Science at the South Pole

The geographic South Pole is located in the center of Antarctica, several hundred miles away from the nearest coast. It sits on top of 3km of ice and the warmest temperature ever recorded is -13.6 °C. Precisely because of its remoteness and unique weather, it is a great place to do scientific research. Despite all the snow at the South Pole, it's actually a desert with almost no precipitation. Snow gets blown in by storms and it piles up year after year. All equipment at the South Pole has to get dug out often and, of course, all stationary buildings eventually get completely covered. The first American station built in the 1950's is completely buried as is a C-130 which crashed just short of the runway in 1970. One of the nicer side benefits of the snow are circular rainbows called "sun dogs". The rainbows are caused by sun light refracting off ice crystals in the air as seen in the picture above. There have been three separate stations built at the South Pole since 1957. The newest station (Amundsen-Scott South Pole Station) which was just completed in 2003, is built on adjustable stilts to accomodate the rising snow. It houses about 200 scientists, construction workers and support staff in the summer and about 90 in the winter (people who "winter-over" stay at the South Pole from February to November and cannot leave for the entirety of the dark winter because it is too cold to land planes safely). The station has all modern amenities including a full court basketball court, but most work is still done outdoors. From construction work to the deployment of scientific instruments, most people spend a good part of their days working outside at -20 °C.

The combination of altitude (9,306 ft.) and dryness makes the South Pole a perfect place for observing the Cosmic Microwave Background Radiation (CMB). The CMB is an extremeley weak microwave signal which was produced 300,000 years after the birth of the Universe and which essentially provides a snap shot of the universe at that time. It has been measured to have a black body spectrum in all directions which means that at some point in the early Universe, all matter was in close proximity - physical proof of a Big Bang. In addition to using CMB measurements to test fundamental physical theories about the origin of the Universe, physicists are currently using the 10m South Pole Telescope to count galaxy clusters by looking at small local variations in the CMB. There are many other experiments at the Soth Pole in addition to the South Pole Telescope. The largest experiment is the IceCube Neutrino Observatory. IceCube uses the 3km deep ice sheet beneath the South Pole to track galactic neutrinos which have traveled through the earth from the Northern Hemisphere. The ice sheet underneath the South Pole was formed by packed snow accumulating over the course of 100,000 years and it is the clearest ice on the planet. To detect neutrino events, IceCube is embedding thousands of photon detectors in the ice. Each detector can see light from an event hundreds of meters away and the goal is to instrument 1km^3 of ice. In order to instrument the ice, the IceCube construction team first has to drill a hole which is 1m in diameter and 3km long. This is done by heating water to near boiling and using a high pressure nozzle as a drill head. The process of "melting" a constant diameter hole straight down requires the use of complicated models and a sophisticated feedback loop fed by many nozzle sensors. Of course, this is complicated by the fact that all this work is done at the South Pole where energy (and therefore water) is hard to come by and weather beaten equipment fails often. Each hole takes 5000 gallons of fuel over the course of 18 hours to drill.

In the next (and last) post I'll write more about IceCube's detector modules and the remote calibration lasers that I worked on.