JWST spots the first known ‘steam world’

An illustration of a blue, cloudy planet in front of a small red star.

This exoplanet’s atmosphere is going full steam ahead. A planet beyond our solar system called GJ 9827d has an atmosphere composed almost completely of hot water molecules, astronomers report in the Astrophysical Journal Letters October 4. “We’re using the term ‘steam world,’” says astronomer Ryan MacDonald at the University of Michigan in Ann Arbor. GJ … Read more