It is said that the Ganymede Ocean contains more water than Europa. This was stated by Oliver Witasse, who is a project scientist that works on the future Jupiter Icy Moon Explorer or JUICE of ESA. He said that the Ganymede Ocean has six times more water than the Earth’s ocean, and three times more than Europa. This discovery sounds like good news.
Three years ago, the Hubble Space Telescope of NASA revealed the best evidence yet for an underground saltwater ocean on Ganymede, which is the largest moon of Jupiter, and that ocean was larger than the planet Mercury, and not quite smaller than the planet Mars. Identifying liquid water is essential when searching for habitable worlds beyond the planet Earth and searching for life, as we all know it.
This is a discovery which makes an important milestone, highlighting what just Hubble can accomplish, according to John Grunsfeld, who is now a retired assistant administrator of the Science Mission Directorate of NASA at NASA Headquarters.
He mentioned that in the last 25 years of being in orbit, Hubble made a lot of scientific discoveries in the solar system. There is a deep ocean under the icy crust of Ganymede which opens up further exciting possibilities for life beyond the planet Earth. Ganymede is also considered the largest moon in the solar system and the only moon that has its own magnetic field.
The magnetic field of this moon causes the aurorae – the ribbons of a glowing, and hot, electrified gas, in regions which circle the north and the south poles of the moon. As it is close to the planet Jupiter, Ganymede also embedded in the magnetic field of this planet. When the magnetic field of Jupiter changes, the aurorae on Ganymede changes too, rocking back and forth.
Just like the moon of the planet Saturn, Dione is perennially overshadowed by Enceladus and Titan. The fame of Ganymede is eclipsed by its sister ocean world, Europa, slated for flybys by the Europa Clipper mission of NASA in the 2020s.
JUICE is going to fly by the several moons at distances between 1000 and 2000 kilometers, also orbiting the Ganymede for about nine months, with the latter four months at an altitude of almost 500 kilometers.
While the oceans of the moons of the planet Jupiter are likely buried at important depth under the icy crusts, the radar is going to have the ability to help piece together clues as to their complex evolution.
It is going to explore the potentially active regions of Europa and it will have the ability to distinguish where the composition changes, for example, if there are local and shallow reservoirs of water sandwiched between icy layers.
It is also going to have the ability to find ‘deflected’ subsurface layers, which are going to help in determining the tectonic history of Ganymede in particular.
The difference between non-ice and ice materials is also going to be possible, maybe enabling the detection of buried cryovolcanic reservoirs.
Witasse said that looking into the subsurface of the moons with the help of the radars is going to be like looking back in time, helping them to determine the geological evolution of such enigmatic world.
NASA also reported that the spacecraft is going to make a few flybys of another potentially ocean-bearing Jovian moon, Callisto. The people from the agency think that Callisto also harbors a subsurface ocean, but the data they have is still not clear.
Witasse says that what they hope to do is to check if there is an ocean or not, and if there exists, at which depth it is.