“...if we understand the CMB distribution and properties, we can learn a lot about the universe itself, not only its origin, but also its current state and future.”

Since an early age I was fascinated by the night sky, and dreamed of being an astronomer. I did my B.Sc. in Physics and my Ph.D. in cosmology at Berkeley with Prof. George Smoot, working on COBE (Cosmic Background Explorer) data—studying the properties and distribution of the Cosmic Microwave Background (CMB).

The more I read about astronomy in general, the more I became fascinated by cosmology. At that point, I realized that the CMB is a unique probe of cosmological parameters and conditions. The study of the CMB allows us to constrain not only the models of structure formation (i.e., to understand how the big structures such as cluster of galaxies formed in the universe), but also to understand the large-scale properties of the space itself. The fact that the CMB is a fantastic and unique laboratory to understand physics was the "selling point" for me to follow this career path.

Cosmology is the study of the origin, current state, and future of our Universe. A CMB map is a snapshot of the early universe, back when all space was filled with hot opaque hydrogen plasma. Over time, this hydrogen expanded, cooled off, became transparent and clumped into the stars, galaxies, and clusters that we see around us in the universe today, 14 billions years later. Therefore, if we understand the CMB distribution and properties, we can learn a lot about the universe itself, not only its origin, but also its current state and future.

Today's cosmological standard model, the so-called inflationary big bang model, provides a remarkably good fit to almost all our measurements. This particular paper pointed out a fly in the ointment that we had discovered: surprising anomalies in the WMAP (Wilkinson Microwave Anisotropy Probe) CMB map on the largest angular scales which didn't fit with the standard model predictions. These results were later confirmed by other groups and have since triggered numerous papers and potential explanations. We still don't know what the explanation is, and the debate goes on.

BOOMERanG was a balloon experiment designed to make maps of the CMB. It flew around Antarctica twice, once in 1998 to map the CMB temperature and again in 2003 to map its polarization. Using these data, we measured fundamental properties of the universe such as its overall density and geometry, as well as the density of its various components such as atoms, dark matter, and dark energy.

Angelica de Oliveira-Costa, Ph.D.
Kavli Institute for Astrophysics & Space Research
Massachusetts Institute of Technology
Cambridge, MA, USA