News Scan Briefs; September 2001; Scientific American Magazine; by Philip Yam, Mariama Orange, Alison McCook, Sarah Simpson; 2 Page(s)

Moons over Saturn-Saturn's family has gotten bigger. Researchers using 11 different telescopes around the world have reported finding 12 new moons, ranging from six to 32 kilometers in diameter and orbiting Saturn in highly eccentric paths, quite unlike the generally circular orbits of its major moons, such as Titan. These tiny moons seem to be clustered in groups of three or four, suggesting that they are remnants of larger bodies that were fractured, probably by collisions, early in the planet's formation. Such irregular bodies may be common for the gas giants; in the past few years astronomers have found five irregulars around Uranus and 12 around Jupiter. The latest finding, in the July 12 Nature, brings Saturn's satellite brood to 30: six major moons and 24 minor ones.-Philip Yam

Built for Speed: IBM attested in June to building the world's fastest silicon-based transistor. Potentially able to operate at 210 gigahertz, this silicon germanium transistor performs 80 percent faster than previous technology, breaking the 200-GHz speed barrier thought to exist for silicon-based transistors. Transistor speed depends largely on the distance electricity must travel within the device, and IBM researchers were able to shrink this distance in socalled heterojunction bipolar transistors, in which electrons flow along a vertical path rather than taking the horizontal route in conventional transistors. IBM expects that within two years the transistors will drive chips used in communications equipment to 100 Ghz-five times faster than today's chips. (The transistors, though, are incompatible with computer processors.) The little super-silicon transistors still have a way to go before they can switch quickly enough to keep up with the theoretical limit of fiber-optic communications. In the June 28 Nature, researchers at Lucent Technologies calculated the limit to be approximately 100 terabits per strand of fiber. Current data transmission rates run as high as 1.6 terabits per second over a single strand.-Mariama Orange