Though it's headed in our direction, the Bernardinelli-Bernstein comet will completely miss Earth.
NOIRLab/NSF/AURA/J. da SilvaAstronomers have just confirmed the largest icy comet ever observed—and it’s headed in our direction. It’s a harmless giant, though. At its closest point to Earth, around the year 2031, astronomers say it will reach 1 billion miles away from the sun, about the distance of the planet Saturn.
The Hubble Space Telescope took new observations of the monster comet, C/2014 UN271, also called the Bernardinelli-Bernstein comet after its discoverers, Pedro Bernardinelli and Gary Bernstein. The comet was first observed in November 2010, when it was about as far away as Neptune, in the outer reaches of our solar system. Since then, astronomers have been trying to determine its true size and trajectory.
The team that just confirmed the comet’s size used the Hubble to take five photos of it on January 8, 2022. They then analyzed those images to see if they could distinguish the rocky nucleus at the center of the comet from the envelope of dust and other particles haloed around it. With those images, they estimate that the Bernardinelli-Bernstein comet’s nucleus is approximately 80 miles across, making it larger than the state of Rhode Island.
This comet is more than 30 percent bigger than the previous record holder, a comet spotted in 2002 with a nucleus of about 60 miles across. It also has a staggering estimated mass of 500 trillion tons, 100,000 times greater than typical comets in our solar system. An illustration comparing of the icy, solid centers of several comets, including Bernardinelli-Bernstein and Halley’s comet .The Bernardinelli-Bernstein comet is currently at the edge of our solar system and has been shooting toward the sun for over 1 million years, traveling at 22,000 mph. Its origin is a mystery, though it is hurtling toward us from the Oort Cloud, which astronomers hypothesize to be a nesting ground for trillions of comets.