SUBJECT: THE SEARCH FOR EXTRATERRESTRIAL INTELLIGENCE        FILE: UFO2804



BY DAVID L. BURKHEAD



Are we alone? The question is often asked by those involved in the search for
extraterrestrial intelligence (SETI). It has tugged at the mind of humankind
since early history, probably since the first time a human looked up at the
sky and realized that some of those lights up there were other worlds.

The ancient Greeks told stories in which they populated the Moon with people,
people who were planning a war with people on the Sun. In the Middle Ages, the
Orlando Furioso had Duke Adolpho, one of Charlemagne's paladins, travel to the
Moon on the back of a hippogrif to meet some of the folk who resided there.

Such ideas seem quaint today, but the idea of life on other worlds is anything
but quaint. While none of the other planets in the Solar System are likely
homes for intelligent, tool-using life, our galaxy alone contains more than a
hundred billion stars, many like our Sun. Current theories postulate that
stars like the Sun are also likely to have planets, and if conditions are
right on those planets, then life should evolve.

The next question is how it might be possible to detect, perhaps even
communicate with, such life. For most of history, no means of observing even
the worlds around another star existed. However, in 1932 radio experimenter
Hiram Percy Maxim suggested that contact with another star might one day be
possible by radio.

The year before, unknown to Maxim, Karl Jansky of Bell Laboratories,
investigating sources of static in radio communications, traced one of these
sources to the heavens, specifically to the Milky Way, and thus created the
science of radio astronomy. Others expanded on Jansky's work, developing new
receivers and large antennas that could examine the sky for radio sources.

None of these radio telescopes sought signs of life elsewhere in the universe,
but they did develop powerful new tools for the detection and analysis of
faint signals coming from deep space. It was these tools that Frank Drake
applied to his Project Ozma, the first serious attempt to look for other life
in the universe. In 1961 at the radio observatory in Green Bank, West
Virginia, Drake observed two nearby sun-like stars considered by many likely
to have planets - Tau Ceti and Epsilon Eridani.

While Project Ozma did not find any extraterrestrial signals, it did lead to a
conference of leading SETI researchers at Grand Bank in 1981. This meeting was
organized by the U.S. National Academy of Science and demonstrated that SETI
could now be taken seriously in science, even at the highest levels.

One result of the conference was the socalled Drake Equation. This equation
purports to estimate the number of intelligent, communicating civilizations in
the galaxy. Taking such factors as the number of stars in the galaxy,
probability of a given star having planets, probability of a given planet
developing life, etc., the equation then calculates the number of
civilizations expected in the galaxy. Unfortunately, many of the factors are
unknown and estimates are little more than wild guesses. Yet estimates are
made, and the most common result is about a million communicating
civilizations. If scattered evenly about the galaxy, this would put the
nearest such civilizations about 700 light years away.

This then, is one of the major problems with SETI projects. According to
Geoffrey Landis of NASA Lewis Research Center, given our current technology,
it would be impossible to detect the Earth from much smaller distances than
700 light years. The only signals that would be detectable even from the
nearest stars would be the Ballistic Missile Early Warning System (BMEWS).
Yet, because of Earth's rotation, any signal a hypothetical extraterrestrial
detected would only appear in short spurts, like many natural sources, unless
the exterrestrial's planet were situated along the line of Earth's axis.
Since there are no nearby stars along the line of the Earth's axis, the
hypothetical alien world could not detect the Earth and realize that they had
found signs of intelligence elsewhere. Likewise, it is extremely unlikely that
we would detect accidental emissions from other planets.

However, there is still the possibility of intentional transmissions. Frank
Drake and Carl sagan directed the transmission of the first (and to date only)
deliberate message sent into space. Transmitting from the Arecibo Observatory
in Puerto Rico, they sent a message consisting of 1,679 pulses that decode
into a crude image containing information about our planet, our place in the
solar system, and ourselves. This message was aimed at the Great Cluster in
the constellation of Hercules. The message will take 24,000 years to reach the
distant cluster, so no reply can be expected anytime soon.

If we can deliberately send a message into space, perhaps others have done so
as well. If any such messages have been sent in our direction, whether or not
Earth or the Sun is the intended target, we may be able to detect them. Such
messages are what various SETI projects have attempted to detect.

The problems faced by SETI researchers are enormous. First is finding the
signal. The signal can come from anywhere in the entire sky, and at any
frequency. Two approaches are generally used to search for signals. In one,
thousands or millions of frequencies are studied in a survey of the entire sky
in the hope of finding the needle in the cosmic haystack. In the other
approach, and attempt is made to determine what frequencies are likely to be
used by extraterrestrials wishing to broadcast to other beings and what stars
are likely to have such extraterrestrials, and then to concentrate the search
there. This is what Drake did for Project Ozma.

The next problem is that even if the signal can be found, it may not be
recognized. Nature has a way of conspiring to deceive astronomers about eh
nature of signals. In 1967, a source of extremely regular, steady pulses was
detected in deep space. Excitement rose, for no known natural source could
explain such regular pulses. The idea that they were from a beacon established
by extraterrestrials was put forward, but SETI advocates were doomed to
disappointment. The pulsating radio sources, known as pulsars, proved to be
rapidly spinning neutron stars. While they were exciting discoveries in their
own right, they had nothing to do with extraterrestrial intelligence.

SETI has largely remained a small sidelight of radio astronomy. Occasionally,
projects were funded, but they had to compete with other, more pressing and
popular projects. However, that seemed likely to change in 1992 when Congress
approved a new, extensive 10-year Search for Extraterrestrial Intelligence to
be conducted by NASA. The project would combine both an all-sky survey and a
concentrated examination of nearby stars.

Ten years proved optimistic. In October of 1993, merely one year after the
initiation of the project, Congress cancelled it. That brought direct
government involvement in SETI to an end. The SETI Institute of California, a
private group, took over the project and renamed it Project Phoenix. So far
the group has raised $4.4 million, more than half the $7.4 million required to
keep the project functioning.

The search for extraterrestrial intelligence is a long, difficult one that
will probably not reach its goal for decades, if ever. Yet, many consider the
search important. We may be alone in the universe or we may share the universe
with possibly hundreds, thousand, or millions of civilizations. Either way,
the thought is staggering.




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