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Graphic shows the 600,000-year orbit of comet Bernardinelli-Bernstein.


Mega-comet is 10 years from closest approach to Earth

By Ninian Carter

September 30, 2021 - Comet Bernardinelli-Bernstein is one of the largest comets ever seen, measuring a colossal 150km wide. The newly discovered comet is set to fly through our inner solar system in 10 years.

Comet Bernardinelli-Bernstein is so large it has been classified as a dwarf planet. It was discovered by two University of Pennsylvania astronomers, Dr. Pedro Bernardinelli and Gary Bernstein, on June 19, 2021 beyond planet Uranus, and is on a trajectory that will bring it into the inner solar system for a once-in 600,000-year visit – reaching its closest approach to Earth in 10 year’s time.

The comet is thought to be a rare long-period variety visiting us from the farthest reaches of the solar system, about half a light-year from our sun. It likely originates from the Oort Cloud, a spherical mass of icy objects 50,000 to 100,000 astronomical units (AU: the Earth–Sun distance) from the Sun. Arguably the most famous comet in history, Halley’s Comet, is also thought to originate from the Oort Cloud.

Unfortunately, Comet Bernardinelli-Bernstein will not pass close enough to Earth for us to see it with the naked-eye, despite being three times larger than the biggest comet photographed to date, Comet Hale-Bopp in 1997.

However, huge telescopes will be able to gather good images of it in 2031, when it makes its closest approach between the orbits of Saturn and Uranus. What makes it so exciting for astronomers though, is that it has been discovered now, giving them 10 years to monitor it, and possibly prepare to launch a nuclear-powered spacecraft to fly out and study it up close.

The timing is also ideally suited to the Vera C. Rubin Observatory in Chile, set to commence operations in 2023. With its 3,200-megapixel camera, it will be able to track the object for at least the next decade, if not longer – possibly uncovering many more mega-comets in the process.

PUBLISHED: 30/09/2021; STORY: Graphic News