An ocean planet, ocean world, water world, aquaplanet or panthalassic planet is a type of terrestrial planet that contains a substantial amount of water either at its surface or subsurface.
Earth is the only astronomical object known to have bodies of liquid water on its surface, although several exoplanets have been found with the right conditions to support liquid water. For exoplanets, current technology cannot directly observe liquid surface water, so atmospheric water vapor may be used as a proxy. The characteristics of ocean worlds—or ocean planets—provide clues to their history, and the formation and evolution of the Solar System as a whole. Of additional interest is their potential to originate and host life.
Water worlds are of extreme interest to astrobiologists for their potential to develop life and sustain biological activity over geological timescales. The five best established water worlds in the Solar System include Europa, Enceladus, Ganymede, and Callisto. A host of other bodies in the outer Solar System are inferred by a single type of observation or by theoretical modeling to have subsurface oceans, and these include: Dione, Pluto, Triton, and Ceres, as well as Mimas, Eris, and Oberon. read more
Storm on Jupiter
NASA / SwRI / MSSS / Gerald Eichstädt / Seán Doran
This image of Neptune was taken by Voyager 2’s wide-angle camera when the spacecraft was 590,000 km (370,000 miles) from the planet.
Image credit: NASA/JPL
This color image, produced from a distance of about 16 million kilometers, shows several complex and puzzling atmospheric features. Credit: NASA/JPL
The Instrument Deployment Camera (IDC), located on the robotic arm of NASA’s InSight lander, took this picture of the Martian surface on Nov. 26, 2018, the same day the spacecraft touched down on the Red Planet. The camera’s transparent dust cover is still on in this image, to prevent particulates kicked up during landing from settling on the camera’s lens. This image was relayed from InSight to Earth via NASA’s Odyssey spacecraft, currently orbiting Mars.