Unusual “steam worlds” could hold the key to understanding where life may exist beyond Earth, according to new findings by astronomers. Although ‘steam worlds’ were first proposed about twenty years ago, they are now supported by observations. The James Webb Space Telescope has detected water vapor around several sub-Neptunes, with many more expected to be studied in the near future. Within sub-Neptunes, water can exist in forms beyond vapor or liquid. “In the future, we may find that a subset of these water worlds represents new niches for life in the galaxy,” Batalha concludes.