Sky Watchers Build Antarctic Base
Observatory at South Pole will afford an especially clear view for scientists testing theories
CHICAGO — SURROUNDED by a vast frozen wasteland that stretches for nearly 1,000 miles in every direction, a small group of astronomers and engineers have just finished the first three months' construction of a state-of-the-art observatory at one of the most remote and inhospitable places on earth: the South Pole. They now face a bone-chilling winter with six months of perpetual darkness.
When the observatory is complete, a few hardy scientists will brave winter temperatures that plummet to minus 100 degrees F. to test theories about how the universe evolved from the ashes of the Big Bang and how matter is distributed in the galaxy.
The South Pole's 2,835-meter (9,300-foot) altitude, combined with an atmosphere containing virtually no water vapor, produces some of the clearest skies on the surface of the earth. The minimal atmospheric distortion will enable the polar astronomers to detect celestial objects 100 times fainter than those observable from temperate latitudes.
"The opportunity to build these telescopes is very exciting because of the potential dramatic increase in sensitivity," says D. A. Harper, an astronomer at the University of Chicago. Dr. Harper will detail the progress of the observatory at the April 20 meeting of the American Physical Society in Washington, D.C.
Harper directs the Center for Astrophysical Research in Antarctica (CARA), located at the Amundsen-Scott Station, a United States scientific research facility established at the South Pole in 1957. A consortium of nine institutions, led by the University of Chicago, teamed up to develop the center, which will be running at full speed by 1994.
The center will operate three projects. Two of them will attempt to unravel one of the greatest unsolved mysteries in astronomy: how and when galaxies formed.
Astronomers place the birth of galaxies a few billion years after the Big Bang, the explosion most scientists believe created the universe. But the first infant galaxies are located near the edge of the observable universe, so far away that telescopes have not been able to detect them.
One experiment now under way will seek clues to their origin by making a map of the primeval structure of the universe, says project co-leader Jeffrey Peterson of Princeton University in Princeton, N.J.
Peterson's group will use sophisticated telescopes to look for subtle variations in the cosmic background radiation, a faint microwave signal that bathes the universe with equal intensity in every direction. Most astronomers assume that this radiation was created moments after the Big Bang spewed matter in every direction.
The discovery of this radiation in 1965 provided crucial support for the Big Bang theory. But recent satellite observations have shown the background radiation to be more uniform than the theory predicts. Astronomers had expected the satellite to reveal slight variations in the radiation's smoothness, representing regions where gravity caused matter to clump together into proto-galaxies.
Surprisingly, the satellite did not find any variation. The South Pole detectors, which will be 30 times more sensitive than the satellite detectors, should be able to find them.
Once the full array of detectors has been put in place in November 1993, Dr. Peterson predicts, "We will see the process of galaxy formation in its early stage with our telescopes."
THE second project will take advantage of the South Pole's bitter-cold temperatures to look directly for these newborn star clusters.
"I'm hoping we will make the best measurements of faint galaxies and fill in important holes in how the universe formed galaxies," says the experiment's principal investigator, Mark Hereld of the University of Chicago.
Dr. Hereld's team will use a telescope designed to detect the infrared light of dim celestial objects in the skies over Antarctica. Infrared light (an invisible form of light emitted by heat) from space is normally washed out by the heat within the earth's atmosphere, but the South Pole's frigid environment enables infrared light from space to dominate.The polar astronomers will compare their inventory with surveys taken from other observatories located south of the equator.
Astronomers will test a prototype instrument at the South Pole during this upcoming Antarctic summer in order to learn how the primary telescope will function in the harsh environment.
The third project will deploy a radio telescope to study immense clouds of gas and dust roaming within our galaxy. Project astronomers hope to learn about the distribution of gaseous material, and they may find evidence for large accumulations of matter that have previously remained hidden from view.
Besides studying deep space, the astronomers will measure the amount of ozone in the atmosphere above the South Pole.
During the past Antarctic summer, engineers partially assembled a building that will house this project's telescope and electronics. In late 1992, Boston University will test the telescope on the top of its physics building. South Pole Observations should begin in March 1994.
Erecting and operating a sophisticated observatory in such a cold and isolated location poses complex technical and organizational challenges.
"The biggest problem is logistics, getting there and getting back," says John Lynch, head of CARA's funding agency, the National Science Foundation's Polar Program. Astronomers must compete for space with geologists, meteorologists, and glaciologists who also work at the South Pole station.
Equipment must be able to survive months of transport at sea. "And once at the Pole, if something hi-tech breaks, it breaks for good," says Thomas Bania, an astronomer at Boston University.
Special grease must be used to lubricate motors, since normal grease freezes in such cold environments. Engineers must also worry about the shrinkage of materials and the cracking of plastic insulation that occurs in low temperatures.
Harper hopes that someday the facility will be nearly completely automated so that astronomers will be able to direct the telescopes from their offices in the US by using computers. When this goal is attained, only one or two support staff for the astrophysical center will be required to winter over each year to monitor and maintain the equipment.
The National Science Foundation has allotted CARA $13.6 million for its first five years of operation. Harper says the center will be significantly less expensive than launching a similarly equipped astronomical satellite into space.