Knowledge Bank

Dr. Martin Pomerantz, a physicist who specialized in cosmic ray research, had a long and distinguished career in polar studies. As a graduate student at the University of Pennsylvania he took a challenging course in 1938 at the Bartol Research Foundation of the Franklin Institute, a course called Cosmic Rays and Nuclear Physics. At the time researchers were using balloons and ships to determine how the intensity of cosmic rays, which came into the Earth’s outer atmosphere from space, varied according to geomagnetic latitude and the location of the Earth. There were only two locations on Earth –the geomagnetic pole in Antarctica, and a second one in northern Canada – where cosmic rays were not impeded by the earth’s magnetic field. Pomerantz found the graduate course at Bartol fascinating, decided to pursue a Ph.D. in physics, and started a long career that took him both to Antarctica and the Arctic region. It was the International Geophysical Year (IGY), from July 1, 1957 to December 31, 1958, that inspired Pomerantz to concentrate on the polar regions. He and a Canadian colleague built a neutron monitor (something like a nuclear reactor in reverse) to detect sensitive cosmic rays. The Pomerantz monitor was placed on a Swedish ship that went from Gottinberg to Cape Town and back. The experiment was very successful, lasted for some years, and got definitive results on the question of the location of the geomagnetic equator, the point on Earth where cosmic ray intensity would be lowest. Conversely, the geomagnetic pole is the place where the geomagnetic intensity is highest.
With a growing reputation, Pomerantz was invited by the Navy Hydrographic Office to put equipment in Project Magnet, an aircraft which produced definitive geomagnetic measurements in fairly close-spaced grids all over the Earth. These advances opened the door for him to participate in the IGY to undertake further cosmic ray research. Concurrently, Pomerantz also loaded an experiment in 1958 aboard Explorer VII, the first satellite to be launched under IGY auspices. James Van Allen, the noted physicist, also loaded some different experiments of his own on Explorer VII, which employed, in part, a Geiger counter. In 1959, encouraged by the progress made on various scientific fronts under the IGY, which ended December 31, 1958, the National Science Foundation established the Office of Polar Programs. In the spring of 1959, Pomerantz received a grant from the National Science Foundation to put a cosmic ray detector in the Antarctic. This was the beginning of his long association with Antarctica. Pomerantz started immediately on his new assignment. A Terry building, a modular unit built with copper shielding inside the whole building, was constructed at the Coast Guard Station at Baltimore, Maryland. Hugo Newberg, a friend from Bartol, joined the project, left immediately in mid-1959 for Antarctica, and oversaw installation of the building at McMurdo Sound in Antarctica. Data was transmitted by teletype using punched paper tape. Pomerantz did not join Newberg in Antarctica until November, 1960. As he arrived at McMurdo, a major solar flare was underway, and, for the first time, data on a solar cosmic ray event was observed at both ends of the earth. McMurdo was considered a 100% Navy base. Pomerantz and the other civilians were considered “visitors,” and stayed at a separate Jamesway hut. In addition to the two centers at Thule and McMurdo, two others were added later, at Swarthmore and the South Pole for a total in time of four neutron detector stations. Once this worldwide network was functioning exciting new discoveries were made. Studies were done on the way the solar wind interacted with cosmic rays, and how it changed with time. Eventually data was collected on three solar cycles. After two very successful years at McMurdo, the Navy decided to build a nuclear reactor there, and within 100 yards of the Cosmic Ray Station. Since such a plant would cause massive interference with the neutron detector, the Cosmic Ray Station was relocated to a completely new, larger, building three miles from the main base. The old building was moved to the South Pole in 1964, and so there were then two Cosmic Ray Detector Stations in Antarctica. That year – 1964 – was designated as the International Quiet Sun Year (IQSY). Pomerantz was the US Chairman of that event. This was envisioned as a successor to the IGY of 1957-58, but it had better funding and a much greater participation. Over 50 nations took part. The South Pole was seen as the best location worldwide for cosmic ray research, and Pomerantz relocated to the South Pole to set up the new station. Over time, Pomerantz spent 26 different summers in Antarctica. Pomerantz and others saw an opportunity to do significant astronomical research at the South Pole. Arnie Wyler, a solar astronomer from Sweden, and Brad Wood, an astronomer from the University of Pennsylvania, joined Pomerantz. The location was ideal for astronomy since there is a constant background – nothing but snow – and any object in the sky is always at the same altitude, and is always there, day after day. Because of the extremely dry atmosphere it seemed particularly well suited to do infrared astronomy. Unfortunately their seven or eight proposals were all turned down. Finally, in 1978, using some surplus equipment from a Swedish observatory, Pomerantz and friends built a solar telescope that was specifically designed for use at the South Pole. Officially it was presented as a part of the cosmic ray program. For the first time anywhere a continuous solar flare patrol was achieved. New pictures were taken every ten minutes for over a week. There was no other place on Earth where this could be done. The results were so impressive that Eric Fossat, a French astronomer, an expert on helio-seismology, secured additional funding so that the new field of solar seismology could also be studied at the Pole. The National Science Foundation (NSF) approved a proposal and this resulted, among other findings, in the best observations ever made of solar oscillations of the sun’s vibrations. It’s the only technique that exists for studying the sun’s interior. One of the telescope pictures appeared on the cover of Nature in January, 1979. That same year a new building was constructed for this project. The outstanding results led to additional funding and support from the National Solar Observatory. Studies of solar oscillations and helio-seismology continued at the South Pole until 1974. In that year the program was shut down since everything had been accomplished that could be done at the time with available technology. In 1975 a new base, “New Pole,” was constructed, and the first one, “Old Pole,” was shut down. Initially no provision was made for cosmic ray facilities at “New Pole, but eventually Pomerantz also secured space there. So there continued to be two cosmic ray stations in Antarctica, one at McMurdo and one at New Pole. This second base at the South Pole became known as Skylab. Through the years equipment was expanded and modernized at both stations. Research on astronomy at the South Pole turned out to be “a spectacular success.” The program was expanded to include infrared or millimeter or sub-millimeter astronomy. In 1984 there was a joint research program with a French team, but the difficulty of getting adequate supplies of liquid helium (needed to cool the detectors) limited its success. Even so enough was accomplished to prove that Skylab was an excellent place to do microwave astronomy. By the time of Pomerantz’s last visit to the South Pole, 38 astronomers were working there, of which 4 or 5 would overwinter. It was decided to build a new observatory. The new AMANDA observatory built at the Pole was named the Martin A. Pomerantz Observatory.

Leading Themes Distinguished career of Pomerantz for many years at South Pole & elsewhere Director of Bartol at the Franklin Institute Major innovations in the field of cosmic ray research Emergence of the South Pole as a major center for astronomy Founding of the Martin A. Pomerantz Observatory Research at the South Pole in helio-seismology International Geophysical Year