At 4 billion years old, largest comet ever observed approaches Earth

posted on 04/13/2022 20:23


The Hubble telescope confirmed data on the comet’s mass and dimensions, but showed that it has a darker nucleus than estimated – (credit: NASA, ESA, Zena Levy (STScI))

The biggest comet ever observed by astronomers is heading towards Earth at a speed of 35,400 km/h. But don’t worry, there’s no need to panic. As usual in astronomy, proximity is a very relative concept. In this case, the closest C/2014 UN271 will come to the Sun (in the year 2031) is a distance of 1.6 billion kilometers. This means that, in nine years, it will pass a little farther from our planet than the path of Saturn — the sixth planet in the Solar System (in relation to the distance from the Sun).

Even so, the phenomenon is considered extraordinary by astronomers and astrophysicists and has been drawing the attention of scholars in the area for over ten years for several reasons. The first of these is the dimension of comet Bernardinelli-Bernstein, as C/2014 UN271 was named. The name is in honor of the two scientists who discovered it in 2010: Brazilian Pedro Bernardinelli and American Gary Bernstein.

With an estimated diameter of 130 km, a little less than the distance between the center of Brasília and the city of Pirenópolis, the comet was mistaken for a dwarf planet — like Pluto — at the time it was found. The confusion arose because finding a comet of this size is extremely rare, since its nucleus is about 50 times larger than the average of celestial bodies of the same category.

In addition, the Bernardinelli-Bernstein is considered a relic of the Solar System for its age, estimated at 4 billion years, and comes from a region about which there is almost no data, only theories, called the Oort Cloud. “This comet is literally the tip of the iceberg of many thousands of comets that are too faint to be seen in the most distant parts of the solar system,” explained David Jewitt, professor of planetary science and astronomy at the University of California (UCLA).

 This diagram compares the size of the icy, solid core of comet C/2014 UN271 (Bernardinelli-Bernstein) with several other comets.  Most observed comet nuclei are smaller than those of Halley's comet
This diagram compares the size of the icy, solid core of comet C/2014 UN271 (Bernardinelli-Bernstein) with several other comets. Most observed comet nuclei are smaller than those of Halley’s comet
(photo: NASA, ESA, Zena Levy)

Hubble confirms mass of approximately 500 trillion tons

Jewitt is co-author of a study on C/2014 UN271 published in The Astrophysical Journal Letters on Tuesday (13/4). For the scientist, one of the most important functions of the new data, collected through the Hubble telescope, is to confirm dimensions that, until then, scientists could only estimate.

With a mass of approximately 500 trillion tons, the comet has a core size equivalent to Mount Everest. That’s a hundred thousand times the mass of a typical comet found much closer to the Sun. C/2014 UN271, however, is less bright than scientists thought, with a rather dark and solid core, in addition to the cloud of dust and gas that surrounds it.

“We thought the comet could be quite large, but we needed the best data to confirm that,” said study lead author Man-To Hui, who earned his PhD at UCLA in 2019 and is now at the University of Science and Technology. of Macau in Taipa, Macau. “This is an amazing object, given how active it is when it’s still so far from the sun,” he added.

Sequence shows how the core of Comet C/2014 UN271 (Bernardinelli-Bernstein) was isolated from a vast shell of dust and gas surrounding the solid ice core
Sequence shows how the core of Comet C/2014 UN271 (Bernardinelli-Bernstein) was isolated from a vast shell of dust and gas surrounding the solid ice core
(photo: NASA, ESA, Man-To Hui (Macao University of Science and Technology), David Jewitt (UCLA). Image Processing: Alyssa Pagan (STScI))

The distance between the Bernardinelli-Bernstein and the sun is less than 3 billion kilometers. In a few million years, it will return to its place of origin in the Oort cloud, according to Professor Jewitt. The theory is that this region is home to trillions of comets and is a few hundred times the distance between the Sun and Earth, at least a quarter of the way to the distance of the closest stars to our Sun in the solar system. Alpha Centauri.

The article Hubble Space Telescope Detection of the Core of Comet C/2014 UN 271 (Bernardinelli–Bernstein) can be read in full (in English) on the The Astrophysical Journal Letters.

  • Comet C/2014 UN271 can be up to 85 miles (128 km) in diameter.

    Comet C/2014 UN271 can be up to 85 miles (128 km) in diameter.
    Photo: NASA, ESA, Zena Levy (STScI)

  •   This diagram compares the size of the icy, solid core of comet C/2014 UN271 (Bernardinelli-Bernstein) with several other comets.  Most observed comet nuclei are smaller than those of Halley's comet.  They are typically a mile in diameter or less.  Comet C/2014 UN271 is currently the record holder for large comets.  And, it may just be the tip of the iceberg.  There could be many more monsters out there for astronomers to identify as sky mappings improve sensitivity.  While astronomers know that this comet must be large to be detected so far at a distance of more than 2 billion miles from Earth, only the Hubble Space Telescope has the sharpness and sensitivity to make a definitive estimate of the size of the nucleus.

    This diagram compares the size of the icy, solid core of comet C/2014 UN271 (Bernardinelli-Bernstein) with several other comets. Most observed comet nuclei are smaller than those of Halley’s comet. They are typically a mile in diameter or less. Comet C/2014 UN271 is currently the record holder for large comets. And, it may just be the tip of the iceberg. There could be many more monsters out there for astronomers to identify as sky mappings improve sensitivity. While astronomers know that this comet must be large to be detected so far at a distance of more than 2 billion miles from Earth, only the Hubble Space Telescope has the sharpness and sensitivity to make a definitive estimate of the size of the nucleus.

    Photo: NASA, ESA, Zena Levy

  • Isolating the nucleus of a comet (IMAGE).  Sequence showing how the core of Comet C/2014 UN271 (Bernardinelli-Bernstein) was isolated from a vast shell of dust and gas surrounding the solid ice core.

    Isolating the nucleus of a comet (IMAGE). Sequence showing how the core of Comet C/2014 UN271 (Bernardinelli-Bernstein) was isolated from a vast shell of dust and gas surrounding the solid ice core.
    Photo: NASA, ESA, Man-To Hui (Macao University of Science and Technology), David Jewitt (UCLA). Image processing: Alyssa Pagan (STScI)

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