Cosmic Background Radiation: A Tool for Exploring the Early Universe
Which laws govern the very early universe where the strength of gravity and the other fundamental forces are comparable? This question spearheads the work of many physicists. They may be armed with precise theories to calculate gravity and the other fundamental forces separately, but progress breaks down when they attempt to calculate them together. There are many promising theoretical avenues, but they need further guidance from experiments and observations to construct the theories. Canada Research Chair Matt Dobbs draws on expertise in particle physics and cosmology to build and deploy new instrumentation that will provide measurements to help guide this theoretical quest.
Gaining understanding about the birth of the universe is perhaps one of mankind's most intriguing quests. Very early in its history, the universe released a cosmic background radiation (CBR). Today this "light" exists at mm-wavelengths and forms a self-portrait of the early universe.
Scientists have learned a great deal through the measurement of this radiation: It is the best evidence we have in support of a "Big Bang." And there is a wealth of information yet to be exploited. Most tantalizing is a measurement of the light's polarization, which is believed to carry information about the earliest moments of the universe's explosive birth. In his research, Dobbs is involved with the design, construction, and deployment of new experiments that have the sensitivity to make accurate measurements of this type of polarization for the first time.
Dobbs is also studying another fundamental unknown, the nature of "dark energy," which accounts for about 70 percent of the energy density in the universe, driving the universe to expand faster and faster. He is contributing to experiments that use a subtle distortion of the CBR from galaxy clusters, called the Sunyaev-Zel'dovich effect, to measure the expansion history of the universe and gain new insight into this powerful energy.
Currently, our ability to identify these cosmic signatures is limited by the sensitivity of the instrumentation used in these experiments. Dobbs' work is moving this instrumentation technology forward into the new era of precision cosmology.