Comet Atlas was the ‘son’ of a comet that passed through Earth 5,000 years ago

Comet Atlas, which intrigued astronomers with its first appearance in our sky in late 2019 but disintegrated into 30 tiny ice fragments months later, has returned to scientists’ focus. They discovered that the star could be the ‘son’ of another comet that passed through Earth 5,000 years ago.

Research carried out while the Atlas was still intact shed light on its “family”, which dates back thousands of years. It was first detected by the Asteroid Terrestrial-impact Last Alert System operated by the University of Hawaii on December 28, 2019.

Quanzhi Ye, an astronomer at the University of Maryland, observed the comet using the Hubble Space Telescope. Ye and his colleagues used their observations to determine that comet Atlas was actually a remnant of another celestial body, which likely streaked our sky 5,000 years ago.

This ancient comet came within 23 million miles of the Sun, closer than Mercury is to our star, and Stone Age civilizations across North Africa and Eurasia likely witnessed the celestial vision.

The study was published in July in the Astronomical Journal. There are no records of this sighting, but studying comets from the way Ye and her team analyzed the Atlas helps trace their origins.

Comets ‘sons’ of the same ‘father’

The Atlas’ orbit around the Sun followed a path similar to that of a comet observed in 1844, suggesting that both comets were “brothers” that came from a “parent” comet that split centuries earlier.

The Atlas and the 1844 star were originally “connected” by amateur astronomer Maik Meyer.

It is not uncommon for a comet to split into a “family”. Several telescopes, including Hubble and even the Galileo spacecraft, focused their lenses on Jupiter in July 1994, when comet Shoemaker-Levy 9 was destroyed by the gas giant’s gravitational pull.

He formed a “comet train” made from pieces of the comet that formed a line.

Comet Atlas is different, having disintegrated when it was farther from the Sun than Earth – unlike its original comet, which was closer to the Sun when it split.

“If it separated so far from the Sun, how did it survive the last pass around the Sun 5,000 years ago? This is the big question,” Ye said in a statement. “It’s very unusual because we didn’t expect it. This is the first time that a member of a comet family this ancient has been seen separating before passing close to the Sun.”