Saturnís moon Titan may have underground ocean
WASHINGTON: A vast ocean of water and ammonia may lurk deep beneath
the surface of Titan, the intriguing, orange moon of Saturn already
known for its blanket of clouds and dense atmosphere, scientists said on
Astronomers have not directly observed this ocean.
But they said observations made by the Cassini spacecraft of Titanís
rotation and shifts in the location of surface features suggest an ocean
exists perhaps 60 miles (100 km) under the surface.
Titan is Saturnís largest moon and the second biggest in the solar
system, only slightly smaller than Jupiterís moon Ganymede.
Titanís diameter of about 3,200 miles (5,150 km) is larger than the
planet Mercury and the dwarf planet Pluto.
Cassini, exploring Saturn and its moons in an ongoing U.S.-European
mission, collected measurements using radar that penetrated Titanís
thick clouds during 19 passes over the moon from October 2005 to May
Data from the early observations allowed researchers to establish the
locations of 50 landmarks including lakes, canyons and mountains on
Titanís surface. They looked at later radar data and discovered that
prominent surface features had shifted location by up to 19 miles (30
The spin of Titanís crust is linked to winds blowing through its
atmosphere, the scientists said. But the type of broad displacement of
surface features seen on Titan would be hard to explain unless its crust
were separated from its core by an internal ocean, allowing the crust
essentially to float.
ďItís because Titanís crust seems to be so mobile that we infer this
internal ocean,Ē Ralph Lorenz of the Johns Hopkins University Applied
Physics Laboratory in Laurel, Maryland, who directed the research
published in the journal Science, said in a telephone interview.
Lorenz said this ocean was probably mostly water with ďa few percentĒ
ammonia. Its atmosphere is mostly made up of nitrogen, with other
hydrocarbon elements that give Titan its orange color.
Titanís atmosphere consists of compounds that may have existed in the
Earthís primordial atmosphere, but Titan may have more of certain
chemicals like methane and ethane.
ďTitan is definitely one of the most Earth-like, if not the most
Earth-like, landscapes in the solar system and probably has the most
Earth-like weather,Ē Lorenz said.
ďItís very much colder than the Earth. But the same processes that go
on in our own weather, particularly the formation of clouds and rain,
happen on Titan but with liquid methane not with water,Ē Lorenz added.
Titan is thought to have hundreds of times more liquid hydrocarbons
than all the known oil and natural gas reserves on Earth, with
hydrocarbons raining from the sky and collecting in vast deposits that
form lakes and dunes.
Scientists have found evidence suggesting underground oceans on other
moons in the solar system including Jupiterís Europa, Callisto and
Ganymede and Saturnís Enceladus.