Number 158, December 30, 1993 by Phillip F. Schewe and Ben Stein
THE LARGE HADRON COLLIDER moved closer to approval when the CERN Council
(consisting of representatives from 19 member nations) renewed its support
for the LHC proposal and promised to make a formal decision on the matter
in the first half of 1994. The $1.7 billion (2.6 billion Swiss franc) machine
would provide two colliding 7-TeV beams of protons and would have physics
goals similar to those of the now-terminated SSC. If approved LHC and its
two detector facilities, ATLAS and CMS, would be housed in the existing
tunnel used by the LEP electron-positron collider. And just as the U.S.
Congress had expected the SSC to receive foreign contributions, so the
CERN governors are counting on a $300 million ante from overseas, in this
case possibly from the U.S. and Japan. (Nature, 23 Dec. and Science, 17
Dec. 1993.)
NICKEL-BASED SUPERCONDUCTORS with transition temperatures above 12 K
have been reported by scientists at the Tata Institute in Bombay, India
(R. Nagarajan et al., Physical Review Letters, 10 Jan. 1994). Previous
superconductors containing ferromagnetic elements (Fe, Co, Ni) had had
transition temperatures below 5 K. The Y-Ni-B compounds (with a small admixture
of carbon) reported by the Tata scientists contain nickel fractions as
high as 60%.
THE CONNECTION BETWEEN CHAOS AND GENERAL RELATIVITY was the subject
of a workshop in July in Alberta, Canada. Just as the nonlinear equations
governing fluid flows lead to chaotic conditions, so Einstein's nonlinear
equations governing spacetime are expected to lead to chaotic behavior,
particularly in the vicinity of strong gravitational fields. For example,
Matthew Choptuik of the University of Texas reported studies of how light
waves might collapse into black holes. David Hobill of the University of
Calgary and others are adapting the "Mixmaster universe" theory---a
model in which the universe at certain times may be expanding in some directions
and contracting in others---in an effort to study localized behavior, such
as gravitational collapse or the origin of galaxies. One obstacle faced
by these researchers is that a good definition of time, necessary in following
the extreme sensitivity of chaotic systems to the specification of boundary
conditions, is problematic in the warped spacetime described by general
relativity. Therefore Richard Churchill of Hunter College is seeking "to
figure out a definition of chaos that doesn't include time." (Science
News, 4 Dec.)
A NEW FISSION REACTOR CONCEPT has been proposed by CERN director Carlo
Rubbia and, independently, by scientists at Los Alamos. In this scheme
protons from an accelerator would bombard a sample of normally nonfissile
thorium-232, causing reactions that would create both fissile uranium-233
and enough neutrons to sustain fission. Rubbia claims that this approach
to providing energy would reduce or eliminate some of the grave problems
facing the nuclear power industry, namely the chance of dangerous accidents,
the accumulation of long- lived radioactive waste, and the production of
weapons-grade materials. Disputes have arisen between Rubbia and the Los
Alamos scientists over patents and over the feasibility of the experimental
details. Rubbia plans to pursue the issue full time after he steps down
from his post at CERN next week. (Science 26 Nov. and Nature, 2 Dec.)
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