An Ocean Planet (aka water world) is a planet with a substantial amount of water on its surface or subsurface. It can be completely or mostly covered in water. The liquid on the surface can consist of different fluids like lava or ammonia.
Probability of life on an ocean planet is high, because water is essential for most life forms (flora, fauna, sentient and non-sentient). Many species evolve in or around a source of water. These are rare and thus more valuable to discover.
Some star systems have multiple ocean planets such as:
- ↑ http://www.omnilexica.com/?q=ocean+planet
- ↑ http://iopscience.iop.org/article/10.1086/524925/fulltext/
- ↑ http://www.nasa.gov/press/2015/march/nasa-s-hubble-observations-suggest-underground-ocean-on-jupiters-largest-moon/#.VQJhMM26t0s
- ↑ https://www.reddit.com/r/EliteDangerous/comments/a00df6/twin_aquatic_worlds/