Number 130, May 27, 1993 by Phillip F. Schewe and Ben Stein
A NEW RADIATION BELT AROUND THE EARTH has been discovered by the Solar
Anomalous and Magnetospheric Particle Explorer (SAMPEX) satellite. The
new belt, which consists mostly of ionized nitrogen, neon, and oxygen,
is located within the inner Van Allen radiation belt (which itself consists
mostly of protons). NASA and Caltech scientists, speaking at this week's
meeting of the American Geophysical Union in Baltimore, said that they
believed the relatively heavy ions had originated as neutral atoms in the
interstellar medium and that the ions had penetrated far into the solar
system before being ionized by solar ultraviolet radiation. The ions later
make their way into the Earth's magnetic field, where they form a belt
structure. The ions sometimes come down to Earth but are replaced by others.
THE INTERSTELLAR SPACE THAT SURROUNDS OUR SOLAR SYSTEM is an elongated,
misshapen region of low-density gas, according to ultraviolet measurements
made by the ROSAT satellite and Extreme Ultraviolet Explorer. The measurements,
presented by Barry Y. Welsh of NASA at an astrophysics meeting in the Netherlands
earlier this month, put to rest speculations that the shape of this low-density
void resembles a single bubble carved out by a lone supernova explosion
millions of years ago. Fred Bruhweiler of Catholic University has proposed
that the region as it is now mapped out could have resulted from a combination
of several supernova explosions or strong stellar winds. (Science News,
22 May 1993.)
INTELLIGENT GELS , gels that can adjust their properties to changes in
their surroundings, promise to lead to synthetic muscles and body-implanted
medicine dispensers that respond to environmental cues. Easier to recognize
than to define, gels have two elements: a liquid solvent and polymer molecules
that link together in long chains, some of which span the entire solvent,
endowing the substance with the properties of a solid. The polymers and
solvent can be made especially sensitive to changes in such properties
as temperature or pH. Ronald A. Siegel and his colleagues at UC-San Francisco
have designed a gel-based membrane that shrinks in acidic regions but expands
in alkaline ones. Such a design can be applied to encapsulate drugs in
the body, preventing or allowing their release depending on the size of
the membrane's pores, which is determined by the environment. Yoshihito
Osada and his colleagues at Hokkaido University in Japan have designed
a "gel looper," a wormlike device that moves by alternately curling
and straightening itself under changing electric fields. Devices like the
gel-looper are precursors to "soft machines," devices that will
perform work by interacting with their liquid surroundings. (Scientific
American, May 1993.)
THE SCIENCE AND ENGINEERING RESEARCH COUNCIL (SERC), Britain's highest
science governing body, is to be replaced by several specialized councils,
including those for engineering and physical sciences, particle physics
and astronomy, and biotechnology and biological sciences. Another component
of the British government's reorganization of research will be a major
campaign for promoting a greater public understanding of science. (For
more information, contact Simon Mitton: sam11@phx.cam.ac.uk)
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