The new measurements show that the Europan field had changed direction to follow Jupiter s lead, arguing for an induced field. Moreover, she notes, the conducting layer is more likely a true liquid, rather than a slush. Still, this tantalizing new evidence for a subsurface ocean is considered indirect. Kivelson and her team present their findings in the August 25th issue of Science . Click on image for larger view.
Radio astronomy is about to gain a powerful new instrument.
The world s largest fully steerable dish antenna was formally dedicated in West Virginia today and will commence regular observations in early 2001. Despite its size, the telescope will maintain a surface accuracy of 0.25 millimeter thanks to a feedback system that adjusts the panels to compensate for minute structural flexing of the dish. Such an accurate surface will allow observations at up to 80 gigahertz and a pointing accuracy of 1 arcsecond. The clear aperture will allow very precise measurements of spectral lines, including the 21-centimeter line of atomic hydrogen. The GBT is a vastly improved replacement for the old 91-meter Green Bank Telescope that collapsed in November 1988.