There might be a type of exoplanet without dry land. They’re called “Hycean” worlds, a portmanteau of “hydrogen” and “ocean.” They’re mostly or entirely covered in oceans and have thick hydrogen atmospheres. There might be a type of exoplanet without dry land. They’re called “Hycean” worlds, a portmanteau of “hydrogen” and “ocean.” They’re mostly or entirely covered in oceans and have thick hydrogen atmospheres. Astrobiology Planetary Sciences Phys.org – latest science and technology news stories