Liquid-filled lakes found on Saturn's moon Titan

PROVO — Saturn's mysterious moon Titan has numerous liquid-filled lakes on its surface, according to one Brigham Young University professor, but tourists wouldn't want to take a dip in these pools.

"We think these (lakes) are filled up with methane," said Jani Radebaugh, co-author of an article about the lakes, which appeared in this week's edition of Nature magazine.

The colorless, odorless gas methane, a component of natural gas, is abundant in the moon's atmosphere.

"That's why it (Titan) looks like kind of a big, smoggy, orange ball," said Radebaugh, a professor with BYU's Department of Geological Sciences.

Scientists discovered more than 75 lakes, which lie at the north pole of the moon, after viewing radar images of Titan's surface taken by the NASA spacecraft Cassini in July.

The lakes range in size from approximately one to 60 miles wide and some share uncanny characteristics with popular lakes on Earth.

"One really stood out to us and looked like Lake Powell," Radebaugh said.

The discovery confirms a long-held belief among scientists that lakes exist on Titan, which is larger than Mercury and one of Saturn's 34 moons. It also reveals a cycle of liquid on the planet that is similar to Earth's hydrological cycle, Radebaugh said, the difference being that the liquid on Titan is methane, not water.

An active liquid cycle, in which liquid moves from the atmosphere to the surface and back again, is a rare find.

"There's no other body in the Solar System like this besides Earth," Radebaugh said.

The discovery may allow scientists to probe the origins of life on Earth because it confirms a similarity between the two planetary bodies. Titan has many of the chemical building blocks of life — nitrogen, carbon, hydrogen and oxygen — and scientists conjecture its atmosphere resembles Earth's billions of years ago, according to NASA's Web site.

"If we look at places that have those chemicals and look at how the processes work, then we might get a little bit closer to understanding how life began (on Earth)," Radebaugh said.

Mars also has evidence of a liquid cycle, but it may be more useful as a projection of Earth's future than its past.

"It looks like something like this has happened in the past (on Mars), but the very distant past," Radebaugh said.

One of about 30 of the article's authors, Radebaugh has also studied radar images of dunes and mountains on the surface of Titan.

The moon's dunes, which appear to number near 10,000, span larger areas than those on Earth and have a much more dangerous composition.

"On Titan, we actually think they (the dunes) are made up of solid particles of gasoline," Radebaugh said.

The spacecraft Cassini is slated for at least another year in Saturn's orbit with a monthly pass by Titan.

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