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Dark Matter Energy is Hydrogen - Speed and Temperature Help Explains Pioneer Anomalies

February 15th 2006

Dark Matter Energy is Hydrogen - Speed and Temperature Help Explains Pioneer Anomalies

Pioneer 11 launch

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.

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By Dan Wilson
Best Syndication staff writer

Physics and Space Books

Keywords and misspellings:  pioneer space craft anamoly 

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Copyright 2005 Best Syndication                                            Last Updated Saturday, July 10, 2010 09:51 PM