Dark Matter Energy is Hydrogen - Speed and
Temperature Help Explains Pioneer Anomalies
February
15th 2006
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Pioneer 11 launch |
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A new study may
help lead to an explanation of the Pioneer 10 and 11 spacecraft
anomalies. The two crafts were launched in 1972 and 1973
respectively, and are now at the outskirts of the solar system.
The anomalies,
sometimes called the Pioneer effect, refer to the observed deviation
from expected trajectories of various unmanned spacecraft as they
travel through the outer solar system. There is no universally
accepted explanation for the phenomenon, but scientists have
speculated that it could be from gas leakage. An entirely new
physics has also been considered – dark matter and energy.
Researchers at
the Cambridge University's Institute of Astronomy in England, with
help from the worlds most advanced optical array, say that the dark
matters is made of hydrogen atoms with temperatures reaching 10,000
degrees C (18,000 F). This is hotter than the surface of the sun.
The particles travel at around six miles per second.
The new paper
examines galaxy rotation curves without exotic dark matter. It also
seeks to describe a “modified” Newtonian acceleration law derived
from a relativistic modification of Einstein’s gravitational
theory.
It was just eight
years ago that astronomers discovered that the universe was
expanding at a faster rate. Previously, most astronomers thought the
expansion would be slowing down.
So why is the
expansion speeding up? There are several theories, including a
hypothetical energy field called quintessence. This may require
changes to Einstein's theory of gravity, the existence of extra
spatial dimensions and the cosmological constant theory.
Scientists need
to find out whether dark energy changes over time. This is a
challenge because dark matter can not be detected directly because
it emits no light or radiation. The only way they can detect the
presence of dark energy is by examining the way galaxies rotate.
Galaxies would
fly apart if it were not for this unseen dark matter. It is
estimated that dark matter makes up about 80-85% of the matter in
the Universe. The gravitational energy of the dark matter holds the
galaxies together.
According to
Einstein’s theory, the inherent dark energy of empty space is
constant (referred to as the cosmological constant). Stephen
Battersby in the New Scientist said “In this favoured scenario, the
density of dark energy is fixed: a litre of space always holds the
same amount of energy, so as space keeps expanding the amount of
dark energy keeps increasing. But the continuing expansion causes
matter and its gravitational influence to thin out, so dark energy
will eventually dominate.”
James Owen from
the National Geographic reports that very little was known about
dark matter and its energy. Gerry Gilmore, a professor of
experimental philosophy and lead researcher on the project said "All
that we knew was that it was transparent and it was heavy. We knew
it had weight because it's what holds stars in the sky; without it
they'd all fly off into space." But now we are learning.
Within a few
months a “Dark Energy Task Force” will recommend projects to study
the phenomena. They may decide to use both ground telescopes and
space probes. They may recommend that space probes are too
expensive. Meanwhile, NASA remains noncommittal about a flagship
space mission to investigate dark energy, and there is concern that
the project could be abandoned.
By Dan Wilson
Best Syndication staff writer
Physics and
Space Books
Keywords and
misspellings: pioneer space craft anamoly |
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