Number 153, November 29, 1993 by Phillip F. Schewe and Ben Stein
GRAVITATIONAL MICROLENSING OF QUASAR IMAGES , the distortion of quasar
light by compact substellar objects lying along the line of sight between
Earth and the quasars, may explain the long-term luminosity variations
of many quasars. M.R.S. Hawkins of the Royal Observatory at Edinburgh,
UK has analyzed 17 years' of data from a large-scale quasar monitoring
program and reports that most of the 300 quasars in the sample have luminosities
which vary semi-sinusoidally with a maximum-to-minimum timescale of about
five years. The timescales do not seem to vary with redshift. Hawkins asserts
that this variability pattern is inconsistent with any known mechanism
intrinsic to quasars themselves and is much more likely to be associated
with microlensing. (Nature, 18 Nov. 1993.) Only a few months ago, two teams
of astronomers attributed the variability of several stars in the Large
Magellanic Cloud to the microlensing influence of presumed massive compact
halo objects (MACHOS) in our galaxy. (Update 145.)
INDIUM-BASED FULLERENES , nested cage molecules made from indium (and
sodium) atoms instead of carbon atoms, have been synthesized by scientists
at Iowa State University. One typical molecule in this new class has a
formula of Na96-In97-Z2, where Z can be nickel, palladium, or platinum;
architecturally, it consists of an In74 cage surrounding a sodium cage,
which in turn encloses In10-Z units. Such metallic endohedrons (polyhedrons
of atoms enclosing other atoms) will facilitate a much more diverse chemistry
than has been possible so far with carbon endohedrons, such as buckyballs
with lanthanum inside. (Slavi Sevov and John Corbett, Science, 5 Nov. 1993.)
ELECTRONIC JOURNALS , delivering information in the form of binary bits
to your computer instead of pounds of paper to your shelf, are slowly conquering
problems in a variety of areas: transmitting graphics, refereeing, non-uniformity
of languages, copyright conventions, shortfall of submitted articles, etc.
One example: Britain's Institute of Physics is collaborating with other
publishers in creating SuperJournal, a demonstration project consisting
of a smorgasbord of existing print journals which can be accessed to varying
degrees over the new SuperJANET high- speed computer network. At a speed
of 100 megabits of data per second, the network can transmit a page of
text in about 0.25 msec. (Physics World, Nov. 1993.) The circulation of
preprints, particularly in particle physics, has been widespread for several
years, but fully electronic physics journals, with electronic submissions
and an exclusively electronic format including figures, are in their infancy
and are learning to crawl before they run. For instance, the Journal of
Chemical Physics puts up some of its articles (with figures) prior to publication
in print form. The bi-monthly publication Computers in Physics hopes to
shift from print to electronic form piecemeal, starting in early 1994,
with a regularly updated summary of physics- related information available
worldwide over Internet. The sub-editor for this online service is Glenn
Ricart of the University of Maryland (301-405-7700, glenn_ricart@umail.umd.edu)
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