For two decades, the search for another Earth has run into the same maddening wall. Astronomers could find rocky planets sitting at exactly the right distance from their star for liquid water to exist, but they had no way to confirm whether any of those planets had actually managed to hold onto an atmosphere. Without one, even a perfectly positioned world is just a bare, airless rock. On July 16, 2026, that wall finally came down.
A Signal Predicted Before It Was Found
A Harvard-led team reported in the journal Science that LHS 1140 b, a rocky super-Earth orbiting a red dwarf star 48 light-years away, shows helium actively escaping from its upper atmosphere, direct confirmation that the planet has a real, persistent atmosphere that has survived for more than three billion years. What makes the result genuinely remarkable is the order events happened in, lead author Collin Cherubim built a theoretical model during his PhD research predicting exactly this signal before anyone had actually gone looking for it. “Twenty years ago we wondered whether other terrestrial-type planets even existed,” said Robin Wordsworth, a co-author at Harvard. “Then we learned they’re common, and found some in the habitable zone. The next question was whether any of them had managed to keep an atmosphere. Now we know at least one has.”
Using the Magellan Clay telescope in Chile, the team observed a transit of LHS 1140 b on September 23, 2024, and caught helium absorption in the planet’s spectrum. A follow-up observation in 2025 found no helium signal at all, evidence that the escape happens in variable bursts rather than a constant, steady leak.
Why Red Dwarfs Make This So Hard
LHS 1140 b orbits a red dwarf, the most common type of star in the galaxy, but also one known for staying magnetically active far longer than Sun-like stars, unleashing frequent flares and radiation bursts capable of stripping a planet’s atmosphere away entirely. That’s exactly why this detection matters so much, it’s the first solid proof that a rocky world can hold onto real air even after billions of years parked close to a temperamental star. A second, more tightly orbiting planet in the same system, LHS 1140 c, receives roughly five times the radiation LHS 1140 b gets, and shows no helium signal at all, exactly what Cherubim’s model predicted for a planet too exposed to retain anything.
If you’re curious about a very different, much closer example of how planetary atmospheres and heat interact, our recent piece on the fluffy, heat-radiating surface of Jupiter’s moon Io covers another world where scientists are only just now measuring what lies beneath the surface.
Not Life, But a Genuine Milestone Toward Finding It
To be clear about what this discovery isn’t, it’s not evidence of oceans, vegetation, or life of any kind. Helium alone doesn’t tell astronomers much about a planet’s surface conditions. What it does confirm is one of the most basic prerequisites for habitability, that a rocky, Earth-sized world genuinely can hold a gaseous envelope over geological timescales, rather than losing it entirely to stellar radiation. “An atmosphere is essential for a planet to support life as we know it,” Cherubim said. “This is the first time anyone has found an atmosphere on a rocky planet in the habitable zone of another star.”
What Comes Next
Confirming helium is only the opening chapter. Over the next four to five years, astronomers plan to point the James Webb Space Telescope at LHS 1140 b specifically to search for water vapor in its atmosphere. Finding it would suggest a genuinely stable, long-term atmosphere rather than an occasional, temporary leak, pushing this distant world even closer to the top of the list of places worth watching closely in the ongoing search for life beyond our solar system.
For more on the discovery, check out the full research summary from EarthSky and the published study in Science.