Since the 70`s, astronomers thought that one of Jupiter`s moon and the largest moon in our solar system, Ganymede, may hold a great amount of water underneath its frozen surface, even greater than the one we have on Earth.
Now this speculation has been confirmed, by the latest discoveries of the astronomers using the Hubble Telescope.They have observed the aurorae near the moon and established that, indeed, there is a salty ocean on Ganymede. The aurorae glimpsed by the Hubble Telescope were located near the North and South poles of Ganymede.
This new discovery widens the area in which researchers hunt for potential life. It is already known that another one of Jupiter`s four moons, Europa, also has an ocean under its crust. Saturn`s moon, Enceladus, is in the same situation. Scientists say they have reasons to believe that Jupiter`s moon, Callisto, holds such a subterranean ocean as well.
Physicists say that the discovery of Ganymede`s ocean will be of help in studying Jupiter`s moon, especially as in 2030 a new European Space Agency mission will arrive at Jupiter. The mission is called Jupiter’s Icy Moons Explorer (JUICE) and it will leave Earth in 2022, travelling eight years through space until it will get to its destination.
“Hubble observations have now confirmed the presence of a salty, electrically conducting ocean under the crust of Ganymede, and so when the JUICE mission ultimately goes into orbit around Ganymede it will have a very, very rich and exciting science mission,”
says Heidi Hammel, who is the executive vice president of the Association of Universities for Research in Astronomy.
Still, there is much to be discovered about the water on Ganymede. Researchers have yet to learn about the ocean`s temperature and depth. For now, they have estimated that the water on Jupiter`s moon is ten times deeper than the oceans of our planet, and that it is trapped under a 95-mile (150-kilometer) crust of ice.
Ganymede is the only moon in our solar system that generates its own magnetic field, because of its liquid iron core. There are two aurorae on Ganymede, one at the North pole, the other one at the South pole. The aurorae move slightly over the moon`s poles. Scientists have calculated how much the aurorae should move if Ganymede harbored a subsurface ocean. An Hubble sent them images according to which their expectations have been confirmed.
Image Source: Daily Galaxy