Did you know that Saturn’s largest moon, Titan, is also the second largest moon in the solar system?
Titan was discovered in 1655 by Dutch astronomer Christiaan Huygens. Much of what we know about Titan is from the Cassini spacecraft that was launched by NASA in 1997 to study Saturn and its moons.
Recently, Cassini has delighted scientists with more details about the mysterious lakes and sand dunes on Titan.
The World Of Titan
Titan is the only moon in the solar system that has clouds and a dense planet-like atmosphere. Its atmosphere, which is made up of methane and nitrogen, is much thicker than that of our Earth's.
The Huygens probe that landed on Titan in 2005 has sent us amazing pictures of lakes and mountains over 10,000 feet tall. Titan's surface is dotted with lakes of liquid methane, mostly near its southern pole. And like water cycles on our Earth, methane evaporates to form clouds that then precipitates to produce methane rain. Large areas of Titan's surface are also covered by sand dunes, and the moon has changing seasons because of its tilted axis.
Fizzy Lakes And Electric Sands
Recently, scientists have found that the sands on Titan are electrically charged. The sand particles get charged as they bump into each other at wind speeds of 30 km/hour. This movement creates static electricity, causing sand to clump up into dunes.
Planetary scientists created a mixture of two hydrocarbons similar to the ones found on Titan’s surface and placed them in a tube. The tube recreated the atmospheric conditions of Titan (98% nitrogen). It was then shaken for 20 minutes, allowing the sand grains to bump into each other. When the scientists tried to pour out the sand, they observed that the electrically charged grains stuck to the inside of the tube!
A second discovery has solved the puzzle of "magic islands" on Titan's surface. Cassini had sent images of shapes appearing and disappearing on Titan's lakes. Scientists now believe these are dissolved nitrogen gases that bubble and fizz, just like a bottle of soda. It is possible that the nitrogen bubbles are released when Titan’s methane seas become warmer during the moon’s changing seasons.
After two decades in orbit, Cassini's days are drawing to a close. Over the next few months, NASA will send the spacecraft crashing through the rings of Saturn at high speeds, so that it self-destructs as it falls through the clouds of methane. And on its final journey, Cassini will capture images of Saturn's rings, send data on the planet's gravity and magnetic fields, and sample particles in Saturn's rings.