Matthew Tanner
June 20, 2015
Dr. Frank Drake, formerly of the University of California, Santa Cruz, formulated the equation which bears his name as a means to estimate the number of intelligent civilizations capable of intragalactic communication that might be extant in the Milky Way galaxy.
R* - The average rate of galactic star formations per year
fp - The fraction of extant stars with planetary systems
ne - Of the starts that have planetary systems, the average number of planets that can support life of some kind.
fl - Of those planets hospitable to life, the fraction that in fact do develope life
fi - Of life bearing planets, the fraction in which intellegent life emerges
fc - Of planets hosting intelligent life, the fraction that develope the means for intragalactic communication or technoloy which is detectable from intragalactic distances
L - The average lifespan of civilizations with detectable technology
The Drake Equation App can be launch from https://matthewtanner.shinyapps.io/shinyApp
Default values are lower bounds of those chosen by Dr. Drake for his original estimation in 1961. Any field may be changed to any valid value. Note that no value may be less than zero and no factional value may be greater than 1. The new estimate is displayed automatically with a change to any factor value.
Milky Way galaxy diameter = 100,000 light years. \( A = \pi r^{2} \)
Area of Milky Way as see from above the galactic plain:
r <- 50000; area <- pi * r^2; area
[1] 7853981634
in square light years. From Dr. Drakes initial 1961 estimation (20), each civilation is sole occupant of, on average:
eachOccupies <- area/20; eachOccupies
[1] 392699082
square light years. Expected distance to closest neighbor:
sqrt(eachOccupies/pi)
[1] 11180.34
in light years. That's a lot longer than we've had radios. If there is other life in the galaxy, according to Dr. Drakes calculations, it's unlikely that they know we're here.