SETI bioastro: Fw: update.569

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From: LARRY KLAES (ljk4@msn.com)
Date: Sat Dec 22 2001 - 20:02:29 PST


----- Original Message -----
From: AIP listserver
Sent: Thursday, December 20, 2001 3:24 AM
To: physnews-mailing@aip.org
Subject: update.569

PHYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 569 December 14, 2001 by Phillip F. Schewe, Ben Stein,
and James Riordon

PHYSICS STORIES OF THE YEAR FOR 2001: In cosmology, the
observations of second and third peaks in the spectrum of the
cosmic microwave background (Update 537), the detection of the
"re-ionization" era in the early universe (555), and some tentative
evidence that the fine structure constant is changing (552); in the
physics of atoms, the effective stopping and storing of light in a gas
(521); in particle physics the observation of CP violation in the
decay of B mesons (525, 547); in condensed matter physics, the
observation of superconductivity at 117 K in a crystal of carbon-60
(555) and at 40 K in MgB (526,530); Bose Einstein condensate on a
chip (559), in helium (532), and the topic meriting the 2001 Nobel
Prize (560); in nuclear physics the first experimental formulation of
a nuclear liquid-gas phase diagram (upcoming Update). Other
stories include the retraction of the element 118 discovery (550);
further evidence for neutrino oscillations, at the new Sudbury
detector (544); doubly strange nuclei (552); chaos insights on
weather (543); crystallization using sound waves (541); room-
temperature spin injection for spintronics (543); quantum
entanglement of macroscopic gas clouds (558); quantum holography
(566); attosecond pulses (567).

OCEANS MIGHT BE COMMON AND DIVERSE in our solar
system and in other solar systems, according to David Stevenson of
Caltech, who regards the old notion of a narrow "habitable zone"
(Venus too hot, Mars too cold, Earth just right) for liquid water
oceans as erroneous. Stevenson spoke earlier this week in San
Francisco at a meeting of the American
Geophysical Union (http://www.agu.org/meetings/fm01top.html) at
a session intended to bring together two scientific communities that
scrutinize very different realms the planets and the seafloor on
Earth. The connection? Observations from the bottom of the ocean
show that microbes thrive both in near-freezing seawater and in
near-boiling effusions from thermal vents. These conditions might
turn up in many other planetary environments. For example, the
Galileo spacecraft has provided evidence for watery oceans on three
of Jupiter's moons Callisto, Ganymede, and Europa. Subsurface
oceans could be kept liquid by warmth from tidal forces (Jove
wringing its satellites) or from radioactivity. Torrance Johnson of
JPL, also speaking that the meeting, said that Europa's ocean might
be 75-150 km thick and could thus harbor twice the water in Earth's
oceans. Stevenson added that observations also hint at oceans on
Titan, Triton, and Pluto. In the case of Titan (soon to get the
Galileo treatment when the Cassini spacecraft reaches Saturn in
2004) an ocean would be a mixture of water and ammonia (acting as
antifreeze). Under some circumstances water might even be found
inside Uranus and Neptune.

A NANO-ELECTRON-VOLT NEUTRAL-ATOM STORAGE
RING, built and tested by physicists at Georgia Tech, should help
the development of atom fiber optics. Generally, storage rings not
only store particles but also serve to define an energy and trajectory
insofar as the particles are guided around a prescribed track by some
kind of magnet system; particles with the wrong energy would fly
away. Normally the magnets exert themselves by grabbing onto the
particles' electric charge. Neutral atoms don't have a net charge but
they can possess a net dipole moment which, if the atom is moving
slowly enough, is sufficient for guidance (see figure at
http://www.aip.org/mgr/png). The Georgia Tech experiment
(Michael Chapman, michael.chapman@physics.gatech.edu, 404-
894-5223, Jacob Sauer, jakesauer@mindspring.com, Murray
Barrett, m.barrett@mindspring.com) is much more modest than
your typical particle accelerator: it's only 2 cm across and corrals
neutral rubidium atoms moving at speeds of 1 meter/sec (equivalent
energy=nano-eV, temperature=microkelvins). So far swarms of one
million atoms have made as many as seven circuits around the ring
(see figure at http://www.aip.org/mgr/png). The same researchers
produced the first all-optical generation of a Bose Einstein
condensate (Update 545), and they hope to load the atoms from a
condensate with their new storage ring (dubbed the "Nevatron").
Possible goals include ultra sensitive gyroscopes and atom lasers.
(Sauer et al., Physical Review Letters, 31 December 2001; website:
www.physics.gatech.edu/ultracool.)


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