Free The Nuclear Winter by Carl Sagan

Carl Sagan / The Nuclear Winter.
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    The Nuclear Winter
    Carl Sagan
    Carl Sagan, a modern-day Renaissance man of science, was horn in 1934 in New York. After graduating with both a B.A. and a B.S.
    degree from the University of Chicago, Sagan completed his M.S.
    in
    physics and earned a Ph.D. in astronomy and astro-physics in 1960.
    Sagan was nominated to join the Smithsonian Astrophysical Observatory in 1962. At the same time, he also worked with the Nobel-prize winner Joshna Lederberg, investigating the origins of life on earth, and taught genetics at Stanford. Sagan then taught astronomy at Harvard until 1968, when he became profossor of astronomy and space sciences at Cornell University. He was then appointed director of the laboratoy for Planetary Studies. Sagan was
    awarded the NASA medal for exceptional scientific achievement in 1972, after his hypotheses about Mars were validated by data obtained from the 1971 Mars Mariner expedition. Beginning in 1968,
    Sagan was editor of Icarus, the international journal of astronomy,
    and wrote many distinguished books. His works include The Cosmic Connection (1973), which received the Campbell Award for best science book; the Pulitzer-prize winning Dragons of Eden (1977); Broca's Brain (1979), on developments in neurophysiology; and Cosmos
    (1980), which accompanied his widety-acclaimed television series.
    In
    "The Nuclear Winter" (1983), Sagan explored the unforeseen and devastating physical and chemical effects of even a small-scale nuclear war on the earth's biosphere and life on earth.
    Except for fools and madmen, everyone knows that nuclear war would he an
    unprecedented human catastrophe. A more or less typical strategic warhead
    has a yield of 2 megatons, the explosive equivalent of 2 million tons of
    TNT. But 2 million tons of TNT is about the same as all the bombs exploded
    in World War II -- a single bomb with the explosive power of the entire Second World War but compressed into a few seconds of time and an area 30
    or 40 miles across …
    In a 2-megaton explosion over a fairly large city, buildings would be vaporized, people reduced to atoms and shadows, outlying structures blown
    down like matchsticks and raging fires ignited. And if the bomb were exploded on the ground, an enormous crater, like those that can be seen through a telescope on the surface of the Moon, would be all that remained
    where midtown once had been. There are now more than 50,000 nuclear weapons, more than 13,000 megatons of yield, deployed in the arsenals of
    the United States and the Soviet Union -- enough to obliterate a million
    Hiroshimas.
    But there are fewer than 3000 cities on the Earth with populations of 100,000 or more. You cannot find anything like a million Hiroshimas to obliterate. Prime military and industrial targets that are far from cities
    are comparatively rare. Thus, there are vastly more nuclear weapons than
    are needed for any plausible deterrence of a potential adversary.
    Nobody knows, of course, how many megatons would be exploded in a real nuclear war. There are some who think that a nuclear war can be
    "contained," bottled up before it runs away to involve much of the world's
    arsenals. But a number of detailed analyses, war games run by the U.S.
    Department of Defense, and official Soviet pronouncements all indicate that this containment may be too much to hope for: Once the bombs begin exploding, communications failures, disorganization, fear, the necessity
    of making in minutes decisions affecting the fates of millions, and the immense psychological burden of knowing that your own loved ones may already have been destroyed are likely to result in a nuclear paroxysm.
    Many investigations, including a number of studies for the U.S.
    government, envision the explosion of 5,000 to 10,000 megatons -- the detonation of tens of thousands of nuclear weapons that now sit quietly,
    inconspicuously, in missile silos, submarines and long-range bombers, faithful servants