Astronomers Find First Atmosphere on Earth-Like Planet

The habitable zone is sometimes called the "Goldilocks zone". It is the region around a star where a planet is neither too hot nor too cold for liquid water to stay on its surface. Scientists have now found more than 6,000 planets around other stars, and hundreds of them lie in these zones. However, only a few dozen are small and rocky like Earth, and none had shown signs of an atmosphere before. Red dwarfs are the most common type of star, but many are very active and blow away their planets' air. LHS 1140b was discovered in 2017. It has 5.6 times the mass of Earth and is 70% wider. One side always faces its star.

The helium did not appear in observations made in 2025. This surprised the team, who checked their data again and ruled out mistakes. Jayne Birkby, an astrophysicist at Oxford, called the work an important step. But Yamila Miguel of Leiden Observatory was more careful. She said the escaping gas comes from the upper atmosphere, far above the surface where life might begin. Helium alone cannot support life, although other gases may lie deeper.