'Megacomet' Bernardinelli-Berstein: The Largest Comet Nucleus Ever Discovered Is Bigger Than Rhode Island

The Hubble Space Telescope has discovered the most giant ice comet nucleus. This comet came from designated C/2014 UN271 Bernardinelli-Bernstein.

Researchers described their study, "Hubble Space Telescope Detection of the Nucleus of Comet C/2014 UN271 (Bernardinelli-Bernstein)," in The Astrophysical Journal Letters.

Hubble Confirms Largest Comet Nucleus Ever Seen — 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. NASA, ESA, Zena Levy (STScI)

NASA Hubble Space Telescope Confirms Largest Comet Nucleus Ever Met

The size of the biggest ice comet nucleus ever observed by astronomers has been established thanks to NASA's Hubble Space Telescope. It has an estimated diameter of 80 miles, making it bigger than the state of Rhode Island.

According to Slash Gear, the nucleus of this comet is nearly 50 times bigger than the nuclei of most known comets. It has a mass of 500 trillion tons, which is a hundred thousand times higher than a normal comet discovered considerably closer to the Sun.

C/2014 UN271 (Bernardinelli-Bernstein), a gigantic comet from the outside of the solar system, is barreling at us at 22,000 miles per hour. But don't be concerned. It will never go closer to the Sun than 1 billion miles, which is somewhat more than the distance between Saturn and the Sun. And it won't happen until 2031.

ALSO READ : Comet Bernardinelli-Bernstein as Big as 15 Mount Everests, Experts Say; Will It Pass By Earth By 2031?

Comet C/2002 VQ94 held the previous record with a nucleus estimated to measure 60 miles wide. The Lincoln Near-Earth Asteroid Research (LINEAR) project detected it in 2002.

Measuring a Comet

In archived pictures from the Dark Energy Survey at the Cerro Tololo Inter-American Observatory in Chile, astronomers Pedro Bernardinelli and Gary Bernstein identified comet C/2014 UN271. It was initially discovered by chance in November 2010, when it was 3 billion miles from the Sun, or almost the typical distance to Neptune. Since then, ground- and space-based telescopes have been studying it extensively.

The difficulty in measuring comets is that they have a dust shell around their solid frozen core or nucleus, making it difficult to view. Ground-based telescopes and space-based observatories like Hubble spotted the comet, albeit Hubble could not discern its nucleus due to its distance. The researchers compared computer predictions of what large it would have to be to shine in that fashion with Hubble photos and radio measurements. They discovered that, based on its size, the comet must weigh a whopping 500 trillion tons, or a hundred thousand times more than a usual comet.

Slash Gear said this ice monster is barreling at us at a pace of 22,000 miles per hour, but the good news is that it won't get much closer to the Sun than Saturn's orbit. However, studying it can aid astronomers in learning more about its smaller siblings.

Paper's lead author Man-To Hui of the Macau University of Science and Technology, Taipa, Macau, said in a NASA statement, "This is an amazing object, given how active it is when it's still so far from the Sun."