Number 6, October 25, 1990 by Phillip F. Schewe and Ben Stein A NEW MEASUREMENT OF THE W BOSON MASS by the CDF (Collider Detector at Fermilab) group at the Tevatron accelerator gives a value of 79.91±0.39 GeV/c². The W and its neutral cousin the Z boson are the carriers of the weak nuclear force and a precise measurement of their masses contributes to a better understanding of the so-called "standard model" of particle physics. The new CDF result, for example, helps to put an upper limit of 220 GeV/c² on the mass of the as-yet-undiscovered top quark. Earlier in the year, Fermilab scientists were able to establish also a lower limit of 89 GeV/c² for the top. (Upcoming article in Physical Review Letters. Contact: Pekka Sinervo, University of Toronto, 416-978-5270.) THE SEARCH FOR THE ELECTRIC DIPOLE MOMENT of the electron has produced a new experimental limit. A group at the University of California at Berkeley, using a pair of counter-propagating beams of thallium atoms, has established a new upper limit of -2.7±8.3 x 10-27 e-cm, a factor of at least seven smaller than all previous measurements. The existence of a nonzero electron electric dipole moment would imply a violation of both parity invariance and time-reversal invariance. (Upcoming article in Physical Review Letters. Contact Eugene D. Commins, University of California at Berkeley, 415-642-2321.) THE SPACECRAFT ULYSSES ,destined to fly over the sun's poles, was launched on October 6. In order to get into its solar polar orbit, Ulysses must first travel to Jupiter, where gravity will help lift the craft up out of the ecliptic plane. Ulysses, which will reach Jupiter on February 11, 1992 and the solar north pole on July 12, 1995, was designed to be one of a pair of probes to fly in opposite directions over the solar poles. NASA canceled funds for the other craft in 1984 because of budget problems. (Science News, October 20, 1990.) PREDICTING EARTHQUAKES IS STILL A SHAKY SCIENCE. Prior to last year's Loma Prieta earthquake, scientists at the U.S. Geological Survey had predicted a 30% chance for a magnitude-6 earthquake in the Santa Cruz area sometime in the next 30 years. The quake that came was quite different: primarily vertical in nature (some areas west of the San Andreas fault rising by as much as two feet) rather than horizontal, 9 miles from the predicted center, and more powerful than expected (magnitude 7.1). Some scientists believe that the vigor of the quake effects as far away as San Francisco may have been due to reflections of the seismic waves from the crust-mantle boundary, much as light waves may undergo total internal reflection at a glass-water interface. The reflected waves then reinforced the seismic waves coming directly from the quake center. (The New York Times, October 23, 1990.) SATURN'S LARGE WHITE SPOT ,an object (perhaps a giant storm) about 20,000 km across has reappeared after 30 years. Past observations show that the spot returns every 27 to 30 years. (New Scientist, October 20, 1990.)