Level 1 — Absolute Beginner
Scientists found air around a planet called LHS 1140b. This is a big discovery. The planet is rocky, like Earth. It moves around a small star called LHS 1140.
The star LHS 1140 is far from Earth. It is about 40 to 48 light years away. It is small and dim. It is a red dwarf star.
Scientists used a telescope called the Magellan Clay telescope. It is in Chile. They looked at light from the planet. They found helium gas leaving the planet's air.
This is the first time scientists see air on a rocky planet in a habitable zone. A habitable zone is a place where water can stay liquid. Scientists think LHS 1140b could be a good place to look for life.
- atmosphere
- the layer of gas around a planet
- rocky
- made of rock, solid like Earth
- star
- a large ball of hot gas in space that gives light
- telescope
- a tool that helps scientists see far away objects in space
- helium
- a type of gas
- habitable zone
- the area around a star where water can be liquid
- gas
- a substance like air, not solid or liquid
- escape
- to get out and leave, or go away from
Level 2 — Elementary
Astronomers have discovered an atmosphere around a rocky planet called LHS 1140b, and part of that atmosphere is escaping into space. This is the first time scientists have confirmed an atmosphere on a rocky planet inside a star's habitable zone, the region where temperatures allow liquid water.
LHS 1140b orbits a small, faint red dwarf star named LHS 1140, located between 40 and 48 light years from Earth. The planet has a mass about 5.6 times greater than Earth's, and it completes one orbit around its star every 24.7 days.
The planet receives about 42 percent of the sunlight that Earth receives from the sun. This amount of light gives LHS 1140b a temperature that keeps it inside the habitable zone, where liquid water could exist.
Using spectral data from the Magellan Clay telescope in Chile, researchers detected helium in the planet's atmosphere in 2024, but the same helium signal was not seen in 2025. The findings, published in the journal Science, suggest the atmosphere changes over time and that the planet is one of the most exciting nearby targets in the search for life beyond our solar system.
- atmosphere
- the mixture of gases surrounding a planet
- exoplanet
- a planet that orbits a star other than our sun
- habitable zone
- the distance from a star where temperatures could allow liquid water
- red dwarf
- a small, cool, dim type of star
- orbit
- the path a planet follows as it circles its star
- mass
- the amount of matter in an object, often compared to Earth's
- spectral data
- information gathered by studying light broken into its colors
- stellar irradiation
- the amount of light and energy a planet receives from its star
Level 3 — Intermediate
For the first time, astronomers have confirmed the presence of an atmosphere on a rocky exoplanet orbiting within its star's habitable zone, the narrow band of distance where conditions could allow liquid water to exist on a planet's surface. The planet, LHS 1140b, orbits a small, faint red dwarf star known as LHS 1140, located roughly 40 to 48 light years from Earth.
LHS 1140b is a substantial world, with a mass about 5.6 times that of Earth, and it completes a full orbit around its star in just 24.7 days. Despite its close orbit, the planet receives only about 42 percent of the stellar irradiation that Earth receives from the sun, a balance that places its surface temperature within the range needed to sustain liquid water.
Researchers relied on spectral data collected by the Magellan Clay telescope at Las Campanas Observatory in Chile to make the detection, and their findings appear in the journal Science. Notably, helium absorption was clearly present in observations from 2024 but absent in follow up observations from 2025, indicating that the planet's atmospheric escape is time variable rather than constant.
Scientists attribute the 2024 helium loss to bursts of X-ray and extreme ultraviolet radiation from the host star, which heated the planet's upper atmosphere and drove helium gas outward into space. The pattern observed, helium dominating the upper atmosphere while hydrogen appears depleted and heavier gases remain trapped closer to the surface, is known as atmospheric fractionation, and it has made LHS 1140b one of the most promising nearby candidates in the ongoing search for signs of life beyond our solar system.
- habitable zone
- the range of orbital distances from a star where a planet's temperature could permit liquid water
- stellar irradiation
- the intensity of light and energy a planet receives from its host star
- spectral data
- measurements of light split into wavelengths, used to identify chemical elements
- atmospheric escape
- the process by which gases in a planet's atmosphere are lost to space
- extreme ultraviolet radiation
- high energy light emitted by stars that can strip away planetary atmospheres
- atmospheric fractionation
- a process in which lighter gases separate and concentrate in the upper atmosphere while heavier gases stay lower
- host star
- the star that a planet orbits
- time variable
- changing over different periods rather than staying constant
Level 4 — Advanced
In a landmark result for exoplanet science, astronomers have confirmed the existence of an atmosphere on a rocky planet situated within its star's habitable zone, the region where stellar irradiation permits the persistence of liquid water. The planet, designated LHS 1140b, circles a diminutive, faint red dwarf star, LHS 1140, positioned somewhere between 40 and 48 light years from Earth, and the discovery marks the first confirmed atmosphere on a rocky world occupying this coveted orbital niche.
With a mass approximately 5.6 times that of Earth and an orbital period of just 24.7 days, LHS 1140b receives around 42 percent of the stellar irradiation Earth gets from the sun, a moderated flux that nonetheless keeps the planet's equilibrium temperature within the liquid water habitable zone. Spectral data gathered by the Magellan Clay telescope at Las Campanas Observatory in Chile, and published in the journal Science, provided the evidence underpinning the discovery.
Crucially, helium absorption was unambiguously detected in observations conducted in 2024, yet the same signal was conspicuously absent when astronomers revisited the planet in 2025, a discrepancy that points to a time variable, rather than continuous, process of atmospheric escape. Researchers attribute this variability to episodic bursts of X-ray and extreme ultraviolet radiation from the host star, which periodically heat the planet's upper atmosphere and expel helium into space.
The resulting compositional profile, an upper atmosphere enriched in helium and depleted in hydrogen, with heavier gases apparently confined to lower altitudes, reflects a phenomenon known as atmospheric fractionation. Taken together, these findings have elevated LHS 1140b to the status of one of the most compelling nearby candidates in the broader search for signs of life beyond our solar system.
- irradiation
- the exposure of an object to light or radiant energy from a source such as a star
- fractionation
- a process of separation in which components of a mixture, here atmospheric gases, distribute unevenly by altitude
- episodic
- occurring in irregular, distinct bursts rather than continuously
- diminutive
- notably small in size
- equilibrium temperature
- the theoretical surface temperature a planet reaches when energy received and emitted are balanced
- habitable zone
- the orbital region around a star within which a planet could maintain liquid water
- spectral data
- measurements derived from analyzing light across wavelengths to infer atmospheric composition
- atmospheric escape
- the loss of a planet's gases to space, often driven by stellar radiation
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