It looks like a sliver of light on the snapshots, but scientists have confirmed that this newly discovered space snowball is the largest comet ever observed, spanning the length of more than three marathons.
A team of scientists used the Hubble Space Telescope, an Earth-orbiting observatory shared by NASA and the European Space Agency, to determine that Comet Bernardinelli-Bernstein has a nucleus about 50 times larger than the average known comets. This shiny ball of ice, dust and rock spans about 85 miles in diameter – more than twice the width of Rhode Island – and weighs 500 trillion tons. In comparison, it is more than 40% larger than the second.
The researchers say the scale of this comet is important because it provides a clue to the size range of comets orbiting in the far outskirts of our solar system. The so-called Oort cloud is a sphere of ancient icy objects surrounding the system. NASA says the cloud remains a theory because comets there have been too faint and too distant to be directly observed.
There could be billions of icy comets in the Oort cloud. That means Comet Bernardinelli-Bernstein may just be “the tip of the iceberg,” David Jewitt, a UCLA astronomer and co-author of the new research, said in a statement. (We hope the pun was intentional.)
A giant telescope based in the Chilean desert detected the comet in 2014. But it took years of intensive computation to sift through numerous sightings and identify the distant object, previously known as C/2014 UN271.
Why the mega comet is so fascinating – and not a threat to Earth
Scientists then knew it was huge but had not confirmed the measurements. A team used Hubble to take five photos of the comet on January 8. The new findings were published in Letters from the Astrophysical Journal April 12.
Given the comet’s activity despite its great distance from the sun (which heats and boils particles from closer comets), it’s “an amazing object”, said the study’s lead author. , Man-To Hui, in a statement.
“We guessed that the comet might be quite big,” said Hui, an astronomer from Macau University of Science and Technology, “but we needed the best data to confirm that.”
“…the tip of the iceberg.”
Comets, known for their million-mile-long streaks, are among the oldest objects in the solar system. These icy bodies are remnants of the early days of the formation of neighboring planets.
The previous record holder for the largest comet was C/2002 VQ94, with a core estimated to be 60 miles in diameter. Astronomers discovered it in 2002 with the Lincoln Near-Earth Asteroid Research (LINEAR) project.
On the left, the Hubble image of Bernardinelli-Bernstein; in the center, a computer model of the comet’s coma; on the right, the nucleus with the modeled coma removed.
Credit: NASA / ESAm / Man-To Hui (Macau University of Science and Technology) / David Jewitt (UCLA) / Image processing: Alyssa Pagan (STScI)
Hale-Bopp is not a competitor for Comet Bernardinelli-Bernstein.
Credit: NASA / ESA / Zena Levy (STScI)
Comet Bernardinelli-Bernstein, named after astronomers Pedro Bernardinelli and Gary Bernstein who discovered it, is approaching the sun from the edge of the solar system at 22,000 mph. Although the towering rock has often been described as “headed this way”, the space is a big place. It will never approach closer than a billion kilometers from the sun, a little further than the orbit of Saturn. Astronomers say it will reach that point in 2031.
Short: It does not approach the Earth.
The comet is now less than 2 billion miles from the sun and in a few million years will return to where it came from in the distant Oort Cloud.