One important aspect of the search is that it encompasses a very wide range of subjects and can be taught across the curriculum. A broad view of the topic can be found in the cornerstone of SETI, the "Drake equation." Developed by astronomer Dr. Frank Drake in 1961, it is a way of organizing information to try to estimate the number of civilizations that might be emitting detectable radio signals. None of the values are really known now and estimates can vary by many orders of magnitude! Indeed, each one of the terms also raises thought provoking questions about nature and ourselves.
(Computer formatting prevents the use of subscripting. In the following equation and definitions the letter(s) following the first letter should actually be subscripts; R(subscript)star, f(subscript)p...)
N = Rstar x fp x ne x fl x fi x fc x L
N= the (estimated) Number of civilizations in our galaxy currently capable of communicating with others. "N" is an estimate since it is the product of estimates.
Rstar= the Rate of star formation during the period when our solar system was born (how are stars born, how long do they live, how do they die?).
fp= the fraction of stars with planets (are planets routinely formed with stars or is our system a fluke?).
ne= the number of planets, per solar system, with an environment suitable for life (why are conditions on Earth suitable for life like ours; why are conditions on other planets in our solar system so hostile?).
fl= the fraction of suitable planets on which life actually appears (are fertile conditions enough to allow life to get a start?).
fi= the fraction of life bearing planets on which intelligence emerges (life has been present on Earth for billions of years but why is intelligence such a recent development?).
fc= the fraction of intelligent societies that develop the ability and desire to communicate with other worlds (we have only had radio communications technology for a few decades; is the desire to know about the universe a natural outgrowth of intelligence?).
L= the Longevity of each technological society in the communicative state (do societies develop the ability to destroy themselves or their environment soon after they develop communication technology?).
The product "N" might be a very large number or a very small one. All that we know for certain is that the value is greater-than-or-equal-to 1; after all, we are here and the fact that we can contemplate this is evidence of intelligence. Without quite a bit more information, it would be totally unrealistic to try to discuss each element of the equation in detail. But each variable can generally be used to point out important points about our Universe. Even defining terms like "galaxy" or "intelligence" will broaden student's views.
For classroom activities, students can be encouraged to make drawings of "aliens" and their worlds. They can write essays about what the impact of a detection of intelligent life would have on society or themselves, or on what message they would send to aliens. Research in astronomy, biology, geology, sociology, ecology, among a great many other sciences, can be given a SETI context.
Most science fiction stories deal with interactions with aliens. Television and movies often do as well--for example: the Star Trek series (both of them), six movies and countless books and short stories. Often the plots involve current social issues. Even most of the cinematographic works featuring Arnold Schwarzenegger deal with interactions with aliens, although the sociological angles are often secondary.
Please remember that, although "N" may be greater than 1, the distances between stars is so great that it might very well be impossible to ever actually visit with aliens. After all, it took Voyager 2 twelve years to reach Neptune. Neptune is four hours away at the speed of light. The nearest star is over four years away at that speed! We may have to be satisfied with radio communications where decades pass between questions and responses.
Few children are disinterested by the idea of extraterrestrial intelligence. Many have had their views distorted by their exposure to supermarket tabloids. It is appropriate to harness their enthusiasm to the constructive use of science and the humanities. Contact the SETI Institute at: 2035 Landings Drive, Mountain View CA 94043 (415) 961-6633.
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