Titan is one of the solar system’s coldest places, but that hasn’t stopped Saturn’s largest moon from being incredibly dynamic. A collection of 13 new studies about Titan show previously undetected craters and river deltas, and provide improved maps of its surface and interior. They also reveal new details about the moon’s mysterious 29.5-Earth-year-long seasonal cycle (the equivalent of one year on Saturn, which orbits the sun at a distance of 890 million miles). “We’re really starting to see quite a lot of profound changes on Titan,” said planetary scientist Ralph Lorenz at Johns Hopkins University’s Applied Physics Laboratory. “We’re learning things now that you could only learn after years of repeat observations.” The findings come from nearly 8 years of observations by NASA’s Cassini spacecraft in the Saturn system. Lorenz both co-authored and edited studies in the new collection published January 2012 in Planetary and Space Science. Browse through some of the most exciting findings about Titan in this gallery. Image: A false-color view of haze and clouds Titan’s north pole on Dec. 22, 2006. (Planetary and Space Science/NASA)

Seasonal Shifts Throughout most of Cassini’s tour of Saturn, which began in July 2004, hazy clouds made of ethane and methane shrouded Titan’s lake-covered north pole. "Then in 2009, the [haze layer] dropped like a brick," Lorenz said. "Until now it's been winter up there. We can start looking with Cassini's optical and infrared instruments, so it's always an ongoing discovery." The dynamic atmospheric veil, shown in the above series of snapshots mapped onto partial radar images, has already granted Cassini better looks at its polar lakes fed by summer and spring rains on Titan. Images: NASA/JPL-Caltech/University of Arizona/CNRS/LPGNantes

New Craters Impact craters left by asteroids, comets and meteorites are useful tools in understanding how a planet’s surface has aged and eroded. Planetary scientists first identified a strange, ring-shaped feature (above and right) called Paxsi on Aug. 25, 2009 in Cassini spectrometer data. It wasn’t until this year, however, that planetary scientists verified that the 75-mile-wide object was indeed an ancient impact crater. Elsewhere on Titan, researchers have found other new impact craters using Cassini’s radar sweeps of the moon. The pair below (dark circles) support notions that Titan's surface is between 1 billion and 200 million years old. “In total, these observations suggest that Titan has a relatively ‘young’ surface, and that something more than erosional processes has been acting there to reduce the number of observed craters,” Lorenz and others wrote in a study of the crater pair. Images: Planetary and Space Science*/NASA*

Hydrocarbon Lakes and Rivers One of Titan’s most curious features is its collection of lakes and rivers filled with liquid hydrocarbons such as ethane and methane. Such compounds are found in natural gas on Earth, but Titan receives little more than 1 percent of the solar intensity received by Earth. As a result, surface temperatures hover around -291 degrees Fahrenheit and cause the compounds to condense into liquid. In 2016, with NASA’s pending approval, Lorenz and others hope to launch a nuclear-powered robotic boat called Titan Mare Explorer, or TiME (right), to the Sea of Ligeia (above). To help select the best splashdown point in that Lake Superior-sized body of liquid hydrocarbons, Lorenz and two other researchers led a study to model its depths, tides and and currents (below). Images: 1) NASA/JPL 2) NASA/JPL 3) Simulated depth in meters, left, and currents, right, in the Ligeia Mare situated near Titan’s north pole. (Planetary and Space Science/NASA)

New Surface Map Because Titan is a hazy world, with an atmosphere about twice as thick as Earth’s, it’s difficult for astronomical instruments to image its surface in visible light. By creatively combining several sets of image data, however, researchers cut through the haze and create the most accurate visible-light map of Titan yet (above). Although the new map has a false-color purple hue, the results suggest Titan’s surface would appear a drab gray to human eyes (below). Images: Planetary and Space Science*/NASA*