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Astrobiology

Contents

1.   Astrobiology: a definition
2.   The Drake formula

Astrobiology: a definition

According to the free encyclopedia Wikipedia, Astrobiology is the study of the origin, evolution, distribution, and future of life in the universe. In addition, Astrobiology addresses the question of whether life exists beyond Earth. Exobiology is a rather a subfield of Astrobiology which covers both the search for life beyond Earth and the effects of extraterrestrial environments on living things. As a consequence, Astrobiology is a interdisciplinary field.

The Drake formula

The Drake equation is an equation used to estimate the number of detectable extraterrestrial civilizations in the Milky Way galaxy. It is used in the fields of exobiology and the Search for ExtraTerrestrial Intelligence (SETI). The equation was devised by Frank Drake in the 1961 while he organized the first SETI meeting at the Green Bank facility (a part of the National Radio Astronomy Observatory in Green Bank, West Virginia). One year ago, this is where Frank Drake began the first search for radio signals from extraterrestrial civilizations.

The Drake equation states that (equation bad display?(*)):
N = R* · fp · ne · fl · fi · fc · L

where:
N = the number of civilizations in our galaxy with which communication might be possible
R* = the average rate of star formation per year in our galaxy
fp = the fraction of those stars that have planets
ne = the average number of planets that can potentially support life per star that has planets
fl = the fraction of the above that actually go on to develop life at some point
fi = the fraction of the above that actually go on to develop intelligent life
fc = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
L = the length of time for which such civilizations release detectable signals into space








(*) This equation have been written using the free software mathml language programming. Of the major web browsers, recent versions of Gecko browsers (e.g., Firefox and Camino) support MathML natively. The MathML option is only available in version 5.1 and higher of Safari. Internet Explorer does not support MathML natively, but support in IE7 and IE8 (not IE9) can be added by installing the MathPlayer plugin.
To learn more about free software philosophy
To learn more about mathml
Mise à jour le 31 octobre 2011
par Olivier Bastien.