Minnesota may have a new rival for the label "land of 10,000
lakes" - but don't break out the jet skis. The rival is 944 million
miles from Earth.
New images of Titan, Saturn's largest moon, reveal lakes that
appear as odd-shaped splotches across the moon's far north. Lakes
seen thus far range in size from just over half a mile to more than
60 miles long. Researchers say they contain liquid ethane and
methane at a frosty -256 degrees F.
The find caps a month of jaw-dropping discoveries about Titan's
Australia-size highlands, dubbed Xanadu, and insights into rainfall
patterns on the moon - an active world sculpted by processes that
are remarkably Earthlike.
"Looking at these images, they could be from Minnesota or
Finland," says planetary scientist Ralph Lorenz, a member of the
team announcing the results.
With the discovery, unveiled Friday, scientists heaved a sigh of
relief. They had long suspected that Titan had a version of Earth's
water cycle, but until now had no evidence of standing bodies of
liquids that should be part of that cycle. Indeed, when NASA's
Cassini spacecraft arrived at Saturn two years ago and began sending
back radar images, it initially failed to turn up any convincing
"We were getting pretty puzzled," says Rosaly Lopes, a researcher
on the Cassini radar team at NASA's Jet Propulsion Laboratory in
California. Now, with the Cassini images taken July 22, the puzzle's
pieces appear to be falling into place.
The lakes show up as dark patches on the surface. Several appear
to be fed via liquid-carved channels. Several display what look like
These are the darkest features seen so far on Titan's surface,
indicating something very smooth. "It's really hard to say whether
the lakes hold liquid or not," notes Dr. Lopes. "They're full of
black stuff," she says, but it's unclear if the smoothness
represents a glassy liquid surface or uniform deposits of
hydrocarbon "meringue topping" left on lake bottoms after liquids
Giddy, scientists await October
Confirmation could come in October, when Cassini makes another
pass close by Titan that will allow the radar to cover some of the
same features from a different angle. This will enable scientists to
build a 3-D image that could pick up the signatures of tiny
wavelets, if they are there.
The nonliquid alternatives, such as hydrocarbon sand or "fluffy
soot," would yield a poorer radar signal than the ones the team has
already received, Dr. …