23-Hubble Uncovers Water Vapor In Small Exoplanet’s Atmosphere
November 5, 2025
Astronomers using NASA’s Hubble Space Telescope have observed water vapor in the atmosphere of the smallest exoplanet ever detected. Located 97 light-years away, planet GJ 9827d is approximately twice the size of Earth.
This finding raises the possibility of other planets with water-rich atmospheres in our galaxy. However, it remains uncertain whether the observed water vapor is in a hydrogen-rich atmosphere or if the planet’s atmosphere is predominantly water.
Water on a planet this small is a landmark discovery, pushing us closer than ever to characterizing truly Earth-like worlds, and thanks to the Hubble Space Telescope we’ll be able to continue our search for more planets like our own.