Methane lake found on Saturn’s moon Titan

LOS ANGELES — In a surprise find, scientists say they have spotted hints of a methane-rich lake and several ponds near the equator of Saturn’s biggest moon.

Lakes were previously spied near Titan’s polar regions. It was long thought that bodies of liquid could not exist at Titan’s midsection because energy from the sun at those latitudes would cause methane pools to evaporate.

“This discovery was completely unexpected because lakes are not stable at tropical latitudes,” said planetary scientist Caitlin Griffith of the University of Arizona, who led the discovery team.

By measuring reflected sunlight from Titan’s surface and atmosphere, the international Cassini spacecraft detected a dark region near the landing site of Huygens, a companion probe that parachuted to Titan’s equator in 2005.

Scientists said further analysis of the dark feature suggests the presence of a 927-square-mile hydrocarbon lake — twice as big as Lake Champlain, a freshwater lake that borders upstate New York and Vermont. Near the equatorial lake were hints of four shallow ponds similar in size and depth to marshes on Earth.

The findings were detailed in Thursday’s issue of the journal Nature.

Titan is among the few bodies in the solar system with a dense atmosphere, but scientists have wrestled over the source of the thick blanket of nitrogen and methane. Methane gas in the atmosphere is constantly broken up by sunlight and falls to the surface where it is transported back to the poles, condensing to form lakes.

Scientists do not think this process is driving the presence of mid-latitude lakes and ponds. Rather, they think there may be an underground source of methane that periodically vents to the surface to form the hydrocarbon bodies of liquid.

“Titan may have oases,” Griffith said.

David Stevenson, a planetary scientist at the California Institute of Technology, said the latest find was interesting, but noted that the evidence was indirect.

If a subterranean source of methane is confirmed, it’s a step toward understanding the persistence of methane in Titan’s atmosphere, said Stevenson, who was not part of the research team.

Online:

Journal: http://www.nature.com/nature

More in Local News

Local police join thousands honoring slain Canadian officer

Abbotsford Const. John Davidson was killed Nov. 6 in a shootout with a suspected car thief.

Herald photos of the week

A weekly collection of The Herald’s best images by staff photographers and… Continue reading

No easy exit from Smokey Point shopping complex

There’s just no easy exit on this one. A reader called in… Continue reading

Lynnwood, Marysville, Sultan consider ban on safe injection sites

If approved, they would join Lake Stevens and Snohomish County, which have temporary bans.

City Council OKs initial funding for Smith Avenue parking lot

The site of the former Smith Street Mill is being developed in anticipation of light rail.

Single fingerprint on robbery note leads to arrest

The holdup occurred at a U.S. Bank branch in Lynnwood in June.

Two windsurfers rescued from Port Susan near Kayak Point

The men had failed to return to shore during Sunday’s windstorm.

Yes to turn signal — eventually

Adding a right-turn signal at 112th St. and 7th Ave. is turning out to be a bit more complicated.

Mill Creek councilman no longer lives in city, panel finds

The Canvassing Board determined Sean Kelly is not eligible to vote there.

Most Read