Revealing images of Titan
Astrophysicists from Lawrence Livermore and the University of California campuses at Berkeley and Los Angeles have captured the best images ever of Titan, one of Saturn's moons. The images reveal what may be the only known liquid bodies in the solar system other than those on Earth, as well as bright regions that may be ice-and-rock continents or highlands. They hint of complex chemical processes that make Titan resemble the prebiotic Earth more closely than any other place in the solar system.
The astrophysicists took the images using the world's largest telescope, the 10-meter Keck I in Mauna Kea, Hawaii, and a special technique called speckle interferometry. The powerful Keck allowed them to "map surface features 240 kilometers in size on a moon that is more than 1,200 million kilometers from Earth," said Livermore astrophysicist Claire Max. With speckle interferometry, the scientists took hundreds of infrared snapshots so fast as to freeze the atmospheric turbulence that otherwise would blur the images. The snapshots were computer-processed together and then converted into a map of Titan's surface features.
Livermore scientists developed a version of speckle interferometry to image satellites during the Cold War. Laboratory engineer Don Gavel adapted it for astronomical use. "Speckle imaging is limited to bright, compact objects; Titan qualifies perfectly," said Gavel.
What astrophysicists have learned about Titan's surface will be useful for the mission of the Cassini spacecraft currently en route to Saturn. Cassini is scheduled to land the Huygens probe on Titan in 2004. Ground-based studies such as these Keck observations using speckle interferometry will help predict whether the probe will land on a solid surface or splash into an extraterrestrial sea.
Contact: Stephen Wampler (925) 423-3107 (email@example.com).
Another use for seimic sensors
Livermore seismologists Steve Myers and Kevin Mayeda are collaborating with Yosemite National Park's rockfall specialists and the U.S. Geological Survey to apply seismic tools and techniques, typically used to study earthquakes, to monitor rockfall. Myers and Mayeda proposed this study after hearing that a climber had been killed by falling rock in Yosemite Park.
In the vicinity of the deadly rockfall that occurred this summer, Livermore field technicians installed a network of seismic sensors to determine whether very small, subtle motions from rock cracking or shifting can be detected. Myers said, "This research will let us see how useful seismic monitoring may be for predicting rockfall."
The sensors, connected to a recording box so detections can be recorded and graphed, are rechecked periodically
and their data downloaded every three weeks. The information provided may help experts better establish the patterns and mechanisms of crack development that precede rockfall, thereby providing a warning system for rockfall hazards.
The seismic monitoring data are being correlated with continuing visual observations made by Yosemite rockfall experts of the area below Glacier Point, where the fatal rockfall occurred.
Contact: Stephen Myers (925) 423-1129 (firstname.lastname@example.org).
Groundwater cleanup goes over 1 billion gallons
The Laboratory's cleanup of contaminated groundwater at its Livermore site has proceeded so efficiently that cleanup is predicted to be completed almost 20 years earlier than expected. In mid-July, the Laboratory reached a milestone when it treated its billionth gallon of contaminated water.
Groundwater contamination dates from the 1940s when the site was a U.S. Naval Air Station and chemical solvents used to clean aircraft parts leaked into the soil. Laboratory operations in the 1950s and 1960s also contributed some contamination. The contamination is deep underground. Drinking water has not been affected, and there have been no threats to human health and the environment.
Ten years ago, the Laboratory began operating its Treatment Facility A to pump and treat contaminated groundwater. Today, four fixed treatment facilities, eight portable units, three solar-powered units, and many special-purpose units have been developed and built by Livermore's environmental restoration specialists to speed the cleanup. Most of these special units are unique and also cost considerably less than a fixed facility.
Over 425 kilograms of contaminants have been removed to date. So, where once the contamination stretched almost
a quarter of a mile to the west of the Laboratory, it now reaches only a few yards beyond the Laboratory's perimeter. And the concentration of the contamination that remains is close to the regulatory limit.
Contact: Bert Heffner (925) 424-4026 (email@example.com).
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