Number 13, December 17, 1990 by Phillip F. Schewe and Ben Stein
A DIGITAL SKY SURVEY , a 10-year, $14-million effort by the University of Chicago, Princeton University, and the Institute for Advanced Study, will map the location of 1 million galaxies and 100,000 quasars. The project, which may begin taking data in 1995, will use a special 2.5-m telescope (to be built in New Mexico) and record the spectra of 600 galaxies simultaneously. By comparison, the galaxy survey conducted by Harvard astronomers Margaret Geller and John Huchra, a survey which revealed the existence of colossal walls and voids of galaxies, mapped only thousands of galaxies, and did it by recording spectra one at a time. (Science, November 30, 1990.)
CONDUCTING POLYMERS , plastics that can carry an electric current, are presently being developed for practical applications, such as for use in "smart windows" that absorb sunlight in summer, in electrolytic capacitors, and in rechargeable batteries which are light, long-lived, and which may soon have an energy density several times that of currently commercially available lead/acid batteries. Polymers such as polyacetylene are normally electrical insulators, but can be made conducting by doping, which improves their conductivity by orders of magnitude. (Chemical and Engineering News, December 3, 1990. Contact: Alan Heeger, UC Santa Barbara, 805-961-3184.)
THE VERY LARGE TELESCOPE (VLT) , the largest optical telescope ever, will be built at Cerro Paranel, a mountaintop in Chile, by the European Southern Observatory (ESO). The VLT will consist of four 8.2-m telescopes, the first of which should be installed by 1995; the equivalent 16-m diameter of the composite device will be much larger than the 10-m Keck or 6-m Hale telescopes. The seeing conditions for VLT, already very good because of the high elevation in the Andean mountains, will be improved by the use of adaptive optics. The resultant optimal resolution for the telescope may be as good as 0.0005 arcseconds. (ESO news release, Dec. 4.)
A WIGNER CRYSTAL , a two-dimensional array of electrons confined to the sites of a lattice, may have been observed by two scientific teams: a Stony Brook-Princeton-AT&T Bell Labs group and a Saclay-Rutgers-Bagneux-Philips collaboration. Unlike the crystalline phase of electron an electron gas observed (in 1979) above a sample of liquid helium, the present electron crystal phase, first hypothesized by Eugene Wigner in the 1930s, is believed to be governed by quantum effects. Evidence for the Wigner crystal comes from experiments on the two-dimensional electron gas which forms (in the presence of a strong magnetic field) at the interface between GaAs and AlGaAs layers in a heterojunction. (Physics Today, December 1990.)
WAVELET TRANSFORMS may be better than the more common Fourier transforms in representing or analyzing various mathematical problems or physical phenomena. Wavelets are particularly adept at processing signals that change abruptly, such as sound or video information, or electrocardiograms. (Scientific American, Jan. 1991.)
|
