- BBC News World
A comet with a nucleus 50 times larger than usual is moving close to Earth at 35,000 kilometers per hour.
NASA’s Hubble Telescope determined that the comet’s icy core has a mass of about 500 billion tons and a width of 137 km, which is larger than the US state of Rhode Island.
But do not worry. Closest is 1.6 billion km from the sun, and it won’t be until 2031.
It was first seen in 2010, but only now has Hubble been able to confirm its existence.
It is larger than any comet that astronomers have seen before.
“We’ve always suspected that this comet should be so big because it’s so bright at such a great distance,” said David Jewett, professor of planetary sciences and astronomy at the University of California, Los Angeles (UCLA). “Now we confirm it.”
NASA, which describes the ice sphere as a “giant ball hurtling in this direction,” named it Bernardinelli-Bernstein after its discovery by astronomers Pedro Bernardinelli and Gary Bernstein.
They first saw it while working at the Cerro Tololo Pan-American Observatory in Chile more than a decade ago when it was more than 4.8 billion kilometers from the sun.
NASA describes comets as icy “LEGO blocks,” leftovers from the early days of planet-building.
“They were unceremoniously expelled from the Solar System in a gravitational pinball game between massive exoplanets,” it said in a statement.
“Ejected comets settled in the Oort Cloud, a vast reservoir of distant comets that surround the Solar System.”
Man Tu Hui, of the Macau University of Science and Technology, described the comet as an “amazing object,” adding: “We assumed that a comet could be very large, but we needed the best data to confirm that.”
Comet Bernardinelli-Bernstein has been following an elliptical orbit for 3 billion years, putting it away from the Sun by about half a light-year.
The comet is now located less than 3.2 billion kilometers from the sun, and falls almost perpendicular to the plane of our solar system.
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