First they make this shit up, then they prove it doesn't exist

Joseph S. Barrera III joe at barrera.org
Wed Dec 17 19:56:18 PST 2003


New doubts on dark energy
17 December 2003

Most astronomers believe that the universe is dominated by "dark energy" 
because it has been the only way to explain why the universe is 
expanding and accelerating at the same time. Now, however, physicists in 
the Netherlands and France are suggesting that this energy might not 
exist. They claim that the absence of dark energy could account for 
recent X-ray observations of the universe that have unearthed puzzling 
differences between ancient and present-day galaxy clusters (Astron. 
Astrophys. to be published and arxiv.org/abs/astro-ph/0311344)

In February, NASA unveiled the first detailed full sky map of the cosmic 
microwave background - the microwave "echo" of the big bang. The data, 
which were collected by the Wilkinson Microwave Anisotropy Probe 
satellite (WMAP), supported the currently popular "concordance model" of 
the universe. This model predicts that the universe is made up of 5% 
ordinary matter, 25% undetectable "dark matter", and 70% dark energy. 
Although the nature of dark energy is not yet known, galaxies in a 
universe with such a low density of matter should have stopped growing 
early in the history of the universe. They should therefore appear the 
same today as they did then.

David Lumb and colleagues at the Space Research Technology Centre in the 
Netherlands (ESTEC) have now measured eight distant galaxies using the 
European Space Agency's X-ray observatory, XMM-Newton. These galaxies - 
the furthest of which is about 10 billion light years away - provide a 
picture of the universe as it was around seven billion years ago. Lumb 
and co-workers surprisingly found that galaxies in the distant universe 
emit more X-rays than those in the near universe.

Moreover, a second group of physicists, led by Alain Blanchard at the 
Observatoire Midi-Pyrénées have analysed the data to demonstrate that 
the universe is a high-density environment that contains more matter 
than commonly assumed (arxiv.org/abs/astro-ph/0311381). "To account for 
these results you have to have a lot of matter in the universe - and 
that leaves little room for dark energy," said Blanchard. The data, if 
confirmed, could have important implications for the concordance model 
and other fundamental assumptions about the nature of the universe.

Author
Belle Dumé is Science Writer at PhysicsWeb



More information about the FoRK mailing list