Number 46, September 6, 1991 by Phillip F. Schewe and Ben Stein
THE FASTEST MOVING PULSAR KNOWN has overtaken the expanding shell of a supernova, according to astronomers studying the radio source G5.4-1.2, an object which possesses a peculiar fan shape with a bullet-like projection to one side. Dale A. Fraile (505-835-7000) of the National Radio Astronomy Observatory in New Mexico and Shrinivas Kulkarni (818-356-4010) of Caltech used the Very Large Array radio telescope to make high-resolution pictures of the object: the fan-shaped part they take to be an expanding gas shell emanating from a supernova, while the bullet-shaped part they take to be a pulsar which was produced in the same supernova, but with such a kick as to propel it, at a speed of 2000 km per sec, past the by-now decelerating gas shell. This hypothesis will be tested by watching the pulsar's progress in coming years. The existence of such an asymmetric supernova explosion may partly answer the question of why there aren't more pulsars located within supernova remnants. (Nature, 29 August 1991.)
CARBON-60 SUPERCONDUCTIVITY at 57 K in an iodine-doped fullerene compound has been claimed, in an article submitted to the Japanese Journal of Applied Physics, by a group led by Hisashi Sekine at the National Research Institute for Metals in Tsukuba, Japan. (Nature, 29 August 1991.)
THE JOINT EUROPEAN TORUS WILL USE TRITIUM in fusion reactions before the end of the year. D-T reactions produce more energy than the customary D-D reactions, but scientists have until now been reluctant to use radioactive tritium for fear of unduly contaminating their reactors. JET's chief rival, Princeton's Tokamak Fusion Test Reactor, plans to introduce tritium next July. (Science, 23 August 1991.)
A LANDSLIDE ON VENUS is evident in pictures taken before and after the event by the Magellan spacecraft. Project scientists believe that a quake may have caused a high cliff in the Aphrodite Terra region to collapse, creating a five-mile-long flow of material. Magellan has also discovered a 4200-mile-long channel on Venus, the largest such feature known in the solar system. (The New York Times, 31 August 1991.)
ACCELERATOR PROJECTS WORLDWIDE were discussed recently at a meeting in San Francisco. With electron-positron machines, for example, the future lies with linear accelerators, for which costs are proportional to the beam energy, as opposed to circular facilities, whose cost varies as the square of the energy. TeV-energy linear machines may not be available until next century, but design research proceeds at many labs: for the Next Linear Collider (NLC) at SLAC, the Japan Linear Collider (JLC) at KEK in Tokyo, the TeV Energy Superconducting Linear Accelerator (TESLA) at Cornell, and the CERN Linear Collider (CLIC) in Geneva. At LEP, plans are underway to double beam energies to 100 GeV in 1994 and to have polarized beams in 1996. HERA, the electron-proton collider under construction in Hamburg, will soon have 820-GeV protons, surpassing the energy of Fermilab's proton beams. The Fermilab Main Injector project seeks to boost the Tevatron's luminosity 25 times above present levels, the better to search for the top quark. (CERN Courier, August 1991.)
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