NASA recently released a report revealing that Jupiter’s moon, Ganymede, has liquid oceans. Ganymede is the largest moon in the solar system and the latest in a long line of moons where water has been discovered. Other moons where liquid water has been found include Saturn’s Enceladus and Titan as well as Jupiter’s Europa.
The discovery was made using the Hubble Telescope to measure the magnetic field of the moon in order to ascertain its interior. Salt water affects the magnetic field produced by the celestial body. By focusing Hubble on the aurora of the planet, scientists were able to collect data supporting the theory of liquid water.
“A very important aspect of our analysis is that Ganymede is also under the influence of Jupiter’s magnetic field,”said Joachim Saur, professor for geophysics at the University of Cologne in Germany. “An important aspect of this magnetic field is it changes with a period of 10 hours. That’s the rotation period of Jupiter. During that time, the magnetic field points toward the moon for five hours and then five hours later, the magnetic field points away from the moon.”
If someone was standing on the moon’s surface, the aurora would have a red glow. If there was no ocean, the aurora would change six degrees over five hours. However, scientists predicted that if there was an ocean, this change would only be two degrees, and that is exactly what Hubble just confirmed.
The European Space Agency is planning an unmanned mission to Jupiter and its three largest moons in 2022. The spacecraft will feature a special radar system being designed by NASA to penetrate the thick layer of ice.
“The solar system is now looking like a pretty soggy place,” said Jim Green, director of planetary science at NASA headquarters. There is more water on Ganymede than on earth because the ocean is much deeper; the extra-planetary ocean is almost 60 miles deep and buried under 95 miles of ice. The moon itself has a diameter of 3,270 miles, making it larger than Mercury.
Heidi Hammel, another Hubble observer and senior executive with the Association of Universities for Research in Astronomy, said Saur’s technique could potentially be used by more powerful telescopes to find water in different solar systems.
Liquid water is crucial in the search for life outside our planet as well as potential places humans could one day colonize. “Every observation that we make, every mission that we send to various places in the solar system is taking us one step further to finding that truly habitable environment, a water-rich environment in our solar system,” Hammel said. “As far as we can tell, almost everywhere we look there’s water. Water, water, everywhere in our solar system.
