July 11 (UPI) -- Scientists believe an interstellar comet discovered earlier this month could be one of the oldest that astronomers have ever encountered.
University of Oxford scientists said the 3I/ATLAS comet could be some 3 billion years older than our solar system, which is believed to be 4.5 billion years old.
The comet was first reported by NASA's Asteroid Terrestrial-impact Last Alert System or ATLAS survey telescope in Chile on July 1, while so-called "pre-discovery" observations date back to June 14.
"Comet 3I/ATLAS was spotted on July 1, but it's not from around here. It came from outside our solar system and is only the 3rd known interstellar comet. Astronomers are studying it before it disappears," NASA's Jet Propulsion Laboratory said on X, accompanied by an image of the comet.
"This is an object from a part of the galaxy we've never seen up close before," University of Oxford astrophysicist Chris Lintott told space.com in a statement.
"We think there's a two-thirds chance this comet is older than the solar system, and that it's been drifting through interstellar space ever since."
It marks just the third known interstellar object from outside Earth's solar system and is expected to reappear on the other side of our sun in December, when it may be visible to amateur telescopes.
"All non-interstellar comets, such as Halley's comet, formed at the same time as our solar system, so they are up to 4.5 billion years old," fellow University of Oxford astronomer Matthew Hopkins said in a statement during the Royal Astronomical Society's annual meeting in Britain.
"But interstellar visitors have the potential to be far older, and of those known about so far, our statistical method suggests that 3I/ATLAS is very likely to be the oldest comet we have ever seen."
Calculations made by Hopkins and other scientists put the comet's age at over 7 billion years old. The astronomer told the conference he believes the comet originated in an area of the Milky Way Galaxy referred to as a "thick disk" of stars.
Comet 1I/'Oumuamua first seen in 2017, and 2I/Borisov observed in 2019, are the other two known interstellar objects detected by scientists on Earth.
