Interstellar Comet Likely Far Older Than Solar System: Astronomers

Paris: An interstellar comet that passed by the Sun last year may be nearly three times older than our Solar System and is unlike anything seen before in our cosmic backyard, astronomers said Monday.

Comet 3I/ATLAS is the third visitor humanity has ever observed from beyond our Solar System; Its unusual brightness offers scientists an unprecedented opportunity to study something from elsewhere in the galaxy.

The space rock caused a stir on the internet after it was detected in July last year; a prominent Harvard researcher speculated that it might be an alien spacecraft; This theory was refuted by NASA.

Now observations made with the world’s most powerful telescopes are revealing more about this unique comet.

According to a new study published in the journal Nature, the age of 3I/ATLAS may be up to 12 billion years old. Our Solar System is believed to have formed approximately 4.5 billion years ago.

“It is perhaps the oldest object observed in our Solar System,” lead study author Martin Cordiner of NASA’s Goddard Space Flight Center told AFP.

But he added that there may be “end-case scenarios” that offer other explanations for the comet’s unusual chemical composition.

The new research is based on the comet’s ratio of chemical elements called isotopes, detected by the James Webb space telescope and the ALMA observatory in Chile.

These measurements “reveal an elemental composition unlike any other body in the Solar System,” the study said.

– Is it a holdover from the ‘cosmic noon’? –

Compared to comets in our Solar System, 3I/ATLAS had about 30 times more deuterium, a type of hydrogen common in heavy water, NASA said.

“According to our understanding of astrochemistry, such a high abundance of heavy water can really only occur in a very cold environment,” Cordiner explained.

This means that the comet is probably among the coldest objects ever seen in our Solar System; Isotopic evidence shows that it formed in an environment at minus 243 degrees Celsius.

Exactly where this comet came from within the Milky Way remains a mystery.

But these interstellar objects are thought to form similarly to comets in our Solar System, ejected during the violent formation of a new planet.

Cordiner said 3I/ATLAS, which is not bound to any star, likely spent billions of years in “unimaginably wide orbits around our galaxy.”

Scientists also detected a strange lack of chemical enrichment in the comet; This suggests that it formed relatively close to the birth of stars.

Cordiner said it may even be a “relic” from a period called the “cosmic noon,” when many stars formed about 10 billion years ago.

Previous interstellar objects (1I/’Oumuamua detected in 2017, followed by 2I/Borisov in 2019) were not bright enough to collect isotopic evidence.

Harvard professor Avi Loeb, who previously sparked controversy by suggesting that ‘Oumuamua could be an alien spacecraft, made similar suggestions about 3I/ATLAS.

However, NASA rejected this possibility. The Extraterrestrial Intelligence Research Institute (SETI) announced last month that there was “no evidence of extraterrestrial technology” on the comet.

Oxford University researcher Steve Croft, of SETI’s Breakthrough Listening Initiative, told AFP that all observations of the comet were “consistent with it being a natural astrophysical object.”

– ‘Just the beginning’ –

Many astronomers who worked on 3I/ATLAS but were not involved in the new research welcomed the “unprecedented” results.

“Until these measurements, we could only really imagine obtaining this kind of information for an interstellar object,” Darryl Seligman of Michigan State University told AFP.

Noting that the comet’s age remains unclear, the official added that it is “a safe bet that it is older than anything that has formed in the Solar System.”

Peter Veres, an astronomer at the International Astronomical Union’s Minor Planet Center who was involved in identifying the comet, described the research as “exciting.”

“The comet is currently leaving the Solar System and will never return again, so future observations will become increasingly difficult,” he told AFP.

But astronomers expect to detect many more interstellar objects in the coming years, especially through the new Vera C. Rubin Observatory in Chile.

“This is just the beginning of an exciting new field; we still have a lot to learn about these things and what they can tell us about our galaxy,” Cordiner concluded.