134 lines
7.8 KiB
Plaintext
134 lines
7.8 KiB
Plaintext
SUBJECT: THE SEARCH FOR EXTRATERRESTRIAL INTELLIGENCE FILE: UFO2804
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BY DAVID L. BURKHEAD
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Are we alone? The question is often asked by those involved in the search for
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extraterrestrial intelligence (SETI). It has tugged at the mind of humankind
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since early history, probably since the first time a human looked up at the
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sky and realized that some of those lights up there were other worlds.
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The ancient Greeks told stories in which they populated the Moon with people,
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people who were planning a war with people on the Sun. In the Middle Ages, the
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Orlando Furioso had Duke Adolpho, one of Charlemagne's paladins, travel to the
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Moon on the back of a hippogrif to meet some of the folk who resided there.
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Such ideas seem quaint today, but the idea of life on other worlds is anything
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but quaint. While none of the other planets in the Solar System are likely
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homes for intelligent, tool-using life, our galaxy alone contains more than a
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hundred billion stars, many like our Sun. Current theories postulate that
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stars like the Sun are also likely to have planets, and if conditions are
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right on those planets, then life should evolve.
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The next question is how it might be possible to detect, perhaps even
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communicate with, such life. For most of history, no means of observing even
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the worlds around another star existed. However, in 1932 radio experimenter
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Hiram Percy Maxim suggested that contact with another star might one day be
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possible by radio.
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The year before, unknown to Maxim, Karl Jansky of Bell Laboratories,
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investigating sources of static in radio communications, traced one of these
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sources to the heavens, specifically to the Milky Way, and thus created the
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science of radio astronomy. Others expanded on Jansky's work, developing new
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receivers and large antennas that could examine the sky for radio sources.
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None of these radio telescopes sought signs of life elsewhere in the universe,
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but they did develop powerful new tools for the detection and analysis of
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faint signals coming from deep space. It was these tools that Frank Drake
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applied to his Project Ozma, the first serious attempt to look for other life
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in the universe. In 1961 at the radio observatory in Green Bank, West
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Virginia, Drake observed two nearby sun-like stars considered by many likely
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to have planets - Tau Ceti and Epsilon Eridani.
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While Project Ozma did not find any extraterrestrial signals, it did lead to a
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conference of leading SETI researchers at Grand Bank in 1981. This meeting was
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organized by the U.S. National Academy of Science and demonstrated that SETI
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could now be taken seriously in science, even at the highest levels.
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One result of the conference was the socalled Drake Equation. This equation
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purports to estimate the number of intelligent, communicating civilizations in
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the galaxy. Taking such factors as the number of stars in the galaxy,
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probability of a given star having planets, probability of a given planet
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developing life, etc., the equation then calculates the number of
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civilizations expected in the galaxy. Unfortunately, many of the factors are
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unknown and estimates are little more than wild guesses. Yet estimates are
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made, and the most common result is about a million communicating
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civilizations. If scattered evenly about the galaxy, this would put the
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nearest such civilizations about 700 light years away.
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This then, is one of the major problems with SETI projects. According to
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Geoffrey Landis of NASA Lewis Research Center, given our current technology,
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it would be impossible to detect the Earth from much smaller distances than
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700 light years. The only signals that would be detectable even from the
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nearest stars would be the Ballistic Missile Early Warning System (BMEWS).
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Yet, because of Earth's rotation, any signal a hypothetical extraterrestrial
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detected would only appear in short spurts, like many natural sources, unless
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the exterrestrial's planet were situated along the line of Earth's axis.
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Since there are no nearby stars along the line of the Earth's axis, the
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hypothetical alien world could not detect the Earth and realize that they had
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found signs of intelligence elsewhere. Likewise, it is extremely unlikely that
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we would detect accidental emissions from other planets.
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However, there is still the possibility of intentional transmissions. Frank
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Drake and Carl sagan directed the transmission of the first (and to date only)
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deliberate message sent into space. Transmitting from the Arecibo Observatory
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in Puerto Rico, they sent a message consisting of 1,679 pulses that decode
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into a crude image containing information about our planet, our place in the
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solar system, and ourselves. This message was aimed at the Great Cluster in
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the constellation of Hercules. The message will take 24,000 years to reach the
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distant cluster, so no reply can be expected anytime soon.
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If we can deliberately send a message into space, perhaps others have done so
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as well. If any such messages have been sent in our direction, whether or not
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Earth or the Sun is the intended target, we may be able to detect them. Such
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messages are what various SETI projects have attempted to detect.
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The problems faced by SETI researchers are enormous. First is finding the
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signal. The signal can come from anywhere in the entire sky, and at any
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frequency. Two approaches are generally used to search for signals. In one,
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thousands or millions of frequencies are studied in a survey of the entire sky
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in the hope of finding the needle in the cosmic haystack. In the other
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approach, and attempt is made to determine what frequencies are likely to be
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used by extraterrestrials wishing to broadcast to other beings and what stars
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are likely to have such extraterrestrials, and then to concentrate the search
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there. This is what Drake did for Project Ozma.
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The next problem is that even if the signal can be found, it may not be
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recognized. Nature has a way of conspiring to deceive astronomers about eh
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nature of signals. In 1967, a source of extremely regular, steady pulses was
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detected in deep space. Excitement rose, for no known natural source could
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explain such regular pulses. The idea that they were from a beacon established
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by extraterrestrials was put forward, but SETI advocates were doomed to
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disappointment. The pulsating radio sources, known as pulsars, proved to be
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rapidly spinning neutron stars. While they were exciting discoveries in their
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own right, they had nothing to do with extraterrestrial intelligence.
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SETI has largely remained a small sidelight of radio astronomy. Occasionally,
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projects were funded, but they had to compete with other, more pressing and
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popular projects. However, that seemed likely to change in 1992 when Congress
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approved a new, extensive 10-year Search for Extraterrestrial Intelligence to
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be conducted by NASA. The project would combine both an all-sky survey and a
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concentrated examination of nearby stars.
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Ten years proved optimistic. In October of 1993, merely one year after the
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initiation of the project, Congress cancelled it. That brought direct
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government involvement in SETI to an end. The SETI Institute of California, a
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private group, took over the project and renamed it Project Phoenix. So far
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the group has raised $4.4 million, more than half the $7.4 million required to
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keep the project functioning.
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The search for extraterrestrial intelligence is a long, difficult one that
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will probably not reach its goal for decades, if ever. Yet, many consider the
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search important. We may be alone in the universe or we may share the universe
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with possibly hundreds, thousand, or millions of civilizations. Either way,
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the thought is staggering.
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**********************************************
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* THE U.F.O. BBS - http://www.ufobbs.com/ufo *
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********************************************** |