The NASA and European Space Agency Cassini mission has revealed hundreds of lakes and seas spread across the north polar region of Saturn’s moon Titan. These lakes are filled not with water but with hydrocarbons, a form of organic compound that is also found naturally on Earth and includes methane. The vast majority of liquid in Titan’s lakes is thought to be replenished by rainfall from clouds in the moon’s atmosphere. But how liquids move and cycle through Titan’s crust and atmosphere is still relatively unknown.
A recent study led by Olivier Mousis, a Cassini research associate at the University of Franche-Comté, France, examined how Titan’s methane rainfall would interact with icy materials within underground reservoirs. They found that the formation of materials called clathrates changes the chemical composition of the rainfall runoff that charges these hydrocarbon “aquifers.” This process leads to the formation of reservoirs of propane and ethane that may feed into some rivers and lakes
“We knew that a significant fraction of the lakes on Titan’s surface might possibly be connected with hidden bodies of liquid beneath Titan’s crust, but we just didn’t know how they would interact,” said Mousis. “Now, we have a better idea of what these hidden lakes or oceans could be like.”
A combined NASA and European Space Agency (ESA)-funded study has found firm evidence that nitrogen in the atmosphere of Saturn’s moon Titan originated in conditions similar to the cold birthplace of the most ancient comets from the Oort cloud. The finding rules out the possibility that Titan’s building blocks formed within the warm disk of material thought to have surrounded the infant planet Saturn during its formation.
The main implication of this new research is that Titan’s building blocks formed early in the solar system’s history, in the cold disk of gas and dust that formed the sun. This was also the birthplace of many comets, which retain a primitive, or largely unchanged, composition today.
NASA’s Cassini spacecraft is providing scientists with key clues about Saturn’s moon Titan, and in particular, its hydrocarbon lakes and seas.
Titan is one of the most Earth-like places in the solar system, and the only place other than our planet that has stable liquid on its surface.
Cassini’s recent close flybys are bringing into sharper focus a region in Titan’s northern hemisphere that sparkles with almost all of the moon’s seas and lakes. Scientists working with the spacecraft’s radar instrument have put together the most detailed multi-image mosaic of that region to date. The image includes all the seas and most of the major lakes. Some of the flybys tracked over areas that previously were seen at a different angle, so researchers have been able to create a flyover of the area around Titan’s largest and second largest seas, known as Kraken Mare and Ligeia Mare, respectively, and some of the nearby lakes.
“Learning about surface features like lakes and seas helps us to understand how Titan’s liquids, solids and gases interact to make it so Earth-like,” said Steve Wall, acting radar team lead at NASA’s Jet Propulsion Laboratory in Pasadena, Calif. “While these two worlds aren’t exactly the same, it shows us more and more Earth-like processes as we get new views.”
An analysis of gravity and topography data from Saturn’s largest moon, Titan, has revealed unexpected features of the moon’s outer ice shell. The best explanation for the findings, the authors said, is that Titan’s ice shell is rigid and that relatively small topographic features on the surface are associated with large roots extending into the underlying ocean. The study is published in the August 29 issue of the journal Nature.
Led by planetary scientists Douglas Hemingway and Francis Nimmo at the University of California, Santa Cruz, the study used new data from NASA’s Cassini spacecraft. The researchers were surprised to find a negative correlation between the gravity and topography signals on Titan.
“Normally, if you fly over a mountain, you expect to see an increase in gravity due to the extra mass of the mountain. On Titan, when you fly over a mountain the gravity gets lower. That’s a very odd observation,” said Nimmo, a professor of Earth and planetary sciences at UC Santa Cruz.
Full Story: http://news.ucsc.edu/2013/08/titan-ice-shell.html
Saturn’s moon Titan might be in for some wild weather as it heads into its spring and summer, if two new models are correct. Scientists think that as the seasons change in Titan’s northern hemisphere, waves could ripple across the moon’s hydrocarbon seas, and hurricanes could begin to swirl over these areas, too. The model predicting waves tries to explain data from the moon obtained so far by NASA’s Cassini spacecraft. Both models help mission team members plan when and where to look for unusual atmospheric disturbances as Titan summer approaches.
“If you think being a weather forecaster on Earth is difficult, it can be even more challenging at Titan,” said Scott Edgington, Cassini’s deputy project scientist at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We know there are weather processes similar to Earth’s at work on this strange world, but differences arise due to the presence of unfamiliar liquids like methane. We can’t wait for Cassini to tell us whether our forecasts are right as it continues its tour through Titan spring into the start of northern summer.”
Scientists have created the first global topographic map of Saturn’s moon Titan, giving researchers a valuable tool for learning more about one of the most Earth-like and interesting worlds in the solar system. The map was just published as part of a paper in the journal Icarus.
Titan is Saturn’s largest moon – with a radius of about 1,600 miles (2,574 kilometers), it’s bigger than planet Mercury – and is the second-largest moon in the solar system. Scientists care about Titan because it’s the only moon in the solar system known to have clouds, surface liquids and a mysterious, thick atmosphere. The cold atmosphere is mostly nitrogen, like Earth’s, but the organic compound methane on Titan acts the way water vapor does on Earth, forming clouds and falling as rain and carving the surface with rivers. Organic chemicals, derived from methane, are present in Titan’s atmosphere, lakes and rivers and may offer clues about the origins of life.
“Titan has so much interesting activity – like flowing liquids and moving sand dunes – but to understand these processes it’s useful to know how the terrain slopes,” said Ralph Lorenz, a member of the Cassini radar team based at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., who led the map-design team. “It’s especially helpful to those studying hydrology and modeling Titan’s climate and weather, who need to know whether there is high ground or low ground driving their models.”
An ice cloud taking shape over Titan’s south pole is the latest sign that the change of seasons is setting off a cascade of radical changes in the atmosphere of Saturn’s largest moon. Made from an unknown ice, this type of cloud has long hung over Titan’s north pole, where it is now fading, according to observations made by the Composite Infrared Spectrometer (CIRS) on NASA’s Cassini spacecraft.
“We associate this particular kind of ice cloud with winter weather on Titan, and this is the first time we have detected it anywhere but the north pole,” said the study’s lead author, Donald E. Jennings, a CIRS Co-Investigator at NASA’s Goddard Space Flight Center in Greenbelt, Md.
The southern ice cloud, which shows up in the far infrared part of the light spectrum, is evidence that an important pattern of global air circulation on Titan has reversed direction. When Cassini first observed the circulation pattern, warm air from the southern hemisphere was rising high in the atmosphere and got transported to the cold north pole. There, the air cooled and sank down to lower layers of the atmosphere, where it formed ice clouds. A similar pattern, called a Hadley cell, carries warm, moist air from Earth’s tropics to the cooler middle latitudes.