# From the SETI Institute ... THE DRAKE EQUATION How can we estimate the number of technolog

```

From the SETI Institute ...

THE DRAKE EQUATION

How can we estimate the number of technological civilizations that
might exist among the stars? While working as a radio astronomer at
the National Radio Astronomy Observatory in Green Bank, West Virginia,
Dr. Frank Drake (now President of the SETI Institute) conceived an
approach to bound the terms involved in estimating the number of
technological civilizations that may exist in our galaxy. The Drake
Equation, as it has come to be known, was first presented by Drake in
1961 and identifies specific factors thought to play a role in the
development of such civilizations. Although there is no unique
solution to this equation, it is a generally accepted tool used by the
scientific community to examine these factors. The equation is
usually written:

N = R* x fp x ne x fl x fi x fc x L

Where,

N = The number of civilizations in The Milky Way Galaxy whose radio
emissions are detectable

R * = The rate of formation of stars suitable for the development of
intelligent life

f p = The fraction of those stars with planetary systems

n e = The number of planets, per solar system, with an environment
suitable for life

f l = The fraction of suitable planets on which life actually appears

f i = The fraction of life bearing planets on which intelligent life
emerges

f c = The fraction of civilizations that develop a technology that
releases detectable signs of their existence into space

L = The length of time such civilizations release detectable signals
into space

Within the limits of our existing technology, any practical search for
distant intelligent life must necessarily be a search for some
manifestation of a distant technology. A search for extraterrestrial
radio signals has long been considered the most promising approach by
the majority of the scientific community. Besides illuminating the
factors involved in such a search, the Drake Equation is a simple,
effective tool for stimulating intellectual curiosity about the
universe around us, for helping us to understand that life as we know
it is the end product of a natural, cosmic evolution, and for making
us realize how much we are a part of that universe. A key goal of the
SETI Institute is to further high quality research that will yield
additional information related to any of the factors of this
fascinating equation.

- end -

```

E-Mail Fredric L. Rice / The Skeptic Tank