Cassini sees tropical lakes on Saturn moon
June 14, 2012
Saturn's rings lie in the distance as the Cassini spacecraft looks toward Titan and its dark region called Shangri-La, east of the landing site of the Huygens Probe. Areas appear dark to the visual and infrared mapping spectrometer when liquid ethane or methane are present. (Credit: NASA/JPL-Caltech/Space Science Institute)
NASA’s Cassini spacecraft has spied long-standing methane lakes, or puddles, in the “tropics” of Saturn’s moon Titan. One of the tropical lakes appears to be about half the size of Utah’s Great Salt Lake, with a depth of at least 3 feet (1 meter).
The result, which is a new analysis of Cassini data, is unexpected because models had assumed the long-standing bodies of liquid would only exist at the poles.
Where could the liquid for these lakes come from? ”A likely supplier is an underground aquifer,” said Caitlin Griffith, the paper’s lead author and a Cassini team associate at the University of Arizona, Tucson. “In essence, Titan may have oases.”
Understanding how lakes or wetlands form on Titan helps scientists learn about the moon’s weather. Like Earth’s hydrological cycle, Titan has a “methane” cycle, with methane rather than water circulating. In Titan’s atmosphere, ultraviolet light breaks apart methane, initiating a chain of complicated organic chemical reactions. But existing models haven’t been able to account for the abundant supply of methane.
“An aquifer could explain one of the puzzling questions about the existence of methane, which is continually depleted,” Griffith said. “Methane is a progenitor of Titan’s organic chemistry, which likely produces interesting molecules like amino acids, the building blocks of life.”
Global circulation models of Titan have theorized that liquid methane in the moon’s equatorial region evaporates and is carried by wind to the north and south poles, where cooler temperatures cause methane to condense. When it falls to the surface, it forms the polar lakes. On Earth, water is similarly transported by the circulation, yet the oceans also transport water, thereby countering the atmospheric effects.
Images of Titan at three wavelengths that probe the surface (credit: Caitlin A. Griffith et al./Nature)
Some regions could be shallow, ankle-deep puddles. Cassini’s radar mapper has seen lakes in the polar region, but hasn’t detected any lakes at low latitudes.
Ref.: Caitlin A. Griffith et al., Possible tropical lakes on Titan from observations of dark terrain, Nature, 2012, DOI: 10.1038/nature11165
Comments (6)
by Alex Burke
I fear that when human created space vehicles come upon totally novel extra terrestrial life forms, they’ll harm them and their world.
by Bri
I like the remote sensing robots, that, transmit sight, touch, and sound. With some more development, it could give you full sensory feedback.( minus the cold). Just think, you could sunbath by a tropical lake on Cassini!
by Guillermo
lol, you mean on Titan!!
by egore
I wonder how it would be to sunbathe on Titan? Might be a trifle uncomfortable. Since Methane seems to be one of the building blocks of life, would it be practicle to say there might be a form of life on Titan?
by Kristoph77
How cool would it have been had Huygens been near one of these lakes on its decent to the surface.
by Khannea Suntzu
Cassini can’t see the lakes at either poles because the refractory qualities of the thick atmosphere at the poles makes it opaque. The lakes are there, yet the combination of haze and angle makes them invisible.