Explained | All we know about the Bernardinelli-Bernstein comet, the largest one ever seen

The challenge in measuring comet Bernardinelli-Bernstein’s size was to separate the nucleus from the coma.

The challenge in measuring comet Bernardinelli-Bernstein’s size was to separate the nucleus from the coma.

The story so far: The National Aeronautics and Space Administration (NASA) Hubble Space Telescope has confirmed that the giant comet Bernardinelli-Bernstein is indeed the largest icy comet nucleus astronomers have ever seen. Officially called C/2014 UN271, this comet has an estimated diameter of nearly 129 kilometers. Its nucleus is about 50 times larger than most known comets, and its mass is estimated to be about 500 trillion tons.

What is the comet Bernardinelli-Berstein?

The comet was discovered by astronomers Pedro Bernardinelli and Gary Bernstein in archive footage from the Dark Energy Survey of an astronomical observatory in Chile. It was discovered by accident in November 2010 and has been intensively studied ever since.

“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. We have always suspected that this comet must be large because it is so bright at such a great distance. Now we confirm that it is,” David Jewitt, a professor of planetary science and astronomy at the University of California, Los Angeles, said in a statement from NASA.

The comet Bernardinelli-Berstein has been traveling to the sun for more than a million years and is believed to have originated in the Oort cloud, a distant region of the solar system that is predicted to be the source of most comets.

The Oort Cloud is still only a theoretical concept, as the comets that make up it are too faint and too far away to be directly observed. It was first hypothesized by Dutch astronomer Jan Oort in 1950.

The comet Bernardinelli-Berstein follows an elliptical orbit spanning 3 million years and has an estimated temperature of minus 348 degrees Fahrenheit — hot enough to sublimate carbon monoxide from its surface to produce the dusty coma.

How was the comet’s size measured?

The challenge in measuring the size of the Bernardinelli-Bernstein comet was to separate its nucleus from the coma — a sheath of dust that surrounds the nucleus. Because the comet is too far away to be accurately measured by the telescope, a team of researchers created a computer model of the surrounding coma and matched it with images taken with the Hubble Space Telescope. The glow from the coma was then subtracted to reveal the nucleus.

Is the comet a threat?

It is unlikely that comet Bernardinelli-Bernstein could become a threat to Earth. It travels at 22,000 miles per hour from the edge of the solar system toward us, but it will never get closer than a billion miles from the sun. That’s a little further than the planet Saturn, and even this situation is unlikely to arise until 2031.

What is the Hubble Space Telescope?

The Hubble Space Telescope was launched by NASA in 1990 and is named after Edwin Hubble, a respected American astronomer of the early 20th century. The telescope is an observatory in space and has made important observations regarding interstellar objects, including moons around Pluto and a comet collapsing on Jupiter. The telescope has been in operation for over thirty years now.

SOURCE – www.thehindu.com

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