CR Answer Drill 4B 8MS4

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The following passage, adapted from an article published in 2000, focuses on a prehistoric lake that exists deep beneath the Antarctic ice cap. In 2006, the drilling project mentioned in the passage was resumed.     To imagine Lake Vostok, you must first envision a great lake in a living landscape, a week's walk from end to end, too wide to see across from the highest hills on its flanks. Now simplify. Erase the surrounding woods and fields; hide the encircling hills. Remove the changing seasons and the replenishing rain. Shut out the sky. Leave only the waters, the minerals, the muddy depths. Then trap, squeeze, and estrange them from everything that lives and dies. From your creation emerges a simple world that hungers for more.     To scientists, Lake Vostok, beneath 2.5 miles of solid ice, is unbearably attractive. If it ever had a direct link with the air above it, that connection ended some millions of years ago. Its sediments contain a unique record of Antarctica's climate that could revolutionize the science of the frozen continent. There could be prehistoric life in its waters, an indigenous ecosystem surviving with few resources -- no sunlight, the tiniest of fresh-food inputs -- and spurring adaptations never seen before. Were Lake Vostok open to the rest of the world, its faint records and fragile life-forms would have been overwritten long ago.     Vostok's existence was unknown until 30 years ago, when radar and seismographs allowed scientists to piece together a map. The first hints of water under the ice were detected in the 1970s; much later, in the early 1990s, satellites and date from earlier seismic surveys revealed Lake Vostok's full extent. In 1995, a borehole was drilled from Russia's Vostok station quite by chance, long before anyone suspected something important might be below. The borehole came within 400 feet of entering the lake, but the drillers stopped short of breaking through to the waters beneath.     Soon, however, millions of years of isolation may come to an end: researchers from several countries have started lobbying their governments for a multimillion- dollar, long-term effort to fathom Vostok's depths. If the multinational teams of scientists get their way, the exploration of Lake Vostok -- perhaps the most ambitious and complex scientific undertaking Antarctica has yet seen -- could begin in less than five years. New bases will be built, some temporary, some permanent; new logistical infrastructures will be created to serve them; fleets of aircraft will transport thousands of gallons of fuel oil. (It takes a hellish amount of energy to get through 2.5 miles of ice.) Tele-operated and autonomous deep- diving robots will launch themselves from the boreholes into the great lake's waters, and then sink through the blackness to the silent ooze below. Long-dark Vostok will be pried open for inspection -- a process that, however carefully undertaken, runs the risk of changing the lake forever and destroying what has made it unique.     Why take that chance? Some believe Vostok should be left alone because exploration might permanently damage its pristine ecosystem. But proponents of drilling believe Vostok could provide new insights into young Earth's spectacular ecological crises, during which the whole planet was frozen solid, its oceans reduced to the very brink of lifelessness. And it could illuminate the possibilities of life farther off -- in a vast ocean on Europa, Jupiter's fourth-largest moon, 483 million miles from the Sun and, along with Mars, the most likely prospect for evidence of life beyond Earth. Isolated from light, warmed only from below, starved of nutrients, the life-forms of Vostok could teach scientists how life might persist in Europa's frigid climate, where temperatures average minus 250 degrees Fahrenheit. It would certainly show them how to look for it there: exploring Vostok would be the nearest thing to a space mission without leaving the planet.