Researchers have announced the discovery of the first atmosphere surrounding an Earth-like, rocky planet located within the habitable zone of a distant star. This finding represents the most compelling evidence to date that worlds with conditions potentially similar to Earth may exist outside our solar system.
The planet, designated LHS 1140b, is situated 48 light-years away and orbits a red dwarf star, which is smaller and cooler than the Sun. Scientists identified helium as a component of the planet's atmosphere, though this gas alone would not support life. However, the presence of an atmosphere on a rocky planet in the habitable zone is considered a critical precursor for habitability.
Dr. Collin Cherubim of Harvard University, the lead author of the study published in the journal Science, described the discovery as a significant development. "This is the first time anyone has found an atmosphere on a rocky planet in the habitable zone of another star," he stated.
The habitable zone, often referred to as the "Goldilocks zone," is the region around a star where temperatures are neither too hot nor too cold for liquid water to exist on a planet's surface. While thousands of exoplanets have been discovered, and hundreds are located within their stars' habitable zones, only a small fraction are rocky like Earth. Until this discovery, none of these rocky, potentially habitable worlds had been confirmed to possess an atmosphere.
"People are generally interested in the big questions: Are we alone? Is there life beyond the Earth or beyond our solar system? To that end, this study reveals the first atmosphere discovered on a rocky planet in the habitable zone of a star outside of our solar system," commented Dr. David Charbonneau, also from Harvard.
While LHS 1140b is now a focal point, other exoplanets continue to be studied. K2-18b, a sub-Neptune, previously showed potential signs of dimethyl sulphide, a gas associated with marine life on Earth. However, a reanalysis in 2025 could not confirm the signal, indicating the gas can also form abiotically. The seven rocky planets of the TRAPPIST-1 system also remain subjects of intense research, though initial findings from the James Webb Space Telescope have ruled out an Earth-like atmosphere on TRAPPIST-1d, and data for TRAPPIST-1e remains inconclusive.