Michael Mcneil wrote:
Dina put me on ignore if you find my hreads so painful.
The Sun
Over an hundred years ago ?we? had no idea what powers the sun. Residual
heat, of the sort ascribed the earth?s core, was clearly out of the
question. Then Radio-Activity was discovered.
But the idea that the sun was full of radium or other radioactive
materials was scotched when research in the 1940?s showed that a nuclear
pile will go critical with very small amounts of radio-active material.
The idea that the sun is a nuclear fission device that splits atoms was
shelved. A decade later, the Hydrogen Bomb was invented.
In the meantime (and since before the history of man) the sun is
continuously putting out radiation is a very small window. Over 98% of
this window is infra-red spectrum through ?visible? heat (light) to
ultra-violet. About 50% of the solar output is the rainbow of visible
radiation.
Not a bad guess for the gods of evolution was it, to place a nuclear
furnace so close to us; and it only puts out safe radiation? Wavelengths
exactly in between x-rays and microwaves. With a margin for error that
is neatly catered for by the earth?s natural production of ozone -which
is itself another miracle.
Alternatively, if you don?t believe in miracles:
No one has yet discerned the mechanism by which a solar system derives
its heat and light.
The Sun's primary energy source is the p-p chain whereby helium is
fused from hydrogen in the core of our sun. Density, pressure and
temperature profiles, solar neutrino (antineutrino) energies and total
radiated energy confirm the standard solar model.
Density, pressure an temperature profiles are measured by analysis
of the Sun's vibration modes, rates, etc.
The [once] Solar Neutrino Problem Has Been Closed
http://www.aip.org/enews/physnews/2002/split/586-1.html
HYSICS NEWS UPDATE
The American Institute of Physics Bulletin of Physics News
Number 617 December 13, 2002 by Phillip F. Schewe, Ben Stein, and James
Riordon
PHYSICS STORIES OF 2002. The top two physics stories for the past 12
months were the total accounting of neutrinos from the sun by the Sudbury
Neutrino Observatory (SNO), thus solving the solar neutrino problem (Update
586;
http://www.aip.org/enews/physnews/20...t/586-1.html); and the formation
and detection of antihydrogen atoms at CERN (Updates 605 and 611,
www.aip.org/enews/physnews/2002/split/605-1.html and
http://www.aip.org/enews/physnews/20...it/611-1.html). Other notable physics
developments for the year include stopping and storing light in a solid
(Update 571), the observation of phase-transition behavior in nuclei (572),
publication of some unsent letters by Niels Bohr to Werner Heisenberg (576),
interferometry with C-70 molecules (579), a dispute over "fusion" in
sonoluminescence (579, 599), most precise tests of special relativity (571,
590), sharper maps of the cosmic microwave background (591), "droplet" of
light (596), claims for element 118 retracted (597), verification of the
notion that the second law of thermodynamics can be violated on small
spacetime intervals (598), high precision measurements of CP violation in B
meson decays and in the g-2 factor of the muon (600), scandal at Lucent
(606), record high laboratory magnetic fields (614), polarization in the
cosmic microwave background detected (606), 2002 Nobel prize for physics
(608), noise can improve balance (612), and longest measured atomic lifetime
(616). All the above Update items can be retrieved from our archive at
www.aip.org/physnews/update.
REACTOR ANTI-NEUTRINO DISAPPEARANCE, measured by a detector in Japan,
supports the idea that neutrinos oscillate from one type to another and that
they possess mass. Nuclear reactors produce several things: heat,
electricity, spent fuel rods, and neutrinos. The neutrinos (or, to be more
exact, electron anti-neutrinos) are a result of fission reactions inside the
reactor core. But some of the electron antineutrinos, once they're underway
and moving through the Earth, manifest one of the weirdest phenomena in all
of physics, namely the ability to exist as a composite of several
sub-species. That is, what we call a neutrino is really several (perhaps
three) neutrinos in one. At any point along its trajectory the generic
neutrino might (if you were to capture it just then) appear as an electron
neutrino, but farther along it might look like a muon neutrino, in which
case it would elude detectors tuned to detect only electron nu's.
The Kamioka Liquid Scintillator Anti-Neutrino Detector (KamLAND) sets out
to sample this odd mode of being. The apparatus, basically a huge reservoir
of optically-active liquid viewed by numerous phototubes, looks for
interactions in which an incoming nu strikes a proton, creating in their
stead a trackable neutron-positron pair. KamLAND resides in an underground
lab beneath Toyama, Japan. It is a sort of telescope peering not at
galaxies in the sky; instead it stares through a block of terrestrial crust
looking for the neutrino warmth cast off by a constellation of 69 reactors
in Japan and Korea.
Taking into account the laws of physics governing the reactions in the
reactor cores, the known power ratings for the reactors, their aggregate
reactor-detector distances, and the duration of the experiment (145 days),
one would expect seeing 86 true events, whereas the actual number was 54.
The researchers conclude that the disappearance of events is due to neutrino
oscillation.
This result is not merely a confirmation of oscillation research carried
out with solar nu's at such detectors as Super Kamiokande in Japan and the
Sudbury Neutrino Observatory (SNO) in Canada (see Update 586,
http://www.aip.org/enews/physnews/20...it/586-1.html). For one thing
KamLAND studies anti-neutrinos rather than neutrinos. Furthermore, the
production of neutrinos in a reactor is much closer at hand and better
understood than is the case for the sun. The KamLAND finding also serves to
narrow the theoretical explanation of the neutrino's split personality.
(Eguchi et al., paper submitted to Physical Review Letters, text and
background information at:
http://hep.stanford.edu/neutrino/KamLAND/KamLAND.html)
The "solar neutrino problem" was solve a few years ago:
http://www.aip.org/enews/physnews/2002/split/586-1.html
http://www.aip.org/enews/physnews/2002/split/608-1.html
Note these papers by John N. Bahcall, Sarbani Basu, M. H. Pinsonneault:
http://xxx.lanl.gov/abs/astro-ph/9805135
http://pdg.lbl.gov/1998/solarnu_s005313.pdf
http://www.slac.stanford.edu/pubs/be...-3-bahcall.pdf
Also read:
http://www.sns.ias.edu/~jnb/Papers/P...ayhistory.html
http://www.fynu.ucl.ac.be/librairie/...ns/node26.html
http://www.mpi-hd.mpg.de/kirsten/gallex/detector.htm
Neutrino producing reactions adapted [by Lang]
from Bahcall (1989). The termination percentage is a fraction of terminations
of the proton-proton (pp) chain, 4p -- alpha + 2e+ + 2v_e, in which each
reaction occurs. Since in essentially all terminations at least one pp neutrino
is produced and in a few terminations one pp and one pep neutrino are created,
the total of pp and pep terminations exceeds 100%
Name Reaction % Termination Neutrino Energy, q
------------------------------------------------------------------------------
pp p + p -- H² + e+ + v_e 100 q 0.420 MeV
pep p + e- + p -- H² + v_e 0.4 q = 1.442 MeV
hep He³ + p -- He4 + v_e 0.00002 q 18.773 MeV
Be7 Be7 + e- -- Li7 + v_e 15 q = 0.862 MeV 89.7%
q = 0.384 MeV 10.3%
B8 B8 -- Be7 + e+ + v_e 0.02 q 15 MeV
Calculated Solar neutrino fluxes at the Earth's Surface
------------------------------------------------------------------------------
pp 6.0 x 10^10 cm^-2 s^-1
pep 0.014 x 10^10 cm^-2 s^-1
hep 8 x 10^3 cm^-2 s^-1
Be7 0.47 x 10^10 cm^-2 s^-1
B8 5.8 x 10^6 cm^-2 s^-1
Other relevant papers by John N. Bahcall, Sarbani Basu, M. H. Pinsonneault:
http://xxx.lanl.gov/abs/astro-ph/9805135
http://pdg.lbl.gov/1998/solarnu_s005313.pdf
http://www.slac.stanford.edu/pubs/be...-3-bahcall.pdf
And here is something fun you can do:
http://www.physics.mun.ca/~jjerrett/...proton/pp.html
More fun references:
http://hyperphysics.phy-astr.gsu.edu...o/solarpp.html
http://www.britannica.com/bcom/eb/ar...+61627,00.html
http://www.eps.org/aps/meet/APR00/ba.../S5690002.html