Still seeking proof of life outside our solar system? Buckle up, because we're one step closer.
A new paper, published today in Science, outlines the discovery of a potentially Earth-like atmosphere surrounding a nearby exoplanet that may provide clearer proof that other rocky masses can sustain the building blocks of life.
"This is the first time that we're seeing a rocky, Earth-like planet that could still have an atmosphere," said study co-author and University of Florida assistant professor of astronomy Jason Dittmann in a recent press release.
Dittman was part of the team that discovered the exoplanet, LHS 1140b, in 2016. LHS 1140b resides in the habitable zone of a nearby red-dwarf star and can only be observed during brief periods of the year due to its orbit. LHS 1140b is also quite old, which typically means most of the planet's atmosphere would have already been lost to space.
But using X-ray data from Chile's Magellan Clay telescope during two observation periods in 2024 and 2025, scientists pinpointed helium gas escaping the planet, indicating that the planet may have an atmosphere replenishing its gases. The composition of the planet's inner atmosphere is still unknown to scientists.
The confirmation of atmospheres that regulate climate on rocky planets has been a white whale for astronomers, who have so far observed only airlessness or faint atmospheric remnants.
"Because there’s helium there, and because the helium is escaping, the question is: Is it a bare rock with no atmosphere that sometimes burps up some gas that then immediately escapes, or is there a steady-state atmosphere there that will leak out stuff like the Earth does from time to time?" Dittmann said.
Should the findings be confirmed in further studies, LHS 1140b will check off at least two of the three life-sustaining boxes (an atmosphere and a rocky surface) that scientists look for in non-Earth planets. All that's left is that liquid gold: water.
