Cassini Finds Titan's Clouds Hang on to Summer

Jun 03, 2009
This infrared image of Saturn’s moon Titan shows a large burst of clouds in the moon’s south polar region. Image credit: NASA/JPL/University of Arizona/University of Nantes

(PhysOrg.com) -- Cloud chasers studying Saturn's moon Titan say its clouds form and move much like those on Earth, but in a much slower, more lingering fashion.

Their forecast for Titan's early autumn -- warm and wetter.

Scientists with NASA's mission have monitored Titan's for three-and-a-half years, between July 2004 and December 2007, and observed more than 200 . They found that the way these clouds are distributed around matches scientists' global circulation models. The only exception is timing -- clouds are still noticeable in the southern hemisphere while fall is approaching.

"Titan's clouds don't move with the seasons exactly as we expected," said Sebastien Rodriguez of the University of Paris Diderot, in collaboration with Cassini visual and infrared mapping spectrometer team members at the University of Nantes, France. "We see lots of clouds during the in the , and this summer weather seems to last into the early fall. It looks like Indian summer on , even if the mechanisms are radically different on Titan from those on Earth. Titan may then experience a warmer and wetter early autumn than forecasted by the models."

On Earth, abnormally warm, dry weather periods in late autumn occur when low-pressure systems are blocked in the winter hemisphere. By contrast, scientists think the sluggishness of temperature changes at the surface and low atmosphere on Titan may be responsible for its unexpected warm and wet, hence cloudy, late summer.

The new infrared images showing the global cloud pattern are now available at: www.nasa.gov/cassini .

As summer changes to fall at the equinox in August 2009, Titan's clouds are expected to disappear altogether. But, circulation models of Titan's weather and climate predict that clouds at the southern latitudes don't wait for the equinox and should have already faded out since 2005. However, Cassini was still able to see clouds at these places late in 2007, and some of them are particularly active at mid-latitudes and the equator.

Titan is the only moon in our solar system with a substantial atmosphere, and its climate shares Earth-like characteristics. Titan's dense, nitrogen-methane atmosphere responds much more slowly than Earth's atmosphere, as it receives about 100 times less sunlight because it is 10 times farther from the sun. Seasons on Titan last more than seven Earth years.

Scientists will continue to observe the long-term changes during Cassini's extended mission, which runs until the fall of 2010. Cassini is set to fly by Titan on May 6.

Provided by JPL/NASA (news : web)

Explore further: Amazing raw Cassini images from this week

add to favorites email to friend print save as pdf

Related Stories

Titan Weather: Cloudy Every 15 Years

Nov 01, 2005

About two years ago, before the Huygens probe arrived at Titan, Henry Roe, a graduate student I was working with at Berkeley, discovered clouds on Titan. He was the first person to get images of what he thought ...

Predicting the weather on Titan?

Jan 23, 2006

Using recent Cassini, Huygens and Earth-based observations, scientists have been able to create a computer model which explains the formation of several types of ethane and methane clouds on Titan.

Titan's icy climate mimics Earth's tropics

Oct 02, 2007

If space travelers ever visit Saturn's largest moon, they will find a tropical world where temperatures plunge to minus 274 degrees Fahrenheit, methane rains from the sky and dunes of ice or tar cover the ...

Cassini Finds Hydrocarbon Rains May Fill Titan Lakes

Jan 30, 2009

(PhysOrg.com) -- A region on Saturn's moon Titan's southern latitudes appears to have been flooded by a summer cloudburst of hydrocarbon rain, as seen in images from NASA's Cassini spacecraft taken before ...

Recommended for you

SpaceX rocket explodes during test flight

3 hours ago

A SpaceX rocket exploded in midair during a test flight, though no one was injured, as the company seeks to develop a spacecraft that can return to Earth and be used again.

Amazing raw Cassini images from this week

21 hours ago

When Saturn is at its closest to Earth, it's three-quarters of a billion miles away—or more than a billion kilometers! That makes these raw images from the ringed planet all the more remarkable.

Europe launches two navigation satellites

21 hours ago

Two satellites for Europe's rival to GPS were lifted into space on Friday to boost the Galileo constellation to six orbiters of a final 30, the European Space Agency (ESA) said.

SpaceX gets 10-year tax exemption for Texas site

22 hours ago

Cameron County commissioners have agreed to waive 10 years of county taxes as part of an agreement bringing the world's first commercial site for orbital rocket launches to the southernmost tip of Texas.

Voyager map details Neptune's strange moon Triton

Aug 22, 2014

(Phys.org) —NASA's Voyager 2 spacecraft gave humanity its first close-up look at Neptune and its moon Triton in the summer of 1989. Like an old film, Voyager's historic footage of Triton has been "restored" ...

User comments : 0