The Rock From Mars Read Online Free Page A

mountain range—a barrier too broad for the ice to flow around it—creating stagnation points. Like surf hitting a steep shoreline, the trapped ice sheet shouldered upward at these places as its billions of tons collided in slow motion with the immovable impediment. The clean, ancient blue ice was thrust up from deep, deep under the glacial mass to the surface.
    The old ice was blue for the same reason that the sky and the ocean were blue: because of the way it scattered light. Familiar ice, like the cube from your fridge, is whitened by air bubbles frozen in millions of little facets. The ancient ice was pressed clean of these “whiteners.” Stepping out on an expanse of blue ice about ten thousand feet thick could seem—visually—like walking on a patch of the Caribbean. Under certain circumstances, Bill Cassidy and his comrades had learned, it was possible to melt a hole in the snow, exposing an expanse of the clear ice, and thus allow the reflected sunlight to fill a dark tent with the azure glow of a jazz club.
    The blue ice here was different in important ways from blue ice in Alaska or at the margins of Earth’s other great ice sheets. Where the Antarctic ice rose into the light, it was exposed to the notorious katabatic (descending) winds. These dry howlers were generated over the polar cap as the colder, denser air sank and gravity drove it downslope toward the ocean. The winds swept loose snow off the ice, exposing it. Two effects then combined to wear away the naked ice: sandblasting by windblown ice crystals and vaporization by the heat of the summer sun. As surface ice was lost in these ways, the continental hydraulics moved just enough fresh upstream ice into the stagnant zone to replace the lost ice and maintain the surface elevation. This progression gradually carried buried meteorites, stones that had once been sprinkled throughout the volume of the ice, to the surface, where they were left lying. Stranded.
    In the places along the coast where the landscape channeled the winds so that they converged, the mean annual wind speed was 50 miles per hour and people had reported maximum gusts of almost 200 miles per hour. Early Antarctic explorers sometimes had to crawl through the blast before they learned the fine art of “hurricane walking” at an extreme angle.
    It appeared that the meteorite conveyor belt had been working away at various sites for tens of thousands of years, hundreds of thousands of years, or, at some surfaces, much longer. Some rare Antarctic meteorites had spent as many as two million years in their slow-moving terrestrial tomb before breaking out. The ones big enough to resist being blown away remained as a lag of cosmic rubble on the ice sheet. Much more than in the driest warm deserts of Earth, the natural deep freeze and incredible dryness here inhibited the weathering away (and contamination) of the rocks.
    The specialists came to understand that, given a properly meticulous and methodical search over the long term, they could assemble from these sites a representative sample of all the meteorites that fell on Earth.
    Out on the ice sheet for at least a six-week stay, Score and her comrades lived in two-person “Scott tents,” whose design had not changed much since they were first used early in the century. Double-walled for insulation, and nine feet on a side, the bright yellow pyramid-shaped structures were designed to withstand winds of 120 miles per hour. Boxes of frozen food (meats, seafood, vegetables, fruit, cheese, rice, breads, chocolate bars, soups, and so on) were stacked outside each tent.
    Outdoor summer temperatures typically ranged between 5 above and 10 below zero degrees Fahrenheit, although a high wind would make it feel much, much colder—like living in a combination meat locker and wind tunnel. Inside, although the snow underfoot might be a subfreezing cold “sink,” when the stoves were going the top of the tent could reach 90 degrees Fahrenheit—good