This is a good question; the answer is yes and no, depending on what you think the controversy is over.
There is indeed controversy that the fine structure constant (and hence the speed of light) may have been diffferent in the distant past, however the maximum allowable difference is very small indeed; too small to have a significant effect on nuclear decay rates.
Some lines of evidence:
The emission/absorption spectra of elements can be calculated with physics; the observed spectra are dependent on the fine structure constant. Observations of gas clouds several billion light years away show spectra very slightly different than what is expected from the known value of the fine structure constant, indicating a possibility that the speed of light may have been different in the distant past. Link to article here However, the change that has been observed is on the order of 1 part in 100,000 over a time span of several billion years .
In any case, this is not a large enough change to affect nuclear decay rates, which are also dependent on the fine structure constant, in any significant way. In fact, measurements of the ratios of decay products at the Oklo natural reactor in Africa lend support to the fact that nuclear decay rates have been practically constant through Earth's natural history. ( Another link here; don't infer anything from the title until you read the article - the title is misleading.)
Other independent measurements of the speed of light show that it has maintained a practically constant value for a very long time; pulsar timing measurements show the constancy of the speed of light in the last 100-200 thousand years, at least. As we speak, experiments continue to search for a possible frequency dependence of the speed of light, so far with null results.
The bottom line - what does this all mean for physics laws (and hence decay rates)? It might mean that theories of physics may need some very fine tuning, but no major physics paradigms are about to be otherthrown. ( Another link on the effects these observations might have on physical theories) In fact, practically all "controversies" in physics (and all science, for that matter) involve the slight modifications of a theory to explain new data, not the possibility of overturning an entire general theory that has worked well for a long time. Newton's Laws of Motion, for example, were modified by quantum physics and relativity, not overturned by them; Newton's physics still works as well today as it did when he was alive. The same analogy applies here; our current physical theories may need some slight modification to accomodate the very slight changes we (may?) observe in the speed of light, but the controersy is over a very fine and complicated detail of a more general theory, not over the replacement of any existing physics.
Thanks for the links. That natural nuclear reactor was fascinating. So was the pulsar timing stuff, good writing.
One question before I go into criticism mode: Is the pulsar timing article considered exemplary? i.e., do I have to go & read more of those to get the full picture or will that one do? I do prefer to read both sides of a story but I can't find the rebuttal.
Well, if that article is exemplary, I still see a scientific controversy. Now while it certainly appears to be a slam-dunk against 6000 year creationism, the latest suggestions are playing with light being 2 to 10 orders of magnitude faster at the beginning, so it is conceivable that the universe could be 1 or 2 orders of magnitude younger. That article only disputed 6000 years old creation, not 6M or 600M year old creation.
Evidences of scientific controversy:
http://smccd.net/accounts/brenner/lsci106/ballein.html
LSCI 106: ONLINE RESEARCH 1: INTRODUCTION TO ONLINE RESEARCH
Student Project
RESEARCH QUESTION:
Is the speed of light slowing down over time?
The punch-line to the familiar joke says the only things you can count on are death and taxes. In the scientific world of physics one key fundamental that could be counted on is the speed of light remaining constant at a speed of 186,000 miles a second, over time. Much of physics is based on this assumption. But now “the times, they are a-changin', and so are the fundamental constants of physics, an international group of physicists reports. After analyzing light from distant quasars, the team has concluded that the fine-structure constant, which is related to the speed of light, has shifted over time” (Seife 1410).
Why is this such a big deal? Einstein’s Theory of Relativity would be wrong. The universe would not be as old as previously thought. While scientists cannot find over 90% of the matter needed to make the Big Bang a feasible theory, faster light speeds would explain it while rendering it unworkable. It would agree and substantiate the Second Law of Thermodynamics. Much of astronomical theory would need to be rethought. One thing is for certain…there will be much debate and research regarding the constancy of the speed of light.
http://physicsweb.org/articles/world/11/4/2
In 1989 it was claimed that room-temperature, resonant-bar, gravitational-wave detectors saw events that correlated with supernova 1987A. But in the very paper that announced this finding, M Aglietta and co-workers said that if our current understanding was correct, the energy seen by the detectors was equivalent to the complete conversion of 2400 solar masses into gravitational waves (1989 Il Nuovo Cimento 12C 1 75) The authors agreed that this was incredible, but nevertheless thought they should report what they had found in print in case something odd was going on. Nearly everyone else thought that the result was wrong, and a critical paper was published that tried to show that it was the outcome of inadvertent statistical massage (1995 Phys. Rev. D 51 2644). Last year, in an internal report from the University of Rome La Sapienza, the original authors rejected the criticism.
Consider the deep disagreement about SN1987A discussed above. Observations, better experimentation, more knowledge, more advanced theories and clearer thinking have not settled the argument - at least, not to the satisfaction of all parties. What happens in deep disputes like this is summed up in the grim Planck dictum: scientists do not give up their disputed ideas, they only die.
from wizbangblog:
http://wizbangblog.com/archives/005452.php
Raina said: There actually is some real scientific controversy over whether or not the speed of light has changed.
This would not rescue Young Earth Creationism, note the bold font. Consider SN1987A: SN1987A was a supernova observed in the Large Magellanic Cloud in 1987. (The progenator was a star blue white supergiant catalogued as SK-69 202). SN1987A has a primary gas ring that allows us to calculate it's distance using simple triangulation. That distance is 168,000 light years. Ergo: SK-69 202 blew up 168,000 years ago or about 160,000 years before you believe the univrerse was created if you're defending YEC. So we know the universe is older than 6,000 - 10,000 years years, because in 1987 we observed the light of a super nova which actually occurred in 166,000 BC.
We also know the light from 1987A has not slowed down during transit because if it had, among other enormous physical problems, events on 1987A would be in 'slow motion' and they're not, again direct observation. SN1987A also gives us rock solid evidence that radiodecay processes operated at the same rate in the remote past as they do today. During the super nova explosion exotic isotopes were created with short half lives such as cobalt 56 and nickel 55. We can observe the decay sequence of those isotopes in the spectral emission of 1987A. They match exactly the empirically measured rates on earth which are also the theoretically predicted rates universally applicable in the entire universe. Thus SN1987A is a 'twofer' in falsifying YEC.
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Startling Scientists, Plant Fixes Its Flawed Gene
In a startling discovery, geneticists at Purdue University say they have found plants that possess a corrected version of a defective gene inherited from both their parents, as if some handy backup copy with the right version had been made in the grandparents' generation or earlier.
The finding implies that some organisms may contain a cryptic backup copy of their genome that bypasses the usual mechanisms of heredity. If confirmed, it would represent an unprecedented exception to the laws of inheritance discovered by Gregor Mendel in the 19th century. Equally surprising, the cryptic genome appears not to be made of DNA, the standard hereditary material.
The discovery also raises interesting biological questions - including whether it gets in the way of evolution, which depends on mutations changing an organism rather than being put right by a backup system.
"It looks like a marvelous discovery," said Dr. Elliott Meyerowitz, a plant geneticist at the California Institute of Technology. Dr. David Haig, an evolutionary biologist at Harvard, described the finding as "a really strange and unexpected result," which would be important if the observation holds up and applies widely in nature.
My argument about evolution* is and will always be, that all you loud mouth people who accept as some sort of fact etched in stone that man evolved from some primordial ooze are just as religious as the people you bash.
The truth is --though you are loath to admit it-- that we don't know jack about the origin of the species. If there is indeed some mechanism built into organisms to repair flawed genes, the whole theory -which is already mathematically astronomically improbable- is now a few dozen more orders of magnitude more improbable. There is something other than DNA that apparently carries some sort of genome and we don't even have a name for it yet, much less understand it!
OK, you can now commence to ranting in the comments about how it is a fact and I'm just some ignorant fool. And make sure you bash religious people... If there is one thing I love to laugh at, it is one religious zealot claiming the other guy is just a religious zealot.
* The nomenclature will always bite you. I don't use "evolution" in the strict definition here, I mean evolution as in the theory that lighting stuck inorganic material and started life that a bazillion years later evolved into every life form on the planet. That version of "evolution" is seriously, seriously flawed.... And no amount of your typing in the comments section will make unflawed.