We’re all familiar with oceans—the big, deep, salty bodies of water that cover 71% of Earth’s surface. We know that there are countless planets in our solar system that have oceans like ours, albeit ones much hotter or colder than ours. But, technically speaking, an ocean doesn’t have to be made of water and scientists have discovered all sorts of different bodies of liquid both above and beneath the surface of other planets. These oceans, as well as several completely hypothetical ones, are listed and described by K.N. Smith in this week’s issue of Astronomy Magazine, titled “These are the Strangest Oceans in our Galaxy”.
On the planet Gliese 1214b, which is 47 lightyears away and positioned in the Ophiuchus constellation, the “ocean” is made of water. Despite being made of water, it would look very different to the oceans we have on Earth. Nowhere on this planet will you find liquid of any kind. The planet’s proximity to its red dwarf star means that the clouds in the atmosphere’s upper layer are roughly 540⁰F and they never disperse into rain. Instead, the entire planet is covered with an incredibly hot steam and other pressurized, heated gases. Under the planets surface, the water is kept at its supercritical point—the point when a liquid becomes a gas—and thus it has characteristics of both a liquid and a gas. Elsewhere on Gliese 1214b, the water takes the form of a plasma, or an ionized gas. Plasmas form when a gas gets enough energy to knock a few of its electrons off its atoms. As a result, the entire substance becomes positively charged.
There are many oceans that are not made of water, too. Saturn’s moon, Titan, is covered in seas made of liquid methane. The surface of Titan is so cold that its ice functions more similarly to the way rocks do on our planet, and liquid methane, which is generally a gas on Earth, functions more like water. Imagine rivers, lakes, and oceans of liquid methane crashing against shores of ice. Another planet much further away, 55 Cancri e, has a surface made of lava, which is covered in oceans of molten rock. While the molten rock on this planet is similar to the lava we could see inside a volcano on Earth, there are other planets so rich in carbon that their lava is made of liquid diamonds. While some of these oceans are intriguing to think about, none would be fun to visit. Our own oceans here on Earth provide a much more enjoyable and relaxing vacation experience.