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Residual radiocarbon in an old-earth scenario.

Radiocarbon dating of ancient organic material is based on the radioactive decay of [sup.14]C, with a half-life of 5730 years, or with a decay constant ln2/(5730 years) = 0.121 per millennium. After 100 millennia, the [sup.14]C has decayed to an undetectably minute fraction of its original value (less than 6 millionths). However, in rocks or minerals millions of years old, contamination by modern carbon or other processes may introduce tiny amounts of [sup.14]C. To interpret these as due to decay of original organic [sup.14]C, and thus to get an apparent age, is quite mistaken. (1)

Recently, Rogland has reinterpreted some data, cited by young-earth creationists, on minute fractions of [sup.14]C in samples dated by other methods as being 0.4 to 2000 million years old. (2) He considers as a possibility that this [sup.14]C is indeed a remnant of original organic [sup.14]C, but that it has not been decaying with a constant rate constant. Instead, a decay equation of stretched exponential form is proposed, N = exp ([-At.sup.1+B]).

The similar Kohlrausch-Williams-Watts (KWW) equation (3) accurately describes the decay or relaxation of stress in some viscoelastic materials after they are stretched, or the analogous relaxation of charge in a dielectric. A viscoelastic polymer, with a broad distribution of molecular weights, has a spectrum of relaxation processes, each with a relaxation time, the analog of the decay constant. When the relaxation processes have gradually decreasing strength as their relaxation time increases, the KWW equation represents their total effect well. However, radioactive decay is entirely different: there is no distribution of atomic weight of the decaying nucleus. Rather, the one decay process has a single decay constant, leading to simple exponential decay. Accordingly, in teaching or presentations on dating, (4) one should keep to the accepted understanding of radioactive decay, without mention of the stretched exponential as an alternative.

Maybe we should focus instead on how much change there is in intervals we experience, such as a year or a lifetime. Because of God's faithfulness in sustaining his creation in a stable way, we see little change in nature during such an interval. The ancient Bible writers, who had no technology to measure tiny changes due to processes taking thousands or millions of years, may have expressed this stability symbolically by attributing life spans of many ordinary lifetimes to the patriarchs (Genesis 5, 11). While the total of several thousand years may then have been effectively infinite to the Bible writers, to our generation with scientific knowledge of Earth's past going back billions of years, it seems short. Instead of debating vainly about ages, we should rather heed the biblical call to stewardship of creation in the light of scientific understanding of Earth's history, as we view its destruction in our lifetime extending from atmosphere to zoosphere.

Notes

(1) R. Isaac, "Assessing the RATE Project," PSCF 59, no. 2 (2007): 143-6.

(2) R. Rogland, "Residual Radiocarbon in an Old-earth Scenario," PSCF 59, no. 3 (2007): 226-8.

(3) Wikipedia, http://en.wikipedia.org/wiki/Stretched_exponential_function. Accessed October 31, 2007.

(4) D. A. Young, "How Old Is It? How Do We Know? A Review of Dating Methods," PSCF 58, no. 4 (2006): 259-65; 59, no. 1 (2007): 28-36; 59, no. 2 (2007): 135-42.

Charles E. Chaffey

CSCA Fellow

Adjunct Professor of Natural Science

Tyndale University College

25 Ballyconnor Court

Toronto, ON, Canada M2M 4B3
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Title Annotation:Letters
Author:Chaffey, Charles E.
Publication:Perspectives on Science and Christian Faith
Article Type:Letter to the editor
Geographic Code:1USA
Date:Mar 1, 2008
Words:578
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