## Friday, June 01, 2007 ... //

### Varying Speed of Light (VSL) theories: crackpots par excellence

The archives and sometimes even journals are continuously flooded with new articles about a theory that was originally invented by young Earth creationists to reconcile the Bible with the Big Bang and that was later adopted by non-Christian crackpots, too. It is called

• Varying Speed of Light (VSL) theory
George Ellis has decided that there should exist an authoritative, published article explaining why all this VSL industry is complete crap. I fully agree. If this nonsense keeps on appearing all the time, there should exist some reactions that can be referred to. He mentions virtually identical arguments that I always say about these VSL theories:
• Their authors don't understand that one can always change her units. They don't know what's the difference between dimensionless and dimensionful quantities.
• The meter is moreover defined as 1/299,792,458 of a light second, so according to current definitions, a varying speed of light is simply a contradiction.
• One doesn't gain anything whatsoever by redefining the speed of light in a time-dependent fashion because it is just a time-dependent change of units (or coordinates in GR).

• When the speed of light is allowed to be different for various phenomena, we need to determine the right modifications in all equations of physics, including Maxwell's equations and others. No VSL paper is doing anything like that.
• Moreover, one expects to end up with a generic non-relativistic theory with infinitely many parameters. The VSL papers never offer any principle that would replace the broken Lorentz symmetry and determine these parameters. They don't even acknowledge this problem.
In other words, VSL theories are 100% vacuous and stupid crap.

Tonight, Magueijo and Moffat have submitted an answer that have made me so upset by its breathtaking stupidity that I simply had to write this text to calm down. ;-) They don't understand a single one among Ellis' obvious complaints. Instead, they paint themselves as new Galileos because they are ready to make a constant variable.

Important physics has never worked like that. Quite on the contrary. Every new major revolution in physics has shown that a certain conversion parameter was not only constant but it was meaningful to set it equal to one.

Joule has figured out that heat and energy can be transformed to each other. We can thus use the same unit for both quantities: to celebrate his discovery, we call the international unit a Joule.

Einstein has found out that space and time are equivalent. This allowed him to declare "c" to be a universal constant. Moreover, all adult physicists who need relativistic phenomena use units where "c=1". This choice also implies that mass and energy are essentially the same thing.

Analogously, quantum physics is closely associated with Planck's constant. Frequencies are the same thing as energies. Adult physicists set "hbar=1". In quantum gravity we may also set Newton's constant "G=1" although in perturbative string theory, it is more natural to set "alpha'=1".

We no longer need degrees to measure angles because rads make equations simpler. Also, we don't need Avogadro's constants and moles because we can count individual atoms and molecules which are better "units" than moles. The number of constants we need to write into our equations decreases.

Making constants variable is going exactly in the opposite direction than what progress in theoretical physics has always been doing. The only "constants" that should be variable are those that depend on some parameters of the environment. But such a declaration of their variability is only interesting once we understand how the environment actually works. Saying that quantities should become variable without understanding how they vary is a meaningless sleight of hand but certainly not a complete theory of anything.

A very similar criticism applies, to a lesser extent, to doubly special relativity etc. The people who work on all these stupid things have a tremendous problem to distinguish physics from conventions, predictions from ways of writing things, deep insights from vacuous sequences of mathematical symbols. They don't understand what a choice of units and field redefinitions means and why they're unphysical. Despite all of their profound ignorance about basics of physics, these crackpots are extremely arrogant (Magueijo is the #1 example, of course) - they view themselves as competitors of inflationary cosmology and many other key segments of science - which makes me quite upset. ;-)

And that's the memo.

#### snail feedback (9) :

'Space expanded' is the orthodox explanation for the apparent disjoint between the approx 14 billion years apparent age of the cosmos, vs the 35 billion lightyear apparent minimum radius of the size of the cosmos.

What happens to c if the 'space' that light is traveling in is expanding?

I'd be interested in reading up on any material on that question. Does anyone know of any?

reader L. Frank Morgan said...

Seldom find more clarity on the subject of physics; think you miht like some of what is posted at www.geocities.com/CapeCanaveral/Hall/2638/

Frank Morgan, Newhall, CAnb

I am one of these crackpots. You seem to be unaware that Einstein was the first to propose a VSL theory to describe gravity. See my comment 0708.2927 on Ellis' paper.

Alexander

reader Luboš Motl said...

Dear Alexander, let me confirm wholeheartedly that you are indeed a crackpot. I doubt - but strictly don't know - whether Einstein sometimes wanted to make the speed of light variable but what I am certain is that this fact is completely irrelevant.

Every decent graduate student today understands these things better than Einstein did simply because science has made some progress. Please choose religion instead of science if you really think that these dumb references to ancient authorities are relevant for science.

Variable light speed concept is dual to the light invariance, as everybody can see at the case of gravitational lensing.

Dear Lumo,
you are saying that you doubt though you don't know - thus religion appears to be *your* business - I however gratefully accept the blessing as a crackpot.
The tremendous progress of modern physics created by all these decent graduate students yielded Einstein's theories marginal, right? Certainly you must be such a child of prodigy since you learned writing before reading and speaking before thinking.

the constant of light does not change,but the speed at which light travels does change.

in other words there is a natural rate/meter at which light travels,but the speed at which light can travel does change.

an apt analogy would be a car which can only travel at speeds of prime numbers,the velocity of the car will change but it will stick to a constant ratio,an underlying
scale.
if the speed of light did not change then diffraction within prisms would be impossible.
futhermore it would be impossible for a bose einstien consensate to slow down light to a relative standstill,it does.

so there is speed of light constant,but no limits to the velocity of light,EM waves can travel at post light speeds,non sranding scalar waves.

furthermore the speed of light should rather be called the speed of space time,which is the constant barometer of all matter and wave travelling through it.
space time is the constant,not light.
thefore the constance of light you refer to is actually the relationship betwee an EM wave and space time.

For someone that thinks variable constants are heresy, can we just take a look at quantum field theory for a moment? As a physicist, I've studied a lot of physics, and like you've said, there are a lot of constants. HOWEVER, even in very modern theories, like QED, constants do vary! Take your prime example, the constant alpha. I think if you took the time to study physics, you would find that alpha is a running constant. i.e. IT VARIES.

If there are variable constants in modern theories that work really well, then why can we not vary constants like c? I suggest you go and get a decent degree in physics, and be a little more open minded to new theories.

reader D. B. said...

what about an open system approach? Instead of considering a local reversible theory, why not local dissipative? There are plenty of known theorems in quantum information theory that shows that the propagation of information can become time dependent where there is local dissipation.

just throwing it there, ..., please be gentle

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