CWRU Physics Faculty

The Cosmic Microwave Background Radiation (CMB) carries an enormous amount of information about the universe at a redshift z = 1,000, a few hundred thousand years after the big bang. Studies of the CMB can tell us about what the universe was like at that time, and answer fundamental questions about the nature of the universe.

The CMBR is almost uniform in its brightness across the sky; its brightness at frequencies from roughly 0.5 mm to 10 cm is very close to that of a 2.7 K Planck blackbody. However, there are small variations in the brightness, at the level of tens of microKelvin. By studying these variations, we are learning many interesting things, including the global curvature of spacetime in the universe, the amount of normal matter (baryons), and the amount and nature of the dark matter and "dark energy" in the universe. Our current research aims to improve our knowlege of the "global properties" of the universe as a whole.

One project is a balloon-borne experiment to map small scale anisotropies and polarization in the CMB. Boomerang has flown twice; once from Texas in 1997, and a second time a 10.5 day flight around Antarctica. In these flights we produced the first large, high-resolution images of the temperature anisotropies of the CMB. We have another Antarctic flight planned for December 2002, this time to measure its polarization, as well as improve our temperature anisotropy measurements.

We are also working on two projects at the South Pole. One of these, Acbar, is using the 2 meter diameter Viper telescope to measure the CMB fluctuations on smaller angular scales than Boomerang. The second, the 8 meter "South Pole Telescope", is in the preliminary design stage. We'll be using that telescope to use the CMB as a backlight to discover thousands of clusters of galaxies; by studying the properties and statistics of these clusters, we hope to study the details of the cosmological constant, and perhaps even see whether its properties are changing over time.