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The Hubble Telescope Confirms The Largest Comet Nucleus Ever Seen By Astronomers

Three side-by-side photos show the nucleus of a comet. Each shows a blue-white dot glowing blue in the blackness of space. The leftmost is grainy, and the dot's light is dispersed to the left. The center one is softer with more light spreading out to the left. The rightmost has very little glow.
This sequence shows how the nucleus of Comet C/2014 UN271 was isolated from a vast shell of dust and gas surrounding the solid icy nucleus. On the left is a photo of the comet taken by the NASA Hubble Space Telescope's Wide Field Camera 3 on Jan. 8. A model of the coma (middle panel) was obtained by fitting the surface brightness profile assembled from the observed image on the left.
(Space Telescope Science Institute
Macau University of Science and Technology)
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NASA's Hubble Space Telescope has confirmed the largest icy comet nucleus ever seen by scientists. The C/2014 UN271 (Bernardinelli-Bernstein) nucleus is about 80 miles in diameter, which is larger than the state of Rhode Island, NASA says.

The comet's nucleus is about 50 times larger than most comets and its mass is estimated to be a staggering 500 trillion tons.

"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," David Jewitt, a professor of planetary science and astronomy at the University of California, Los Angeles, said in a statement.

"We've always suspected this comet had to be big because it is so bright at such a large distance. Now we confirm it is," Jewitt added.

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Comet C/2014 UN271 was first discovered by astronomers Pedro Bernardinelli and Gary Bernstein using archival images from the Cerro Tololo Inter-American Observatory in Chile. The comet has been observed since 2010, when it was 3 billion miles away from the sun, and has been studied since then.

NASA says there was a challenge in measuring the comet's nucleus, because it was too far away for the Hubble telescope to determine its size. Instead, scientists had to make a computer model that was adjusted to fit the images of the bright light of the comet they got from the telescope's data.

Despite traveling at 22,000 mph, the massive comet is still coming from the edge of the solar system. But NASA assures that it will never get closer than 1 billion miles away from the sun — and even then, it won't be until 2031.

The previous record holder for largest comet nucleus was discovered in 2002. Comet C/2002 VQ94 was approximately 60 miles across.

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