lightspeedYoung earth creationists (YEC) have long maintained that the earth and universe are very young (less than 10K years old!)  primarily based on their reading of the creation story and genealogies of Genesis 1 in the Bible. In order to make this jive with science, they had to claim that our methods of estimating the age of the universe are wrong.

One method of dating the Universe is based on the idea that the speed of light is constant, and travels from distant stars, and so if we are seeing light from distant galaxies, the Universe would have to be that many million years old for us to actually see it.

The YEC solution is to claim that the speed of light has been slowing – so in the past, if light was much faster, the time it would take to get here would be much less. Also, if the stars were created and then stretched out, rather than formed much later after a big bang, the light would have had much smaller distances to travel.

Well, as with any model, you have to test it against real data, right? Is there evidence that the speed of light has been slowing, as shown in the graph above? Strangely, recent research papers say yes. Below are just a few sources discussing the issue, and only the last is from a Creationist site.

Redshift quantization

http://en.wikipedia.org/wiki/Redshift_quantization

Redshift quantization is the hypothesis that the redshifts of cosmologically distant objects (in particular galaxies) tend to cluster around multiples of some particular value. Since there is a correlation of distance and redshift as expressed in Hubble’s Law, redshift quantization would either indicate a quantization of the distances of galaxies from the Earth or a problem with the redshift-distance correlation, either of which would have serious implications for cosmology. Many scientists who oppose the Big Bang theory, including Halton Arp,[1][2] have referred to observations claimed to be in favor of redshift quantization as reason to reject the standard account of the origin and evolution of the universe.

The Scharnhorst Effect claims we’ve got the speed of light wrong

http://io9.com/the-scharnhorst-effect-claims-weve-got-the-speed-of-li-458766433

Faster than light travel might be possible – but only over very small distances. And only because the light speed that we think of as absolute is actually already being slowed down.

Is Light Slowing Down?

http://opfocus.org/index.php?topic=story&v=8&s=4

The speed of light is a universal constant — or is it? Some evidence seems to suggest it might actually be slowing down. Will we soon have to revise our cosmological beliefs?

If light were slowing down, we would have to revise many of our astronomical beliefs: from the age of the Universe to the distances between galaxies, from the dark matter to the definition of many physical constants. What a tremendous set of implications! Some evidence that this might indeed be the case starts piling up, as recently reported by Yves-Henri Sanejouand from the University of Nantes in France

First of all, it was observed by Hubble at the beginning of the XX century that galaxies appear to be moving away from the Earth at a velocity that is proportional to their distance from us. The standard explanation is that galaxies are being thrown apart from the expansion of space-time. Imagine drawing some red spots on a balloon and inflating it, the spots (galaxies) would recede from each other at a speed proportional to their distance due to the dilatation of the plastic (space-time). The drawback of this hypothesis is that it needs to postulate the existence of the famous dark matter, which has never been observed and would still constitute 70% of the Universe’s mass. However, if c were decreasing over time, the Hubble effect would turn out to be a simple optical effect, eliminating the need to postulate the existence of the dark matter, as proposed by P. I. Wold back in 1935.
Another open puzzle in the astronomical community is the so-called Pioneer anomaly. The spaceships Pioneer 10 and Pioneer 11 were sent in the 1970s by NASA to explore the outer planets and then eventually they left the solar system. These are regarded as highly successful missions and have brought in plenty of data, which is still keeping astronomers busy today. However, both spaceships appear to be slightly and inexplicably accelerating towards the Sun, with an acceleration that increases with the distance. Again this can be explained once c is taken as being not constant over time, as Sanejouand recently proposed.

Galaxies Are Billions of Light-Years Away, So Isn’t the Universe Billions of Years Old?

http://www.creationscience.com/onlinebook/FAQ13.html

During the past 300 years, at least 164 separate measurements of the speed of light have been published. Sixteen different measurement techniques were used. Astronomer Barry Setterfield has studied these measurements, especially their precision and experimental errors.1 His results show that the speed of light has apparently decreased so rapidly that experimental error cannot explain it! Montgomery and Dolphin have critically reexamined all of Setterfield’s data, applied various statistical tests, and reached similar conclusions.2 In the seven instances where the same scientists remeasured the speed of light with the same equipment years later, a decrease was always reported. The decreases were often several times greater than the reported experimental errors.

Russian cosmologist, V. S. Troitskii, at the Radiophysical Research Institute in Gorky, also questioned some old beliefs. He concluded, independently of Setterfield, that most red shifts of distant starlight are the result of the slowing speed of light, and at the beginning the speed of light was 10 billion times faster at time zero!8 Furthermore, he attributed the cosmic microwave background radiation to this rapidly decreasing speed of light. Setterfield reached the same conclusion concerning redshifts by a different method. If either Setterfield or Troitskii is correct, the big bang theory will fall (with a big bang).

Several of their theoretical problems with the big bang theory are solved if light once traveled millions of times faster. For example, “the horizon problem” recognizes that opposite extremes of the universe have the same temperature. Why should this be? The universe isn’t old enough for such vastly separated regions ever to have had contact with each other. Light doesn’t travel fast enough—at least not today.

Atomic vs. Orbital Time. Why would the speed of light decrease? In 1981, T. C. Van Flandern, working at the U.S. Naval Observatory, showed that atomic clocks are probably slowing relative to orbital clocks.10 He wrote:
The number of atomic seconds in a dynamical interval (such as a revolution of the Earth about the Sun) is becoming fewer. Presumably, if the result has any generality to it, this means that atomic phenomena are slowing down with respect to dynamical phenomena. … we cannot tell from existing data whether the changes are occurring on the atomic level or the dynamical level.

Orbital clocks are based on orbiting astronomical bodies, especially Earth’s one-year period about the Sun. Before 1967, one second of time was defined by international agreement as 1/31,556,925.9747 of the average time it takes Earth to orbit the Sun. However, atomic clocks are based on the vibrational period of the cesium-133 atom. In 1967, a second was redefined as 9,192,631,770 oscillations of the cesium-133 atom. Van Flandern showed that if atomic clocks are “correct,” the orbital speeds of Mercury, Venus, and Mars are increasing, so the gravitational “constant” should be changing. He also noted that if orbital clocks are “correct,” the gravitational constant is truly constant, but atomic vibrations and the speed of light are decreasing. The drift between the two types of clocks is only several parts per billion per year. But again, the precision of the measurements is so good that the discrepancy is probably real.

For the following three reasons, orbital clocks seem to be correct and the frequencies of atomic vibrations are probably slowing very slightly.

  • If Van Flandern’s studies are correct, the gravitational “constant” should be changing or else atomic vibrations are slowing slightly. Other studies have not detected variations in the gravitational constant.
  • If a planet’s orbital speed increased (and all other orbital parameters remained the same), the planet’s energy would increase. That would violate the law of conservation of mass-energy.
  • If atomic frequencies are decreasing, then five “properties” of the atom, such as Planck’s constant, should also be changing. Statistical studies of past measurements show that four of the five “constants” are changing—and in the right direction.2

So, orbital clocks seem to be more accurate than the extremely precise atomic clocks.