SETI [ASTRO] Possible Hydrocarbon Seas On Saturn's Moon Titan

Larry Klaes (
Thu, 29 Jul 1999 12:35:55 -0400

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>Date: Thu, 29 Jul 1999 6:13:01 GMT
>From: Ron Baalke <>
>Subject: [ASTRO] Possible Hydrocarbon Seas On Saturn's Moon Titan
>Reply-To: Ron Baalke <>
>Public Affairs Office
>Lawrence Livermore National Laboratory
>Contact: Stephen Wampler
>Phone: (925) 423-3107
>LIVERMORE, July 28 -- The best images ever taken of Saturn's mysterious
>moon Titan reveal a complex surface that may be home to icy landforms
>and frigid hydrocarbon seas. Astrophysicists from the Department of
>Energy's Lawrence Livermore National Laboratory and the University of
>California campuses at Los Angeles and Berkeley captured the images
>using a special technique on the world's largest telescope.
>According to Livermore astrophysicist Claire Max, these images from the
>Keck telescope are sharper than those from the Hubble Space Telescope,
>and show dark regions that may be seas of liquid hydrocarbons, as well
>as bright regions that may be ice-and-rock continents or highlands. The
>results appear this month in the planetary-science journal Icarus.
>The science team used a special observing technique known as "speckle
>interferometry" to obtain the high-resolution images of Titan, Saturn's
>largest moon. At 3,200 miles in diameter, Titan is larger than the planet
>Mercury and is the only body in the solar system with a nitrogen-rich
>atmosphere like the Earth's. Of course, located 900 million miles from
>the Sun, Titan is much colder than Earth, with a surface temperature of
>minus 180 degrees Celsius (-290 F).
>Observing Titan is extremely difficult. High in Titan's atmosphere,
>ultraviolet light changes methane gases into a thick smog-like organic
>haze that hides Titan's surface. When the Voyager spacecraft passed by
>in 1980, it saw only the orange-brown top of Titan's smoggy skies.
>Infrared light can penetrate the smog to see Titan's surface. Unfortunately,
>Titan is so far away that conventional telescopes see only a fuzzy blob
>because the image is blurred by Earth's atmosphere. Even the Hubble Space
>Telescope lacks sufficient resolution, especially in infra-red light, to see
>much detail, though both Hubble and ground-based studies have shown that
>Titan has a complex surface.
>"With the tremendous power of the Keck Telescope we are able to map
>surface features 150 miles in size on a moon that is more than 800 million
>miles from Earth. I find this tremendously exciting to think about," Max
>The Livermore-UC group, including Livermore astrophysicsts Bruce Macintosh
>and Claire Max, planetary scientist Seran Gibbard, engineer Don Gavel, and
>UC Berkeley Professor Imke de Pater, studied Titan using the 10-meter
>Keck I telescope, the world's largest, on Mauna Kea, Hawaii.
>The blurring of the Earth's atmosphere was overcome using "speckle
>interferometry," a technique whereby hundreds of short snapshots, each fast
>enough to freeze the atmospheric turbulence, are computer-processed
>UCLA Professor Andrea Ghez was a pioneer in applying this technique to
>infra-red astronomy. Livermore scientists developed a version of speckle
>interferometry to image manmade satellites during the height of the Cold
>War; it was adapted to astronomical use by Laboratory engineer Don Gavel.
>"Speckle imaging is limited to bright, compact objects; Titan qualifies
>perfectly," Gavel said.
>Livermore's Gibbard worked with Chris McKay at NASA's Ames Research
>Center and Eliot Young of the Southwest Research Institute to convert
>these images into a map of surface features. The researchers removed light
>scattered in Titan's atmosphere to produce an image uncontaminated by haze.
>"These models give the first quantitative map of Titan's surface. The bright
>region shaped somewhat like a rubber duck seems to be made of a mixture
>of rock and ice," Gibbard said. A kidney-shaped region near the left edge of
>that image is made of an extremely dark material. Scientists have long
>suggested that ethane smog could condense and rain onto Titan's surface as
>a black liquid.
>"The dark material could be a sea of liquid methane, ethane, or other
>hydrocarbons," Macintosh said. "It's one of the darkest things in the solar
>system. It could also be solid organic material."
>Either possibility is exciting to scientists. If it is a sea, it represents
>the only such open body of liquid known beyond planet Earth. Whether the
>material is liquid or solid, the breakdown and re-assembly of complex
>organic molecules on Titan is similar to the complex chemistry that took
>place on Earth before life evolved. In some ways Titan is closer to the
>pre-biotic Earth than any other place in the solar system.
>Currently en route to Saturn, the Cassini spacecraft built by NASA and the
>European Space Agency is scheduled to land the Huygens probe on Titan in
>2004. Ground-based studies such as the Keck observations will help predict
>whether the probe will land on a solid surface or splash into an
>extra-terrestrial sea.
>For information on the W.M. Keck Observatory, Mauna Kea, Hawaii, contact:
>Andrew Perala (808) 885-7887, e-mail
>[Image 1:]
>A near-infrared image of Titan's surface obtained from speckle images taken
>with the Keck telescope. The brightest regions reflect about 15 percent of
>incoming light; the dark region in the lower left reflects essentially no
>indicating that it is probably dark organic material, either liquid
methane and
>ethane or a more complex solid. Credit: Lawrence Livermore National
>[Image 2:]
>For comparison purposes, an image of Titan taken with conventional techniques
>under excellent conditions shows no detail. Credit: Lawrence Livermore

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