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               |                                    |  
               |         Biuletyn PTA nr 14         |  
               |                                    |  
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  Biuletyn informacyjny Zarzadu Glownego Polskiego Towarzystwa Astro-  
  nomicznego (Adres kontaktowy: M. Ostrowski, pta@oa.uj.edu.pl , 
  a w bardzo pilnych sprawach: mio@oa.uj.edu.pl )  
=======================================================================  
  
Spis tresci:  
  
   I.   Nota redakcyjna
   II.  Nowy Zarzad Polskiego Towarzystwa Astronomicznego
   III. Seminaria
   IV.  Nowinki naukowe 

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I.  Nota redakcyjna

Przypominam, ze Biuletyn PTA jest wydawany jako forum do prezentacji 
aktualnych informacji, ktore moga interesowac ogol polskich astronomow.
Nie jest on organem PTA, a nasze Towarzystwo przesylan swoim czlonkom
komunikaty w postaci internetowej lub drukowanej jako Komunikaty PTA. 

Bardzo prosze o przesylanie na podany wyzej adres wszelkich istatnych
informacji, ktore moga byc interesujace dla naszego srodowiska. 
Informacje do Biuletynu nalezy przesylac w postaci zwyklych zbiorow 
ASCII, bez polskich liter (!). 

Osoby pragnace otrzymywac Biuletyn (takze studenci) proszeni sa o 
nadsylanie krotkich "mejli" z taka prosba.

M. Ostrowski

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II. Nowy Zarzad Polskiego Towarzystwa Astronomicznego
    wybrany na Zjezdzie w Olsztynie.

                     Prezes:      Andrzej Woszczyk 
                 Wiceprezes:      Janusz Ziolkowski 
                  Sekretarz:      Adam Michalec 
                   Skarbnik:      Andrzej Niedzielski 
         Czlonkowie Zarzadu:      Ewa Janaszak 
                                  Tadeusz Michalowski 
                                  Michal Ostrowski 

From: Adam Michalec <michalec@oa.uj.edu.pl>
   
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III. Seminaria

        SEMINARIUM "FIZYKA MATERII MIEDZYGWIAZDOWEJ"

Kolejne seminarium poswiecone zagadnieniom fizyki materii
miedzygwiazdowej odbylo sie 5 listopada 1999 w Obserwatorium
Astronomicznym Uniwersytetu Mikolaja Kopernika w Piwnicach
kolo Torunia. 

Referaty:

Piotr Gnancinski (IFTiA Uniwersytet Gdanski) 

      Wyznaczanie obfitosci miedzygwiazdowego wegla z ultrafioletowych
      linii CI i CII

Jacek Krelowskiego i Jan Fulara (CA Uniwersytet M. Kopernika
     i Instytut Fizyki PAN Warszawa) 

     Precyzyjne profile rozmytych linii miedzygwiazdowych
     i co mozna z nich wywnioskowac


Funkcje LKO pelni Jacek Krelowski (jacek@astri.uni.torun.pl). Na ten 
adres nalezy nadsylac zgloszenia uczestnictwa oraz dezyderaty: czy
zamowic obiad, oraz odnosnie menu - ryba vs. nalesniki. Prosimy
tez o podanie dokladnego terminu przyjazdu i wyjazdu, a takze srodka
komunikacji. Uczestnikom z "daleka" oferujemy mozliwosc przenocowania
w Piwnicach. 

Zapytania o dalsze spotkania nalezy nadsylac do Jacka  Krelowskiego.

From: jacek@astri.uni.torun.pl   
Przeredagowal M. Ostrowski, ktory przeprasza za opoznienie z rozpowsze-
chnieniem tej informacji.

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IV. Nowinki naukowe 

Uwaga:
Zrodlem ponizszych nowinek naukowych jest
                PHYSICS NEWS UPDATE                         
    The American Institute of Physics Bulletin of Physics News
    by Phillip F. Schewe and Ben Stein
Przedruk za zgoda wydawcy.

THE SHADOW OF A PLANET slipping across the face of a distant
star has been detected, for the first time, by veteran extrasolar-planet
stalkers Geoffrey Marcy of UC Berkeley and Paul Butler of the
Carnegie Institution, working with Greg Henry of Tennessee State
University.  Prior indirect "sightings" of extrasolar planets consisted
of small feints in the apparent position of the stars caused by the
suspected gravity pull of an orbiting planet.  Astronomers have felt
that from among the growing sample of such planets (up to 25 as of
now) a few (whose orbits would be viewed at Earth edge-on) might
be detected directly as they pass in front of the star.  One such
candidate was HD 209458.  Prediction of a planetary transit for the
night of November 7 proved accurate and a 1.7% dimming in the
star's light was seen.  (Announcement made in an International
Astronomical Union circular.)

IO SODIUM JET.  Astronomers have previously known of a
sodium cloud which precedes the moon Io in its orbit around
Jupiter. The cloud is believed to arise from slow escape of sodium
from Io.  Now the Galileo spacecraft is providing details of another
sodium feature at Io, more of a fast-escaping spray or jet, thought
to come about when Io plows through Jupiter's potent magnetic
field, a process which induces mega-amp currents through Io's
atmosphere (see schematic at www.aip.org/physnews/graphics). 
New pictures, reported by scientists at the University of Colorado
(Matthew Burger, burger@ganesh.colorado.edu, 303-492-3395,
and Nicholas Schneider) and Boston University (Jody Wilson),
localize the source of the sodium to a region smaller than Io's
diameter, suggesting that Io's atmosphere might not be global; that
is, the atmosphere might be patchy and not extend all the way to
the poles.  (Geophysical Research Letters, 15 November.)

ORIGIN OF RADIO JETS NEAR A BLACK HOLE.  Black holes
don't just sit there spiderlike swallowing stars.  They also fling out vast
plumes of light-emitting material; these collimated streams can stretch
for hundreds of thousands of light years.  One of the closest of these
conspicuous jets is to be found at the heart of galaxy M87, about 50
million light years away from Earth.  Presumably the jet originates at
an accretion disk surrounding a supermassive black hole.  Previously
radio mapping of this spot in the sky did not possess sufficient
resolving power to see precisely where the jet begins.  But now, by
pooling the extended radiowave gathering power of the Very Long
Baseline Array (VLBA), the Very Large Array (VLA), and telescopes
in Italy Sweden, Finland, Germany, and Spain, astronomers have
nailed down the jet origin to within tenths of a light year of the black
hole's location.  The resulting image (see
www.aip.org/physnews/graphics) shows that the jet's initial opening
angle is 60 degrees, the widest ever seen for a jet, although the jet
becomes much more focused (6 degrees) further downstream. (Junor et
al., Nature, 28 Oct.)

GRAVITY'S GRAVITY. A new experiment at the University of
Washington seeks to determine whether the gravitational binding
energy of an object  generates gravity of its own.  As formulated by
Albert Einstein, the Equivalence Principle (EP) states that if we stand
in a closed room we cannot tell whether the weight we feel is the
result of gravity pulling down or the force of a rocket carrying us
forward through otherwise empty space.  All of this gets complicated
in some theories of gravity, which predict that the EP will be violated
to a small degree since in addition to the usual gravity, carried from
place to place by spin-two particles called gravitons, there should
exist another, fainter kind of gravity carried by spin-zero particles
(sometimes called dilatons).  For this reason, and because recent
observations of supernovas suggest that some repulsive gravitational
effects might be at work in the cosmos, scientists  want to explore the
possibility of EP violations.  Three decades of lunar laser ranging
(bouncing light off reflectors placed on the Moon) show that the
Moon and the Earth fall toward the Sun with the same acceleration to
within half a part in a trillion (10^12).  What the Washington
physicists (Eric Adelberger, 206-543-4294,
eric@gluon.npl.washington.edu) have done is focus attention on the
subject of gravitational binding energy, or self-energy, and whether it
too obeys the EP.  To illustrate the concept of binding energy,
consider that the mass of an alpha particle is actually about 28 MeV
less than the sum of its constituents.  This energy (about 7.6 parts in a
thousand of the alpha mass) represents the energy (vested in the
strong nuclear force) needed to hold two protons and two neutrons
together inside the alpha.  Gravity being very much weaker than the
strong nuclear force, the gravitational binding energy, the self-energy
of gravity attraction, is almost infinitesimal.   For example, self-
energy effectively reduces the mass energy of the Earth by a factor of
only about 4.6 parts in 10^10.  Is this tiny "mass" also subject to the
EP?  Supplementing existing lunar laser ranging results with new data
from special test masses mounted on a sensitive torsion balance (see
www.aip.org/physnews/graphics) to take into account the different
compositions of the Earth and Moon, the Washington physicists show
that gravitational self energy does obey the equivalence principle at
the level of at least one part in a thousand.  Thus gravitational self
energy does indeed generate its own gravity. (Baessler et al., Physical
Review Letters, 1 November; see also Clifford Will's article, Physics
Today, Oct 1999.)

NEPTUNE DIAMONDS.  The crushing conditions inside Neptune
and Uranus are recreated at UC Berkeley, where a tiny sample of
methane is squeezed in a diamond anvil press up to pressures of 30-
50 GPa (more than 10 million atm) and heated with laser light to
temperatures to 3000 K.  Scattered x rays and infrared light indicate
that some of the methane is being converted into 10-micron-sized
diamonds and certain polymers at pressures much below what had
been expected. This result might lead to some re-assessment of
planetary interiors since a widespread dissociation of methane would
release considerable energy, affecting the dynamics and evolution of
the planet in a big way.  (Benedetti et al., Science, 1 October 1999.)

CORRECTIONS: 1. Diamonds precipitated from methane in an anvil
press (Update 451) squeezed up to pressures of 50 GPa, equivalent to
0.5 (not 10) million atm.  

CHILLING MIRRORS WITH LIGHT.  In astronomy the effect of
atmospheric turbulence on the quality of images acquired by
ground-based telescopes can be greatly reduced by "adaptive
optics," a corrective process in which parts of the telescope mirror
are flexed mechanically by piezoelectric motors in an amount
typically equal to a fraction of the wavelength of the incoming light. 
In interferometric measurements adjustments in mirrors are also
desirable, not because of turbulence in the intervening medium but
because of thermal noise in the mirror itself.  The LIGO and VIRGO
interferometers (Update 442), searching for gravity waves, need
very still mirrors, the better to observe the flexing of space-time on a
scale far smaller than the size of an atom. A new technique might
help in this regard. Physicists at the Ecole Normale Superieure and
Universit‚ P. et M. Curie in Paris (Antoine Heidmann and Michel
Pinard, heidmann@spectro.jussieu.fr, 011-33.1-4427-4405), can
measure the thermal agitation of mirrors and reduce this unwanted
noise by a factor of 20, with pressure from laser light.  This
corresponds to a spatial sensitivity of the mirror at a level of a
billionth of an angstrom.  (P.F. Cohadon et al., upcoming article in
Physical Review Letters; see figure at
www.aip.org/physnews/graphics.)

ANOMALOUS ACCELERATION UPDATE.  Last year a team of
scientists published an assessment of the longterm trajectories of
certain spacecraft, including Pioneer 10 and 11, showing that even
after all known sources of gravity (sun, planets, comets, etc.) and
other forces were taken into account, an extra acceleration seemed to
be present (Anderson et al., Physical Review Letters, 5 Oct 98;
Update 391).  Now a series of letters concerning this assessment
appears in the same journal (30 August 1999).  John Murphy of
Johns Hopkins (301-953-6214) argues that the explanation lies in
the asymmetric radiation given off by the crafts' electronics as waste
heat.  Jonathan Katz of Washington University (314-935-6202)
implicates the recoil of radiation (from radioactive thermal
generators, or RTG, powering the craft) off the rear of the high-gain
antenna.  The authors of the original paper (contact John Anderson,
JPL, 818-354-3956) basically assert that these two particular
explanations fall short of accounting for the anomalous acceleration
by roughly a factor of five or more.  (All PRL papers are available
to journalists from AIP Public Information.)

DARK MATTER ANNIHILATION AT THE GALACTIC CENTER.
How does the presumed massive black hole at the center of our galaxy
shape the distribution of the presumed halo of dark matter in its
vicinity?  Paolo Gondolo of the Max Planck Institute of Physics
(Munich, Germany) and Joseph Silk of Oxford (UK; also UC
Berkeley) suggest the black hole sculpts the dark matter into a dense
spike where particle annihilation (or, more to the point, self-
annihilation, since one of the leading hypothetical dark-matter particles
is the "neutralino," which is its own antiparticle) would be enhanced. 
Of all the annihilation products (e.g., electrons, positrons, protons,
etc.) issuing from the galactic center (a region half a light year wide)
neutrinos would be the most serviceable since they can travel to Earth
undeflected by magnetic fields.  Gondolo and Silk have calculated
how present and future neutrino telescopes can probe the density of
inner halo dark matter.  (Physical Review Letters, 30 August;
gondolo@mppmu.mpg.de, 011-49-893-235-4427.)

GRAVITY WAVE ANALYSIS FROM LIGO PROTOTYPE.  The
Laser Interferometer Gravitational-wave Observatory (LIGO),
when fully deployed, will consist of two facilities (Hanford, WA
and Livingston, LA).  At each site laser beams pass up and down
two perpendicular 4-km-long vacuum pipes, reflecting repeatedly
from mirrors hung from wires.  The presence of a passing
gravitational wave would announce itself by a flexing of space-
time which would very slightly lengthen the path of light in one
arm and shorten the path in the other arm, causing a subtle change
in the interference pattern made by the converging light beams
from the two arms. The full LIGO, by about November 2001,
should be able to detect a strain, defined as the fractional change in
the position of the mirrors divided by the length of the arm (4 km),
of 10^-21.  This is the expected disturbance one expects from the
gravity waves emitted by the coalescence of two solar-sized stars at
a distance from Earth of 30-50 million light years.  But before
LIGO scientists possess their full instrument, they do have a 40-m
prototype at Caltech, built for doing engineering studies but also
capable of sensing gravity waves, albeit with the lesser strain
sensitivity of a few times 10^-19.  Thus the LIGO team, while
testing methods for searching (directly via gravity waves) for
binary coalescences, have thereby rendered an upper limit for such
events of less than one every two hours in our galaxy.  This result
is useful for the test of the procedures, but is not significant for
astronomers, who have previously established more stringent upper
bounds with electromagnetic waves (visible and radio).  (Contact 
Barry Barish at Caltech, 626-395-3853 or 818-601-2643; Stan
Whitcomb 626-395-2131; or Bruce Allen, University of
Wisconsin-Milwaukee, 626-893-2003 or 414-229-6439; Allen et
al., Physical Review Letters, 16 August 1999.)

THE CHANDRA X-RAY TELESCOPE is now installed in its
highly elliptical orbit, where the Earth itself, and not just its
atmosphere, will not interfere with x-ray reception.  Named for
astrophysicist Subrahmanyan Chandrasekher, the 14-m-long
telescope is considered one of NASA's three "great observatories";
the other telescopes in this battleship class are the Hubble Space
Telescope and the Compton Gamma Ray Observatory.  Chandra
will have superb angular resolution (half an arc-second, 8 times
better than previous x-ray telescopes),  sensitivity to faint objects
(20 times better), and spectral resolution (1 eV).  The object of the
mission is unflinchingly to explore graphic violence wherever it can
be found at x-ray wavelengths: quasars, black holes, pulsars,
supernovas, and intergalactic plasmas. 
(http://www1.msfc.nasa.gov/NEWSROOM/background/facts/cxoqu
ick.htm)

THE SURFACE OF MARS has been mapped to 13-meter precision,
better than for some places on Earth.  Laser light sent from and
returning to the orbiting Mars Global Surveyor spacecraft reveals
that the southern hemisphere is one big highland (6 km higher)
compared to the northern hemisphere.  Surface water, if there was
any, would have collected in the North, although there is not yet
definitive proof of any boreal ocean.  One thing that is known about
the northern lowland: it is the flattest place in the solar system.  The
South's elevation is due at least in part to an immense amount of
material raised during an ancient impact which fashioned a huge
crater known as the Hellas basin.  (Science, 28 May 1999.)

MEASURED VALUES FOR THE HUBBLE CONSTANT are
converging nicely.  At a press conference on May 25, Wendy
Freedman of the Carnegie Institution reported a new value of 70
km/sec/megaparsec (with an uncertainty of 10%), down from a
value of 80 reported back in 1994.  She is one of the leaders of a
group that uses the Hubble Space Telescope (HST) to track the
light emission of Cepheid variable stars in nearby galaxies.
Another Carnegie astronomer, Allan Sandage, has been a leader of
a group that consistently measures a smaller value for the Hubble
constant, the latest number being about 59, up from an earlier value
of 57.   Thus the observed Hubble constant, which is a measure of
the overall expansion of the cosmos, is now providing an estimate
for the age of the universe about 12 billion years that is no
longer in contradiction with the apparent age of the oldest stars. 
(NASA press release, 25 May 1999.)

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