Astronomy

What has been Revealed by the Wilkinson Microwave Anisotropy Probe Wmap Launched in 2001



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The Wilkinson Microwave Anisotropy Probe (WMAP) was launched by NASA in June of 2001 to make fundamental measurements of the universe. It was spectacularly successful and the results are now affecting every aspect of cosmology (the study of the universe).  Out of this study has come a new Standard Model of Cosmology.

Anisotropy means the state or quality of having different properties along different axes and this is a fundamental property of the universe. Cosmologists use this term to describe the differences in the cosmic background radiation (CMB), which is not evenly distributed across the universe and which indicates the conditions that occurred at the time of the "Big Bang" and the subsequent expansion that led to the current distribution of matter and galaxies in the universe.

WMAP produced a "baby picture of the universe" by mapping the cosmic background radiation, which is the afterglow of the hot, young
universe produced when it was only 375,000 years old, over 13 billion years. ago. The patterns found in that picture were used to limit what could have possibly happened earlier, and what happened in the billions of years since that early time. The data show that the young universe was hot and dense, and has been expanding and cooling ever since.

Using the results of the WMAP picture, scientists were able to accurately age the universe as 13.77 billion years old, with an accuracy to within a half a percent. They measured the curvature of space to within 0.4 percent of "flat" Euclidean. They determined that ordinary atoms make up only 4.6 percent of the universe, while dark matter (which does not consist of atoms) makes up 24 percent and dark energy makes up the rest. This dark energy is the cause of the speeding up of the expansion rate of the universe since the first inflation event.

The WMAP results support the theory of "inflation," that the early universe went through a period of rapid expansion, growing by more than a trillion trillion fold in less than a trillionth of a trillionth of a second. Tiny fluctuations were generated during this expansion that eventually grew to form galaxies and the current structure of the universe, where the galaxies are not distributed uniformly.

For their ground-breaking work, the WMAP team won the Gruber Cosmological Prize in 2012. "The Gruber Foundation proudly presents the 2012 Cosmology Prize to Charles Bennett and the Wilkinson Microwave Anisotropy Probe team for their exquisite measurements of anisotropies in the relic radiation from the Big Bang-the Cosmic Microwave Background. These measurements have helped to secure rigorous constraints on the origin, content, age, and geometry of the universe, transforming our current paradigm of structure formation from appealing scenario into precise science."

The importance of the WMAP work cannot be underestimated in human understanding of the structure and history of the Universe. Stephen Hawking told the journal New Scientist that WMAP's evidence for inflation was the most exciting development in physics during his career. According to John Bahcall of the Institute for Advanced Study in Princeton, N.J.: "The announcement today (of the Gruber Prize) represents a rite of passage for cosmology from speculation to precision science."

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ARTICLE SOURCES AND CITATIONS
  • InfoBoxCallToAction ActionArrowhttp://map.gsfc.nasa.gov/
  • InfoBoxCallToAction ActionArrowhttp://www.nasa.gov/
  • InfoBoxCallToAction ActionArrowhttp://www.thefreedictionary.com/anisotropy
  • InfoBoxCallToAction ActionArrowhttp://It is the residual heat of creation-the afterglow of the big bang-streaming through space these last 14 billion years
  • InfoBoxCallToAction ActionArrowhttp://map.gsfc.nasa.gov/news/index.html
  • InfoBoxCallToAction ActionArrowhttp://map.gsfc.nasa.gov/universe/bb_cosmo_infl.html
  • InfoBoxCallToAction ActionArrowhttp://releases.jhu.edu/2012/06/20/johns-hopkins%E2%80%99-bennett-and-wmap-team-awarded-the-2012-gruber-cosmology-prize/
  • InfoBoxCallToAction ActionArrowhttp://www.newscientist.com/article/mg21628965.700-2013-smart-guide-new-maps-to-rein-in-cosmic-inflation.html