The scientific potential for astronomy from the Antarctic Plateau

Our knowledge of the universe comes from recording the photon and particle fluxes incident on the Earth from space. We thus require sensitive measurement across the entire energy spectrum, using large telescopes with efficient instrumentation located on superb sites. Major advances in the future will come from improving the quality of the site. The ultimate site is, of course, beyond the Earth's atmosphere, such as on the Moon, but economic limitations prevent our exploiting this avenue to the degree that the scientific community desires. Here we describe an alternative, which offers many of the advantages of space for a fraction of the cost: the Antarctic Plateau. Its advantages are manifold: The extreme cold reduces the thermal background in the near infrared. The low atmospheric water vapor content, by far the driest on the Earth, significantly improves transmission throughout the infrared and millimeter regimes. The tenuous air reduces absorption at all wavelengths. The steadiest air offers superior seeing to any other ground-based location. It has the clearest air, with the minimum of man-made and natural interference, both particulate and electromagnetic, on the Earth. The geographical location contributes in several ways: the high latitude allows continuous monitoring of sources; long north-south baselines for Very Long Baseline Interferometry (VLBI) exist, and complete global coverage of some phenomena is possible; the proximity to the South Magnetic Pole extends to lower energy the cosmic ray secondaries that reach the surface; huge quantities of ice are available as pure absorbers of incident particles such as neutrinos. There are formidable logistical and engineering obstacles to developing an observatory on the Antarctic Plateau. The scientific case for Antarctic astronomy rests on the merit of programs that could be carried on exclusively on the Plateau. This document analyzes and presents these programs. After consideration of the scientific issues, we conclude that the case for the development of Antarctic astronomy is overwhelming. We propose, therefore, that a program be drawn up to this end. Its ultimate goal will be to construct a major observatory at the premier site on the Antarctic Plateau, most likely the summit of Dome Argus in the Australian Antarctic Territory. We recognize that such a goal is truly ambitious, and that concerted international collaboration will be required to achieve it.