Constant of light

**Chaigidel** · May 07, 2007, 04:25 PM

I dont have the article but recently i read that scientists discovered that ancient light was moving at a different constant than modern light so the constant of light has not been constant since the universe began its apparently mutable depending on something :O--- any thoughts on the constant of light not being constant?

**Darth Wong** · May 07, 2007, 04:27 PM

When they say "ancient", they are referring to light in the first few instants of the universe, when the universe was very small and very hot and very dense. They're not saying that the speed of light changes all over the place for no reason.

**Chaigidel** · May 07, 2007, 04:36 PM

oh I know that of course our constant of light is preserved- it is constant now-- but will it change in the future?

**Darth Wong** · May 07, 2007, 04:41 PM

Originally Posted by Chaigidel

oh I know that of course our constant of light is preserved- it is constant now-- but will it change in the future?

All kinds of things won't work or will behave much differently if the constant of light changes too much. Things like nuclear reactions, for example. And gravity. It's all inter-connected. Imagine a really complicated computer program where 90% of the code is related to a single constant "c". Change that constant and everything goes haywire.

**~~Ummon~~** · May 07, 2007, 04:42 PM

c infact changes according to the medium light trespasses, and therefore speed of light in water is different from speed of light in glass, which is different from speed of light in void.

**Darth Wong** · May 07, 2007, 04:45 PM

Originally Posted by Ummon

c infact changes according to the medium light trespasses, and therefore speed of light in water is different from speed of light in glass, which is different from speed of light in void.

True, but I think he's referring to some of the research indicating that the speed of light in vacuum might have been a few percent off during the early period of the universe.

**~~Ummon~~** · May 07, 2007, 04:46 PM

As you said though, the properties of "void" might have been different by then.

**Darth Wong** · May 07, 2007, 04:47 PM

Oh yes, I see what you're getting at now.

**ajm317** · May 07, 2007, 05:00 PM

Just to nitpick, c does not depend on the medium, the speed of light does, but in those situations the speed of light is not c. The constant c is the speed of light in a vacuum.

There are studies which seem to indicate that c HAS been changing, or at least was changing. These studies in general have nothing to do with the optical transmission properties of the universe in the distant past, as generally they work by measuring the fine constant, which in turn depends upon c.

**~~Ummon~~** · May 07, 2007, 05:03 PM

Yes, you are right. Often simplification gets in the way of correct expression. At least in my case, models replace facts all too often.

**ajm317** · May 07, 2007, 05:16 PM

I don't believe there is much of a consensus regarding whether or not c has changed, although I'm certainly no expert on the subject. Most scientists believe that it is NOT changing now, and that it will not change in the future, although there are desenters even on this I believe.

All I really know is that there are a few studies which say c is changing, but you can always question the method used to obtain those results or the conclusions drawn from them. Scientists are reluctant to accept that c is not constant because it would require a major reworking of, among other things, the standard model.

**Darth Wong** · May 07, 2007, 05:21 PM

It should be noted that a lot of religious people are trying to twist this research to pretend that it supports a young Earth. What they don't realize is that if the speed of light was millions of times faster in the past (as is necessary to support their incredibly compressed cosmological timeframe), then everything would have been different. The laws of physics would have been so radically different that no life could have possibly existed, the Earth would not form in its current configuration, the Sun would not work the same way, etc.

**ajm317** · May 07, 2007, 05:26 PM

Yes, well, although I'm sure creationists would love to dump their "light trails" the fact is that I don't think there's any evidence that the speed of light has changed that much. I don't know that it particularly matters if the earth could form, but if they're trying to explain why we can see stars from billions of light years away, well THOSE wouldn't form either most likely.

**Chaigidel** · May 07, 2007, 06:46 PM

blagh please god dont drop that yella cake....

creationists will latch onto anything because the science is simply not there for them so they try to attach themselves to unresolved issues...