Alter any of the values found in the Drake equation to see how it affects the estimated number of civilizations in our galaxy that might be detectable/communicative at the present time.
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Drake Equation Formula
The following equation is used to estimate the number of civilizations in the Milky Way Galaxy whose signals might be detectable (and therefore potentially communicative) at the present time.
N = R_{*} \cdot f_p \cdot n_e \cdot f_l \cdot f_i \cdot f_c \cdot L- Where N is the number of civilizations humans could potentially detect/communicate with (at present)
- R* is the mean rate of star formation in the Milky Way (stars per year).
- fp is the fraction of stars that have planets
- ne is the average number of potentially habitable planets per star with planets
- fl is the fraction of those potentially habitable planets that develop life
- fi is the fraction of planets with life where intelligent life develops
- fc is the fraction of intelligent civilizations that develop detectable communications/signals
- L is the length of time that such communications/signals remain detectable (years)
What is the Drake Equation?
The Drake equation is a theoretical equation developed by Dr. Frank Drake in 1961. This equation attempts to estimate the number of civilizations that humans could possibly detect and communicate with, given the factors presented in the equation.
Sounds great, but what’s the problem? The problem is that several of the factors in the equation are still poorly constrained in astronomy and astrobiology. Some (like R* and fp) have observational constraints, while others (especially fl, fi, fc, and L) remain highly uncertain. In that regard, the equation is best treated as a framework for thinking about the problem, not a source of precise “known” values.
What are example values for the Drake Equation factors?
The following list gives illustrative values/ranges often used in discussions of the Drake equation. Several terms are not meaningfully constrained, so these should not be read as accepted scientific “estimates.”
- R* = about 1–3 stars per year
- fp = roughly 0.5–1 (many studies suggest it may be near 1)
- ne = roughly 0.1–1 (highly dependent on definitions and the type of star considered)
- fl = unknown (could plausibly range anywhere from near 0 to 1)
- fi = unknown (could plausibly range anywhere from near 0 to 1)
- fc = unknown (could plausibly range anywhere from near 0 to 1)
- L = highly uncertain; often explored over a very wide range (for example, decades to millions of years)
