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J. R. Bond (CITA)
The tiny fluctuations in the 3K photon afterglow of the Big Bang are geometrical mappings of sound waves when this ``oldest light in the Universe'' decoupled from matter some 14 Gigayears ago. In work spanning two decades, my collaborators and I have shown how these encode information on the many parameters that define cosmic structure formation theory. We have developed tools to analyze the sequence of heroic experiments that have always pushed technology to the edge, from even before the COBE satellite of the early 90s through Boomerang, the Cosmic Background Imager, and other recent experiments that have now directly imaged these acoustic patterns. The patterns appear to be Gaussian-distributed and their power spectra show multiple peaks and troughs and a damping tail.
Our analyses support the remarkable neo-Big-Bang paradigm: that quantum noise generated during an ultra-early accelerated expansion amplified via gravitational instability to form the galaxies and their hierarchical clustering patterns that we observe as the interconnected ``cosmic web''. When combined with precise theoretical calculations, the CMB and cosmic web data have allowed us to accurately infer the mass-energy densities in ordinary (baryonic) matter, "cold" dark matter, and "vacuum" dark energy to be about 5%, 30% and 65%, summing to ensure a nearly flat large scale geometry. The dominance of dark energy is arguably the greatest mystery in physics. A host of new high precision CMB experiments, many targeting polarization and secondary CMB processes associated with nonlinear effects, will help to establish its properties.
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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.