Thanks. This is what I was looking for.
From: Todd S. Greene [mailto:firstname.lastname@example.org]
Sent: Monday March 12, 2001 11:56 AM
Cc: Vandergraaf, Chuck
Subject: Re: halos
Note to Chuck:
At his website, Robert Gentry provides more detailed information about
his polonium halo ideas at
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.
Todd S. Greene
###### 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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