From: LARRY KLAES (ljk4_at_msn.com)
Date: Tue Oct 28 2003 - 11:28:20 PST
----- Original Message -----
From: physnews_at_aip.org
Sent: Tuesday, October 28, 2003 1:36 PM
To: ljk4_at_MSN.COM
Subject: Physics News Update 659
PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 659 October 28, 2003 by Phillip F. Schewe, Ben Stein, and
James Riordon
A MAP OF THE UNIVERSE produced by the Sloan Digital Sky Survey
contains 200,000 galaxies at distances of up to two billion light
years, and spread out across 2400 square degrees of sky. According
to Sloan astronomer Michael Blanton (NYU), this is "the best
three-dimensional map of the universe to date." The Sloan effort
uses a telescope in New Mexico optimized to record spectra from many
galaxies at the same time. One of the standout features of the map
is the Sloan Great Wall of galaxies, some 1.37 billion light years
long and the "largest observed structure in the universe"
(preprint:astro-ph 0310/0310571) Combined with data from other
telescopes, such as the Wilkinson Microwave Anisotropy Probe (WMAP),
the new Sloan observations help tamp down uncertainties in several
pivotal astronomical numbers. The new best value for the Hubble
constant is 0.70 with an uncertainty of about 0.04; the amount of
energy in the universe vested in matter is 30% with an uncertainty
of 4%; the upper limit on neutrino mass is 0.6 eV; and the age of
the universe is 14.1 billion years with an uncertainty of 1 billion
(Preprint astro-ph/0310/0310723; Sloan website at
http://www.sdss.org/news/releases/20031028.powerspectrum.html ).
AN ELECTRICAL MICRO-GENERATOR might provide electric power for
portable microscale devices. At a modern power station, high
pressure fluids (water, steam, or gas) are dashed against turbine
blades, thus turning a shaft which cranks out electricity. At an
MIT lab, all of this is done on a centimeter-size scale. At an
upcoming meeting of the AVS Science and Technology Society in
Baltimore, Carol Livermore will describe a micromotor with a 4-mm
rotor which puts out 20 milliwatts of power, far more power than any
other existing rotating micromotor. The motor may be incorporated
into a microscale gas turbine generator. This is, in effect, a tiny
jet engine: air and gas mix in a small combustion chamber and the
resultant explosion powers the turbine (figure at
http://www.aip.org/mgr/png/2003/204.htm ). The MIT researchers
expect that soon the output will be at the level of 300 volts, and 1
watt of mechanical power or 0.5 watt of electrical power. The
device might not yet be as compact as the best micro-batteries
currently available, but it will be able to do what batteries
cannot, namely supply power over long periods. (Paper MM-TuA3,
Carol Livermore, 617-253-6761, livermor_at_mit.edu; meeting will be
held November 2-7; website at
http://www.avs.org/symposium/baltimore/default.asp ; background
article, http://www.aip.org/tip/INPHFA/vol-7/iss-6/p20.pdf )
THE HIGH AND LOW NOTES OF THE UNIVERSE. The Cornell nano-guitar,
first built in 1997 but only now played for the first time, twangs
at a frequency of 40 megahertz, some 17 octaves (or a factor of
130,000) higher than a normal guitar (see figure at
http://www.aip.org/mgr/png/2003/205.htm ). Researchers at Cornell
University used laser light to set the delicate silicon "strings"
(actually slender planks of silicon) of the 10-micron-long guitar in
motion (see figure at www.aip.org/mgr/png ). There is no practical
microphone available for picking up the guitar sounds, but the
reflected laser light could be computer processed to provide an
equivalent acoustic trace at a much lower frequency. The laser
light could excite more than one string, creating megahertz
"chords." The playing of the nano-guitar will be described by
Lidija Sekaric (now at IBM) at the AVS meeting (paper MM-WeM1;
lidija_at_us.ibm.com, 914-945-1802;
www.avs.org/symposium/baltimore/default.asp ).
If the nano-guitar's natural tones are among the most high-pitched
sounds in the universe, some of the lowest pitched are to be found
in the vicinity of the black hole in the Perseus galaxy cluster.
The Chandra x-ray telescope recently saw concentric circles in the
inter-galactic gas cloud surrounding the cluster core; some
astronomers interpret the ripples as being sound waves (with a
frequency some 57 octaves below human hearing, and possibly "the
deepest note ever detected from an object in the universe") caused
by jets from the black hole shooting outwards into the nearby
matter.
(http://chandra.harvard.edu/press/03_releases/press_090903.html )
***********
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