Mon Aug 26 13:01:08 1996

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Date: Mon, 26 Aug 96 09:55:18 PDT
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From: Vincent Broman 
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In-Reply-To: <960825191455_509650713@emout19.mail.aol.com> (DrJDPrice@aol.com)
Subject: Re: Carbon dating
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There is a little confusion about who adjusts C-14 dates and how.
The order of events goes like this
 a. People do C-14 dating assuming constant production of C-14 in
    the upper atmosphere by cosmic rays.
 b. They eventually see some discrepancies compared to known dates of
    artefacts, too large to be explainable as isotope measurement error.
 c. They _estimate_ the nonconstant rate of C-14 formation by fitting
    measurements to known dates.  The variation is not huge.
    This gives an adjusted scale of concentrations <-> dates.
 d. They validate the estimates by tests of new known-date artefacts
    not included in the curve fitting process.
    After this point no more "adjusting" of dates occurs.
 e. They use the new validated curves, which give more accurate
    dates than before, and they occasionally scratch their heads
    over unrepeatable anomalies, just like in any other science.

Anyone who fudges his data by "adjusting" a C-14 date just to
fit some a priori theory of his (and admits it) gets laughed
out of a job, I imagine.


Vincent Broman             Email: broman@nosc.mil                    =   o     
2224 33d St.               Phone: +1 619 284 3775                  =  _ /- _   
San Diego, CA  92104-5605  Starship: 32d42m22s N 117d14m13s W     =  (_)> (_)  
___ PGP protected mail preferred.  For public key finger broman@np.nosc.mil ___

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