ASTRONOMY IN ANTARCTICA - 1 Sydney, Tuesday October 19, 1993 by Michael Burton, for a weekend edition of a quality newspaper. ⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ Astronomy in Antarctica

⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯⎯ The Antarctic Plateau offers the best location on the Earth to view the stars. Sydney astronomer Dr. Michael Burton explains the plans that are being developed world-wide to build an observatory there. Most people envisage Antarctica as a land of howling blizzards, and express great surprise when they hear of astronomers’ plans to build telescopes there. This is a common misconception, for the storms are purely a coastal phenomenon. They are caused by the cold, dense air from the high Antarctic Plateau cascading downwards and picking up speed as it nears the coast. On the crest the winds are light, the skies clear and the air very, very cold. The summit, the 4,300m Dome Argus, may prove to be the ultimate observatory location on the Earth. In the eternal quest to better comprehend the Universe astronomers continually strive to make ever more sensitive observations of the radiation from faint and distant objects. By endeavouring to open up new windows in the electromagnetic spectrum through which to view the Cosmos, astronomy has not only driven advances in science and technology, but raised self-awareness of our place in the Universe and contributed positively to the culture of society. The quest is conducted with the telescope. Through understanding what limits the capability of a telescope it is possible to map out the route to be followed to further our knowledge about the Universe. That route is now leading astronomers to Antarctica. Ever since the invention of the telescope in 1610 by Galileo, developments in astronomy have been driven by the building of better telescopes, with larger collecting areas, and placing ever more efficient detectors on them to record the radiation arriving from beyond the Earth. We have moved so far along the road that we are nearing the fundamental limits which determine our ability to collect and record light from a distant object. There remains one area where astronomers still have considerable room for improvement. It is the location where they place their telescopes. From the city observatories of the 17th and 18th

ASTRONOMY IN ANTARCTICA - 2 century, telescopes have gradually been moving out to more remote sites. First to the country to escape city lights, then to mountain tops to improve the clarity of the sky. Today the major observatories are located on high volcanic peaks on oceanic islands, or on the peaks of desert mountain ranges, where the air is dry and the skies exceptionally clear. In Australia our premier observatory is at Siding Spring, in the Warrumbungle National Park, home to the 4-metre Anglo Australian Telescope. But even this site can’t compare to the summit of the Hawaiian volcano Mauna Kea, or the mountains on the edge of the Atacama desert in northern Chile, where the world’s major observatories have been established over the last decade. Located in arid regions, high above the inversion layer, their telescopes have made the most sensitive measurements of astronomical objects across the spectrum to date. These sites, good as they are, still have their limitations. The ultimate observatory would be placed in space, beyond the debilitating effects of the Earth’s atmosphere. This, of course, has already been accomplished with a number of small telescopes, revealing a richer and more diverse picture of the Universe than we could ever have imagined. However the cost of placing large observatories in space is proving to be economically untenable, with each mission costing several billion dollars. And as the unfortunate example of the Hubble Space telescope has shown, mistakes are hard to rectify. There is an alternative, offering many of the advantages of space for a fraction of the cost. It is the Antarctic Plateau. Astronomers worldwide are now turning their thoughts towards how to build an observatory in this, the most remote location on the planet. Antarctica is simultaneously the highest, driest and coldest continent on the Earth. These factors lead to significant gains for astronomy. The great height means tenuous air, providing a clarity for viewing unequalled elsewhere. The dry air, by far the driest on Earth, dramatically improves the transmission of infrared radiation through the atmosphere. This opens up new windows in the spectrum for viewing into space. The extreme cold vastly reduces the amount of heat emitted by the telescope, tremendously improving the sensitivity for infrared observations. Today there are extensive research programmes underway in Antarctica conducted by over 20 countries. They mostly operate around the coast, studying the indigenous life, and the unique geology, glaciology and meteorology of Antarctica. The Australian Antarctic Division operates 3 coastal stations, at Davis, Casey and Mawson.

ASTRONOMY IN ANTARCTICA - 3 Human activity on the Antarctic Plateau, however, has been limited. Scientific studies were initiated in earnest during the International Geophysical Year in 1957, principally concentrated at the US Scott-Amundsen base at the South Pole and the Russian base at Vostok. France is now planning a base at another inland summit, Dome Circe, inland from Casey. Dome Argus remains unexplored. All these sites have great potential for astronomy. They all lie within, or on the edge, of the Australian Antarctic Territory. Australia operates a cosmic ray observatory at Mawson, but conditions on the coast are not conducive to other types of astronomical observation. Astronomy has till recently played a small part in the plans of nations active in Antarctica due to the inherent difficulties of operating complex facilities on the high plateau. This is now changing as technology has advanced to the extent we can sensibly undertake such an endeavour. Considerable interest is being focussed on the construction of an observatory at the South Pole. The Center for Astrophysical Research in Antarctica’ (CARA) has been created by the USA for this purpose. The initial aims of CARA are relatively modest, but to achieve their goals international involvement is essential. Australia has recently joined the project, and in January 1994 two experiments will be taken to the South Pole by astronomers from the University of New South Wales. One experiment also involves French astronomers from the Universite de Nice. There purpose is to determine the limiting factors affecting the performance of a telescope in Antarctica. This activity is seen by astronomers as the first stage of a major initiative over the next decade, with its ultimate goal as the construction of a major observatory at the summit of the Antarctic Plateau. Such a goal is truly ambitious, and the engineering and logistical problems to be overcome will provide a supreme challenge to the ablest people. The observatory will also be expensive, certainly more so than a comparably-sized facility built at a more accessible mainland site. On the other hand it will be very much less expensive than placing the same observatory in space. It might even be a stepping stone towards such an endeavour in the middle of next century, as both projects face many of the same logistical problems associated with remote operations in a harsh environment. Astronomers are justifying an Antarctic observatory on its scientific merits, arguing that the potential for fundamental new understanding of the Universe is so great that it must be a part of the agenda of a developed nation. There is a long road ahead and they have barely begun the political lobbying that is necessary for its fruition. It is already apparent that for such a project to succeed it must be international in scope, with the resources needed beyond the means of

ASTRONOMY IN ANTARCTICA - 4 any one country. Such a concept fits naturally into the role Antarctica plays in international affairs. Australia now has before itself the opportunity to play a lead role in what may prove to be one of the major endeavours of the next century. It is an opportunity that nations confident of their own destiny cannot chose to ignore. International interest in an Antarctic observatory is sufficiently strong that it will surely get developed some day. The question is who will develop it, and who will be a follower? Australia has been unable to play a significant role in many of the great endeavours of the 20th century, such as the space programme, due to our lack of available resources. An Antarctic observatory, however, is a project for which we have the acknowledged expertise. Australia has an eminent record both in the pursuits of Antarctic science and exploration, and of astronomy. Few other nations can claim such a combination, and with our geographical position we are uniquely positioned to promote it further. Is Australia bold enough to accept the challenge? ___________________________________________________________________________ ENDS 1403 Words

ASTRONOMY IN ANTARCTICA - 5 Illustrations 1. Map of Antarctica, showing the Australian Antarctic Territory, the Australian coastal stations, the inland locations being considered for astronomy, and the Australian continent. 2. Overland traverse from Casey station, in the direction of Dome Circe. Antarctic Division copyright required. 3.

The GASP telescope at the South Pole during Polar sunset. CARA copyright required.

___________________________________________________________________________ Dr Michael Burton is a lecturer in astronomy and physics at the University of New South Wales. He is chair of the Australian Working Group for Antarctic Astronomy. He is an active astronomer, specialising in infrared observations. His research interests include star formation, molecular clouds, shock waves, supernova remnants and the Galactic centre. For further information please contact Michael Burton at the School of Physics, University of New South Wales, PO Box 1, Kensington, NSW 2033. Tel 02-697-5618 (W), 02-315-8973 (H), Fax 02-663-3420