Number 8, November 12, 1990 by Phillip F. Schewe and Ben Stein USING COMPUTER ENHANCEMENT TECHNIQUES to compensate for primary-mirror flaws, Hubble Space Telescope scientists have been able to produce pictures of various celestial objects, such as Pluto with its moon Charon, which would have been difficult or impossible to produce using ground-based telescopes. (The Washington Post, November 1, 1990.) SPIN EFFECTS IN PROTON-PROTON SCATTERING cannot be explained by quantum chromodynamics (QCD), the prevailing theory of the strong nuclear force, asserts Alan Krisch of the University of Michigan. Krisch is the leader of a team of scientists at Brookhaven National Lab where a beam of 24-GeV protons is smashed into a target in which 96% of all protons are oriented in a single direction. The observed left-right asymmetry in the way beam protons scatter form the polarized target protons (confirming previous experiments at Brookhaven, but now with greater precision) is at odds with QCD, Krisch believes. Other scientists feel that the QCD could yet account for the apparent spin effects. (Science News, November 3. Contact: Alan Krisch, University of Michigan, 313-936-1027.) IS THERE A BLACK HOLE AT THE CENTER OF THE MILKY WAY? Studies remain inconclusive. Observations in the infrared indicate a great clustering of stars within the central parsec (3.3 light years) but no tangible evidence for a black hole. At gamma-ray wavelengths radiation is weak and the observed sources are not coincident with the center. At radio wavelengths, Sagittarius A*, which does sit within the central parsec, seems to be a weak version of the cores of active galaxies and appears to be stationary with respect to surrounding objects, implying a great mass. Recent measurements of certain radio-emitting objects within the galaxy's central arcsecond suggest that they are related to Sgr A*, which makes Sgr A*, if not yet a black hole, more interesting as an object of study. (Nature November 1.) ACOUSTIC MEASUREMENTS OF OCEAN TEMPERATURES may contribute to the study of greenhouse effects. Scientists at Heard Island, 2550 miles southwest of Australia plan to place low-frequency loudspeakers underwater and microphones at many locations in other parts of the world. Since the speed of sound through seawater depends on water temperature, the measurement of transit times can be used to calculate water temperatures. Future studies may last five to ten years each, and would aid in measuring global temperature trends. (The New York Times, November 6.) ARE EARTHQUAKES CHAOTIC? ARE FAULTS FRACTAL? Geophysicists have long recognized that earthquakes have some of the characteristics of fractals, phenomena that look and behave the same on many different scales. In particular, the frequency and magnitude of an earthquake are related by a power law over a very wide range of earthquake intensities. This behavior has now been closely reproduced by physicists, who have applied the concepts of nonlinear systems to old models of fault zones. These models simulate fault zones by chains of springs and blocks that stick and slip. (Physics Today, November 1990.)