Researchers have identified the first atmosphere enveloping a rocky, Earth-like planet situated within the habitable zone of a distant star, a discovery that constitutes the most compelling evidence yet that worlds with conditions analogousanalogous/əˈnæl.ə.ɡəs/L3类似的；相似的similar or comparable to something else to our own may exist beyond the solar system. The planet, designated LHS 1140 b and located 48 light-years from Earth, orbits a red dwarf star considerably smaller and cooler than the Sun. Although the only gas detected thus far—helium, likely residing in the upper atmosphere—cannot sustain life as we know it, the presence of an atmosphere itself marks a watershedwatershed/ˈwɔːtərʃɛd/L3转折点；分水岭a turning point or a critical moment that marks a change in direction moment in exoplanetary science. Dr. Collin Cherubim of Harvard University, the lead author of the study published in the journal Science, characterized the finding as "a big deal," emphasizing that it represents the first instance of an atmosphere on a rocky world within another star's habitable zone. Consequently, this breakthrough brings humanity incrementally closer to addressing one of science's most profound questions: whether life exists beyond Earth.
The significance of this detection lies not merely in the atmospheric discovery itself but in its broader implicationsimplications/ˌɪmplɪˈkeɪʃənz/L3影响；意义；可能的结果the possible effects or results of an action or decision for planetary habitabilityhabitability/ˌhæbɪtəˈbɪləti/L3宜居性；可居住性the suitability of an environment for supporting life. For a planet to support life, it must possess liquid water, which in turn requires a precise orbital distance from its host star—neither so close that water vaporizes nor so far that it freezes, but rather a temperate intermediate zone that planetary scientists term the "Goldilocks zone." While hundreds of exoplanets have been found within their respective stars' habitable zones, only a few dozen are small and rocky like Earth, and prior to this study, none had been confirmed to possess an atmosphere. That said, the detection of helium alone does not confirm habitability; however, researchers speculate that other, more life-sustaining gases, such as nitrogen or carbon dioxide, may exist in lower atmospheric layers, awaiting detection by future observations.
LHS 1140 b is not the only exoplanet under intense scrutiny in the search for extraterrestrial life, though its atmospheric confirmation sets it apart. K2-18b, a sub-Neptune with a potentially water-rich interior, generated headlines when scientists tentatively identified dimethyl sulphide—a gas associated with marine biology on Earth—but a NASA-led reanalysis in 2025 deemed the signal too weak for confirmation, also demonstrating that the gas can form abiotically. Similarly, the seven rocky worlds of the TRAPPIST-1 system remain tantalizing targets; the James Webb Space Telescope has ruled out an Earth-like atmosphere on TRAPPIST-1d, while data for TRAPPIST-1e stay frustratingly inconclusive. Notwithstanding these setbacks, the detection of an atmosphere on LHS 1140 b offers a tangible foothold for future investigations, arguably shifting the search for habitable exoplanets from theoretical possibility to empiricalempirical/ɪmˈpɪrɪkəl/L3经验主义的；以观察为依据的based on observation or experience rather than theory reality.
