Concepts
Drake Equation
Also Known As Green Bank Equation Named after the National Radio Astronomy Observatory's Green Bank facility, where Frank Drake convened the 1961 meeting that produced the equation.
Citation Formats
General Reference
APA Style
BibTeX
A formula combining astronomical, biological and sociological estimate factors, such as star formation rate, the fraction of stars with planets, and the lifetime of a communicating civilization, to produce an order of magnitude estimate of the number of communicating extraterrestrial civilizations in the Milky Way. Devised as an organizing framework for an early SETI conference rather than a rigorous predictive tool, it is widely regarded as illustrative rather than quantitatively reliable because most of its terms are essentially unconstrained by data.
Facts
Concept Domain Formulated Year Cross-Tradition Connections
Associated With
Fermi Paradox, Concepts The Drake equation is the standard attempt to quantify the terms behind the Fermi paradox.
Sources
Frequently Asked Questions
What values do scientists use in the Drake Equation today?
They vary widely; some terms are now well measured (star and planet formation rates), others remain guesses (odds of life arising, civilization lifetime).
Frank Drake devised the equation in 1961 as a way to organize discussion at a Green Bank meeting, not to produce one authoritative number, and the values plugged into it still vary enormously by researcher. Several of its terms, such as the rate of star formation and the fraction of stars with planets, are now measured far more precisely than in 1961 thanks to exoplanet surveys; others, such as the fraction of habitable planets where life actually arises or the average lifetime of a communicating civilization, remain essentially unknown, so estimates of the final answer still range from less than one to many millions.
Reader Challenges (0 open reader challenges)
No disputes yet. Spotted an error or a better source? Open the first one.
Sign in to dispute this or suggest a correction.
View At A Past Year
The atlas records no dated fact of its own for this entry, so there is no other year to choose.