Jupiter’s moon Ganymede has ocean [2015/03/27 09:43]

Ganymede, which *orbits Jupiter and is the largest moon in the *solar system, has an ocean beneath its icy surface, raising the prospects for life to exist there, NASA said on March 12.

The evidence comes from the Hubble Space Telescope, which observed Ganymede's *magnetic field to get a glimpse of its interior.

Ganymede, in addition to being the largest moon in the solar system, is also the only moon to have its own magnetic field.

This magnetic field *gives rise to aurorae. Interestingly, Ganymede’s field is *embedded within Jupiter’s magnetic field, so as Jupiter *rotates, its magnetic field shifts, causing Ganymede’s aurora to rock back and forth.

Using computer models, scientists realized that a salty, electrically *conductive ocean beneath the moon’s surface was counteracting Jupiter’s magnetic field.

“With the ocean, the rocking is significantly reduced,” *geophysicist Joachim Saur with the University of Cologne in Germany told Reuters.

Scientists estimate that the ocean is 100 km thick, 10 times deeper than Earth’s oceans, and is buried under a 150 km *crust of mostly ice.

Ganymede joins a growing list of moons in the solar system with subsurface water. On March 11, scientists reported that Saturn’s moon Enceladus had hot springs beneath its icy crust. Other water-rich worlds include Jupiter moons Europa and Callisto.

The European Space Agency is planning to launch a *mission in 2022 on an eight-year journey toward Jupiter. After *circling Jupiter, the spacecraft will slip into orbit around Ganymede for a close-up look.
출처: 주니어 영자신문 주니어헤럴드(junior.heraldm.com)