Cloudy days on exoplanets may hide atmospheric water

Astronomers have found many hot Jupiters with water in their atmospheres, but others appear to have none. Scientists wanted to find out what the atmospheres of these giant worlds have in common. Researchers focused on a collection of hot Jupiters studied by NASA’s Hubble Space Telescope. They found that the atmospheres of about half of the planets were blocked by clouds or haze.