scientists using  the hubble space telescope have confirmed that the  jupiter orbiting moon ganymede has an ocean beneath its icy  surface, raising the prospects for life, nasa has revealed the finding resolves a mystery about the largest moon in the  solar system after nasa's now defunct galileo spacecraft  provided hints that ganymede has a subsurface ocean during  exploration of jupiter and its moons from 1995 to 2003 scientists told reporters on a conference call that it took  some detective work to confirm the discovery in this artist’s concept, the moon ganymede orbits the giant planet jupiter a saline ocean under the moon’s icy crust best explains shifting in the auroral belts measured by hubble scientists first suspected an ocean in ganymede in the 1970s, based on models of the large moon nasa's galileo mission measured ganymede's magnetic field in 2002, providing the first evidence supporting those suspicions the galileo spacecraft took brief 'snapshot' measurements of the magnetic field in 20 minute intervals, but its observations were too brief to distinctly catch the cyclical rocking of the ocean's secondary magnetic field like earth, ganymede has a liquid iron core that generates a  magnetic field, though ganymede's field is embedded within  jupiter's magnetic field that sets up an interesting dynamic  with telltale visuals   twin bands of glowing aurora around  ganymede's northern and southern polar regions as jupiter rotates, its magnetic field shifts, causing  ganymede's aurora to rock scientists measured the motion and  found it fell short using computer models, they realized that a  salty, electrically conductive ocean beneath the moon's surface  was counteracting jupiter's magnetic pull 'jupiter is like a lighthouse whose magnetic field changes  with the rotation of the lighthouse it influences the aurora,' said geophysicist joachim saur, with the university of cologne  in germany 'with the ocean, the rocking is significantly  reduced' scientists ran more than 100 computer models to see if  anything else could be having an impact on ganymede's aurora they also repeated the seven hour, ultraviolet hubble  observations and analyzed data for both belts of aurora 'this gives us confidence in the measurement,' saur said nasa associate administrator jim green called the finding  'an astounding demonstration' 'they developed new approach to look inside a planetary body  with a telescope,' green said ganymede joins a growing list of moons in the outer solar  system with subsurface water on wednesday, scientists reported  that saturn's moon enceladus has hot springs beneath its icy  crust other water rich worlds include jupiter moons europa and  callisto nasa hubble space telescope images of ganymede's auroral belts (colored blue in this illustration) are overlaid on a galileo orbiter image of the moon the amount of rocking of the moon's magnetic field suggests that the moon has a subsurface saltwater ocean scientists estimate the ocean is 60 miles (100 km) thick, 10  times deeper than earth's oceans, and is buried under a 95 mile  (150 km) crust of mostly ice 'it is one step further toward finding that habitable,  water rich environment in our solar system,' said astronomer  heidi hammel with the washington based association of  universities for research in astronomy
hubble space telescope jupiter
finding resolves a mystery about the largest moon in the solar system . hubble space telescope confirmed jupiter orbiting moon  has an ocean 