Monday, November 19, 2007

The Big Bang a Fizzle?

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Let the peer review begin!
Gerrit Verschuur of the University of Memphis in Tennessee, US, noticed alignments between the bright patches seen by WMAP and the distribution of hydrogen in our own galaxy.
In a paper posted online that will appear in the Astrophysical Journal, he points out dozens of cases where bright patches in the WMAP data are closely aligned with concentrations of hydrogen in our own galaxy.
The distribution of hydrogen was mapped by a project called the Leiden-Argentina-Bonn (LAB) survey, which was completed in 2005, as well as the Leiden-Dwingeloo survey completed in 1997 – both of which used ground-based radio telescopes to observe radio emissions from the hydrogen.
He does not dispute that the majority of the radiation comes from the early universe, but says small amounts of additional radiation from sources in our own galaxy are causing many if not all of the apparent variations from uniformity.
He suspects the bright patches seen by WMAP are spots of plasma – a soup of charged particles made by electrons being torn from hydrogen atoms – where knots or filaments of hydrogen in our galaxy have collided.
'No correlation'
But in response to Verschuur's claim, cosmologists Kate Land of the University of Oxford, UK, and An┼że Slosar of the Berkeley Center for Cosmological Physics in California, US, who are not on the WMAP team, did a statistical comparison of the two maps. They found no statistically significant connection between the two.
"If the correlation he claimed was true then this would be major news," Slosar told New Scientist. "I would be surprised if such a big effect which Verschuur claims would escape the WMAP team anyway, but nevertheless, it is worth testing. What we found is what is expected, that there is no correlation between these two maps."
Verschuur says he does not trust the statistical method used by Land and Slosar, which he believes under-represents the significance of the alignments. When the data is filtered to show only hydrogen moving in specific ranges of velocities, the connection between particular colliding hydrogen filaments and WMAP bright spots is more obvious, he says.
Big-bang satellite data 'not flawed'
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