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"There are things that have been proven conclusively about geologic time, unless you deny that there are any scientific means for testing the age of rocks, such as radiometric dating, a technique many creationists have assaulted as flawed. The criticisms of radiometric dating -- and I've read them -- do not fly by any standard that meets the test of true science. There are such things as "parent" and "daughter" elements within igneous rocks that exhibit constant rates of radioactive decay of isotopes. .... a key part of that knowledge is radioactive decay of isotopes. Radiometric dating under controlled conditions does work and there is not an accredited university offering a degree in Physics anywhere in this country that will deny that. "
***Okay, then how do you reconcile the information below? All of the radiometric dating techniques assume that the speed of light is a constant, which is demonstrably untrue.

Has Speed Of Light Slowed Down?

SYDNEY, Australia, Aug. 7, 2002

(Photo: AP)

"When one of the cornerstones of physics collapses, it's not obvious what you hang onto and what you discard."
Paul Davies, theoretical physicist

Albert Einstein (Photo: AP)

(REUTERS) A team of Australian scientists has proposed that the speed of light may not be a constant, a revolutionary idea that could unseat one of the most cherished laws of modern physics -- Einstein's theory of relativity.

The team, led by theoretical physicist Paul Davies of Sydney's Macquarie University, say it is possible that the speed of light has slowed over billions of years.

If so, physicists will have to rethink many of their basic ideas about the laws of the universe.

"That means giving up the theory of relativity and E=mc squared and all that sort of stuff," Davies told Reuters.

"But of course it doesn't mean we just throw the books in the bin, because it's in the nature of scientific revolution that the old theories become incorporated in the new ones."

Davies, and astrophysicists Tamara Davis and Charles Lineweaver from the University of New South Wales published the proposal in the Aug. 8 edition of scientific journal Nature.

The suggestion that the speed of light can change is based on data collected by UNSW astronomer John Webb, who posed a conundrum when he found that light from a distant quasar, a star-like object, had absorbed the wrong type of photons from interstellar clouds on its 12 billion year journey to earth.

Davies said fundamentally Webb's observations meant that the structure of atoms emitting quasar light was slightly but ever so significantly different to the structure of atoms in humans.

The discrepancy could only be explained if either the electron charge, or the speed of light, had changed.

"But two of the cherished laws of the universe are the law that electron charge shall not change and that the speed of light shall not change, so whichever way you look at it we're in trouble," Davies said.

To establish which of the two constants might not be that constant after all, Davies' team resorted to the study of black holes, mysterious astronomical bodies that suck in stars and other galactic features.

They also applied another dogma of physics, the second law of of thermodynamics, which Davies summarises as "you can't get something for nothing."

After considering that a change in the electron charge over time would violate the sacrosanct second law of thermodynamics, they concluded that the only option was to challenge the constancy of the speed of light.

More study of quasar light is needed in order to validate Webb's observations, and to back up the proposal that light speed may vary, a theory Davies stresses represents only the first chink in the armour of the theory of relativity.

In the meantime, the implications are as unclear as the unexplored depths of the universe themselves.

"When one of the cornerstones of physics collapses, it's not obvious what you hang onto and what you discard," Davies said.

"If what we're seeing is the beginnings of a paradigm shift in physics like what happened 100 years ago with the theory of relativity and quantum theory, it is very hard to know what sort of reasoning to bring to bear."

It could be that the possible change in light speed will only matter in the study of the large scale structure of the universe, its origins and evolution.

For example, varying light speed could explain why two distant and causally unconnected parts of the universe can be so similar even if, according to conventional thought, there has not been enough time for light or other forces to pass between them.

It may only matter when scientists are studying effects over billions of years or billions of light years.

Or there may be startling implications that could change not only the way cosmologists view the universe but also its potential for human exploitation.

"For example there's a cherished law that says nothing can go faster than light and that follows from the theory of relativity," Davies said. The accepted speed of light is 300,000 km (186,300 miles) per second.

"Maybe it's possible to get around that restriction, in which case it would enthrall Star Trek fans because at the moment even at the speed of light it would take 100,000 years to cross the galaxy. It's a bit of a bore really and if the speed of light limit could go, then who knows? All bets are off," Davies said.

There is a debate now ranging among physicists over the constancy of the speed of light. But if you want to introduce this as a challenge to the dating of the earth in billions of years, you are woefully mistaken, because the origin of the observable phenomena that raises the issue is emitted light from a distant part of the universe so far removed from us that it is believed we may be viewing light that is on the nature of 11 to 12 billion years old.

Here is a brief examination of the speed of light controversy as it stood before NASA tested its validity:

Speed of Light Controversy in Brief

This is what the story says about what the origins of the phenomena are:

". . . Studying how light was absorbed by metallic atoms in gas clouds some 12 billion light-years away, researchers found that the fine structure constant, as it is called, may be changing subtly as the universe grows older. The universe is thought to be roughly 13 billion years old, so the light observed in the new study was emitted when the universe was roughly a billion years old. . . ."

And the following is what the article says about the possible impact of the adjustment:

". . . The apparent change in the fine structure constant, also called alpha, was very small, amounting to 1 part in 100,000. . . ."

That would mean extremely small adjustments to radiometric dating techniques, IF the theoretical proposition that the speed of light is NOT constant is proven, more on that in a second. But the way the above change would work is this; for every billion years of geologic time the speed of light would slow about 1,000 miles per hour. That would mean at 4 billion years ago its speed would be about 190,000 miles per second, rather than 186,000, which would be the range of calculation for dating what could potentially be the oldest rocks on earth. This will not move the radiometricaly-derived dates any more than 2 to 4 thousand years at that range, which would be the biggest change one could potentially expect from all of this if the new constant is applied to the dating of the oldest rocks found on earth.

I'm not troubled by this at all.

And by the way, there is an explanation that Paul Davies (who is quoted in the article you posted) and his partner John Barrow are offering to explain why there may be a change in this constant, which is that "the speed of light may have slowed down over billions of years, since the expansion rate of the universe seems to be accelerating." I would like to know if you are comfortable with their explanation.

Now; on the possibility that this theory that the speed of light is not constant, let me say that the best evidence I can find says that they are mistaken. NASA has concluded that the speed of light is NOT slowing. This is what NASA has concluded:

". . . The speed of light, one of the constants scientists rely on to study the universe, appears to have held its ground under some tight NASA scrutiny despite other theories that it may slow as it moves through space.

By comparing gamma ray observations of two nearby galaxies, a NASA researcher found evidence that the speed of light is still traveling as fast as it ever has. The finding reinforces the relevance of Albert Einstein's special theory of relativity, which depends on a constant speed of light as the maximum speed attainable by any object."

I tend to agree with NASA's findings here, but I won't be bothered if it turns out they are wrong. And I am certain that disproving NASA's conclusions, something I doubt will happen, will not have any significant effect on the dating of Geologic Time.

I am aware that many creationist web sites are making all sorts of fantastic claims about this scientific debate, but I would encourage you to pay attention to the science involved here, and I would urge that you be careful in selecting assessments of the impact of this hypothesis as factual and meaningful. A change of "one part in every 100,000" within a constant used in calculating radiometric-based dates is going to be extremely small indeed.