Speed of light slowing down?

Seeing all these Big Bang questions has reminded me about something I wanted to ask: I stumbled across a pretty good documentary about two years ago on British TV. This student physicist had theorised that the speed of light was actually slowing down very slowly and this explained many unanswered questions. I’ll skip the details (to do with Expansion Theory), but basically he said that the speed of light could be slowing down. This would explain a certain amount of redshifting of galaxies but also sets up a very neat view of the universe:

His theory resurrects one of Einsteins forgotten and, in Einsteins view, wasteful, studies: ‘the cosmological constant’. As the speed of light slows, tempered with the cosmological constant it would create energy - energy which might explain how matter came into being. Matter would then radiate into nothing over time before once again light caused another beginning. They said the cosmological constant was like a void, so creation of the universe goes thus: First there was a void, then there was light, then there was matter, then there was a void, then there was light, etc.

A couple of weeks ago I saw a report saying that light coming from distant quasars appeared to leave the quasars at a different speed to our current light speed.

Does anyone know anything about this theory? Can someone clarify it for me, because my explanation is probably pretty bad (I’m no physicist)? Does it hold up?

I have absolutely no ability to inform your discussion or to begin to answer your question. But I am impressed as hell at myself because I have wondered this for a long time. Since “discovering” that the speed of light is the absolute speed limit in the universe, and basing numerous theories on the assumption that the speed of light does not vary, scientists have, it seems to me, been guilty of constructing a scaffolding of ideas that may be wrong. What if -Just what if the speed of light has not been a constant through history. Wouldn’t that obviate or negate many of the fundamental ideas that cosmologists work with? And wouldn’t they, in turn, force the evaluation of all those postulates and theories that are based on those fundamental ideas?

I also am not competent to answer your question. However, I wanted to point out that I also heard recently (on NOVA or some such show) that Einstein’s discarded “cosmological constant” theory was being revived in connection with the dark-matter/dark-energy/missing-mass question.

Just thought I’d share this link:


the speed of light is slower in optical fibres is it not? about 2/3 or so.

Of course physcists have just recently been able to intentionally slow down the speed of light.

I was always curious as to how, if at all, this would affect the ever popular E=MC[sup]2[/sup].

Of course physicists have just recently been able to intentionally slow down the speed of light.

I was always curious as to how, if at all, this would affect the ever popular E=MC[sup]2[/sup].

Wait - first I’m tickled pink that I came up with an idea that’s being batted around on NOVA, and then, thanks to Chekmate, I’m classified with the creationists. Boy, talk about going from sugar to shit!

This is why it is better to refer to c as Einstein’s constant (like Planck’s constant h, or Boltzmann’s constant k[sub]B[/sub]) instead of the speed of light.
Einstein’s constant is the speed of light in a vacuum. But the speed of light in other mediums is different. The c in E = mc[sup]2[/sup] does not depend on the medium that light is traveling through. In fact, it doesn’t depend on the speed of light at all–Einstein’s famous equation is not about light, but matter and energy, and Einstein’s constant is just a conversion factor.

As for the OP, everything of physics that I’m familiar with assumes that Einstein’s constant is truly constant. I’m not sure what effect a gradient in it would have on space-time. However, I should mention that until recently, there was no credible evidence that the constant changes.

It’s a while since I looked at the Albrecht and Magueijo paper and I don’t remember the details, but they are very up front about that the model necessarily screws up GR. I can’t remember which of the principles involved they throw out, but to my taste the result sure ain’t pretty. Worth someone kicking it around, but not theoretically compelling.

Link saying that the physical constants of the universe have not changed over time

no recent indication of light slowing down

another no

some consequences if light had been faster in the past

more reading about whether the speed of light is constant (in general)

Thanks for the links. Pretty useful. I don’t think the theory has anything to do with creationist priniciples by the way.

The link about the consequences of light being faster in the past are interesting - especially about expansion. Expansion is fairly problematic as we see it now (with light-speed a constant over time) because parts of the galaxy would have been expanding at over the speed of light. It’s also worth noting that some of the links contain reports which are older than the more recent observation I noted concerning quasars (only reported in the last month or so - but I haven’t heard of it since).