One week after the Huygens space probe landed on distant Titan, European and American scientists have revealed startling new information about this largest and most mysterious moon of the planet Saturn. There appear to be rocklike structures and flowing liquid on Titan - even, they believe, a form of liquid methane rainfall. Earth-like characteristics described Friday by scientists at the European Space Institute in Paris.
Just a week ago, scientists were applauding the successful landing of the space probe, which plunged through the murky, chilling air of Titan to land on a spongy surface they described as wet sand or soft clay. It appears a mysterious, pinkish orangey world. Pictures sent by the probe showed a flat terrain with fist-sized objects that researchers described as chunks of ice.
Now, scientists have been able to sift through dozens of images sent by the Huygens space probe over the space of several hours before its batteries went dead. Martin Tomasko, one of the principal investigators for the Titan project, describes some of the grainy, black and white images to reporters. "This is a field of view one kilometer across and you see this very rugged terrain," he says. "We see a ridge system."
The pictures show spidery dark lines etched on Titan's surface. There are also lighter areas. They appear a mystery to ordinary viewers. But the projects scientists believe they are rivers, streams and channels of liquid. Only the liquid isn't water, which would be frozen solid at on Titan, where it's around 170 degrees below zero. Instead, the evidence is that it's liquid methane. Scientists even believe it rains regularly on this far-off moon, located a four billion kilometer journey through the Solar System from earth. Only it's methane rain.
And that's not all. There appears to be stuff like dirt on Titan, and large chunks that are similar to rocks. Scientists believe the sandy substance is in fact shards of crushed ice on Titan. The rocklike substances are larger chunks of ice.
Titan seems vastly different from our home planet, but European Space Agency mission manager Jean-Pierre Lebreton says he is struck by the similarities. "Our new picture of Titan is really fascinating. And what we are seeing is earth-like processes on Titan. But the big difference is the ingredients are somewhat different. The liquid on Titan is methane, the liquid on earth is water. The rocks on earth are silicate. The rocks on Titan are ice blocks. And the dirt on earth is our dirt. The dirt on Titan is organic matter," he says.
Only a week after receiving date from the Huygens probe, the scientists' findings are still preliminary. They say it will take weeks and months to sift through the rich trove of data sent by the space probe. And they say many mysteries remain.
The Titan landing is a joint project by European and American scientists. It took the Huygens probe seven years to reach the planet, traveling aboard the Saturn probe Cassini. And it took Huygens more than two hours to float down to Titan's surface, slowed down by parachutes. The probe settled some 10-15 centimeters into the top layers of Titans spongy surface.
Scientist Martin Tomasko says the probe seems to have settled in a dry corner of the planet - similar to parts of Africa or the United States. "The region we landed in is more typical of arid regions on the earth. We don't think we have open pools of liquid methane, but the methane kind of sinks down into the surface material, into the sand, if you will. It's more like Arizona, or a place like that, where the river beds are dry most of the time," he says.
Because the probe landed on only one area of Titan, scientists have no idea whether it's representative of the entire moon, or whether there are more humid regions elsewhere. They also don't know whether Titan has seasons - like a rainy season and a dry season. But they do believe there is regular precipitation on Titan; it could very well have rained liquid methane the day before the probe landed.
The Titan findings mark a coup for the 15-country European Space Agency, which worked in collaboration with America's NASA. The Europeans are also savoring an earlier success of a Mars mission, which produced photographs, which its scientists say offer the most direct evidence that water in the form of ice may exist on that planet. Other future projects include two other missions to Mars and one to Venus. And scientists Friday suggested it might be possible to explore Titan in the future with a moving rover.
Even with its earth-like characteristics, it's almost impossible to imagine existing in Saturn's frozen, far-off moon. But there may come a day - a very long time from now - when Titan may actually be livable for carbon-based life forms like we know here on Earth. Scientist Toby Owen, from the Institute for Astronomy in Hawaii, explains. "In about four billion years, our sun will expand and will become a red giant. And when than happens, there's been a couple of scientific papers that have suggested that the temperatures in the outer solar system will rise, long after life has become impossible on earth. Temperatures will rise on Titan, the water ice will melt, the water ice will be released, and because we have the very basic building blocks for life in the form of organic molecules, for a very brief time, Titan may be a very good place," he says.for life.
But for right now, it seems clear that humans are far better off exploring Titan from where we are now -- our warm, oxygenated and faraway planet, Earth.
