The Cosmic Microwave Background (CMB) radiation allows a direct view of the universe when it was 1/35,000 of its present age (~14 billion years). Encoded in the intensity of the CMB radiation are the seeds of all the structure that are seen in the universe today. By studying the tiny variations in the intensity of the CMB on the sky (of order a part in 100,000), cosmologists are able to critically test theories of the origin and evolution of our universe, as well as determine what stuff makes up the universe. I will discuss recent measurements of the CMB anisotropy with emphasis on our DASI experiment, a novel 13-element interferometric array operating at the South Pole. Recent CMB measurements have shown that the geometry of the universe is flat, confirming one of the basic expectations of the inflation theory for the origin of the big bang. The measurements have also revealed that the ordinary matter from which stars and us are made only accounts for 4.5% of the density of the universe. Another form of matter, called dark matter, is found to be seven times more abundant although it has yet to be identified by physicists. The rest of density of the universe, and therefore the most abundant, is contributed by the equivalent density of a mysterious `dark energy' which requires new physics. My talk will review these results and the status the current status of the field, including recent efforts to measure the polarization of the CMB. If time permits, I will briefly discuss our plans to build a new, much larger telescope at the South Pole that will allow us to probe the the equation of state of the mysterious dark energy.
ANL Physics Division Colloquium Schedule