Deep in the Florida Everglades, a team of snake hunters spent hours searching for one of the swamp's most elusive predators. Just when it seemed like another slow day, a trained dog picked up a scent.

The Hubble Space Telescope has made multiple observations of exoplanet WASP-121 b, also known as Tylos. The extreme temperature changes the massive 'hot Jupiter'-type planet may make it rain iron at ...