Ganymede appears to have enormous oceans, but objects without water appear to be very uncommon in our solar system.
This week, data from the Hubble Space Telescope was used to monitor the auroras at the poles of Jupiter’s mood Ganymede. The data shows that the moon likely has massive oceans beneath its icy surface. According to the researchers the oceans are likely 60 miles deep, that’s almost nine times the deepest parts of Earth’s surface oceans.
Those oceans are buried beneath a 95 mile crust of ice, which is likely also made mostly of water.
The list of objects with water in the solar system is now very long. Starting from the innermost planet; water was discovered on Mercury in 2012, at least at the poles and possibly in deep craters. Because of Mercury’s proximity to the sun it is very hot and ice can only exist in places with little or no direct sunlight.
Venus, due to the runaway greenhouse effect has very tiny amounts of water in it’s upper atmosphere but nothing worth mentioning. According to NASA’s Jet Propulsion Lab, even the sun has trace amounts of water vapor. It is likely that Venus had water once, but it is simply too hot to keep it.
The Earth, of course, has water as does our Moon.
Mars has water, at the poles and probably underground. It was revealed this week that it once had much more water including an ocean that covered 19 percent of its surface.
Beyond Mars is the asteroid belt, including the dwarf planet Ceres. Many of the objects in that asteroid belt have water, including Ceres which has an icy crust and a subsurface ocean.
Jupiter probably has some amount of water, but it is mixed in with a bunch of toxic chemicals. However, many of Jupiter’s moons have quite a bit of water including Ganymede, Callisto and Europa, which NASA is planning to visit.
Saturn, like Jupiter probably wouldn’t be a good place to look for water, but there is water in its rings and on many of its moons including Enceladus which appears to have a warm ocean beneath the surface.
Then there are the “ice giants”: Uranus has water and it’s moons likely do as well. Neptune, named for the Roman God of the Sea, has water. Then there is the dwarf planet Pluto, which may have a subsurface ocean, the Kuiper belt and the Oort cloud.
The massive array of objects beyond Neptune, and many of the comets, asteroids and meteorites in the solar system definitely have water as well.
Water is, in short, one of the most common substances in the solar system and many of the exoplanets suggest that we are not alone in that regard. Some of the exoplanets that have been detected by researchers are believed to be entirely covered in liquid water and some of those are very large.