archive: SETI FW: update.393

SETI FW: update.393

Larry Klaes ( lklaes@zoomtel.com )
Thu, 1 Oct 1998 09:34:59 -0400

----------
From: AIP listserver
Sent: Monday, September 28, 1998 2:11 PM
To: physnews-mailing@aip.org
Subject: update.393

PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 393 September 28, 1998 by Phillip F. Schewe and Ben
Stein

THE EXTRASOLAR PLANET PARADE continues with the
discovery of two new planets with unique features. As before,
astronomers Geoffrey Marcy (San Francisco State) and Paul Butler
(Anglo-Australian Observatory) have inferred the presence of the
planets from their observed influence on the companion star. One
of the new objects orbits its star (HD187123) in a mere three days
in an orbit 9 times closer than Mercury's around our sun. The other
new planet has a very Earth-like orbit of 437 days around star
HD21027. This comes as a reassurance to those who were
beginning to wonder whether Earth was an anomaly; all previously
discovered extrasolar planets have had orbits much smaller or much
larger than Earth's. (San Francisco State University press release,
23 September 1998.)

MILLIKELVIN MOLECULES can now be clasped in the same sort
of magnetic trap used to chill atoms down to nanokelvins.
Molecules are extended objects and not so easily cooled by laser
beams, normally the first step in cooling several atom species to
ultracold temperatures. Instead, Harvard researchers put calcium-
monohydride molecules on the road to refrigeration by mixing them
with a buffer gas of helium. Thereafter they were cold enough to
load into a system of magnetic fields where the more energetic
molecules are allowed to escape. This evaporative cooling brings
the molecular temperature to below 1 K, opening up a new regime
for collision studies and spectroscopy of cold molecules.
(Weinstein et al., Nature, 10 September 1998.)

MILKY WAY IN THE LABORATORY? A plasma with a
spiral-shaped pattern of particle density, similar to that of the Milky
Way galaxy, has been created stably in the laboratory, supporting
the possibility that fluid dynamics effects rather than gravitational
ones may be responsible for our home galaxy's structure. Injecting
a hot argon plasma (rotating at supersonic speeds) into a cold,
stationary argon gas, researchers in Japan (Takashi Ikehata,Ibariki
University, ikehata@ee.ibaraki.ac.jp) observed a spiral-armed
structure (with low-density halos of charged particles) that persisted
for as long as they kept rotating the plasma. The vortices that
typically appear in such hot plasmas became spirals because of the
outward "centrifugal" forces introduced by the rotation. Curiously,
the spiral structure was not observed to form in the absence of the
stationary gas, suggesting that the fluid dynamics interactions
between the gas and plasma are central to the spiral formation
process. This experiment intensifies the fascinating (and still
undecided) question of whether similar interactions occur between
hot, bright stars (corresponding to the plasma) and gas clouds
(analogous to the stationary gas) to form spiral galaxies. (Ikehata
et al., Physical Review Letters, 31 August 1998.)

A TRAVEL GUIDE TO EUROPEAN SCIENCE would proceed
from London to Paris to Moscow to Amsterdam. These cities,
according to Institute of Scientific Information (ISI), were
responsible for the greatest number of published scientific papers
during the period 1994-1996. If one ranks by per-capita output the
order of top European cities becomes Cambridge, Oxford, and then
Geneva/Lausanne. In the field of physics the leaders in producing
papers are Moscow, Paris, Geneva, St. Petersburg, and Warsaw.
Narrowing further to condensed matter physics, the order begins
with two Russian cities, Moscow and St. Petersburg, followed by
Paris, Berlin, and Stuttgart. (Science, 21 August 1998.)