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There is a region on Mars, roughly the size
of Australia, that rises high above the surface
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of the planet. Three of the largest volcanoes
in the solar system line up to guard its western
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To the East, a vast canyon, six to seven times
deeper than the Grand Canyon, cuts into the
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barren Martian plain. This strange region,
once so baffling to scientists, recalls the
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planet's violent past, a time long ago when
the planet's core erupted, pushing molten
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rock to the surface.
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It's part of a larger story, a planetary tragedy,
in which Mars began its descent into the cold,
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dry, and lifeless state that we see today.
We are now scouring its surprisingly complex
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surface for clues to the events that long
ago doomed the Red Planet, Mars.
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Since the early 1960s, we've tried 46 times
to send spacecraft to Mars across the 55 million
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kilometers of its closest approach to Earth.
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Over half failed at launch or upon arrival.
The rest flew around the planet, snapping
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pictures, recording data. Or they landed to
test its soil and rocks, and crawl around
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its canyons and craters.
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These probes may one day pave the way for
human explorers, who will dig deeper still,
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in search of answers to our most pressing
question:
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Did Mars, at some point long ago develop far
enough for life to arise? If so, does anything
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still live within Mars' dusty plains, beneath
its ice caps, or somewhere underground?
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Mars does not give up its secrets easily.
Over the years, that has led observers on
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this planet to jump to all sorts of conclusions.
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In the year 1877, the Italian astronomer Giovanni
Schiaparelli noted markings on Mars' surface,
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a latticework of lines. He called them "canali"
in Italian, meaning "channels" in English.
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A careful and thorough observer, Schiaparelli
began to sketch them and name them, connecting
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them in a vast global network.
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Over a 15-year period, beginning in 1894,
the American astronomer, Percival Lowell,
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closely examined these features. He saw a
remarkable drama unfolding on our neighboring
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In his view, Schiaparelli's channels were
artificial canals, designed perhaps to carry
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melting snow from the poles to the dry interior.
After all, on Earth, the Suez Canal had been
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open since 1869. Construction on the Panama
Canal had just gotten underway.
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The Martian canals, Lowell surmised, had been
built by a sophisticated society confronting
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an environmental catastrophe on the grandest
of scales. Its inhabitants faced an urgent
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choice: move water across vast arid regions,
or perish on an increasingly dry planet.
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In a series of three best-selling books, Lowell
took his case to the public. The public responded
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with some ideas of their own.
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With the means to remake an entire planet,
perhaps these Martians were more advanced
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than humans. Some of us began offering schemes
for making contact. Giant mirrors to flash
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greetings. Light beams. Mental telepathy.
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Lowell vision fell by the wayside in 1964.
The Mariner Four spacecraft flew by Mars and
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got a good look. What it saw looked more like
the Moon than the Earth. Three more Mariners
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followed, culminating in the arrival of Mariner
Nine in 1971, the first spacecraft to go into
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orbit around Mars.
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These missions documented a heavily cratered
landscape, pocked with huge dormant volcanoes...
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and cut with the deepest and longest canyon
in the solar system. They saw no traces of
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life, present or past.
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Then, in the mid-1970's, two lander-orbiter
robot teams, named Viking, went in for an
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even closer look. The landers tested the soil
for the chemical residues of life. All the
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evidence from Viking told us: Mars is dead.
And extremely harsh.
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The mission recorded Martian surface temperatures
from -17 degrees Celsius down to -107. We
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