It is the factor "fc" from which the meaning of "N"
derives in part.
At the SETI Institute web site "fc" is defined as:
"the fraction of planets where technology develops"
Based on this, then "N" should read as the "number of
planets where technology develops", which is not in
agreement with "N --- The number of communicative
civilizations" ...
I looked up the definition of "fc" in Frank Drake's
book "Is Anyone Out There?". Here "fc" is defined as:
"the fraction of planets with intelligent creatures
capable of interstellar communication". Personally I
would add in terms like "and willing to communicate
right now" in there myself, but ...
As you can see, it seems, even the SETI Institute
personnel can not agree on the definition of terms for
the Drake Equation.
The SETI Institutes definition should be the standard,
but it must be self-consistent. It should not be
specific but general ...
I agree with Jim Deardorff that the specific mention
of "radio communication" needs to be removed as it
doesn't really come into the equation from any of the
other definitions of the terms such as "fc", "fi", ...,
etc...
Perhaps we should contact someone at the SETI Institute
(Seth Shostak?) ...
Al Aburto
aburto@cts.com
> "Dr. H. Paul Shuch" wrote:
>
> At 05:48 AM 2/1/99 -0800, Alfred A. Aburto Jr. wrote:
> >Please see:
> >
> >http://www.seti-inst.edu/drake-eq.html
>
> That page defines N as:
>
> "The number of communicative civilizations" (Drake's original definition)
> and then further clarifies it with:
> "The number of civilizations in the Milky Way Galaxy whose radio emissions
> are detectable."
>
> Steve Ford's QST sidebar, found on The SETI League website at
> <http://www.setileague.org/general/drake.htm>, defines it simply as:
> "The number of communicative civilizations."
>
> I think Frank's intent is clear, and the articles are consistent with it.
> -----------------------------------------------------------------
> H. Paul Shuch, Ph.D. Executive Director, The SETI League, Inc.
> 433 Liberty Street, PO Box 555, Little Ferry NJ 07643 USA
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>
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