Physical constants are only assumed constant (Talk.Origins)
Physicists only assume that physical constants have been constant over billions of years. In particular, this untestable assumption underlies all radiometric dating techniques.
Source: Brown, Walt, 1995. In the Beginning: Compelling Evidence for Creation and the Flood. Phoenix, AZ: Center for Scientific Creation, p. 24.
It needs to be noted that decay rates are the only attributes of an atom that need to be varied to produce accelerated decay. It is theoretically possible to induce accelerated decay without affecting basic physical constants. These could occur as a result of some agent that is not normally a factor in decay rates
(Talk.Origins quotes in blue)
1. The constancy of constants is a conclusion, not an assumption. It is tested whenever possible. For example:
- The fine structure constant affects neutron capture rates, which can be measured from products of the Oklo reactor, where a natural nuclear reaction occurred 1,800 million years ago. These measurements show that the fine structure constant has remained constant (within one part in 1017 per year) for almost two billion years .
- Despite some weak evidence that the fine structure constant may have varied slightly more than six billion years ago (Musser 1998; Webb et al. 1999), analysis of the spectra of quasars shows that it has changed less than 0.6 parts per million over the last ten billion years.
The fine structure constant is defined as:
None of the constants that define the fine structure constant are likely candidates for variability during an accelerated decay event. They affect too many other physical properties. Furthermore while the fine structure constant affects neuron capture rates, it is not the only factor that does so. This would be particularly true inside a fission reactor.
Reference: Fine structure constant - Wikipedia
Furthermore, Talk.Origin's is only telling one side of the story. Chaffin showed that though the change in well depth is very small (not nonexistent as Talk.Origin puts it), " even these small variations could allow the U-238 half-life to vary by more than one order of magnitude." So the Oklo reactor is actually PROOF of accelerated decay.
Chaffin. The Oklo Constraints on Alpha-Decay Half-Lives. American Physical Society, The 70th Annual Meeting of the Southeastern Section, November 6-8, 2003, Wilmington, North Carolina.
- Experiments with atomic clocks show that any change is less than a rate of about 10-15 per year.
This does not preclude some past events the may have temporarily affected their rate, assuming that accelerated decay would affect an atomic clock.