PROOF OF METHANE LAKES ON MOON TITAN

[Anonymous]

‘Proof’ of methane lakes on Titan
The
Cassini probe has spotted what scientists say is unequivocal evidence
of lakes of liquid methane on Titan, Saturn’s largest moon.Radar images
reveal dark, smooth patches that range in size from three to 70km
across (two to 44 miles).The team says the features, which were spied
in the moon’s far north, look like crater or caldera lakes on Earth.The
researchers tell the journal Nature that everything about the patches
points to them being pools of liquid.”They look very similar to lakes
on Earth,” explained Dr Ellen Stofan, a Cassini radar team member from
Proxemy Research in Washington DC, US.”They have channels feeding into
them just like you have rivers feeding into lakes on the Earth. Their
shapes, their shore-lines, all of those geologic aspects are actually
very familiar.”

Northern strip
The
atmospheric chemistry on Titan is dominated by nitrogen and
carbon-based compounds.And with temperatures on the Saturnian satellite
rarely venturing above -179C (-290F), it has long been hypothesised
that abundant volumes of methane should pool on the surface into lakes,
and even large seas.But evidence for current bodies of liquid material
on the surface has until now been sparse and equivocal.Cassini must use
radar to pierce the photochemical haze that obscures Titan’s surface
from its optical camera system.The latest data was obtained last July,
when the probe made its most northern radar pass of Titan to date.The
spacecraft imaged a narrow strip about 250km wide and over 1,000km
long. It was found to contain more than 75 lakes.Everything scientists
know about the atmospheric chemistry on Titan suggests the liquid in
the lakes should be predominantly methane, with some ethane also mixed
in.Some of the liquid would be expected to rain out of the sky, some
could have welled up from below the surface.

Methane cycle
“The
methane-ethane would become transparent, the way water is on Earth; it
would be behaving like water, the lakes could have small waves on the
surfaces,” speculated Dr Stofan.”So if it was possible for you to stand
on Titan and look at the lakes, you wouldn’t really know it’s this
weird chemistry.”On Earth, the cycling of water between the atmosphere,
the land and oceans is known as the hydrological cycle. Titan would
appear to be the only other place in the Solar System to have a
similar, active fluid cycle. Scientists have already dubbed it the
“methane-ologic cycle”.Last month, it was announced that the radar
instrument on Cassini had found an enormous mountain range on Titan.The
range lies south of the equator and is about 150km long (93 miles),
30km (19 miles) wide and about 1.5km (nearly a mile) high.Scientists
told the American Geophysical Union (AGU) Fall Meeting that the range
was probably as hard as rock, but made of icy materials.The mountains
appeared in the radar images to be coated with layers of material that
researchers thought could be methane “snow”.The Cassini-Huygens mission
is a cooperative project of the US space agency (Nasa), the European
Space Agency (Esa) and the Italian Space Agency (Asi). 

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January 8, 2007 at 1:41 PM