For the 35th year, the United States is mounting its annual campaign to gather space rocks from the wind-hammered icefields of Antarctica.
“We’ll be living two to a tent for six weeks, and everybody’s got a snowmobile,” said Harvey, a geologist at Case Western Reserve University who is leading the expedition for the 21st time. “I guess we’re almost like cowboys trying to round up cows.”
Except these cows don’t moo. They hunker on the blue ice, half-buried, dark and inert. In the 24-hour sunshine of the austral summer — starting now — meteorites stick out like Angus among Holsteins.
“If you want to find stuff falling out of the sky, get a big white sheet,” Harvey said during a phone call from McMurdo Station, the U.S. research base on the continent. “We’ve got a white sheet as big as the continental United States.”
Getting to that sheet is a feat of logistical largesse. The eight-person expedition requires 20,000 pounds of gear, hauled first to McMurdo. From there, three giant C-130 transport planes plop the tents, food, water, fuel, snowmobiles, generators and spare parts on the ice halfway to the final destination. From there, many flights of a smaller Otter plane shuttle the expedition to its camp site, which this year is near the Miller Range along the Transantarctic Mountains.
“I feel more like I’m moving a city than doing science,” Harvey said. “It will be a three- or four-day process” that will begin Wednesday or Thursday.
Scientists say meteorites bombard the Earth from all directions, falling everywhere in roughly equal proportions. But geologic forces concentrate them at the foot of Antarctica’s mountains.
Giant ice sheets push against these peaks, churning fallen meteorites toward the surface. Harsh winds knifing down the mountains blow off a layer of snow and ice each year, exposing a new batch. The whole process is a meteorite-generating machine. The expedition collects hundreds each year.
“The ice continues to produce more and more meteorites that have been buried below,” said Linda Welzenbach, manager of the National Meteorite Collection at the Smithsonian Institution, where most of the Antarctic finds eventually reside.
As a bonus, the continent serves as a natural deep-freeze, keeping the ancient space rocks nearly pristine.
Finding them is as straightforward as riding out across the ice with open eyes. Because few Earthly minerals exist out there, anything rocky is bound to come from space.
Of every 1,000 meteorites picked off the ice, about 50 hold “outstanding interest to a broad range of scientists,” Harvey said.
The smallest are marbles. The largest weigh hundreds of pounds. Some originate at asteroids. Others are free-floating detritus from the birth of the solar system some 4.6 billion years ago. A few — the rarest and, to many scientific minds, the most precious — come from the moon and Mars. An asteroid or comet blasted them into space on an improbable trajectory that eventually landed them at the bottom of the Earth.