Cosmology from Antarctica

Summary

We are now in a golden age of observational cosmology, where measurements of the Universe have progressed from crude estimates to precise knowledge. Many of these observations are made from the Antarctic, where conditions are particularly favorable. When we use telescopes to look out at the distant Universe, we are also looking back in time, because the speed of light is finite. Looking out 13.7 billion years, the Cosmic Microwave Background (CMB) is the oldest thing we can see. The first attempt at CMB observations from the Antarctic Plateau was an expedition to the South Pole in December 1986 by the Radio Physics Research group at Bell Laboratories. No CMB anisotropies were observed, but sky noise and opacity were measured. The results were sufficiently encouraging that in 1988-1989, three CMB groups participated in the “Cucumber” campaign, establishing a temporary site for CMB anisotropy measurements 2 km from South Pole Station. These were summer-only campaigns. Winter-time observations became possible with the establishment in 1990 of the Center for Astrophysical Research in Antarctica (CARA), a U.S. National Science Foundation Science and Technology Center. CARA developed year-round observing facilities in the “Dark Sector”, a section of Amundsen-Scott South Pole Station dedicated to astronomical observations using several astronomical instruments: AST/RO, SPIREX, White Dish, Python, Viper, ACBAR, and DASI. By 2001, data from CARA, together with BOOMERANG, a CMB experiment on a long-duration balloon launched from McMurdo Station, showed clear evidence that the overall geometry of the Universe is flat, as opposed to being positively or negatively curved. In 2002, the DASI group reported the detection of polarization in the CMB. These observations strongly support a “Concordance Model” of cosmology, where the dynamics of a flat Universe are dominated by forces exerted by the mysterious Dark Energy and Dark Matter. CMB observations continue on the Antarctic Plateau. The South Pole Telescope is a 10 m diameter offset telescope that is beginning to measure anisotropies on scales much smaller than 1°, as well as discovering new protogalaxies and clusters of galaxies. Plans are in progress to measure CMB polarization in detail, observations that will yield insights to phenomena in the first second of time.

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