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SCIENCE OBSERVER

Pole Vaulting

David Schneider

The Amundsen-Scott South Pole Station made headlines in April when the doctor for that remote science facility was taken seriously ill in the middle of the dark, frigid Antarctic winter. Thankfully, Canadian pilots successfully evacuated the stricken physician—but he was not all that was ailing at the bottom of the world. The station itself has been deteriorating for years, prompting the National Science Foundation to begin this past year a $153 million modernization, which should be complete by early 2006.

Built in the 1970s to replace an even older South Pole base (which is now buried under nine meters of snow), the Amundsen-Scott Station consists of a large geodesic dome and several smaller outbuildings. The dome is half-buried in drifts and suffers from an unstable foundation that threatens its integrity. Many other parts of the infrastructure—from fuel distribution to waste disposal—are also in dire need of refurbishment. But construction at this remote site is no small task. All materials have to be carried in by air from McMurdo Station on the coast using special ski-equipped transport planes. And workers have to contend with temperatures that average around –32 degrees Celsius over the summer months.

New research facilities . . .Click to Enlarge Image

The logistical difficulties and great expense prompt one to ask: Why maintain a permanent science base at the South Pole at all? One answer is that certain kinds of research can be done in no other spot. In particular, the South Pole is said to offer an ideal setting for astronomers, because the air is exceptionally cold, thin and dry, making this locale the next best place to space for siting a telescope. The South Pole also provides astrophysicists with a remarkable laboratory to study high-energy neutrinos: AMANDA (Antarctic Muon and Neutrino Detector Array) uses deeply buried sensors at the South Pole to register the rare interactions between these particles and the ice itself.

Such rationales for a base at the South Pole do not, however, hold up very well under scrutiny. AMANDA could, for example, be installed at any Antarctic site where the glacial ice is thick and free of dust. Also, the air at the South Pole is, in fact, not so perfect for astronomy, because it is colder at the surface than a few hundred meters above. John Bally, an astronomer now at the University of Colorado, Boulder, who was responsible for site testing at the South Pole, points out that this temperature inversion combined with the stiff winds there give rise to a turbulent layer of air that blurs optical and infrared images. Bally also notes that there is a perpetual ice fog at the South Pole in winter and that the base is situated on the auroral circle, the locus where charged particles in the upper atmosphere light up the sky most intensely: "You would not go about picking astronomical sites the way this was done."

Indeed, these problems make the South Pole appropriate for only a limited number of astronomical observations, primarily those in the submillimeter to millimeter regime. Shorter wavelengths (infrared and optical) can be better studied in places like Mauna Kea in Hawaii, which lacks a troublesome inversion layer. And longer wavelengths (centimeter- and longer-wave radio frequencies) are so little bothered by atmospheric absorption that siting the receiving antennas at the ends of the earth is not necessary.

The submillimeter- to millimeter-scale observations are, however, critical to the study of the cosmic microwave background radiation, and they are useful too for examining molecular clouds in stellar nurseries. So some astronomers are quite keen to set up their instruments in Antarctica to take advantage of the thin, cold air. Still, the South Pole is probably not the best place to conduct these operations from a purely scientific perspective, because higher elevations on the Antarctic Plateau offer even thinner and colder air.

One such place is Dome C (located in the Australian sector, at roughly 73 degrees South latitude), where French and Italian scientists are now setting up a permanent base, called Concordia Station. Peter Timbie, a physicist at the University of Wisconsin, Madison, who plans to study the microwave background radiation from Antarctica, says that although Dome C might be a slightly better place to deploy his instrument, he plans to use South Pole Station because he is reluctant to ask the NSF for money to do astronomy at a French-Italian base: "My guess is that they would not be real excited about that." Timbie notes that there is really very little difference between the two sites for his research, but he points out that the turbulent inversion layer may be absent at Concordia, making it superior to the Pole for optical and infrared astronomy.

European and Australian astronomers are indeed quite interested in the opportunities that Dome C affords. Still, U.S. participation will probably not amount to much, because, as Bally notes, "the U.S. has put all its eggs in South Pole." This strategy is hard to defend on the basis of doing the best astronomy, the discipline most often cited in official statements about the scientific importance of Amundsen-Scott Station. Why then is keeping a base at the South Pole worth the $153 million price tag?

The fundamental reason is that a permanent South Pole station is a political necessity. The Under Secretary of State for Global Affairs summed up the situation well in a 1997 letter to Norman Augustine, then Chairman of the Board for Lockheed Martin Corporation and head of an external panel to review the U.S. Antarctic program: "? maintaining an active and influential United States presence in Antarctica serves important strategic and foreign policy objectives. This presence in Antarctica, anchored at the South Pole, gives us a decisive voice in the Antarctic Treaty system, which is the basis for the peace and stability of the area."

How the U.S. earned the privilege of siting one of its Antarctic bases at the geographic pole in the first place is a charming piece of history. American scientists first suggested the idea to the Department of Defense in September of 1954 as part of their strategy for the International Geophysical Year, a multi-nation research effort focused on Antarctica. At the time, U.S. officials were unwilling to commit to such a difficult undertaking. But just 10 months later at a planning conference in Paris, Russian scientists announced that the Soviet government intended to erect a station at the South Pole. The Americans in attendance were dumbstruck. Paul Siple, a member of the U.S. delegation, recounts what followed in his 1959 book 90° South:

Taking up the reins, Prof. G. Laclavere, the French chairman of the conference, turned toward the Russians and shook his head. "I'm sorry," he told them, "but we have already accepted the offer of the United States to erect and man a South Pole Station. We don't think there should be two stations there.

Siple further explains that the Russians subsequently accepted Laclavère's suggestion that they build their station at the geomagnetic south pole (a base called Vostok, which remains in place today), making it impossible for the U.S. not to set up a South Pole station.

Vostok, the consolation prize, is arguably a more valuable site for scientific research in that by sheer luck it overlies a huge subglacial lake, which investigators are eager to probe for signs of life. And the glacial ice above this lake contains a longer record of past climates than can be found at the South Pole. Vostok Station also sits at a higher elevation, offering astronomers thinner and colder air. Indeed Vostok boasts the lowest temperature ever recorded on the surface of the earth: about –90 degrees C. So in this sense at least, it was the Russians who won the cold war.—David Schneider


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