When we last reported on the Cassini-Huygens space mission in July, Cassini had just made a first, distant flyby of Titan, Saturn's largest moon--the only moon in the solar system known to have an atmosphere.
In September the busy space probe was successfully inserted into the rings of Saturn, discovering a previously unknown ring.
Yesterday, Cassini made the first of four close flybys of Titan, 750 miles (1200 kilometers) from the surface, 300 times closer than in July. It's sending back amazing, surprisingly clear new views, atmospheric and minerological data.
CICLOPS, the Cassini mission imaging center, has put up this nifty 44-hour movie of Cassini's approach to Titan--although they don't make this clear, it's been significantly speeded up. (It's also available at NASA's web site.)
It will take scientists a while to interpret the information beamed back by Cassini. But they're already saying that the surface features on Titan could not have been made by comet or asteroid impacts alone--there are likely to be tectonic forces at work. The long skinny features may be canyons, or ridges.
In July, scientists theorized that the light areas might be rich in hydrocarbons, and the dark ones ice. The new data seems to suggest that the areas are composed of the same stuff, and covered with dust, like the surface of Mars.
"With the sun at our backs, we had an ideal view down to the surface," said CICLOPS chief Carolyn Porco at a Wednesday briefing. "We are still mystified and not quite sure what we are looking at."
Tomorrow, Cassini has a date with Tethys, another Saturnian moon--flying within 152,857 miles (246,000 kilometers) of the solid ice body.
The Huygens probe, designed by the European Space Agency, will be leaving Cassini on December 24 for a 22-day journey down onto Titan. If all goes well, it will gather data on the moon's clouds, atmosphere and surface.
What will Titan sound like? Microphones on Huygens may tell us-- if they survive the descent and landing--and we'll be able to compare it to this audio captured last June by Cassini of "bow shock," a solar wind colliding with Saturn's magnetic field.