Ralph Harvey holds a shooting star in his mitten. It’s a meteorite, a piece of outer space some 4.5 billion years old. This rock has seen the infancy of the solar system, the extinction of the dinosaurs, the birth of Dick Clark. Meteorites are without rival the oldest things on Earth. To gaze upon this rock, you cannot help feeling a sense of awe. You might feel other things as well, if only you weren’t numb from riding around on a Ski-doo in a -40 degree windchill for the past three hours.
Meteorite hunting is not for wimps. The best places to look are also the coldest and windiest. You need very old ice, and you need wind, lots of it, strong and unrelenting. Antarctica fits the bill. This year, the Antarctic Search for Meteorites (ANSMET) has set up camp out beyond the Transantarctic Mountains, smack dab nowhere on something called the East Antarctic Ice Sheet. It’s not that more meteorites fall in polar regions. (Earth gets an evenly distributed smattering--about one meteorite falls to the ground every two days.) It’s that they keep better here and are easier to spot. The Barbados Search for Meteorites would be pleasanter but ultimately fruitless.
Here is what happens: Meteorites that fall on Antarctica are buried beneath snow that is in turn buried under more snow until the pressure of the weight turns it to ice. This ice, with its chocolate-chip load of meteorites, makes its way slowly, on the order of about ten feet a year, downhill toward the fringes of the continent, where it eventually calves off into the sea. Unless a mountain range gets in its way. In which case the ice collides with the mountains and, like water against a cliff, surges upward, albeit infinitesimally. Enter the wind. A cold, dense katabatic wind rolls down from the top of the gently sloping plateau. It clears the snow off the ice and powers a battalion of airborne ice crystals that scour away at the surface ice, wearing it down so that the meteorites trapped within are gradually exposed. One by one, a hundred millennia’s worth of meteorites appear at the surface.
One by one, Harvey and his colleagues find them (including ALH84001, the famed Life on Mars meteorite, found by 1984 ANSMET member Roberta Score).This season’s tally is 374, including the 15 found so far this afternoon. Meteorite hunting is a one-of-a-kind pursuit, combining the systematic precision of a crime-scene search for evidence with the giddy anticipation of an Easter-egg hunt. The six team members ride on snowmobiles 50 feet apart, moving slowly forward in a line while scanning the ice around them. When they reach the perimeter of the area they’re searching, they turn around, line up on the next strip of ice, and go back the other way.
While it is wind that allows them to do what they do, it is also wind that gets in their way. When the gusts top 20 miles an hour, blowing snow obscures the ice, and not even expedition-weight thermal underwear and Darth Vader-style face shields (actually motocross masks) can keep out the chill. The team spent ten straight days tent-bound during its first month. War and Peace made the rounds. We thought about strip poker, deadpans Harvey. But it’d take us four days to get through all the layers. Harvey speaks out of one side of his mouth, every now and then switching sides like a sailor shifting ballast in a storm. At 36, he is younger than you expect a Ralph to be. This is his eighth season on the ice; he took over the grant from his former adviser, meteoriticist Bill Cassidy, who founded ansmet in 1976. When he’s not stalking space rocks in Antarctica, Harvey is hunkering down in Cleveland, where he teaches at Case Western Reserve University and does research on the rocks he and others have found.
