claim from anti-science booklet << But it is a known fact among scientists that such changes in decay rates can and do occur. Laboratory testing has established that such resetting of specimen clocks does happen. Field evidence reveals that decay rates have indeed varied in the past. >>
Answered again by
Dalrymple,
The Age of the Earth:
The assumption is that the rate at which decay proceeds in any given nuclide is either unalterable or that variations are quite negligible over a wide variety of physical and chemical conditions and for millions or billions of years of time. How reliable is this assumption? Unless there has been some undiscovered change in the fundamental nature of matter and energy since the universe formed, the presumption of constancy for radioactive decay is eminently reasonable (Dalrymple [1991], page 86-87). There are two basic reasons for this:
– the nuclei of atoms are extremely small and well insulated by their cloud of orbiting electrons; these electrons separate nuclei and thus cannot interact; they also provide a “shield” that prevents ordinary chemical or physical factors from affecting the nucleus. Chemical activity in an atom occurs almost entirely among the outermost electrons and does not involve the nucleus at all.
– the energies involved in nuclear changes are 10^6 times greater than those involved in chemical activity, and 10^4 to 10^5 times greater than energies that bind the electrons to the nucleus. This is why nuclear reactors and powerful particle accelerators are required to penetrate and make changes in atomic nuclei. Except in nuclear reactions, such energies are generally not available in natural processes such as those that form, change, or destroy rocks on the Earth and Solar System (Dalrymple [1991], page 87).
Several experiments have been conducted attempting to seriously change radioactive decay rates, those of Rutherford / Petavel in 1907 on 220Rn radon using a steel-encased cordite bomb: they observed no change in the activity of the sample even though the explosion generated an estimated temperature of 2,500 degrees Celsius and a pressure of 1,013 bars; and that of Madame Curie / M. Kamerlingh Onnes in 1913 who lowered the temperature of a radium compound to -252.8 degrees Celsius (the boiling point of liquid hydrogen) and observed no change in the radium activity by more than 0.05% (Emery 1972; Hopke 1974).
Other experiments involved varying gravity by measuring the rates on mountain-tops, in the depths of mines, by whirling in a centrifuge, or subjecting to magnetic fields as much as 8.3 Teslas. These early experiments and subsequent ones involving extremes of temperature, pressure, chemical state, electrical and magnetic fields have uniformly failed to induce any changes in the decay rates of a wide variety of alpha and beta emitters involved in radiometric dating (Dalrymple [1991], page 87-88).
However, tiny changes in decay rates are theoretically possible. Example: The maximum difference in activity yet found between any two beryllium Be compounds is 0.18%. Although chemically induced changes in the electron capture (e.c.) decay rates of zirconium 89Zr (0.08%) and strontium 85Sr (0.005%) have been reported (Emery 1972), 7Be is the only isotope for which changes have been observed by more than one investigator (Hopke 1974).
In summary, both theory and experiment have shown that changes in alpha, beta, and e.c. rates (the three main types of radioactive decay) are not only rare but exceedingly small. Even the largest observed change of 0.18% in beryllium 7Be would have a negligible effect on a calculated radiometric age. Also important is the fact that no changes have ever been detected in any of the isotopes used for dating and none of significance are theoretically expected.
Of the physical and chemical processes that affect meteorites and rocks from the Earth and Moon, including pressure, temperature, gravity, magnetic and electric fields, none should affect radioactive decay to any significant degree. The assumption of constant decay rates is further strengthened by the consistency of the dating results received using the various radiometric methods (all “ticking” at different “clock” rates) from the past and present (Dalrymple [1991], page 89-90).
Dalrymple, G. Brent. 1991.
The Age of the Earth (Stanford Univ Press).
Emery, G. T. 1972. “Perturbation of nuclear decay rates.”
Annual Reviews of Nuclear Science, vol 22, pages 165-202.
Hopke, P.K. 1974. “Extranuclear effects on nuclear decay rates.”
Journal of Chemical Education, vol 51, pages 517-519.
Another
tiny objection answered.
Phil P