Discovery on rocky habitable-zone planet marks breakthrough in search for alien life

Escaping helium confirms the planet is wrapped in gas, opening a new path to studying distant worlds

LHS 1140 b, a potentially rocky world, larger than earth via NASA.gov

Scientists have detected an atmosphere around a rocky, potentially habitable planet for the first time, a discovery hailed as a major milestone in the search for extraterrestrial life.

The planet, LHS 1140 b, was identified a decade ago and is known to closely resemble Earth in composition, though somewhat larger, states The Independent.

It orbits within its star's “habitable zone”, where conditions allow for liquid water, a key requirement for life.

"An atmosphere is essential for a planet to support life as we know it. This is the first time anyone has found an atmosphere on a rocky planet in the habitable zone of another star," said Collin Cherubim of Harvard University, who led the research.

Researchers had theorised the planet's upper atmosphere would be rich in helium, slowly leaking into space.

Using the WINERED Spectrograph at the Magellan Observatory in Chile, the team confirmed the escaping helium, verifying the atmosphere's presence.

"This was clear evidence of an atmosphere on a habitable-zone exoplanet," said Shreyas Vissapragada, also of Harvard University. "It was an absolute thrill to see the transit spectra and slowly realise the implications."

Unlike earlier methods tracking dips in starlight, this approach detected escaping gases directly, offering a new way to identify atmospheres on distant rocky worlds.

Scientists now hope to study the planet further, including with NASA's James Webb Space Telescope, to confirm the atmosphere's makeup.

"Is it a bare rock that sometimes burps up gas that then escapes, or is there a steady-state atmosphere there?" said Jason Dittmann of the University of Florida, who discovered the planet.

"JWST data over the next four to five years will look for water. If there's water, it's probably a stable atmosphere."

The findings are published in the journal Science under the title "Helium escaping from the atmosphere of a nearby rocky exoplanet orbiting in a habitable zone".