A few years ago, Dr. Gentry was a featured speaker of the local young-earth group. I saw an ad (on the local access cable channel) for it that made numerous ridiculous claims about the mysterious nature of granite formation. At the time I assumed that the local group had failed to do basic research on the topic, but perhaps some of the claims were received. I had a conflict, but a graduate student doing research on granites, then president of the UNC graduate chapter of InterVarsity Christian fellowship, was able to attend and comment.
Dr. David Campbell
"Old Seashells"
Biology Department
Saint Mary's College of Maryland
18952 E. Fisher Road
St. Mary's City, MD 20686-3001 USA
dcampbell@osprey.smcm.edu, 301 862-0372 Fax: 301 862-0996
"Mollusks murmured 'Morning!'. And salmon chanted 'Evening!'."-Frank Muir, Oh My Word!
---------- Original Message ----------------------------------
From: "Todd S. Greene" <tgreene@presortservices.com>
Reply-To: "Todd S. Greene" <tgreene@presortservices.com>
Date: Mon, 12 Mar 2001 12:56:23 -0500
>Note to Chuck:
>
>At his website, Robert Gentry provides more detailed information about
>his polonium halo ideas at
>
> http://www.halos.com/book01/book.htm
>
>in an article called "Radioactive Halos in a Radiochronological and
>Cosmological Perspective." Proceedings of the 63rd Annual Meeting of
>the Pacific Division. American Association for the Advancement of
>Science 1, 38.
>
>See also "Fingerprints of Creation" at http://www.halos.com/finger.htm
>where Gentry discusses some of Kurt Wise's criticisms regarding these
>halos being good arguments for a young earth.
>
>Regards,
>Todd S. Greene
>http://www.geocities.com/Athens/Thebes/7755/
>
>
>
>###### Chuck Vandergraaf, 3/8/01 10:11 AM ######
>The web page that Gentry refers to ( http://www.halos.com ) does not say
>very much. I don't understand how he can decide that the halo is due to
>Po-218 that, by his own admission, has a short half life (3 minutes).
>Po-218 is formed by alpha decay from Rn-222 which in turn is formed by
>alpha decay of Ra-226 and the "ultimate parent" is U-238. The end
>product of this decay scheme is Pb-206. Thus, there is a constant supply
>of Po-218 and I would expect to find Po-218 in my lungs as a result of
>breathing trace amounts of Radon gas. Granite contains typically ~5 ppm
>U and, with time, these daughter products will be formed. Even if there
>is no U-238 in the immediate vicinity of the halo, the mineral that
>contains the halo could have been crystallized with a trace amount of
>Ra-226 or even Rn-222. But, maybe I'm missing something in his argument.
>Regardless, the natural reactor operating at Oklo, Gabon is, to me,
>proof positive that the earth is very old because nuclear chain
>reactions are not possible with the current U isotopic composition.
>
>
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