NASA’s Hubble Space Telescope scientists, on 12th of March, have confirmed that Jupiter’s moon Ganymede has an ocean under its icy surface, and it may contain life.

NASA’s findings have resolved a mystery about the largest moon in the solar system following NASA’s now-defunct Galileo spacecraft, which had previously, during the exploration of Jupiter and its moons from 1995 to 2003, provided hints that Ganymede has a subsurface ocean.

Scientists have revealed that just like Earth, Ganymede too has a liquid iron core that generates a magnetic field, though Ganymede’s field is embedded within Jupiter’s magnetic field. This leads to a set up of an interesting dynamic with tell-tale visuals, twin bands of glowing aurora around Ganymede’s northern and southern polar region.

The rotation of Jupiter shifts its magnetic field and cause Ganymede’s aurora to rock. Scientists measured the motion and found it fell short.

Then, with the use of computer models, they realized that there is a salty, electrically conductive ocean beneath the moon’s surface, which was counteracting Jupiter’s magnetic pull.

Joachim Saur, geophysicist, with the University of Cologne in Germany, said, “Jupiter is like a lighthouse whose magnetic field changes with the rotation of the lighthouse. It influences the aurora. With the ocean, the rocking is significantly reduced”.

Saur added that scientists used more than 100 computer models to observe if anything else also had any impact on Ganymede’s aurora. Also, they repeated the seven-hour, ultraviolet Hubble observations and analyzed data for both belts of aurora, which gave them confidence in the measurement.

Jim Green, Director, NASA Planetary Science Division, has called the finding an amazing demonstration of a latest approach to look inside a planetary body with the help of a telescope.

Scientists, on March 11, reported that Saturn’s moon Enceladus has hot springs beneath its icy crust. With this finding, Ganymede has also joined an increasing list of moons in the outer solar system with subsurface water.