Comet Bernardinelli-Bernstein is the largest – NASA confirms “incredible object”

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Comet Bernardinelli-Bernstein (C/2014 UN271) is larger than any other comet known to date. © IMAGO/Cover images

NASA’s Hubble Space Telescope confirms what researchers have long suspected: Bernardinelli-Bernstein is the largest comet ever observed.

Los Angeles – Shortly after the discovery of comet Bernardinelli-Bernstein (C/2014 UN271) in the summer of 2021, one thing was clear: the comet is huge. “We may have discovered the largest comet ever seen,” said Gary Bernstein, who discovered the comet with his colleague Pedro Bernardinelli. Since then, the comet has been regularly observed. Now, a new study confirms what researchers had already guessed after the first sightings of the comet. “We’ve always suspected this comet must be big because it’s so bright at such a great distance. Now we can confirm that’s the case,” says astronomer David Jewitt of the University of California at Los Angeles (UCLA).

Jewitt is involved in a study of comet Bernardinelli-Bernstein published in Astrophysical Journal Letters. The comet is “an incredible object given its activity despite being so far from the Sun,” said study lead author Man-To Hui of Macau University of Science and Technology in Taipa. . Bernardinelli’s amber is currently about three billion kilometers from Earth, moving through the solar system at a speed of about 35,000 kilometers per hour. “We suspected the comet might be quite large, but we needed the best data to confirm that.” To obtain this data, the research team used NASA’s Hubble Space Telescope.

The giant comet Bernardinelli-Bernstein (C/2014 UN271) is larger than any comet before it

On January 8, 2022, the space telescope took five photos of the comet, which is currently heading towards the center of the solar system. The goal of the researchers: to know the size of the comet’s nucleus – an extremely difficult task since the star is very far away. Even in Hubble images, it’s very difficult to distinguish between the comet’s solid core and the surrounding coma – a diffuse, hazy envelope that can stretch for millions of miles. The Hui researchers eventually created computer models to distinguish the coma core.

C/2014 UN271 (amber Bernardinelli)
Oort cloud comet
Pedro Bernardinelli and Gary Bernstein
June 2021, oldest telescopic image subsequently discovered from October 20, 2014
119 to 137 kilometers
35,000 km/h
1.6 billion kilometers as of 01/31/2031

The comet’s nucleus is “bigger and blacker than coal,” Jewitt said in a statement from his university. The researchers estimate the comet’s nucleus to be between 119 and 137 kilometers in diameter – the previous record holder was comet C/2002 VQ94, whose nucleus was around 96 kilometers in diameter. Bernardinelli-Bernstein is more than 50 times larger than the nuclei of most known comets, explains the American space agency Nasa in a press release. Additionally, according to the research team’s calculations, Comet Bernardinelli-Bernstein has a mass of 450 trillion tons, 100,000 times more than the mass of a typical comet closer to the Sun.

Comet Bernardinelli-Bernstein comes from the Oort cloud

Comet C/2014 UN271 comes from a region at the edge of the solar system, the Oort cloud. The current research opinion is that there are trillions of comets out there. The Oort cloud would be about 300 to 750 billion kilometers from the sun. It stems from a theory by Dutch astronomer Jan Oort from 1950. Because the comets it contains are too far away and shine too faintly, the Oort cloud has not been observed to date – but it is considered the largest structure in the solar system. .

Comet Bernardinelli-Bernstein has been moving away from the Oort cloud for more than a million years and heading towards the Sun. Its elliptical orbit around the Sun will take it to its closest point to the Sun, called perihelion, in January 2031. The comet will then still be about 1.6 billion kilometers from the Sun. Before that, it must never have come as close to the sun as comet discoverers Bernardinelli, Bernstein and other researchers write in a study. “In fact, it may be the most pristine comet ever observed,” he says.

Comet size comparison: C/2014 UN271 (Bernardinelli-Bernstein) is significantly larger than any other comet observed so far.
Comet size comparison: C/2014 UN271 (Bernardinelli-Bernstein) is significantly larger than any other comet observed so far. © NASA, ESA, Zena Levy (STScI)

A comet is a “freezer” resulting from the formation of the solar system

Comets are considered “dirty snowballs” because their cores are usually made of dust and rock frozen together. When a comet approaches the sun, its surroundings heat up and the ice sublimes – it changes directly from a solid state to a gaseous state. This is how the comma and the tail of the comet are formed. The region of space where C/2014 UN271 is located is -211 degrees Celsius – a temperature at which carbon monoxide ice already sublimates. The researchers suspect that Comet Bernardinelli-Bernstein may have been active since 2008*.

Because the comets of the Oort cloud did not form on the outskirts of the solar system, but were right in the middle of what happened when planets were forming, they are considered valuable celestial bodies that can offer a overview of that time. Research suggests that when planets and moons formed, comets were thrown around the outskirts of the solar system and act as a “freezer” to preserve the elements of that time.

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The giant comet Bernardinelli-Bernstein will be observed more closely in the near future with new knowledge of its size. For nearly nine more years, the comet will approach Earth before returning to the Oort Cloud. (Tanya Banner) * is an offer of IPPEN.MEDIA.

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