Modeling - The
Drake equation is a
probabilistic argument used to estimate the number of active, communicative
extraterrestrial civilizations in the
Milky Way galaxy.
[1][2] https://en.wikipedia.org/wiki/Drake_equation
It was meant to generate thought and discussion. It is a theory/hypothesis/educated guess which includes a fair number of variables. Astronomers are currently updating the second variable
fp as they find more and more exoplanets around stars and they are developing techniques to actually find signals of water molecules in the light/radiation coming from these star/planet systems to update variable
ne. This is how new data gets found and plugged in to a model's equation to generate a new answer. Lot's of variables in the Infectious Disease Model.
The Drake equation is:
where:
N = the number of
civilizations in our galaxy with which communication might be possible (i.e. which are on our current past
light cone);
and
R∗ = the average rate of
star formation 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 planets that could support life that actually develop life at some point
fi = the fraction of planets with life that actually go on to develop
intelligent life (civilizations)
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
[5][6]