Number 149, October 28, 1993 by Phillip F. Schewe and Ben Stein THE AMERICAN INSTITUTE OF PHYSICS (AIP) has moved its headquarters to College Park, Maryland, just outside Washington, DC. After 60 years in New York City, AIP now occupies a new building, the American Center for Physics (ACP), with three of its Member Societies, The American Physical Society, the American Association of Physics Teachers, and the American Association of Physicists in Medicine. AIP is a not-for-profit corporation chartered for the purpose of promoting the advancement and diffusion of the knowledge of physics and its applications; it is the largest publisher of physics journals in the world. PHYSICS NEWS UPDATE is prepared by the AIP Public Information division. Our new address (including that of yours truly) is One Physics Ellipse, College Park, MD 20740-3843; Phone: 301-209-3090; Fax: 301-209-0846; electronic mail: pfs2@aip.org THE SUPERCONDUCTING SUPER COLLIDER has been emphatically terminated by the action of last week's vote in the U.S. Congress. Denied the research tool of their choice, particle physicists must now think of alternatives. It's too soon to decide the issue, but two possibilities would be to participate substantially in the Large Hadron Collider project proposed for CERN in Europe or perhaps to consider building a next-generation linear electron-positron collider. COLD CESIUM ATOMS BOUNCE UP TO EIGHT TIMES in a new atomic mirror. Scientists at the College de France in Paris use evanescent light, the electromagnetic field at the surface of a piece of curved glass in which laser light is undergoing total internal reflection, to reflect cesium atoms dropped from above. Previous demonstrations of atomic mirrors had been limited to one or two bounces. The development of such a mirror is the first step toward creating a Fabry-Perot- type interferometer for atom waves. (C.G. Aminoff et al., 8 Nov. Physical Review Letters.) THE EXISTENCE OF STABLE STRANGE MATTER , matter containing nuclei whose quark inventories include strange quarks, has been hypothesized since the 1970s. Such strange matter might exist, perhaps in the form of a quark-gluon plasma, in the cores of collapsed stars. A new theory introduced by Carl Dover of Brookhaven (30 August 1993 Physical Review Letters) suggests that under some conditions strange baryons (quark triplets containing one, two, or even three strange quarks) might clump together in large globs. Scientists at Brookhaven will search for evidence of the strange-matter states in high-energy collisions between gold nuclei. (Science, 8 Oct. 1993.) CARBON AEROGEL properties are in many respects better than those of their inorganic counterparts. Aerogels are microcellular foam materials; they are quite porous, low in density (0.1 g/cm**3), and have an area-to-mass ratio of 400-1000 m**2/g. Organic aerogels produced by scientists at Lawrence Livermore National Lab have an extremely low thermal conductivity, 0.012 watts per meter-kelvin, have greater strength and are better electrical conductors than inorganic aerogels, making them potentially useful as battery electrodes. Their pore size, as small as 5 nm, may make them valuable as gas filters. (Energy & Technology Review, May 1993.)