There are roughly 100 billion galaxies in the visible universe, each containing an average of about 100 billion stars. Given the truly vast number of stars, it is almost inconceivable that life, and even intelligent life, is unique to our little planet, though of course intelligent life may be very thinly scattered throughout these galaxies.
Astronomers Carl Sagan and Frank Drake noted this, and even generated the “Drake Equation” to estimate the number of intelligent, communicating species one might expect in the universe. Under reasonable assumptions it ought to number in the hundreds, if not thousands. In the summer of 1950, the great physicist Enrico Fermi, discussing this with his colleagues over lunch one day here in
Proposed resolutions have ranged from the whimsical “They are among us and call themselves Hungarians” (proposed by Fermi’s friend Leo Szilard, who along with Fermi’s other regular lunchtime companions Edward Teller, Eugene Wigner, Theodore von Kàrmàn, and John von Neumann were all born in Hungary.) to serious discussions about how long civilizations might last, how difficult is it for simple unicellular life to make the step to multicellular organisms, what special conditions must obtain on a planet for life to have enough time to evolve, and the like.
Physicist Stephen Webb. who is fascinated with Fermi’s paradox, has assembled into a delightful book (Where is Everybody, Copernicus Books, 2002, ISBN 0-387-95501-1) fifty solutions to the paradox that have been proposed at various times, along with serious but very readable discussions of each. The result is a wonderful and wide-ranging education spanning astronomy and cosmology, mathematics and statistics, the sociology of civilizations, the nature of life and evolutionary processes, and many other subjects. One can open the book at random and become fascinated with whatever discussion appears.
I heartily recommend this book to those who enjoy having their horizons stretched.
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