NASA discovers an underground ocean on Jupiter’s largest moon

This is an illustration of the interior of Jupiter' s
largest moon , Ganymede . It is based on
theoretical models, in-situ observations by
NASA ' s Galileo orbiter , and Hubble Space
Telescope observations of the moon ' s aurorae,
which allows for a probe of the moon ' s interior .
The cake- layering of the moon shows that ice
and a saline ocean dominate the outer layers . A
denser rock mantle lies deeper in the moon and
an iron core beneath that . (NASA , ESA and A .
Feild )NASA announced evidence on Thursday that
Jupiter ' s largest moon , Ganymede , has a
saltwater ocean under its icy surface. The
ocean seems to have more water than all the
water on Earth ' s surface, according to new
Hubble observations .
Scientists estimate that the ocean is 60 miles
thick, which is about 10 times deeper than
Earth' s oceans. But unlike our salty waters,
Ganymede ' s ocean is buried under 95 miles
of ice .
While scientists have speculated since the
1970s about the presence of an ocean on
Ganymede - - the largest moon in our solar
system -- until now the only observational
evidence came from a brief flyby by the
Galileo spacecraft , which didn ' t observe the
moon long enough to confirm a liquid ocean.
“This discovery marks a significant milestone ,
highlighting what only Hubble can
accomplish, ” John Grunsfeld , assistant
administrator of NASA’ s Science Mission
Directorate at NASA Headquarters, said in a
statement. “In its 25 years in orbit, Hubble
has made many scientific discoveries in our
own solar system . A deep ocean under the icy
crust of Ganymede opens up further exciting
possibilities for life beyond Earth .”
Scientists have already confirmed the
existence of an ocean on Europa , another
moon orbiting Jupiter , and NASA has
announced plans to send an unmanned
mission there searching for the life that
might come with liquid water .
[ Hubble catches a rare three-moon - parade in
front of Jupiter]
This animation , based on images taken by
NASA ' s Galileo orbiter , shows what Jupiter' s
moon , Ganymede , looks like, with each color
indicating a different type of terrain . "Brown
regions are those that are heavily cratered and
much older than the light shaded regions that
are smoother with few craters . These lighter
shaded regions are believed to be formed by
flooding of the surface with water coming from
faults or even cryo- volcanos that have taken
place over billions of years. Perhaps even
tectonic processes are at work with some crustal
ice sheets being forced downward by the
emergence of newer icy material . " ( NASA via
YouTube)
The Hubble is a telescope that orbits Earth ,
but because of these impressive gravitational
analyses it can be used to study the interior
of planets far off in the distance. Using these
same principles, Hubble senior project
scientist Jennifer Wiseman said during a
NASA news conference on Thursday ,
scientists could theoretically detect oceans on
distant exoplanets as well.
[ From the Hubble , a new image of a glittering
cosmic wonderland with stars ]
"It may require a telescope larger than the
Hubble, it may require a new space
telescope, but nevertheless it is a tool we
have now , " Wiseman said .
This news comes just a day after the
announcement that one of Saturn' s moons
might have hydrothermal activity in its
subsurface ocean - - a phenomenon that could
allow it to support life . It seems that water
may be relatively common in our solar
system, making the search for life all the
more exciting and mysterious