From: hamilton@hitler.chem.uab.edu ()
Subject: Re: In case Bales has convinced you of his honesty
Organization: Chemistry Department, Univ. of Alabama at Birmingham
Date: Fri, 18 Dec 1992 15:24:55 GMT

In article <1992Dec18.051937.5940@panix.com> mls@panix.com (Michael Siemon) writes:
>In article <8001@tekig7.PEN.TEK.COM> bobb@tekig1.PEN.TEK.COM (Robert W Bales)
>writes:
>
>>Not really.  To control error in measurement, *standards* are used.
>
>Have you the SLIGHTEST understanding of what a "standard" is??????
>It is nothing BUT a (consensually nonproblematic) method against which
>*other* methods may be checked.  You are *trying* to summon out of some
>realm of ghosts a "problem" with radioactive dating methods.  This is
>particularly ludicrous in view of the STANDARD for time measurement
>being a particular radiative decay (Cesium, I think?).
>
>Once again, there is a VERY simple logical structure to the case:
>
>	a) radioactive decay is THE standard by which time is measured
>	b) a sample of rock will either have been "closed" as a chemical
>	   system with respect to all the parent and daughter isoptopes
>	   of a decay series, or else it will have been subject to some
>	   addition or subtraction of its chemical makeup
>	c) any measurement at time X of putative decay products from a
>	   consitutent of the rock at formation is subject to question
>	   with regard to the chemical history of the rock (hence; some
>	   methods REQUIRE external caliration -- C14 being the type case)
>	d) if a particular decay series involves chemicals that persist
>	   in the parent rock, while having substantially different chem-
>	   istries, then relative proportions of the parent and daughter
>	   isotopes CROSS_CHECK against any contaminating processes.
>	e) in the absence of any evidence of a disruption of proportion
>	   (i.e., unless one assumes a miracle -- rather a no-no for
>	   experimental science, eh Bob?), the STANDARD of time-keeping
>	   applies uncontroversially, and we get billions of years for
>	   the ages of samples, neatly confirmed by the isochron.
>	f) the history of a given rock sample may include events that
>	   leave its chemical composition in flux for some indefinite
>	   period of time before the "closure" of the chemical system;
>	   in such cases, isochrons will give LATER dates than the "real"
>	   ones -- an earlier date is impossible without some miraculous
>	   on-going "adjustment" of the composition
>	g) since you object to the EARLY dates, YOU had better be able
>	   to demonstrate some such miraculous processes, or be dismissed
>	   as a crank.  Reference to *un*self-calibrating methods is in
>	   this context evidence of i) lack of understanding or ii) dis-
>	   honesty.
>	   
>>past, for example, the length standard was a bar maintained by a government
>>under controlled conditions.  Now I believe it is a certain number of wave-
>
>natter, natter, natter.  *do* please look up what the standard second is.
>I am beginning to think that the "proper" use of the standard metre is
>for someone to go to Paris and check it out and use it to beat you about
>the head and shoulders.

Talking out of my hat, I believe that the standard for a second is the
frequency of a photon required for a transition between two energy
levels in cesium atoms (probably a hyperfine structure splitting),   
and not a radioactive decay.

However, I wonder if Bob Bales or any other Creationist has done any
calculations of isochrons from data that are known from independent
methods to obey the conditions necessary.

>-- 
>Michael L. Siemon	"We honour founders of these starving cities
>mls@panix.com		 Whose honour is the image of our sorrow ...
>			 They built by rivers and at night the water
>			 Running past the windows comforted their sorrow."

Tracy P. Hamilton (ex-Creationist)   
Dept. of Chemistry
Univ. of Alabama at Birmingham
Newsgroups: talk.origins