Astronomers have, for the first time, detected an atmosphere surrounding a rocky exoplanet in the habitable zone of its star—a major step forward in the search for life beyond Earth. The planet, known as LHS 1140 b, is about five times the mass of Earth and orbits a red dwarf star roughly 48 light-years away. It sits in the so-called “Goldilocks zone,” where temperatures are just right for liquid water to exist on the surface.
The discovery provides the strongest evidence yet that planets with Earth-like conditions and rocky surfaces can retain atmospheres for billions of years. This is important because an atmosphere shields a planet from cosmic radiation, helps regulate its climate, and is considered essential for supporting life as we know it.
The research team led by Collin Cherubim of Harvard University used the Warm Infrared Echelle (WINERED) Spectrograph at the Magellan Observatory in Chile to study LHS 1140 b. During a rare astronomical event in 2024, both LHS 1140 b and another planet crossed in front of their star. Only LHS 1140 b showed signs of helium escaping from its upper atmosphere—a clear indicator that the planet is surrounded by a long-lasting layer of gas.
The study, published in Science, suggests that the planet’s upper atmosphere is rich in helium, while other potential gases like water vapor may be found lower down. The team observed that the atmospheric escape likely changes over time, as researchers noted that their 2025 observations did not detect escaping helium, hinting at a dynamic atmosphere influenced by the planet’s star.
LHS 1140 b’s atmosphere is thought to have survived for more than three billion years, making it a promising candidate for further study. Scientists hope to analyze the full chemical makeup of its atmosphere and look for signs of water or even oceans in future research. These findings also pave the way for using ground-based telescopes to search for atmospheres on other rocky exoplanets.
The discovery marks a milestone in exoplanet research, moving scientists closer to finding potentially habitable worlds beyond our solar system.
Recent Comments