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Martin A. Pomerantz (December 17, 1916 - October 25,
2008) was an American physicist who served as Director
of the Bartol Research Institute and who had been a leader
in developing Antarctic astronomy.When the astronomical
observatory at the United States Amundsen-Scott South
Pole Station was opened in 1995, it was named the Martin
A. Pomerantz Observatory (MAPO) in his honor. Pomerantz
published his scientific autobiography, Astronomy on
Ice, in 2004
Life
Pomerantz was born and raised in New York City, and graduated
from Manual Training High School in Brooklyn. In 1937,
Pomerantz received an A.B. in physics from Syracuse University.
He received an M.S. from the University of Pennsylvania
in 1938. In 1938, Pomerantz joined the Bartol Research
Foundation, where he spent nearly his entire career. He
became a permanent member of the Foundation's scientific
staff in 1943. In 1951, he received his Ph.D. in physics
from Temple University for a thesis based on his extensive
scientific work at Bartol. In 1959, Pomerantz became the
second Director of the Foundation, replacing W. F. G.
Swann upon the latter's retirement.
In 1977, Pomerantz presided over the Foundation's move
from its original location at Swarthmore College to its
present location at the University of Delaware. Despite
Pomerantz' efforts, Swarthmore had decided not to renew
its 50-year contract with Bartol; there had been a number
of conflicts during its decades of residence at Swarthmore.
The Foundation was renamed the Bartol Research Institute
following the move to Delaware.Pomerantz stepped down
as the Institute's president in 1987; he was replaced
as president by Norman F. Ness. In 1990, Pomerantz retired,
becoming a professor emeritus at the Institute and at
the University of Delaware.
Pomerantz had served on the board of trustees for the
Franklin Institute and edited the Journal of the Franklin
Institute. He had also served on the editorial board for
Space Science Reviews. Pomerantz' scientific papers and
documents have been archived at the American Institute
of Physics.
Martin A. Pomerantz Observatory at the South Pole.
Cosmic ray research
Pomerantz was one of the pioneers in balloon-borne cosmic
ray research in the 1940's and 1950's. The initial work
was done at the Bartol Institute near Philadelphia. However,
the large majority of cosmic rays are charged particles,
and the Earth's magnetic field strongly affects the paths
of the these cosmic rays. Since the Earth's magnetic field
varies significantly with latitude, Pomerantz led a number
of expeditions measuring cosmic rays from sites at varying
latitudes around the Earth. Several of these expeditions
were sponsored by the National Geographic Society. He
supervised the installation of a stationary cosmic ray
detector facility at Thule Air Base in Greenland, and
in 1960 Pomerantz installed a cosmic ray detector at McMurdo
Station in Antarctica. Pomerantz' experiments at the South
Pole commenced in 1964.
These experiments and expeditions led to several insights,
one of which was an inference about the magnetic field
of the sun. Like the Earth, the sun has a magnetic field.
Initial estimates suggested that the sun's magnetic strength
was about fifty times that of the Earth. The cosmic ray
experiments indicated that the sun's magnetic strength
was of the same magnitude as the Earth's; this result
is now well-established by many subsequent measurements.The
work on the magnetic field of the sun was featured in
a 1949 article in Time magazine.
Topographic map of the Pomerantz Tableland in the Usarp
Mountains of Antarctica.In 1971, Pomerantz published Cosmic
Rays, which is a semipopular book that describes cosmic
ray observations and the scientific understanding of their
origins.
Antarctic astronomy and astrophysics
Pomerantz saw the potential of the South Pole as an observing
platform remarkably early. Its proximity to the South
magnetic pole of the Earth means that charged cosmic rays
can be detected there without the deflections they experience
when detected at lower latitudes. Astronomical observations
near the Earth's poles can be done over long periods,
without the diurnal variations at lower latitudes. The
South Pole is at an altitude of nearly 3,000 metres (9,800
ft), so the astronomical seeing should be comparable to
other high-altitude observatories; the extreme cold in
Antarctica also corresponds to relatively little water
vapor in the atmosphere there, which is a particular advantage
for infrared astronomy. Finally, the South Pole lies at
the top of a very deep, nearly permanent ice sheet that
has been used to advantage in experiments such as the
IceCube Neutrino Detector.
Pomerantz' own research is particularly noted for his
development of helioseismology, which is study of pressure
waves in the sun. In 1960, observations of the sun revealed
unexpected pulsations in the image. By 1975 it was becoming
clear that these pulsations could be understood if the
sun was considered as an enormous bell ringing at very
low frequencies (one oscillation per minute and lower),
and that they provided important insight into the structure
of the sun.
In 1979, Pomerantz, along with Eric Fossat and Gerard
Grec, conducted the first Antarctic observations by coupling
a small telescope with a "sodium vapor resonance
cell." The observations were not formally authorized;
as Pomerantz later described it, "We had to find
a way to convince people that the South Pole was the place
for astronomy. Sometimes you need to circumvent the rules.
Our bootleg experiment enabled us to obtain the clearest
pictures of the sun that had ever been obtained from any
place on earth. It proved once and for all this was a
superb place for astronomy."Fossat, Grec, and Pomerantz
were able to record the sun's vibrations without interruption
for more than 100 hours. Their results greatly extended
the knowledge of the sun's vibrational frequency spectrum,
and they marked the beginning of an extensive astronomy
program at the South Pole.
In 1995 the Martin A. Pomerantz Observatory was dedicated.
In 1999, Norman F. Ness wrote that Pomerantz had "developed
and operated instruments in Antarctica for observing similar
sun-quake signals in the newly emerging field of helioseismology,
a discipline in which he was one of the true pioneers."
Pomerantz "also showed tremendous courage, working
in Antarctica when it was still a very hazardous proposition."
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