May 21 1998
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(New page: Chryssa Kouveliotou of the Universities Space Research Association led a team of astronomers at NASA's Marshall Space Flight Center in confirming the existence of magnetars, a special ...)
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Chryssa Kouveliotou of the Universities Space Research Association led a team of astronomers at NASA's Marshall Space Flight Center in confirming the existence of magnetars, a special class of neutron stars with a magnetic field one thousand trillion times the strength of Earth's. The team calculated the strength of SGR1806-20, first discovered in 1979, by combining data from NASA's Rossi X-ray Timing Explorer satellite and the Advanced Satellite for Cosmology and Astrophysics.
John S. Lewis, Codirector of the Space Engineering Research Center at the University of Arizona in Tucson, testified before the House Science Subcommittee on Space and Aeronautics concerning the potential danger of nearby asteroids. His testimony supported the idea that any asteroid colliding with Earth in the next 100 years could only be an asteroid not yet known to scientists. Lewis argued that, since an international scientific effort could identify such an asteroid easily, he advocated "a systematic, globally-coordinated search and characterization program that costs less than a single small space mission." Such a search, he argued, would "give us adequate warning of a threatened asteroid impact," so that we would "have ample time to design, build, test, and deploy an effective defense against the threat.
The U.S. House of Representatives approved Representative David Weldon Jr.'s (R-FL) amendment to the US$271 billion defense authorization bill, to protect funding for launch ranges. In the past six years, the U.S. Department of Defense had diverted money, which would have modernized U.S. Air Force-controlled launch ranges, to cover costs associated with overseas deployments, such as ongoing operations in Bosnia. Weldon stated that diverting funds away from the launch ranges was a "national security issue as well as a critical issue for NASA and commercial space." Weldon's amendment reserved US$273.3 million for the Cape Canaveral Range in Florida and US$109.1 million for the Western Launch Range at Vandenberg Air Force Base in California.
Scientists published a study in the journal Science, using images from the Galileo probe as evidence that an ocean beneath the surface of Europa, one of Jupiter's moons, was once warm and salty. James K. Crowley of the U.S. Geological Survey stated that Galileo data showed that "salt absorption patterns on Europa were similar to those on Earth." Gary B. Hansen, a University of Hawaii geophysicist, added the observation that "the size of the salt bands on Europa's surface are continuous and stretch across much of the moon," evidence of a salty ocean beneath the moon's icy surface. Jeffrey S. Kargel, also of the U.S. Geological Survey, commented on his colleague's study in Science, saying that salt is an important "piece in the puzzle," but in the absence of other evidence, does not prove that a salty ocean lies beneath Europa's surface. Scientists seek other evidence, such as shifting ice plates, cracks in the frozen surface, and a magnetic field.
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