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Author Topic: Has the speed of light changed since the Big Bang?  (Read 2973 times)

Offline Fluid_thinker

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I read that some think that the speed of light has changed since the big bang. In fact they believe it has slowed.

Many different particles travel at the speed of light, e.g. Photons, Gauge Bosons and a Neutrino.

If the Speed of Light has slowed.

a) Could particles be out there with residual speed 'faster than the current SoL'?

b) What principle area is universal between all such particles than it would cause them all to slow with the same value of the SoL?
« Last Edit: 11/06/2013 21:32:20 by chris »


 

Offline Alan McDougall

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Re: Has the speed of light changed since the Big Bang?
« Reply #1 on: 18/06/2013 16:45:23 »
Hi,

There is some debate that the physical universal constants might change over a huge period of time. The original early estimations of the Speed of Light, compared to the most recent, suggest that the Speed of Light is slowing down from the moment of creation. This, however, might just be the result of much more accurate measuring by modern means.

I will look for more information and return to the topic later

Alan
 

Offline syhprum

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Re: Has the speed of light changed since the Big Bang?
« Reply #2 on: 18/06/2013 17:25:34 »
There is good evidence that Neutrinos have rest mass hence cannot travel at the speed of light.
 

Offline Pr. snoerkel

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Re: Has the speed of light changed since the Big Bang?
« Reply #3 on: 23/06/2013 14:51:41 »
Since speed is distance/time, you could as well ask if time has changed  - or distance. Since time is affected by mass and since the concentration of mass is constantly getting smaller in the Universe, maybe it it more meaningful to say that time changes.
 

Offline Alan McDougall

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Re: Has the speed of light changed since the Big Bang?
« Reply #4 on: 23/06/2013 22:41:05 »
Since speed is distance/time, you could as well ask if time has changed  - or distance. Since time is affected by mass and since the concentration of mass is constantly getting smaller in the Universe, maybe it it more meaningful to say that time changes.
Since speed is distance/time, you could as well ask if time has changed  - or distance. Since time is affected by mass and since the concentration of mass is constantly getting smaller in the Universe, maybe it it more meaningful to say that time changes.

The speed of light is one of the "Fundamental Constants" that hold our universe together, so to speak, time and distant are not constants and do not effect the speed of light, light speed is supposed to be constant in the fabric of space/time

Alan
 

Offline AndroidNeox

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Re: Has the speed of light changed since the Big Bang?
« Reply #5 on: 24/06/2013 20:22:04 »
I think it's better to refer to c rather than the speed of light. c isn't an attribute of light but of the geometry of spacetime, the angle between space and time. This angle appears the same for all observers so the value c, (distance/time), is always the same for all observers. Relativity works the way it does because c is constant for all observers, space and time adjust to accommodate different frames of reference.
 

Offline Bill S

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Re: Has the speed of light changed since the Big Bang?
« Reply #6 on: 26/06/2013 23:19:20 »
Magueijo. Jo„o, Faster Than the Speed of Light.  Arrow Books, London.  2003.

May not throw a lot of light on the subject, but a good read.
 

Offline Pr. snoerkel

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Re: Has the speed of light changed since the Big Bang?
« Reply #7 on: 04/07/2013 17:40:39 »
Why is it so difficult to believe that faster tahn light travel is impossible? According to the theory of relativity it certainly is impossiblem at least in space-time. Since we do not know anything about the higher dimensions, we can speculate that it is in fact possible there. But even so, we face some paradoxes, bacause faster than light travel also implies that it is possible to travel backwards in time. So you will never have to buy another burger, just go back in time and eat the same one again?
Is it because accepting the speed of light limitation, we acknowledge that there are places we can never reach, information we will never be able to extract? quite contrary to traditional scientifical thinking.
I confess that I dream of faster-than-light travel myself, but the hard facts as we know them are not supporting that dream
 

Offline Pmb

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Re: Has the speed of light changed since the Big Bang?
« Reply #8 on: 04/07/2013 19:27:48 »
Quote from: Pr. snoerkel
Why is it so difficult to believe that faster tahn light travel is impossible?
Perhaps its an arrogance thing. Some people donít like to be told that you canít do something. I had a friend who loved to tell me that Nothing is impossible!  When I asked him if was possible for him to be wrong he changed his tune. Lol!!

It also has to do with the notion that every once in a while a laymen hear that someone once thought that something wasnít possible only to find out later that it wasnít true. So now they think nothing is impossible, that we are making the same mistake they did,  that eventually weíll be able to figure everything out etc. And some people just donít understand relativity. They think about getting in a rocket ship and going 75% the speed of light and from that ship launch a ship which can go 75% the speed of light and then heíll be going 150% the speed of light. I.e. people assume weíre stupid, that we havenít figured out what they can so easily see. I see that a lot, i.e. people thinking that because they havenít heard what I told them that I must be wrong. That happened the other day. Some undergraduate whoís studying relativity, tensors, differential geometry, etc. thought he knew more than I do. Why he thought that I have no idea. After all Iíve been a physicist/studying relativity longer than heís been alive and this kid thinks he knows more than I do. Itís really irritating since he knows nothing about me.

In a recent argument he did the same thing and made a blatant error. I knew the error he was making too. Like a great many people who learn vectors in a flat space he thought he knew what vectors are. He was wrong. What he didnít know was the most basic fact of all vectors and thatís the fact that until youíve chosen a point of reference on the manifold you are unable to define the prototype for vectors, i.e. the position vector. Many people donít understand the position vector. They confuse it with a point in space. By definition the position vector is displacement of one point relative to a reference point. Until youíve chosen a reference point you havenít properly defined the vector space. Each point is then the vector displacement from the origin point to the point of interest. And he refused to listen to me explain it. And sure as shinola he and others failed to trip me up. He posted a space with a point in it and told me to write the coordinates of the point. I asked him to give me the reference point but he wasnít in a listening mood yet. Or he was unable to grasp what I was telling him. What I explained applies to flat spaces and holonomic bases.

Luckily not everyone is as ignorant as they are. Kip Thorne (from Cal Tech) explains all of this very well in his new book which is online at

www.pma.caltech.edu/Courses/ph136/

See the chapter on special relativity.

http://www.pma.caltech.edu/Courses/ph136/yr2011/1102.2.K.pdf

He explains all of this including the all important reference point.
 

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Re: Has the speed of light changed since the Big Bang?
« Reply #8 on: 04/07/2013 19:27:48 »

 

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