The Impact of Contact

Two fields of study are beginning to come together, with fascinating results: the Search for Extraterrestrial Intelligence (SETI) and the search for extrasolar planets, or exoplanets (SEP).

            To some extent, SEP is a subset of SETI, because we have always assumed (consciously or unconsciously) that we are looking for intelligence that is like ourselves, which therefore evolved on a planet like the Earth. The Drake Equation, formulated in the 1960s to estimate the number of extraterrestrial civilizations in existence in our galaxy and/or the universe, begins with the number of stars in the galaxy/universe, all of which might be suns. It then narrows down the overall result by estimating the number of planets revolving around those stars, and then the percentage of those planets that might bring forth life. (In this analysis, we will focus on the galaxy to simplify the conversation.)

            The assumption is, then, that those habitable planets will nurture not only life but also at least one, and probably many more, intelligent species. The Drake equation has been used to develop a wide range of predictions regarding how many advanced technical civilizations might exist in our galaxy. Given the large number of stars in the Milky Way galaxy, it is difficult, even with conservative assumptions, to reduce the estimate below 10,000.

            Regardless of the final number, the focus of SETI has reflected its name, in that it involves a search for intelligence, and without clearly saying so, a search for intelligence more or less at the level of development of our own civilization.
To be continued
(c) Copyright, Frank White, 2016, All Rights Reserved

The Overview Effect: Space Exploration and Human Evolution is available at aiaa.org and amazon.com 
The SETI Factor, which explores the impact of contact with extraterrestrial intelligence, is out of print, but some copies may be available at amazon.com