Here we explore some simple implications of the poorly done science supporting the idea of extensive accelerated radioactive decay, specifically those advocated by the ICR in the RATE ("Radioactivity and the Age of The Earth") document and at Answers in Genesis. Accelerated radioactive decay is occasionally invoked by creationists to explain radiometric dating results. By retreating to this position, they are essentially abandoning claims that isochron dating is seriously flawed. Here we examine some simple requirements for accelerated decay to effectively "mimic" the appearance of long ratioisotopic ages and some of the problems with currently proposed mechanisms for accelerating decay rates.
Here we consider two separate sets of claims
There are a number of online resources on the principles underlying radioactive decay.
Rebuttal Links:The articles linked below deal with helium diffusion claims and geology used in RATE.
Page numbers correspond to the RATE document linked above.
|In this graph, we plot the ratio of decay rates for different parent isotopes (Sm-147, Th-232, U-235, U-238) with a changing pion mass. The vertical line at a pion mass 0.749325 times the current value accelerates the U-238 decay rate by a factor of 750,000.0, the amount of acceleration Humphreys requires. We see that with this pion mass, Sm-147 experiences a rate increase of only 28,200, less than 4 percent of the required value. This means that for a given sample, the Sm-147 ages should be significantly less than U-238 ages.|
|Here we combine the pion mass determined above and look for a W-boson mass change to accelerate the decay of Re-187 by the same factor of 750,000. We find a W-boson mass factor of 0.034724 which alters the decay rates of other beta-emitters by significant amounts (though not a dramatic as the pion mass changes). Unfortunately, the scaling makes it difficult to distinguish the different elements. Computed values in the table below.|
The interesting thing about this analysis is that these flaws in Humphreys model were immediately apparent. I identified them on my first reading of the RATE document. The fact that Z and/or A appeared in the rate equations was a dead giveaway that these rates would vary by element and isotope. It took me an evening to estimate these values, an additional few days to explore other implications and generate nice graphics.
These errors were trivial to find. They could be recognized by a bright high-school student, yet none of the Ph.D.s at the ICR, including Humphreys, noticed before they made it into print. This points to a very serious failure in their peer-review process (though it is far from the first...).
At Answers in Genesis (hereafter referred to as AIG) their "model" for decay acceleration is non-existent beyond promoting the experimental work of others as supporting their claims. AIG has propagated some misinformation about recent experiments which suggest radioactive decay rates can vary significantly.
What is it that AIG doesn't tell you?
The authors of the original paper (Dependence of the decay rate of 7Be on chemical forms) make the statement
"The observed difference, by as much as 1.5%, clearly indicates that decay rates of nuclides undergoing electron capture decay are not necessarily constant as has always been assumed in geological, oceanographic, and environmental studies."
The authors seem oblivious to the history of this reaction. That the beryllium-7 decay rate could be influenced by the surrounding electron environment was explored for astrophysical environments by John Bahcall as far back as 1962 (Electron Capture and Nuclear Matrix Elements of Be-7). For Bahcall, this issue was important in the proton-proton chain powering the Sun and other stars as well as understanding the issues of neutrino production. The experiment approximates the electron density of the astrophysical environment in a laboratory setting and successfully demonstrated that electron screening can alter decay rates under these conditions, as predicted over forty years earlier.
In other articles, such as Radioactivity speeds up (September 2004), it's made much clearer that these results are primarily applicable to extreme astrophysical environments:
"Increasing the decay rate by just 0.83% will have little effect on radioisotopes with half-lives of thousands or millions of years. However, Ohtsuki and co-workers say that their results will help identify the sort of environments that increase the decay rate. These could include the high-pressure conditions found inside neutron stars."
While I've yet to find an article at AIG or other creationist organization on this result (A cool solution to waste disposal (July 2006)), I'll include an evaluation here. Here again, we see that different decays will occur at different rates:
"But Rolfs realized that the reverse reaction might also occur and that free electrons could enhance the ejection of positively charged particles from a nucleus. This would reduce the half-lives of alpha-decay or beta+-decay, and increase half-lives for processes involving electrons (which are repelled by the free electrons within the metal), i.e. beta--decay and electron capture."
In the original article (High-Z electron screening: the cases 50V(p,n)50Cr and 176Lu(p,n)176Hf), the authors explain their analysis. I see several problems with their attempts to extrapolate the accelerated decay rates to factors of hundreds and more: