleus. Lead author Nathan Roth of American University and NASA Goddard Space Flight Center said: <\/p>\n
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These measurements give us a look at how this enormous, icy world works. We\u2019re seeing explosive outgassing patterns that raise new questions about how this comet will evolve as it continues its journey toward the inner solar system.<\/p>\n<\/blockquote>\n
The astronomers published their peer-reviewed research in The Astrophysical Journal Letters<\/em> on June 12, 2025.<\/p>\n
More insight on Comet Bernardinelli-Bernstein<\/h3>\n
This is the first time astronomers have detected outgassing in the giant Bernardinelli-Bernstein. And astronomers expect it to increase its outgassing and jet activity as it gets closer to the sun, with its solar radiation pressure and solar wind. Continued observations of the comet\u2019s gases will help astronomers understand more about the comet\u2019s composition. In turn, that will provide more insight into the conditions of the early solar system. As the press release said: <\/p>\n
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Such discoveries help answer fundamental questions about where Earth and its water came from, and how life-friendly environments might form elsewhere.<\/p>\n<\/blockquote>\n
Previous news on Comet Bernardinelli-Bernstein<\/h3>\n
Scientists announced on April 12, 2022, that they created a high-quality image confirming C\/2014 UN271 (Bernardinelli-Bernstein), affectionately known as BB, is the largest Oort Cloud comet yet discovered. The new comet\u2019s nucleus, or core, is about 85 miles (140 km) wide, or about twice the size of Comet Hale-Bopp, which put on such a good show for us in 1997. And BB is headed for the inner regions of the solar system now.<\/p>\n
The good news is NASA says it\u2019ll come nowhere near Earth. From NASA\u2019s official announcement:<\/p>\n
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The behemoth comet, C\/2014 UN271 (Bernardinelli-Bernstein) is barreling this way at 22,000 miles per hour (35,400 kph), from the edge of the solar system. But not to worry. It will never get closer than 1 billion miles away from the sun, which is slightly farther than the distance of the planet Saturn. And that won\u2019t be until the year 2031.<\/p>\n<\/blockquote>\n
The team behind the study published their results on April 10, 2022, in the peer-reviewed Astrophysical Journal Letters<\/em>.<\/p>\nView larger. | Using these images from the Hubble Space Telescope\u2019s Wide Field Camera 3 taken on January 8, 2022, astronomers confirmed the biggest comet yet discovered is headed to the inner solar system. Image via NASA.<\/figcaption><\/figure>\n
Discovery of the biggest comet yet<\/h3>\n
University of Pennsylvania astronomers Pedro Bernardinelli and Gary Bernstein discovered the comet. They were reviewing images from 2014 to 2018 from the Dark Energy Survey as part of their computer-aided search for trans-Neptunian objects.<\/p>\nView larger. | This diagram compares the size of the icy, solid nucleus of comet C\/2014 UN271 (Bernardinelli-Bernstein or BB) to several other comets. The majority of comet nuclei are smaller than Halley\u2019s comet. They are typically a mile across or less. Comet C\/2014 UN271 is currently the record-holder for big comets. Though astronomers know this comet must be big for them to see it from more than 2 billion miles from Earth, only the Hubble Space Telescope has the sharpness and sensitivity to make a definitive estimate of the nucleus\u2019 size. Image via NASA\/ ESA\/ Zena Levy (STScI).<\/figcaption><\/figure>\n
Other big comets<\/h3>\n
The previous record holder for the largest comet nucleus was C\/2002 VQ94 (LINEAR). It measures about 60 miles (100 km) at its widest.<\/p>\n
The new big kid on the cosmic block is far from alone, said David Jewitt. Jewitt is a professor of planetary science and astronomy at UCLA and co-author of the study that refined the comet\u2019s measurements. Jewitt said:<\/p>\n
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This comet is literally the tip of the iceberg for many thousands of comets that are too faint to see in the more distant parts of the solar system. We\u2019ve always suspected this comet had to be big because it is so bright at such a large distance. Now we confirm it is.<\/p>\n<\/blockquote>\n
Comet BB is getting closer<\/h3>\n
While the discovery of Comet BB came in 2014, its first appearance on image data was in 2010. At that time, BB was 3 billion miles (4.8 billion km) from Earth, coincidentally about the average distance to Neptune.<\/p>\n
Already the core is shedding gas and dust at an impressive rate of about 2,200 pounds (1,000 kg) a second. The authors of the paper described it as:<\/p>\n
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\u2026 an enormous (albeit uncertain) mass-loss rate.<\/p>\n<\/blockquote>\n
It was that voluminous outpouring of gas and dust coming from a body so distant in the solar system that prompted the research team to try measuring what they suspected was a huge cometary body. Man-To Hui of the Macau University of Science and Technology, Taipa, Macau, led the team. Hui said:<\/p>\n
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This is an amazing object, given how active it is when it\u2019s still so far from the sun. We guessed the comet might be pretty big, but we needed the best data to confirm this.<\/p>\n<\/blockquote>\n
Obtaining images of Comet BB<\/h3>\n
To gather that data, Hui\u2019s team used the Hubble Space Telescope\u2019s Wide Field Camera 3 to take five photos of the comet on January 8, 2022.<\/p>\n
In announcing the team\u2019s find, NASA described the process team members used to discern the size of the nucleus against the backdrop of the glare of the comet\u2019s coma and tails:<\/p>\n
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The comet is currently too far away for its nucleus to be visually resolved by Hubble. Instead, the Hubble data show a bright spike of light at the nucleus\u2019 location. Hui and his team next made a computer model of the surrounding coma and adjusted it to fit the Hubble images. Then, the glow of the coma was subtracted to leave behind the starlike nucleus.<\/p>\n<\/blockquote>\n
By combining the Hubble data set with radio observations made by the Atacama Large Millimeter\/Submillimeter Array (ALMA) in Chile, the team was able to assign upper and lower limits to the size of C\/2014 UN271.<\/p>\n
The team also found the comet is less reflective than they originally thought. According to Jewitt:<\/p>\n
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It\u2019s big and it\u2019s blacker than coal.<\/p>\n<\/blockquote>\n
Bottom line: Astronomers have made new observations of the mega comet Bernardinelli-Bernstein. They\u2019ve found the comet is erupting with jets as it barrels toward the sun.<\/p>\n
Source: The First Detection of Molecular Activity in the Largest Known Oort Cloud Comet: ALMA Imaging of C\/2014 UN271 (Bernardinelli\u2013Bernstein) at 16.6 au from the Sun<\/p>\n
Source: Hubble Space Telescope Detection of the Nucleus of Comet C\/2014 UN271 (Bernardinelli\u2013Bernstein)<\/p>\n
Via NRAO<\/p>\n
Via NASA<\/p>\n
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Kelly Kizer Whitt<\/h4>\n
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About the Author:<\/h6>\n
Kelly Kizer Whitt – EarthSky\u2019s nature and travel vlogger on YouTube – writes and edits some of the most fascinating stories at EarthSky.org. She’s been writing about science, with a focus on astronomy, for decades. She began her career at Astronomy Magazine and made regular contributions to other outlets, including AstronomyToday and the Sierra Club. She has nine published books, including a children’s picture book, Solar System Forecast, and a young adult dystopian novel, A Different Sky.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n
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Dave Adalian<\/h4>\n
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About the Author:<\/h6>\n
Award-winning reporter and editor Dave Adalian’s fascination with the cosmos began during a long-ago summer school trip. That fieldtrip never ended, and still Dave pursues adventures under the night sky.
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\nDave grew up in California’s Tulare County – where the San Joaquin Valley meets the Sierra Nevada – a wilderness larger than Delaware and Rhode Island combined.
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\nHe studied English, American literature and mass communications at the College of the Sequoias and the University of California, Santa Barbara. He has worked as a reporter and editor for a variety news publications on- and offline during a career spanning more than 30 years.<\/p>\n<\/p><\/div>\n<\/p><\/div>\n
![\"Biggest](\"https:\/\/earthsky.org\/upl\/2022\/04\/Bernardellini-Bernstein-Hubble-NASA-ESA-e1649950867719.jpg\")
![\"Comparison](\"https:\/\/earthsky.org\/upl\/2022\/04\/Comet-BB-2-Size-Comparison-e1649919026826.jpg\")