Earth-Like Planet's Atmosphere Confirmed In Major Search For Alien Life
Located 49 light years away in the Cetus constellation, LHS 1140b has a mass roughly 5.6 times that of Earth and a radius about 70% larger. Unlike gas giants or the larger, puffier sub-Neptunes class where atmospheric detections are more common, LHS 1140b is firmly rocky. Crucially, it orbits within the temperate Goldilocks zone of its red dwarf star where temperatures are mild enough that liquid water could pool on its surface.
Published this week in the Science journal, the discovery was led by Dr. Collin Cherubim, an astrophysicist based at Harvard University and the Harvard-Smithsonian Center for Astrophysics. Cherubim and his team analyzed data captured using the infrared multi-object spectrograph (MIRMOS) mounted on the Magellan Clay telescope at the Las Campanas Observatory in Chile. By watching the planet transit in front of its star, the researchers detected a signal of helium escaping from the planet's upper atmosphere into space, which represents the first direct identification of an atmospheric gas on any rocky exoplanet.
It must be noted that though the team spotted the distinct helium signature in observations from 2024, the signal was absent in data gathered in 2025. This variation led to rigorous testing to rule out terrestrial contamination or instrument errors, ultimately confirming that the fluctuations are real.
Finding an atmosphere on a planet orbiting a red dwarf star is particularly cool and significant. Indeed, red dwarfs, being the most common stars in the galaxy as they are, makes them our most frequent targets in the hunt for habitable worlds. However, these stars are notorious for blasting nearby planets with intense radiation and violent flares, which can completely strip away protective gas atmospheres over time. The fact that LHS 1140b has managed to retain an atmosphere suggests its host star is unusually calm.
While the current observations focused on escaping helium in the planet’s outer boundary, the presence of this envelope raises the possibility that heavier, life-supporting molecules like nitrogen, carbon dioxide, or water vapor are trapped closer to the surface. LHS 1140b is tidally locked, meaning one side permanently faces its star while the other remains in darkness. Because of this, scientists have hypothesize it could be an "eyeball world", i.e. a planet covered mostly in thick ice, but featuring a circular, open ocean of liquid water on the side continuously bathed in starlight.
Main image credit: Harvard University
