Cassini takes a close look at Titan (again)

[Rick]

NASA's Cassini Finds Monstrous Ice Cloud in Titan's South Polar Region

New observations made near the south pole of Titan by NASA's Cassini spacecraft add to the evidence that winter comes in like a lion on this moon of Saturn.

Scientists have detected a monstrous new cloud of frozen compounds in the moon's low- to mid-stratosphere – a stable atmospheric region above the troposphere, or active weather layer.

Cassini's camera had already imaged an impressive cloud hovering over Titan's south pole at an altitude of about 186 miles (300 kilometers). However, that cloud, first seen in 2012, turned out to be just the tip of the iceberg. A much more massive ice cloud system has now been found lower in the stratosphere, peaking at an altitude of about 124 miles (200 kilometers).

More: http://www.nasa.gov/feature/goddard/monstrous-ice-cloud-in-titans-south-polar-region

[Rick]

Cassini Spies Titan's Tallest Peaks

In a nod to extraterrestrial mountaineers of the future, scientists working on NASA's Cassini mission have identified the highest point on Saturn's largest moon, Titan.

Titan's tallest peak is 10,948 feet (3,337 meters) high and is found within a trio of mountainous ridges called the Mithrim Montes. The researchers found that all of Titan's highest peaks are about 10,000 feet (3,000 meters) in elevation. The study used images and other data from Cassini's radar instrument, which can peer through the obscuring smog of Titan's atmosphere to reveal the surface in detail.

"It's not only the highest point we've found so far on Titan, but we think it's the highest point we're likely to find," said Stephen Wall, deputy lead of the Cassini radar team at NASA's Jet Propulsion Laboratory in Pasadena, California.

More: http://www.jpl.nasa.gov/news/news.php?feature=6179

[Rick]

Working Toward 'Seamless' Infrared Maps of Titan

Producing a seamless global map of Titan is a challenging task, because observing conditions can vary greatly between each flyby. Among these variations are changes in the angle of the sun with respect to the surface and in the spacecraft's viewing direction. Such variations can make it even more difficult to remove the effects of scattering and absorption of light by Titan's thick, hazy atmosphere. These effects can also influence how bright different areas of the surface appear. Seasonal changes may also have played a role in changing the appearance of Titan's surface over the course of Cassini's long mission. These factors create a complex problem that researchers are still working to solve.

More from NASA

[Rick]

Cassini Finds Flooded Canyons on Titan

NASA's Cassini spacecraft has found deep, steep-sided canyons on Saturn's moon Titan that are flooded with liquid hydrocarbons. The finding represents the first direct evidence of the presence of liquid-filled channels on Titan, as well as the first observation of canyons hundreds of meters deep.

A new paper in the journal Geophysical Research Letters describes how scientists analyzed Cassini data from a close pass the spacecraft made over Titan in May 2013. During the flyby, Cassini's radar instrument focused on channels that branch out from the large, northern sea Ligeia Mare.

The Cassini observations reveal that the channels -- in particular, a network of them named Vid Flumina -- are narrow canyons, generally less than half a mile (a bit less than a kilometer) wide, with slopes steeper than 40 degrees. The canyons also are quite deep -- those measured are 790 to 1,870 feet (240 to 570 meters) from top to bottom.

More: http://www.jpl.nasa.gov/news/news.php?feature=6589

[Rick]

Cassini Sees Dramatic Seasonal Changes on Titan

s southern winter solstice approaches in the Saturn system, NASA's Cassini spacecraft has been revealing dramatic seasonal changes in the atmospheric temperature and composition of Saturn's largest moon, Titan.

Winter is taking a grip on Titan's southern hemisphere, and a strong, whirling atmospheric circulation pattern -- a vortex -- has developed in the upper atmosphere over the south pole. Cassini has observed that this vortex is enriched in trace gases -- gases that are otherwise quite rare in Titan's atmosphere. Cassini's observations show a reversal in the atmosphere above Titan's poles since the spacecraft arrived at Saturn in 2004, when similar features were seen in the northern hemisphere.

More: http://www.jpl.nasa.gov/news/news.php?feature=6655

[Rick]

Watching Summer Clouds on Titan

NASA's Cassini spacecraft watched clouds of methane moving across the far northern regions of Saturn's largest moon, Titan, on Oct. 29­­­­ and 30, 2016.

Several sets of clouds develop, move over the surface and fade during the course of this movie sequence, which spans 11 hours, with one frame taken every 20 minutes. Most prominent are long cloud streaks that lie between 49 and 55 degrees north latitude. While the general region of cloud activity is persistent over the course of the observation, individual streaks appear to develop then fade. These clouds are measured to move at a speed of about 14 to 22 miles per hour (7 to 10 meters per second).

More: http://www.jpl.nasa.gov/news/news.php?feature=6670

[Rick]

Experiments Show Titan Lakes May Fizz with Nitrogen

A recent NASA-funded study has shown how the hydrocarbon lakes and seas of Saturn's moon Titan might occasionally erupt with dramatic patches of bubbles.

For the study, researchers at NASA's Jet Propulsion Laboratory in Pasadena, California, simulated the frigid surface conditions on Titan, finding that significant amounts of nitrogen can be dissolved in the extremely cold liquid methane that rains from the skies and collects in rivers, lakes and seas. They demonstrated that slight changes in temperature, air pressure or composition can cause the nitrogen to rapidly separate out of solution, like the fizz that results when opening a bottle of carbonated soda.

NASA's Cassini spacecraft has found that the composition of Titan's lakes and seas varies from place to place, with some reservoirs being richer in ethane than methane. "Our experiments showed that when methane-rich liquids mix with ethane-rich ones -- for example from a heavy rain, or when runoff from a methane river mixes into an ethane-rich lake -- the nitrogen is less able to stay in solution," said Michael Malaska of JPL, who led the study.

More: https://www.jpl.nasa.gov/news/news.php?feature=6778