Researchers have made a groundbreaking discovery, identifying the first atmosphere on an Earth-like, rocky planet situated within the habitable zone of a distant star. This finding, detailed in the journal Science, represents a significant leap forward in the quest to determine if life exists beyond our solar system.
The exoplanet, designated LHS 1140 b, orbits a red star approximately 48 light-years from Earth. It resides in what planetary scientists term the 'Goldilocks zone' – an orbital distance where temperatures are neither too hot nor too cold, making the presence of liquid water, a key ingredient for life, a possibility. While thousands of exoplanets have been found, LHS 1140 b stands out as one of the rare few that are both rocky and located within this crucial habitable region.
The gas detected in LHS 1140 b's atmosphere is helium, likely concentrated in its upper layers. While helium itself cannot support life, its presence confirms the existence of an atmospheric envelope, a critical component for retaining water and regulating surface temperatures. Researchers suggest that other, potentially more life-sustaining gases could be present deeper within the atmosphere.
Dr. Collin Cherubim, lead author from Harvard University, described the discovery as a "big deal," emphasising that it is the first time an atmosphere has been found on a rocky planet within another star's habitable zone. Dr. David Charbonneau, also from Harvard, highlighted the broader implications, stating that the study addresses fundamental questions about humanity's place in the universe: "Are we alone? Is there life beyond the Earth or beyond our solar system?"
This discovery places LHS 1140 b at the forefront of exoplanet research, alongside other intriguing candidates. Previous investigations into worlds like K2-18b, a sub-Neptune, had hinted at possible signs of dimethyl sulphide, a gas linked to marine life on Earth. However, a NASA-led reanalysis in 2025 concluded that the signal was too weak for confirmation and could arise from non-biological processes. Similarly, while the seven rocky planets of TRAPPIST-1 remain compelling, data from the James Webb Space Telescope has ruled out an Earth-like atmosphere on TRAPPIST-1d, with results for TRAPPIST-1e remaining inconclusive.