Paul Davies suggests light speed is slowing down. (http://aca.mq.edu.au/lightspeed.html)

Needless to say this is a major result if found to be correct. Time to rewrite the rule books in fact. Doubtless this will be debated incessantly on news://sci.physics and news://sci.physics.relativity

Another link for the same, at New Scientist (http://www.newscientist.com/news/news.jsp?id=ns99992650).

This Davies guy seems suspect to me. Some of his statements like "One assumes that these are God-given, fixed numbers" sound very amateurish and aren't very scientific.
Also, from CNN,
"That means giving up the theory of relativity and E = mc2 and all that sort of stuff".
We should completely give up on the theory now? This guy is prone to a knee jerk reaction.

His suggestion that light speed was infinte at the time of the big bang makes no sense to me...perhaps that should be a new thread.

The CNN article itself was overly dramatic as usual.

No doubt this is something to be studied but it doesn't sound like we have anything close to conclusive evidence yet.

When I suggested that the speed of light is not an independent constant, but a constant derived from two other constants (electric permittivity and magnetic permeability), I was told I was wrong.

http://www.sciforums.com/t9142/s/showthread.php?s=&threadid=9142&perpage=20&pagenumber=1

James and Tom2, who's wrong now???:)


Tom

Originally posted by Prosoothus
When I suggested that the speed of light is not an independent constant, but a constant derived from two other constants (electric permittivity and magnetic permeability), I was told I was wrong.

http://www.sciforums.com/t9142/s/showthread.php?s=&threadid=9142&perpage=20&pagenumber=1


What on Earth does this have to do with the time-variation of the speed of light?


James and Tom2, who's wrong now???:)


I'm sure James can answer for himself, but as for you and I, we were talking about whether QED is more fundamental than Maxwell's Electrodynamics.

As far as that goes: Don't worry, you're still wrong. :)

Tom2,

You were claiming that the c was an independent constant. This would mean that the speed of light would have always had to have been 300,000 km/s.

I, on the other hand, suggested that the speed of light in a vacuum is dependent on the electric permittivity and magnetic permeability of empty space. Therefore, if the electric permittivity or magnetic permeability of empty space was smaller in the past, then light would have traveled faster in the past.

My suggestion would explain why it would have been possible for light to travel faster than 300,000 km/s in the past, yours does not. :)

Tom

Sorry Tom, you're parading your closed mindedness in public again.

If this datum is shown to be correct it only shows that a new physics is needed in extreme circumstances in the same way that Einstein superceded Newton. Einstein still holds in the same circumstances just as Newton does. It's been well known amongst Physicists that Einstein will be overruled by a new Physics eventually. Only complete loons see evidence like this as evidence of their pet theorems against Einstein.

If Davies is right, more power to him. It will help advance our understanding of the cosmos. Unfortunately, people like you, Tom, will forever ridicule legitimate attempts at disproving current ideas.

Of course anyone, like Tom2 and james R, who has studied QED and maxwell, knows that c is dependant on the permeability and permuabilty of free space. This result of Davies, if true, also means that these two fundamental constants are variable in time.

I have yet to see Proosoothus, AKA tom, forward a theorem explaining how these constants vary in time.

Thed,

You always find a way to make me laugh.

My quote:

I, on the other hand, suggested that the speed of light in a vacuum is dependent on the electric permittivity and magnetic permeability of empty space. Therefore, if the electric permittivity or magnetic permeability of empty space was smaller in the past, then light would have traveled faster in the past.

Your quote:

Sorry Tom, you're parading your closed mindedness in public again.

You continue....

Of course anyone, like Tom2 and james R, who has studied QED and maxwell, knows that c is dependant on the permeability and permuabilty of free space. This result of Davies, if true, also means that these two fundamental constants are variable in time.

Funny, even when you agree with me, I'm still wrong.

Let me remind you that Tom2 and James DO NOT think that c is dependent on electric permittivity and magnetic permeability of free space. If you bothered to read the "The Speed of Light" thread I posted, you will find that Tom2 and James believe that electric permittivity is derived from c, and not the other way around.

I'm really sorry if your life sucks, but take it out on someone else.

I have yet to see Proosoothus, AKA tom, forward a theorem explaining how these constants vary in time.

I'm sure that you, and others, have seen enough of my theories on sciforums. I'm still waiting to see an original thought from you, or James, posted here. C'mon Thed, you must have at least one tiny original thought in that hard head of yours.

Tom

Paul Davies is regarded as a bit of a nut by most mainstream physicists. His pet projects include trying to use physics to prove that god exists and trying to prove tha the Big Bang didn't happen. His books on these subjects have made him quite a lot of money.

Of course that doesn't mean he's necessarily wrong, but we should bear in mind that his ideas about the speed of light aren't part mainstream science. He'll need to come up with some pretty incontrovertible evidence before anyone will take his ideas about light slowing down seriously.

Originally posted by Prosoothus
Thed,

Funny, even when you agree with me, I'm still wrong.

Only when you start crowing that this hypothesis vindicates some pet theory.

Let me remind you that Tom2 and James DO NOT think that c is dependent on electric permittivity and magnetic permeability of free space. If you bothered to read the "The Speed of Light" thread I posted, you will find that Tom2 and James believe that electric permittivity is derived from c, and not the other way around.

What they said was that the values for ε₀ and μ₀ where derived from the value of c. That is, c was calculated first then the values for the other 2 constants worked out. To do this it is obvious that c is dependant on their values. They did not imply c was not dependant on their values.

Unfortunately you can't spot the semantical difference. Or willfully ignore the difference.

I'm really sorry if your life sucks, but take it out on someone else.

Now that's a wild leap.

I'm sure that you, and others, have seen enough of my theories on sciforums. I'm still waiting to see an original thought from you, or James, posted here. C'mon Thed, you must have at least one tiny original thought in that hard head of yours.

Maybe because I find arguing about the same tired old things a tad boring. If I get time I'll post some thoughts on the validity of Dark Energy or CPT violations and it's relevance in the Big bang models to the dominance of matter over anti-matter. As I've noted a few times in the past I for one am not happy with the Higgs mechanism as the cause of mass, sounds too much like magic for me. Perhaps a discussion on the relevance of Lin-shu density waves as the generator of spiral galaxies is in order or the structure of Elliptical Galaxies and why S0 types are always found in the center of clusters. But as you are still struggling with relativity I doubt you would have much to contribute on more advanced topics.

Prosoothus,

Let me be clear: I don't deny that c=(sqrt(e0u0))-1 is a mathematical identity (how could I?). What I deny is that c depends on either of those two things. In other words, I think it's just a coincidence. Why? Because any massless particle (like a gluon) also travels at speed 'c'. Since gluons are not subject to the EM interaction, why should its speed be governed by electromagnetic parameters? The answer is that they shouldn't: 'c' is just the speed at which any massless object travels.

Also, even if c does depend on e0 and u0, nothing you said actually explains anything (re. the speed of light slowing down). All it does is change the question from, "Why is c varying with time?" to "Why are e0 and u0 varying with time?"

Tom

Ah, I guess the subscript and superscript notation don't work here. Rats.

Tom2,

Ah, I guess the subscript and superscript notation don't work here. Rats.

Yeah, it really sucks. :(

Let me be clear: I don't deny that c=(sqrt(e0u0))-1 is a mathematical identity (how could I?). What I deny is that c depends on either of those two things. In other words, I think it's just a coincidence.

Is it also a coincidence that electric permittivity and magnetic permeability are used to calculate the speed of a particle (photon) that has both electric and magnetic fields??

Why? Because any massless particle (like a gluon) also travels at speed 'c'. Since gluons are not subject to the EM interaction, why should its speed be governed by electromagnetic parameters? The answer is that they shouldn't: 'c' is just the speed at which any massless object travels.

First of all, do gluons really exist?? If they do, do they travel at light speed??

As far as I know, gluons are still hypothetical particles. To compare them with photons, which have been confirmed to exist, is not a valid argument.

I personally believe that all particles that travel at light speed, break down into the simplist particles. As a result, I don't think that any particles, besides photons, can travel at c. If this is the case, and since all photons have electric and magnetic fields, it would be very likely the photon's electric and magnetic fields are the culprits that limit the photon's speed.

Also, even if c does depend on e0 and u0, nothing you said actually explains anything (re. the speed of light slowing down). All it does is change the question from, "Why is c varying with time?" to "Why are e0 and u0 varying with time?"

You're right. But since we know that different materials have different er and ur values, it would be any easier task theorizing why they were different in the past, than explaining why c was slower in the past.

Tom

Thed,

If I get time I'll post some thoughts on the validity of Dark Energy or CPT violations and it's relevance in the Big bang models to the dominance of matter over anti-matter. As I've noted a few times in the past I for one am not happy with the Higgs mechanism as the cause of mass, sounds too much like magic for me. Perhaps a discussion on the relevance of Lin-shu density waves as the generator of spiral galaxies is in order or the structure of Elliptical Galaxies and why S0 types are always found in the center of clusters. But as you are still struggling with relativity I doubt you would have much to contribute on more advanced topics.

Oh, please share with us your grand theories!!

Let's all bow down to the Great Thed!!!!

Just be gentle with me.....You don't want me to get an brain aneurysm as a result of your divine wisdom. :)

Tom

Originally posted by Prosoothus
Is it also a coincidence that electric permittivity and magnetic permeability are used to calculate the speed of a particle (photon) that has both electric and magnetic fields??


Well, the photon doesn't have electric or magnetic fields. But, yes, that is the very coincidence I am talking about.


First of all, do gluons really exist?? If they do, do they travel at light speed??


Gluons are the postulated carrier of the strong force. They are postulated to be massless and travel at speed 'c'.


As far as I know, gluons are still hypothetical particles. To compare them with photons, which have been confirmed to exist, is not a valid argument.


It is true that no free colored particles have ever been observed. However, the massless gluon is part of QCD, whose predictions correlate well with experiment, when predictions can be made. This is tough to do, because QCD can't be solved exactly. But, the agreement with experiment that we do see is enough to tell us that we are on the right track. If not, that would be one hell of a coincidence!

Tom2,

It is true that no free colored particles have ever been observed. However, the massless gluon is part of QCD, whose predictions correlate well with experiment, when predictions can be made.

Quantum Chromodynamics has to be one of the dumbest theories I have ever heard of. I'm surprised you even brought it up.

I'm still waiting for physicists to find a quark. You wouldn't expect that to be so hard to to do, considering that all protons and neutrons are made from them.

Tom

Originally posted by Prosoothus
Quantum Chromodynamics has to be one of the dumbest theories I have ever heard of. I'm surprised you even brought it up.


Come on, this is a science forum. You've got to do better than that. There isn't even enough substance in this quote for a proper response, other than "Can you elaborate?"


I'm still waiting for physicists to find a quark. You wouldn't expect that to be so hard to to do, considering that all protons and neutrons are made from them.


It is hard because color is confined. We have no idea of why that should be so.

Tom2,

"Quantum Chromodynamics has to be one of the dumbest theories I have ever heard of. I'm surprised you even brought it up."

Come on, this is a science forum. You've got to do better than that. There isn't even enough substance in this quote for a proper response, other than "Can you elaborate?"

Sorry for being so vague, its just that I don't like anything about the theory. The three most foolish things about QCD are:

1) How can you assume that all nucleons are composed of particles (quarks) that have never been detected, and that can't be verified to even exist??

2) Where the hell did they get the idea that quarks can have 1/3 charges???

3) If a neutron is composed of three quarks, and a neutron decays into a proton, electron, and antineutrino, how can a quark be a fundamental particle???

It sounds like the physicist was smoking a joint when he came up with this theory. I'm really surprised it has been accepted in the scientific community at all.

Tom

Prosoothus--thank you for elaborating. These are excellent questions.

Originally posted by Prosoothus
1) How can you assume that all nucleons are composed of particles (quarks) that have never been detected, and that can't be verified to even exist??


Well, it is clear that nucleons are composed of something. This much is clear from the way they absorb and emit photons. So, why not call these things "quarks"?


2) Where the hell did they get the idea that quarks can have 1/3 charges???


Where the hell did you get the idea that there can't be 1/3 charges? :)

Seriously, this is not a fundamental law of nature (like, say, the conservation of charge). Integer multiples of 'e' are inexplicable, and so violations of that "law" should not cause any surprise.


3) If a neutron is composed of three quarks, and a neutron decays into a proton, electron, and antineutrino, how can a quark be a fundamental particle???


This has nothing to do with QCD. This transition is governed by the weak interaction, not the strong.


It sounds like the physicist was smoking a joint when he came up with this theory. I'm really surprised it has been accepted in the scientific community at all.


I will ask you to suspend your "surprise" until you've had a chance to look at the experimental confirmation of QCD. I know that its postulates are a lot to swallow, but what is even more diffilcult to believe (for me, anyway!) is that the agreement of QCD with experiment is just a coincidence.

Take care,
Tom

Tom2,

"3) If a neutron is composed of three quarks, and a neutron decays into a proton, electron, and antineutrino, how can a quark be a fundamental particle???"

This has nothing to do with QCD. This transition is governed by the weak interaction, not the strong.

You missed my point. Even though the decay of a neutron is governed by the weak interaction, why doesn't the neutron decay into three quarks? Instead, it decays into three completely different particles, one of which is still composed of three quarks. If a neutron (three quarks) decay into an electron, proton, and antineutrino then how many quarks is an electron made of? What about the antineutrino? If any one of these particles (electron or antineutrino) are composed of "fractions" of one quark, then the quark isn't a fundamental particle (if it even exists).

Tom

Originally posted by Prosoothus
You missed my point.


I thought your point was to criticize QCD??


Even though the decay of a neutron is governed by the weak interaction, why doesn't the neutron decay into three quarks?


The neutron goes from |udd> to a proton state |uud>. The electron is required to conserve charge (a well-understood conservation law) and the neutrino is required to conserve lepton number (a not-so-well understood conservation law).


Instead, it decays into three completely different particles, one of which is still composed of three quarks.


That is not a problem--I don't know why you think it is.


If a neutron (three quarks) decay into an electron, proton, and antineutrino then how many quarks is an electron made of? What about the antineutrino? If any one of these particles (electron or antineutrino) are composed of "fractions" of one quark, then the quark isn't a fundamental particle (if it even exists).


The leptons you mentioned are not composed of any quarks.

It seems you missed my point as well. I was trying to emphasize that, like it or not, the Standard Model works. That's why it is not a "dumb theory", as you assert, and that's why I brought it up.