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First Contact

First Contact

Over a century ago, the astronomer Percival Lowell thought that he had glimpsed artificial canals on Mars and the radio pioneer Nikola Tesla believed that he had intercepted a Martian radio broadcast. Later attempts to signal Mars by means of huge bonfires and powerful radio broadcasts proved unsuccessful. Today people realize that although remnants of microbial life may exist within the solar system, the search for extraterrestrial intelligence (SETI) must extend to distant stars.

Search Strategies

Microwave SETI, which uses radio telescopes, was popularized in Carl Sagan's novel Contact (1985) and in the 1997 Jodie Foster movie of the same name. Dish antennas collect faint microwaves that are fed into receivers that scan billions of channels simultaneously. Computers flag the signals that merit a closer look. Some astronomers have employed optical SETI and use optical telescopes fitted with special devices to hunt for flashes from extraterrestrial lasers pointed toward Earth. There are other search strategies, but because these two are in widespread use, they have the greatest chance of success. Most likely, first contact will involve intercepting a faint signal from a civilization many light-years away.

Initial Reactions

So many people have become used to the idea that "we are not alone" that intercepting a signal from another solar system is unlikely to cause widespread psychological meltdown or social collapse. Indeed, when a prankster convinced the media that a microwave search had located ET, the public was not upset. An authenticated discovery would prove that humans are the product of processes that are not limited to Earth. Scientists estimate that the average extraterrestrial civilization could be about a billion years older than that on Earth. Finding such an old-timer would prove that civilizations can survive population growth, resource depletion, atomic warfare, and other threats. This would renew hope for the future of human society.

What We Might Learn

In light of the likely differences between two civilizations that are located in different parts of the galactic neighborhood, those civilizations may have trouble recognizing each other, let alone communicating. Still, an ancient civilization may have solved the problem of communicating with a civilization such as Earth's, or after years of research, humans may learn to communicate with creatures that are not from around here. Our reactions will be shaped by our impressions of the alien civilization's capabilities, intentions, and desire to travel to Earth. These reactions will depend on our expectations, whether the discovery occurs during a time of peace or war, how the media handle the story, as well as other considerations.

Most discussions of first contact are optimistic and suggest benefits for humankind. Earth's new acquaintances might share practical ways to solve energy needs, cure illnesses, and eliminate crime. Their advanced ideas could have a deep and lasting impact on our philosophy, science, religion, and the arts. Learning about their ways could transform the way people think about themselves and prompt humans to redefine their place in the universe. Of course, contact may never occur or may proceed in a less pleasant way. If generations of searches fail, people will come to grips with the reality that humans are alone. Perhaps in the very distant future, as an advanced space-faring civilization, humankind will fill the universe with intelligent life.

see also Life in the Universe, Search for (volume 2); SETI (volume 2).

Albert A. Harrison


Billingham, John. Societal Implications of the Detection of an Extraterrestrial Civilization. Mountain View, CA: SETI Institute, 1999.

Dick, Steven J. The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science. Cambridge, UK: Cambridge University Press, 1996.

Harrison, Albert A. After Contact: The Human Response to Extraterrestrial Life. New York: Plenum, 1997.

Shostak, Seth. Sharing the Universe: Perspectives on Extraterrestrial Life. Berkeley, CA:Berkeley Hills Books, 1998.

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