Astronomers have identified LHS 1140b as a rocky exoplanet with a helium-rich atmosphere, marking the first clear evidence of a potentially habitable planet with an atmosphere. According to a study published in the journal Science, the planet resides in its star’s habitable zone, where temperatures allow for the existence of liquid water.
LHS 1140b: A New Blueprint for Habitable Worlds
LHS 1140b sits a few dozen light-years from our solar system. While it is larger and more massive than Earth, it shares three critical traits required for life as we know it: a rocky composition, a temperature suitable for liquid water, and a protective atmosphere.
Collin Cherubim, a planetary scientist and Harvard University Ph.D., stated that while there is currently no evidence of life on the planet, the “essential ingredients” are present. The detection of its atmosphere is a milestone because scientists previously struggled to determine if small, rocky worlds—which are harder to detect than gas giants—could retain their atmospheres against the vacuum of space.
Did you know? An atmosphere is vital for habitability because it regulates climate, helps a planet retain water, and shields the surface from space radiation.
The Role of Red Dwarfs and Atmospheric Loss
The planet orbits a red dwarf, the most common star type in the galaxy. These stars are smaller and cooler, making rocky planets easier to spot. However, red dwarfs often emit violent radiation flares that can strip a planet’s atmosphere away.
According to Dr. Cherubim, the star hosting LHS 1140b is less active than typical red dwarfs. This stability makes the planet a “front-runner” for studying habitability. Using a telescope at the Las Campanas Observatory in Chile in 2024, researchers observed the planet passing in front of its star, detecting helium at high altitudes. This indicated that helium was escaping from an atmosphere that is otherwise difficult to detect.
Real-Time Atmospheric Changes and the Helium Mystery
In 2025, the research team observed another eclipse of the host star but found no signs of escaping helium. Shreyas Vissapragada, a planetary scientist at the Carnegie Observatories and study author, described this result as a “big shock,” though not entirely unexpected.
While differing helium levels have been seen in gas giants, this is the first time such a phenomenon has been observed on a rocky exoplanet. Vissapragada noted that the team is essentially watching the atmosphere of an Earth-like planet change in real time.
LHS 1140b vs. Earth: Key Differences
| Feature | Earth | LHS 1140b |
|---|---|---|
| Orbit Duration | 365 Days | Less than 25 Days |
| Atmospheric Base | Nitrogen-rich | Helium-rich |
| Rotation | Day and night cycle | Always presents the same face to its host star |
Can Life Exist in a Helium Atmosphere?
The prospect of a helium-rich world might seem alien, but scientific data suggests it is biologically possible. Sara Seager, an M.I.T. astrophysicist, led a 2020 study demonstrating that E. coli and yeast could survive in an atmosphere of pure helium.
Seager, who was not involved in the recent LHS 1140b study, described the detection as “beautiful” and noted that “when there’s one, there’s more in exoplanets,” suggesting this discovery could be the start of something new in identifying habitable worlds.
Frequently Asked Questions
Is there life on LHS 1140b?
No. According to planetary scientist Collin Cherubim, there is absolutely no evidence for life on the planet at this time, though the necessary ingredients for habitability are present.
What makes LHS 1140b different from Earth?
LHS 1140b is larger and more massive than Earth, has a helium-rich atmosphere instead of nitrogen, and always presents the same face to its host star, meaning it does not have a day-night cycle.
Why is the atmosphere significant?
An atmosphere regulates temperature and protects the surface from radiation. Finding one on a rocky planet proves that such worlds can retain the gases necessary to support liquid water.
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