Sunlight glints off a lake near the north pole of Titan, the largest moon of Saturn, in this image from the Cassini spacecraft. The image confirmed the presence of lakes on Titan. Titan is so cold, however, that they are filled with liquid nitrogen or liquid methane instead of water. [NASA/JPL/SSI]
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Moon and Companions
SPILKER: Cassini has discovered that the Saturn system is like a curiosity shop -- there are many unusual and unexpected things that we’re finding there.
Linda Spilker is the project scientist for Cassini, a spacecraft that’s been orbiting Saturn for six-and-a-half years. Its mission was recently extended through the end of 2017 to give it extra time to explore the unusual and unexpected.
Among many other discoveries, it’s found geysers squirting into space from a small moon...waves in Saturn’s rings...and the glint of sunlight reflecting off of lakes on the moon Titan.
SPILKER: Titan has lakes at its north pole, and what we didn’t know was if those lakes contain liquid. And as the sunlight is just now peeking up over the edge of the north polar region, we saw a reflection. The light can reflect off the surface of the lake, and comes back as a very bright spot. If you’ve ever ridden in an airplane, looking out the window in the afternoon, you might notice as you go over a lake or a stream, there’s this bright spot that seems to track with the Sun. What it’s telling us is that, for the first time, we can say with certainty that there’s liquid in the lakes on Titan.
The liquid isn’t water, though -- water on Titan is frozen as hard as rock. Instead, it’s ethane or methane -- organic compounds that lead some to speculate that Titan could be a good place to look for life.
Look for Saturn to the left or upper left of the Moon before dawn tomorrow. Saturn looks like a bright golden star. The true star Spica and the brilliant planet Venus are below them. More about this lineup tomorrow.
Script by Damond Benningfield, Copyright 2010
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