Exploring Science Through Science Fiction by Barry B. Luokkala

Author:Barry B. Luokkala
Language: eng
Format: epub
Publisher: Springer New York, New York, NY

Exactly how many stars in the galaxy have planets is not yet known. What is known is that the fraction f p in Eq. (5.1) is a number less than one. How much less was a complete unknown in the early 1960s, but we now have growing evidence that it may be as large as 1/2.

The next parameter in the Drake Equation is n e, the number of Earth-type planets per star system (of those that actually have planets). When the Drake Equation was originally formulated, it was hoped that n e would be large enough, so that the product of f p and n e would be approximately equal to 1. This was wild speculation at the time, but this assumption is becoming more and more plausible, as NASA’s Kepler mission continues to gather data.

The assumptions about the next three parameters in Eq. (5.1) are all based on exactly one observation: intelligent life exists on Earth, and has developed radio communication. The assumption motivating the SETI project is that all Earth-type planets WILL support life, and that once life exists, it WILL evolve into intelligent life, and that intelligent civilizations WILL develop radio communication. In other words, f l = f i = f c = 1. This may be true, or it may not be true. We simply do not know at the present time. But the assumption about the final parameter in the Drake Equation is pure speculation, beyond the bounds of any data: L = 10,000 years. The only radio-communicating civilization that we know about is our own, and we have only had this capability for roughly 100 years. The number was chosen in hopes of predicting many thousands of intelligent, radio-communicating civilizations elsewhere in the galaxy, so that we might listen for signs of intelligent life with our radio telescopes and have a reasonable chance of finding something. The search has been going on for 50 years, and to date there have been no signs of an artificially generated extraterrestrial radio signal. But the tremendous advances in computer technology over the past 50 years now make it possible to analyze the data much more quickly and efficiently. So there is still hope that something may turn up [7].

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