IS THE SPEED OF LIGHT SLOWING DOWN?

I’ve received a number of letters regarding the constancy of the speed of light as discussed in Aristotle, Einstein, and Ayn Rand . They ask about an argument claiming that the speed of light is slowing down.

The basis for asserting that the universe is billions of years old with galaxies billions of light years away is substantially based on what’s called the red-shift. It’s like a train whistle with its sound waves bunched up coming towards you, then the pitch shifts dramatically as the train passes by with the sound waves stretched out. Light waves from sources racing away from us (such as distant galaxies) are shifted towards the infra-red part of the spectrum. The amount of the shift indicates the distance the light source is from us, because the speed increases with the distance.

The claim is that light from distant galaxies is not red-shifted at random but is “quantized,” grouped into “quantum bands.” Light slowing down supposedly causes quantum shifts in the atoms of which these galaxies are composed, and it is this that shifts the light spectra. If this were the case then, it is further claimed the universe could be drastically younger than astronomers assert and the billions of galaxies surrounding us much closer.

Notwithstanding that the gravitational fields of billions of galaxies much closer would be horrendously stronger, the problem is that there is simply no evidence whatever for “quantized red-shifts.” So-called "quantum bands" turn out to be statistical distributions which show clusters of galaxies condensed from the Big Bang. There is an unhomogeneous galactic distribution in the universe with bands of empty space and bands of space crowded with galaxies, caused by plasma acoustic ripples of the Big Bang.

The spectra of light from distant stars shows the same speed of light within far less than one part per million. If this speed were slowing down, then chemical reactions change. Chemical compounds which can be identified in galactic spectra – such as carbon monoxide, formaldehyde, or water vapor – would become unstable and break down. That they have not is ample evidence that the speed of light is not slowing down, and that Einstein’s theory of the constancy of light speed remains valid.