Not Like Venus Or Mars, Distant Exoplanet May Have Atmosphere Like Earth's

A distant exoplanet might have an atmosphere similar to Earth's, early observations from the James Webb Space Telescope (JWST) suggest. It is part of a group of planets orbiting a star called TRAPPIST-1, about 40 light-years away from Earth.

The TRAPPIST-1 system, discovered in 2016 by five Belgian astronomers who named it after their favourite beer, has been studied extensively ever since. It has several planets that could potentially have conditions suitable for life, according to a report by CNN.

Nestor Espinoza, an astronomer at the Space Telescope Science Institute in Baltimore, described the TRAPPIST-1 system as "as alien as it gets." He explained that the star is very small, about the size of Jupiter, and is orbited by at least seven rocky planets.

"Three of those are in what we call the habitable zone, which means they are close enough to the star that if they had an atmosphere, they could sustain liquid water," he said.

The study, published last week in The Astrophysical Journal Letters, analysed data from four observations made with the JWST in 2023. These observations didn't confirm an atmosphere but scientists have 15 more observations planned, which could provide a clearer picture in the future, said Mr Espinoza.

The study suggests that TRAPPIST-1 e probably doesn't have an atmosphere like Venus or Mars, which are full of carbon dioxide. Instead, they believe that the atmosphere might be rich in nitrogen, which makes it more like Earth's atmosphere or the atmosphere of Saturn's icy moon, Titan.

If confirmed, this would be the first time an Earth-like atmosphere has been detected on a planet outside our solar system.

TRAPPIST-1 e is similar in size to Earth, but it orbits its star much faster than Earth does around the sun. "If you could magically bring the TRAPPIST-1 star to our solar system, all the planets and their orbits would fit within the orbit of Mercury," said Espinoza.

Sara Seager, a professor of planetary science at the Massachusetts Institute of Technology and coauthor of both studies, said, "The evidence pointing away from Venus- and Mars-like atmospheres sharpens our focus on the scenarios still in play."

Mr Espinoza said that even if TRAPPIST-1 e is found to have no atmosphere, the finding would still be important as it paves the way for future studies.