We detected an atmosphere on a rocky planet in the habitable zone
Astronomers have detected an atmosphere around a small, rocky planet sitting in its star's habitable zone, the band where temperatures allow liquid water. It is the first time an atmosphere has been confirmed on a rocky world in that zone.
The signal came from starlight. As the planet crossed in front of its star, some of that light filtered through its atmosphere, and because different gases absorb light at different wavelengths, they left a chemical fingerprint scientists could read.
An atmosphere is one of the ingredients we expect a life-friendly world to have. Finding one on a rocky planet at the right distance from its star is a real step toward answering whether we are alone.
Why it matters: this is the kind of measurement that moves the search for life from science fiction to actual data.