What if the speed of light (c) is not the absolute constant that we have always thought it to be?

Question

Recent experiments have shown that the velocity of light can be increased and decreased. What if c is a function of the rate of expansion of the universe? Any thoughts?

What if the speed of light (c) is a function of the rate of expanson of the universe. Since the rate of expansion is increasing (even if ever so slightly)--the change in c would be infintisimal. But I have not been able to employ this into the equations of general relativity.?????

Answer 1

If c were variable in any way, it would probably have a huge impact on cosmology and the Big Bang theory.

Do not confuse experiments in which light is made to move at different speeds with changing the universal constant c. The speed of light varies with the medium it is traveling through. Recent experiments with Bose-Einstein condensates have slowed light to a crawl. Other experiments have shown that the group velocity (Google it if you're interested) of a light wave can exceed c.

c is a property of space itself, and we know of no ways to change it. However, some experiments have suggested that the fine structure constant, of which c is a part, may change over time. The change, if it's real, is only a few thousandths of a percent, but even that would rewrite cosmology and general relativity. The link below has the story.

Answer 2

"Speed of light may have changed recently"
30 June 2004
Exclusive from New Scientist Print Edition.

excerpt from article:

"A varying speed of light contradicts Einstein's theory of relativity, and would undermine much of traditional physics. But some physicists believe it would elegantly explain puzzling cosmological phenomena such as the nearly uniform temperature of the universe. It might also support string theories that predict extra spatial dimensions.

The threat to the idea of an invariable speed of light comes from measurements of another parameter called the fine structure constant, or alpha, which dictates the strength of the electromagnetic force. The speed of light is inversely proportional to alpha, and though alpha also depends on two other constants (see graphic), many physicists tend to interpret a change in alpha as a change in the speed of light. It is a valid simplification, says Victor Flambaum of the University of New South Wales in Sydney.

It was Flambaum, along with John Webb and colleagues, who first seriously challenged alpha's status as a constant in 1998. Then, after exhaustively analysing how the light from distant quasars was absorbed by intervening gas clouds, they claimed in 2001 that alpha had increased by a few parts in 105 in the past 12 billion years."

For full article, go to source website.

Thus far, as the article states, "it is a valid simplification" to say that the speed of light has changed. The prime outcome, IF this is true, would likely be a new direction in thought regarding the possible inter-relation between the electromagnetic and gravitational forces, of primacy to the quest for the Grand Unified Theory, the ultimate descriptive goal of physics.

Answer 3

The speed being relative, wouldn't variations in time contract and expand in relation to the velocity of the expansion of the universe. There is no constant time. Rather, use the size of universal expansion as the constant to explain the conditions in a set point.

For example: if the universe is 3 feet across, the relation of energy to mass, is different then if the universe is 4 feet across.

Try looking at it that way, and prediction becomes alot easier.

Answer 4

It has been proved that light is affected by temperature: lower temperatures slow down movement of not only matter but photons as well. Not significantly, unless the temperature difference is enourmous. Light also moves faster at higher temperatures - again just like matter: the very differentiation between solid, liquid, gas, and plasma is the movement of the matter in those states. Light moves faster at higher temperatures.
Now, as to the speed of light as a function of the rate of expansion of the universe: it would seem that the relative expansion of the universe with itself would make it irrelevant to create such a function for c. It would be impossible for us to find the rate of such expansion and apply it to the speed of light, because the rate of expansion is non-existent to our perception (at least a rate of expansion as all inclusive as to include even photons). That does not mean it is not true, just impossible or improbable for us to find out right now. However, finding such a function would be extremely benificial; what constants could there be in such a function, and where else do they apply to our universe.

Answer 5

The speed of light varies depending on the medium through which it passes. That's what causes refraction. Einstein's theory holds that it holds the speed record in a vacuum. Recent experiments claiming to have made light go faster, have done so only in rare gases and the top speed through the gas was not as fast as when light travels in a vacuum.

The speed of light is not a fuction of the rate of expansion, it is a rate of propagation and the particles we see as light do not travel at that speed. Electrons whizzing through a wire do not travel individualy at the speed of light. They push over the ones next to it and this continues on down through the wire and the net effect can be measured as happening at c, yet each electron moved very little distance.

Can something ever beat out c? I hope so...I love the idea of intergalactic travel a la Star Trek in a faster than light space ship. But so far....no.

Answer 6

Thats really interesting thought. If this were true, which has been shown to be the case in labs, then it would prove that time is the actual 4th dimension. Did you come up with this thought on your own, or read it somewhere?

Answer 7

The article I read about that said that the laws involving the speed of light actually predicted that what happened would happen.

Answer 8

Thinking like that could put Quantum Physics on its ear.

Answer 9

C Squared.

Answer 10

good question, anything is possible, and why not. if you speed up light then you are braking all the rules. cant have that! and why not. the world is flat you know.