Tuesday, June 22, 2010

Not Only is the Space Black, Its also Silent - Where are the Aliens?

Not only is space black, it is also silent. Surrounded by endless stellar reaches, Earth seems a lonely outpost devoid of communications from any other world. Given the likelihood of planetary systems orbiting many (if not most) of the stars we see, why hasn’t a single one of them sent us a simple hello? Could space be as empty of life as it is of light, or might there be another explanation?
The great Italian physicist Enrico Fermi pondered this dilemma in 1950 while taking a break from the rigors of Los Alamos Laboratory. It was the era of the UFO craze, and newspapers were brimming with speculations about the prospects for alien visitors. A clever cartoon about the subject caught his eye and led him to estimate the probability of extraterrestrial contact. During a casual lunch, he raised the topic with three of his colleagues— Edward Teller, Herbert York, and Emil Konopinski. While discussing sundry matters, Fermi suddenly asked, “Where is everybody?”

The “everybody” in question referred to the preponderance of extraterrestrials our vast universe ought to contain. As Fermi pointed out, given a sufficient number of worlds in space, at least a fraction of them should harbor civilizations advanced enough to attempt contact with us. Then, considering that the cosmos has been around for billions of years, why haven’t any of them sent signals by now? The curious situation that Earth has never encountered alien communications has come to be known as Fermi’s paradox. Drake and Sagan were leading proponents of the Search for Extraterrestrial Intelligence (SETI), a systematic hunt for radio signals from alien civilizations. Beginning in the 1960s, radio dishes around the world have scanned the skies for telltale coded patterns. In the intervening decades the SETI program has been greatly expanded, encompassing a wider range of frequencies and a broader array of targets. Improved software and faster processing rates have made it easier to wade through the haystack of radio noise, thereby enhancing the prospects for uncovering buried messages. Alas, despite a number of false alarms, not one has been found.


Even if advanced life is rare in the Milky Way, that does not preclude an abundance of civilizations in other galaxies. An infinite universe would render even the slimmest chance for intelligence a reality somewhere else in space. Given enough room in the cosmos and enough time for intelligence to develop, the cosmic roulette wheel would be bound to hit the lucky number. It would be just like placing a million monkeys in front of a million computers and letting them bang on the keyboards for an extremely long time. Eventually, through their random actions, one of them would type a Shakespearian sonnet. The lower the probability for intelligent life to evolve, the farther we need to look to find it. Hence, before drawing conclusions about the current failure of the SETI mission to discern signals from within the Milky Way, we must expand our search to include other galaxies. Although the present-day program envisions civilizations with the capacity to broadcast messages over tens or hundreds of light-years, we can easily imagine extragalactic cultures with even greater capabilities. Moreover, because each galaxy potentially harbors hundreds of billions of worlds, there could very well be far more civilizations able to reach us with their signals outside the Milky Way than within it. Therefore, by aiming our radio dishes at intergalactic as well as intragalactic targets we might improve our search for extraterrestrial intelligence.

Well, this is it for now folks. For blokes up in the North West, hope you didn't miss the blazin' comet last fortnight. Stay tuned for my next post on the Beauty of Quantum Mechanics and Whether Alien Civilizations have already beat us to Hyperspace, the final frontier.

P.S: To enthusiastic readers, if you have any information on any upcoming meteor showers or Comet passby's near the Equator or the Tropic of Capricorn, do let me know. The astronomical society down here isn't too big on fabulous cosmic events. Leave some comments and I'll get back to you!

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