The Naked Scientists

The Naked Scientists Forum

Author Topic: Somewhat uninformed enquiry regarding the varying speed of light  (Read 7823 times)

Offline Jabulon

  • First timers
  • *
  • Posts: 2
    • View Profile
I was reading in another thread about a higgs-boson condensate, where it was stated that the speed of light has been reduced to around 40m/h (or something like that).

This brings up 2 questions on my behalf, which im hoping to clarify, atleas somewhat.

Isnt the speed of light constant? Im pretty sure that einstein claimed (without being disproven) that light travels at the maximum speed possible within a certain space, or length. As the pohotons propogate themselves as fast as, well, universally possible.

the article about higgs-boson condesates also said something about a null-energy field, or something, indicating that the is mass constantly existing, even within a vacuum, at 0k.

is this correct? if so


Is there a chance that, after observing the relative low speed of light in higgs-boson condensates (HBC)that not only does the speed of light (maximum velocity of mass) vary, but that this can be a function, atleast to a degree defined by the temperature of space? (not stricly outside of earth, but generally).

Also, could this assumption make possible, and i know this is a stretch, that interspellar space is smaller than imagined, and that by measuring relative distances by the speed of light, in fact produces faulty numbers?

say a box with the dimensions 1m(squared) is filled with a HBC, light would take alot longer to travel thru, than it would say on a stretch of highway, and that calculating the size of this given box with the light speed calculations, would give a false answer? as we know for a fact that the box isnt more than 1meters long each side?

so to conclude;

1; given HBC's, is the speed of light constant? (from a relative viewpoint, where we know how far a distance is, using another measurement than lightspeed)

2; may objects in the hubble mirror, in fact be closer than they seem?

hope to get some informed answers, short time lurker, first time poster. :)


 

Offline Foolosophy

  • Sr. Member
  • ****
  • Posts: 218
    • View Profile
The speed of light that is commonly used in Einstein's relativity equations (c) is a maximum speed limit in a vacuum.

...there are theoretical physicists who have postulated a variable speed for light.

In fact the theory allows for a much higher speed of light during the early stages of the big bang event.

Early in the big bang expansion the speed of light was up to 3 orders of magnitude higher than what it is today (ie 1000c)
« Last Edit: 26/12/2010 11:39:19 by Foolosophy »
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Take a look at this explanation for how to trap atoms BEC

When you cool 'light' you do the same, you send them into this 'gas' where they(it) get 'trapped'.

As for the idea of light should be 'trapped' by a vacuum? In a way it makes sense but there are very little 'dust' out there compared to the volume of 'space'. But I like that one, it's a clever and interesting question. I don't know really? There is a difference between the 'coldness' we create and space but I'm not sure what temperature one would need? Temperature differences.

Don't know why, but BEC:s make me think of supra conducting magnets :) And there we are reaching higher and higher temperatures. Maybe there could be some 'entrapments' done? Chilled light enters a new phase 
« Last Edit: 26/12/2010 20:13:18 by yor_on »
 

Offline QuantumClue

  • Hero Member
  • *****
  • Posts: 613
    • View Profile
I was reading in another thread about a higgs-boson condensate, where it was stated that the speed of light has been reduced to around 40m/h (or something like that).

This brings up 2 questions on my behalf, which im hoping to clarify, atleas somewhat.

Isnt the speed of light constant? Im pretty sure that einstein claimed (without being disproven) that light travels at the maximum speed possible within a certain space, or length. As the pohotons propogate themselves as fast as, well, universally possible.

the article about higgs-boson condesates also said something about a null-energy field, or something, indicating that the is mass constantly existing, even within a vacuum, at 0k.

is this correct? if so


Is there a chance that, after observing the relative low speed of light in higgs-boson condensates (HBC)that not only does the speed of light (maximum velocity of mass) vary, but that this can be a function, atleast to a degree defined by the temperature of space? (not stricly outside of earth, but generally).

Also, could this assumption make possible, and i know this is a stretch, that interspellar space is smaller than imagined, and that by measuring relative distances by the speed of light, in fact produces faulty numbers?

say a box with the dimensions 1m(squared) is filled with a HBC, light would take alot longer to travel thru, than it would say on a stretch of highway, and that calculating the size of this given box with the light speed calculations, would give a false answer? as we know for a fact that the box isnt more than 1meters long each side?

so to conclude;

1; given HBC's, is the speed of light constant? (from a relative viewpoint, where we know how far a distance is, using another measurement than lightspeed)

2; may objects in the hubble mirror, in fact be closer than they seem?

hope to get some informed answers, short time lurker, first time poster. :)

I'm going to reply to this as the OP questions.

Interestingly enough, the speed of light might have varied. The energy density of the vacuum can be allowed to variate which means this directly effects the speed of light; some very prominent scientists have speculated on this, such as John Barrow. I will find a better list for you soon.

The mathematics require that εμ=1/c^2. This is the speed of radiation in a vacuum, and the energy density ρ of the vacuum durectly related to moving objects.
 

Offline QuantumClue

  • Hero Member
  • *****
  • Posts: 613
    • View Profile
V.S triotskii propsed that speed of light is 1010 times than the general speed today, which is all cited below accordingly. Moffat proposed it was 1060 times less than what it is today, who also had some agreement from Albrect and Magueijo. And John Barrow agreed with the value also.

[1]. V S Troitskii, Astrophys. & Space Science 139 (1987) 389.
[2]. J Moffat, Int. J. Mod. Phys. D 2 (1993) 351 and Int. J. Mod. Phys. D 23 (1993) 411.
[3]. A Albrecht, J Magueijo,Phys. Rev. D 59:4 (1999) 3515 .
[4]. J D Barrow, Phys. Rev. D 59:4 (1999) 043515-1.
 
 

Offline Geezer

  • Neilep Level Member
  • ******
  • Posts: 8328
  • "Vive la résistance!"
    • View Profile
I was reading in another thread about a higgs-boson condensate, where it was stated that the speed of light has been reduced to around 40m/h (or something like that).


Isn't it a Bose-Einstein Condensate that has that effect?
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
In what way would the energy density reflect on the speed of light QC?
That's a new one to me, maybe you have a link?
 

Offline QuantumClue

  • Hero Member
  • *****
  • Posts: 613
    • View Profile
In what way would the energy density reflect on the speed of light QC?
That's a new one to me, maybe you have a link?

There are four references there my friend.

On the note of an explanation, you can think of objects ''ploughing'' through spacetime. The speed of objects will vary if you alter the energy density of the vacuum, simply because the ploughing receives more effort to do so. Think of it this way: Moving an object in water is relatively easy. Moving an object through sand is even harder - if water and sand was to be replaced by a density relating to the energy of the vacuum, then the density of sand is much greater than the water density.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
That would turn 'space' into a medium though?
I will have to look that up :)




 

Offline QuantumClue

  • Hero Member
  • *****
  • Posts: 613
    • View Profile
Spacetime is always a medium. The vacuum is a medium.
 

Offline Geezer

  • Neilep Level Member
  • ******
  • Posts: 8328
  • "Vive la résistance!"
    • View Profile
Spacetime is always a medium. The vacuum is a medium.

Yoron,

That had me confused for a very long time. I believe it is a medium as QC says. It certainly has interesting properties that we can observe experimentally.

Just don't try calling it "the aether".
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
I know, but classically we still call it a 'nothing'. Assuming 'Space' to have a density though makes it into something new. I will need to read more about that idea.
 

Offline QuantumClue

  • Hero Member
  • *****
  • Posts: 613
    • View Profile
Well, actually we don't view the vacuum as nothing meaning our classical picture is wrong. It is a bubbling sheet of virtual particles, so even if you remove all the particles in a particular region of space, there will still be movement left over, and is called the ZPF (zero point field) which is an energy part of the vacuum itself.

And contrary to typical belief systems, that is not entirely true Geezer. There is what scientists are now calling a ''quantum aether'' which takes the form of a bubbling couldron of particles.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
Yes QC, but the virtual world is mostly seen as being under Plank time, meaning that discussing it as 'existing' inside SpaceTime becomes very weird. Anything under Plank time makes no sense to us, just like the idea of singularities. And being under Plank time is also what allows virtual particles to 'QM tunnel' out of 'black holes' as I understands it. Which is a different idea than Hawking radiation which builds on entanglements and positive/negative pair production, as I see it.

That we have them defined is because we 'need them.' to explain what otherwise become unexplainable. But if you could prove them to be measurable in themselves I might change my tune :)
 

Offline lightarrow

  • Neilep Level Member
  • ******
  • Posts: 4586
  • Thanked: 7 times
    • View Profile
Well, actually we don't view the vacuum as nothing meaning our classical picture is wrong. It is a bubbling sheet of virtual particles, so even if you remove all the particles in a particular region of space, there will still be movement left over, and is called the ZPF (zero point field) which is an energy part of the vacuum itself.

And contrary to typical belief systems, that is not entirely true Geezer. There is what scientists are now calling a ''quantum aether'' which takes the form of a bubbling couldron of particles.
I think it's quite difficult to talk about these concepts without a deep understanding of what physicists exactly mean with the terms.
For example many says that virtual particles are nothing else than a convenient mathematical trick (which comes out from the perturbation theory only) and that the average energy of the void is zero by definition...
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
The energy density of a vacuum is, as I understand it, a 'negative' one, also called the cosmological constant as that is what is thought to define this 'negative density', and also called Einsteins biggest blunder. Maybe it isn't though, a blunder I mean. QM 'zero point energies' if added up differs from the measured cosmological observation by a magnitude of one hundred and twenty orders, making the discrepancy very large and unexplainable. It is also thought of as one of the, or the, reason(s) why we see an expansion as it corresponds mathematically to a gravitational repulsion.

Now, if someone just could explain to me how this negative 'energy' creates 'space' and just how it is thought to 'pop up'?
==

How about this?
'Negative energy' when not meeting matter inside a certain amount of 'time' transforms into 'space'?
Yep..

Ah :)

Naaah.. I don't even know how to imagine a 'negative density'. Sounds like a time reversal to me?

"Enterprise, beam me up, no wait , down.."
==

I'm assuming here that with a density we will have some sort of 'energy'?
Maybe I'm wrong though? As it builds on equations describing gravity?

And gravity was no 'force' for Einstein, was it?
=

Casimir force is thought to correspond to the wavelengths of 'virtual particles' if I remember right. The closer you move two plates against each other, the smaller (and so fewer) are the 'wave lengths' allowed to exist between them. Am I right there? So what we do then is to create a 'negative pressure' or 'density' that will bring the plates together due to the pressure outside our plates. Not because there suddenly comes to be some mysterious 'attraction'. That is, if my memory doesn't fail me.

So a 'unfettered space' have all possibilities of 'virtual particles' making it 'even out' I guess, becoming a zero density. Nope, that's wrong, a 'unfettered space' have all those wavelengths outside Plank time as I see it. When we introduce the plates we disallow some of them, creating a effect inside our arrow of time, as the equilibrium is destroyed. So yes, it has to do with time.
« Last Edit: 28/12/2010 02:21:12 by yor_on »
 

Offline Geezer

  • Neilep Level Member
  • ******
  • Posts: 8328
  • "Vive la résistance!"
    • View Profile
I have to confess my perspective is from the viewpoint of an engineer. All I know is that electromagnetic effects take some time to get from one place to another.

If they are particles (photons), something must have limited their speed. If they are waves, they have to be propagating through something.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
well, with normal waves they need a medium (ocean), and light is explainable as waves, having a lot of the same behavior. It might have to do with how we perceive space, maybe? Like everything we do we do 'linearly' inside that 'times arrow'. But if we just could lift ourselves out of it?
=

But why should the introduction of 'matter' disallow 'Space density'
Is it workable with something else than matter?
How about a magnetic field?

If it's not? I think you can see it as a clear statement of matter being fundamentally different in some way from 'fields', even though having a energy equivalence. And I then get water on my mill as we say in Sweden :) in my assumptions that we have the 'arrow of time' defining most of what we see, creating the order and the 'laws' we live by. And then distance isn't what we think it is inside that arrow. I think of distance more like some 'magnifying shrinking/contracting effect' that times arrow translates into 'distance'. Distance is defined by your arrow, and with a different frame of reference your 'distance' will shrink/contract.
==

Nah, that isn't right either, but it has to do with the arrow anyway, in some way, if I got it right with the Casimir effect? Ah, maybe 'Room time geometries' is the thing. It's stupid to differ out the arrow of time from the room. They go together right :)

So what we have is something changing the 'room time geometry' locally between those plates if I'm thinking right? And that should be the introduction of matter, right? And matter you can translate into gravitational potential too, and motion you can translate into ? Relative mass, momentum, energy expended.

I think I'll go with the last one for now. Energy expended.
« Last Edit: 28/12/2010 00:17:56 by yor_on »
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
And if "When we introduce the plates we disallow some of them, creating a effect inside our arrow of time, as the equilibrium is destroyed." is correct then we have a new statement telling us that the 'arrow of time' must be a local phenomena. to get it you need to remember that what make the plates meet is not a 'pressure' in the normal sense. We define pressures from zero and up inside SpaceTimes arrow.

But between those plates we have created a 'negative pressure-density' that's not 'allowed'. SpaceTime wants to close it. The question might also be how a clock would run inside that 'room time geometry'?

Anyone have an view about that?

It's like we have 'state of equilibrium' from where we get our 'energy' transforming into 'energy done'. Inside this 'state' we all have have our personal 'room time geometry' communicating  and defined through that 'arrow', creating the 'wholeness' we all believe to be our common 'SpaceTime'.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
I don't know, times arrow can't be described the same way as light. Light will in all 'frames of reference' have the same 'speed', inside as well as outside, but 'distances' will differ with it, and so will the overall time taken. But maybe I'm wrong? Maybe you can describe the 'times arrow' you have the same way you describe light? It never differs for you, does it? Just like the speed of light.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
If so everyone would have a 'room time geometry' that will contract and expand with 'potential gravity' created out of what we call 'matter' and 'motion', but not 'potential energy' that is a concept describing what 'might happen'. I'm using 'potential gravity' here as it seems a better description of 'magnitude and position' inside SpaceTime than invariant proper rest mass.

You can apply the idea of 'potential gravity' to both motion and invariant mass I think? As long as you think of it as 'geodesics' getting 'twisted/distorted' through matter and motion. Like the two dimensional surface with drawn lines describing 'gravity' that JP introduced. The lines there are what I call the 'geodesics' and when you accelerate you distort them locally. Well. that's the only way you can interfere in fact. And if you accept that 'SpaceTime' in fact is defined by your personal 'room time geometry' then what you see as 'distance' also must be a 'local definition', don't you agree?
« Last Edit: 28/12/2010 01:07:31 by yor_on »
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
And 'frames of reference' is why i believe in a fractal reality too. As you can define them ad infinitum, from Plank size and up, and they should all 'locally' be slightly different as I think. As long as we think of our 'room time geometries' that is, not in form of 'distances' as those are mutable with potential gravity. And the way those 'room time geometries' glide into each other have to be similar to the idea of 'magnifying contracting' which then should make them into some sort of fractals.
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
I'm getting mystic here huh?
Talking by myself, a sure sign of senility :)
 

Offline Geezer

  • Neilep Level Member
  • ******
  • Posts: 8328
  • "Vive la résistance!"
    • View Profile
Go and take a nap. I'm sure it will all be perfectly clear in the morning  ;D
 

Offline yor_on

  • Naked Science Forum GOD!
  • *******
  • Posts: 11978
  • Thanked: 4 times
  • (Ah, yes:) *a table is always good to hide under*
    • View Profile
ahem :)

Yeah ::))

Anyway, can I at least suggest a equivalence between light and our 'arrow of time'?

Will light leave you at 'c' on the Event horizon?
Will your wristwatch keep the same time against your heartbeats?
(probably not, but, that's humans for you, by my tentacle:)

Can we translate it into something defining 'events'
Well, a wave can be 'infinite' right? A photon on the other hand, isn't that a 'discrete event'?

What differs them?
==

And 'potential gravity' as I think of it, is just a 'metric', nothing potential about it at all. For you, the potential gravity you measure will have a defined position and magnitude. I should have found a better word for it really but it's so commonly used that that was what I remembered, da*n :)
« Last Edit: 28/12/2010 01:38:50 by yor_on »
 

The Naked Scientists Forum


 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums
 
Login
Login with username, password and session length