Hubble announces largest comet ever seen 500 trillion tons heading towards Earth

Comets are among the oldest objects in the solar system and are inhabitants of deep space. These cold "Lego bricks" are left over from when planets were first being built. 

In a gravitational pinball game between the huge outer planets, they were abruptly flung out of the solar system. The expelled comets settled in the Oort Cloud, a large collection of distant comets that surrounds the solar system and extends billions of kilometers into deep space.

This clip demonstrates how the solid, ice nucleus of Comet C/2014 UN271 (Bernardinelli-Bernstein) was separated from a sizable shell of dust and gas. A picture of the comet obtained by the Wide Field Camera 3 on January 8, 2022, is seen on the left. By fitting the surface brightness profile created from the observed picture on the left, a model of the coma (middle panel) was created. This made it possible to remove the coma and see the nucleus's pointlike light.

The nucleus size was precisely determined by astronomers using data from radio telescopes combined with their observations. That's a significant accomplishment coming from something 2 billion miles away. Despite being up to 85 miles across, the nucleus is so far away that Hubble cannot resolve it. Its size is calculated using Hubble's measurements of reflectance. According to estimates, the nucleus is as dark as charcoal. Based on radio measurements, the nucleus area is determined. Credit: David Jewitt (UCLA), Man-To Hui (Macau University of Science and Technology), NASA, ESA, and Alyssa Pagan for image processing (STScI)

The magnificent multimillion-mile-long tail of a typical comet, which gives it the appearance of a skyrocket, conceals the reality that the cause of the explosions is a solid core of ice mixed with dust, or a filthy snowball. Hubble scientists have discovered a comet with a nucleus that is larger than the majority, which are a few miles wide and could fit within a small town. It is possible for Comet C/2014 UN271 (Bernardinelli-Bernstein) to measure up to 85 miles wide, which is more than twice the breadth of the state of Rhode Island.

Astronomers Pedro Bernardinelli and Gary Bernstein found comet C/2014 UN271 in old photographs from the Dark Energy Survey at the Cerro Tololo Inter-American Observatory in Chile. It was accidentally noticed for the first time in 2010. With the aid of radio measurements, Hubble observations were required in 2022 to distinguish the solid nucleus from the vast dusty shell encasing it.

The comet will cycle back to its nesting area in the Oort Cloud in a few million years from now when it is fewer than 2 billion miles from the Sun.

The size of the biggest ice comet nucleus ever discovered was measured by Hubble. Also, it's huge! It is around 50 times bigger than regular comets, with a diameter of 80 miles. Its mass of 500 trillion tons is 100,000 times bigger than that of the typical comet. Credit: Paul Morris, lead producer; NASA's Goddard Space Flight Center

Largest Comet Nucleus Ever Observed Is Confirmed by Hubble

The Hubble Space Telescope of NASA has measured the dimensions of the biggest ice comet nucleus that has ever been seen. It is bigger than the state of Rhode Island, with an estimated circumference of around 80 miles. The nucleus is around 50 times bigger than the center of the majority of observed comets. It is thought to be 500 trillion times heavier than the average comet discovered far closer to the Sun in mass, or about 500 trillion tons.

C/2014 UN271 (Bernardinelli-Bernstein), a massive comet, is hurtling toward Earth at a speed of 22,000 miles per hour. But don't be alarmed. It will never be any closer to the Sun than 1 billion miles away, which is a little further than Saturn's distance. And it won't happen until 2031.

Comet C/2002 VQ94, whose nucleus is thought to be 60 miles large, previously held the record. The Lincoln Near-Earth Asteroid Research (LINEAR) team made the discovery of it in 2002.

According to David Jewitt, a professor of planetary science and astronomy at the University of California, Los Angeles (UCLA) and co-author of the recent study published in The Astrophysical Journal Letters, "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." The fact that this comet is so dazzling from such a great distance has long led us to believe it must be massive. We can now affirm that it is.

Astronomers Pedro Bernardinelli and Gary Bernstein found comet C/2014 UN271 in old photographs from the Dark Energy Survey at the Cerro Tololo Inter-American Observatory in Chile. It was accidentally discovered in November 2010, when it was a staggering 3 billion miles from the Sun—pretty close to Neptune's typical distance. Since then, ground- and space-based observatories have conducted extensive research on it.

Man-To Hui of the Macau University of Science and Technology in Taipa, Macau, who is the paper's main author, said: "This is an astonishing object, considering how active it is while it's still so distant from the Sun. We had a rough idea of the comet's size, but we required the best information to confirm it. So, on January 8, 2022, his team utilized Hubble to capture five images of the comet.

How to separate the solid core of this comet from the massive dusty coma that surrounded it was a measurement difficulty. The comet is now too far away for Hubble to discern its nucleus optically. Instead, a brilliant spike of light may be seen in the Hubble data around the nucleus. The last step was to create a computer model of the surrounding coma that Hui and his colleagues then modified to suit the Hubble photos. The coma's light was then removed to reveal the star-like core.

The brightness of the nucleus was compared by Hui and his colleagues to prior radio measurements made in Chile using the Atacama Large Millimeter/submillimeter Array (ALMA). The diameter and reflectivity of the nucleus are restricted by the combined data. The new Hubble observations strongly point to a darker nucleus surface than was previously believed, yet they are close to the earlier ALMA size estimates. It's large and darker than coal, according to Jewitt.

For well over a million years, the comet has been moving in the direction of the Sun. The Oort Cloud, which is thought to be the home of billions of comets, is where it is coming from. The inner edge of the diffuse cloud is estimated to be between 2,000 and 5,000 times further away from the Earth than the Sun. Its outer border may reach at least a fourth of the way out to the Alpha Centauri system, which contains the closest stars to our Sun.

The comets of the Oort Cloud didn't originate that far from the Sun; rather, they were flung out of the solar system billions of years ago by a gravitational "pinball game" between the enormous outer planets, while Jupiter and Saturn's orbits were still forming. The far-far comets can only return to the Sun and planets if a passing star's gravitational pull disturbs their orbits, tossing them from the tree like apples.

In its 3-million-year-long elliptical orbit, the comet Bernardinelli-Bernstein travels as far from the Sun as almost half a light-year. Currently, the comet is plummeting roughly perpendicular to the plane of our solar system and is fewer than 2 billion miles from the Sun. Temperatures are just around - 348 degrees Fahrenheit at that distance. The dusty coma is the result of carbon monoxide sublimating off the surface at such temperature, however.

The comet Bernardinelli-Bernstein offers crucial information on the Oort Cloud's overall mass and the size distribution of its comets. The mass of the Oort Cloud has been estimated to be as much as 20 times that of Earth.

The Oort Cloud, first proposed by Dutch astronomer Jan Oort in 1950, is still just a hypothesis since the many comets that make up it are too weak and far enough to be directly spotted. Ironically, this implies that the biggest structure in the solar system is almost undetectable. According to estimates, it might take up to 30,000 years for NASA's two Voyager probes to traverse the Oort Cloud and another 300 years to reach its core region.

Infalling comets that may be traced back to this breeding habitat provide circumstantial proof. The cloud must be spherical in form because of the many ways they approach the Sun. These comets are long-preserved, deep-freeze samples of the early solar system's makeup. Theoretical simulations of the solar system's genesis and development support the actuality of the Oort Cloud. The more observational data that can be acquired by multiwavelength and deep sky surveys, the more astronomers will be able to comprehend the Oort Cloud's function in the development of the solar system.

The size of comet C/2014 UN271 (Bernstein-Bernstein)'s icy, solid nucleus is shown in this diagram in comparison to those of several other comets. Most of the detected comet nuclei are smaller than Halley's comet. Usually, they are a mile across or smaller. For large comets, Comet C/2014 UN271 currently holds the record. And that could just be the very top of the iceberg. As sky surveys become more sensitive, there may be many more monsters for astronomers to find. Only the Hubble Space Telescope has the clarity and sensitivity to provide a precise estimate of the nucleus size, despite the fact that astronomers already know this comet must be large to have been detected at a distance of over 2 billion miles from Earth. Illustration credit: NASA, ESA, and Zena Levy