[Image: ESA/Hubble / Flickr]
A giant planet 124 light years from Earth has yielded the strongest evidence yet that extraterrestrial life may be thriving beyond our solar system, astronomers claim.
Using data from the James Webb Space Telescope (JWST), astronomers have identified the chemical fingerprints of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) – molecules that indicate life.
The molecules have been detected in the atmosphere of exoplanet K2-18b, which is located around 124 light-years from Earth in the constellation of Leo.
It is orbiting a red dwarf star in what is known as the ‘habitable zone’ – considered the most promising location to find life-supporting planets.
K2-18b is 2.6 times larger and 8.6 times as massive as Earth, and experts believe it is likely covered in an ocean, making it what they call a ‘Hycean world’.
The planet’s temperature is similar to Earth’s, but it is orbiting so close to its star that a year there lasts just 33 days. When the Hubble space telescope appeared to spot water vapour in its atmosphere in 2019, scientists declared it “the most habitable known world” beyond the solar system.
“This is the strongest evidence to date for a biological activity beyond the solar system,” said Prof Nikku Madhusudhan, an astrophysicist at the University of Cambridge who led the observations. “We are very cautious. We have to question ourselves both on whether the signal is real and what it means.”
He added: “Decades from now, we may look back at this point in time and recognise it was when the living universe came within reach.” “
This could be the tipping point, where suddenly the fundamental question of whether we’re alone in the universe is one we’re capable of answering.”
Earlier observations identified methane and carbon dioxide in its atmosphere – the first time that carbon-based molecules had been discovered on an exoplanet in the habitable zone. Now, analysis of new data has unearthed the compounds which, as far as scientists are aware, are only produced by living organisms.
The findings, published in The Astrophysical Journal Letters, suggest concentrations of DMS, DMDS or both (their signatures overlap) thousands of times stronger than the levels on Earth.
“There may be processes that we don’t know about that are producing these molecules,” Madhusudhan said. “But I don’t think there is any known process that can explain this without biology.”
“This suggests the planet may be teeming with microbial life.”
Dr Nora Hänni, a chemist at the Physics Institute of the University of Berne, whose research revealed that DMS was present on an icy, lifeless comet, is a little more wary of the claims of ‘life.’
“Life is one of the options, but it’s one among many. We would have to strictly rule out all the other options before claiming life.”
At 120 light years away, however, nobody will be travelling to K2-18b soon. But if there is indeed life, we should definitely slap some tariffs on them.
[Source: Daily Mail & Guardian]
