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Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: simplified on 06/04/2012 15:34:55

Title: Are photons faster in cold or hot transparent environment?
Post by: simplified on 06/04/2012 15:34:55
Are photons faster in cold or hot transparent environment?
Title: Re: Are photons faster in cold or hot transparent environment?
Post by: yor_on on 07/04/2012 14:40:11
Simplified :)
I'm sure you have a certain meaning with that question.
So, what do you mean by a hot/cold 'transparent' environment?

Photons are photons as far as I know?

But if we assume a very cold environment, a Bose/Einstein condensate?

Title: Re: Are photons faster in cold or hot transparent environment?
Post by: MikeS on 08/04/2012 11:20:21
They are the same but time passes faster in a hot environment and slower in a cold one.  So looked at from the perspective of a distant observer they would appear to travel faster in a hot environment.  The photons in the hot environment would complete their journey sooner than the photons in the cold environment.  Both sets would have taken the same local time but a second is shorter in the hot environment.
Title: Re: Are photons faster in cold or hot transparent environment?
Post by: Soul Surfer on 08/04/2012 12:18:18
Presumably the questioner is talking about normal solid liquid or gaseous environments and not plasma environments Which are much more opaque to photons because of the different sorts of interactions

Photons travel slower than the vacuum speed of light in normal transparent materials and as materials usually become less dense (ie expand) a temperature rises the refractive index (a measure of the difference in the speed of light between two media usually falls i.e. the photon velocity rises as the temperature goes up but this is not always the case near to frequencies where light may be absorbed.
Title: Re: Are photons faster in cold or hot transparent environment?
Post by: simplified on 08/04/2012 13:22:34
Simplified :)
I'm sure you have a certain meaning with that question.
So, what do you mean by a hot/cold 'transparent' environment?

Photons are photons as far as I know?

But if we assume a very cold environment, a Bose/Einstein condensate?


There is time frozen?
Title: Re: Are photons faster in cold or hot transparent environment?
Post by: simplified on 08/04/2012 13:31:01
They are the same but time passes faster in a hot environment and slower in a cold one.  So looked at from the perspective of a distant observer they would appear to travel faster in a hot environment.  The photons in the hot environment would complete their journey sooner than the photons in the cold environment.  Both sets would have taken the same local time but a second is shorter in the hot environment.
And so does cold environment take much time for own needs?
Title: Re: Are photons faster in cold or hot transparent environment?
Post by: simplified on 08/04/2012 13:54:18
Presumably the questioner is talking about normal solid liquid or gaseous environments and not plasma environments Which are much more opaque to photons because of the different sorts of interactions

Photons travel slower than the vacuum speed of light in normal transparent materials and as materials usually become less dense (ie expand) a temperature rises the refractive index (a measure of the difference in the speed of light between two media usually falls i.e. the photon velocity rises as the temperature goes up but this is not always the case near to frequencies where light may be absorbed.
Does density eat time?I think low energy has high ability to eat time.Yes, smaller volume resieves less time.
Title: Re: Are photons faster in cold or hot transparent environment?
Post by: yor_on on 09/04/2012 07:52:08
You're connecting the dots, right?

Thinking of if it could be possible that 'change' is 'energy expended', and that without 'change' (as in a Bose Einstein condensate) there is no energy expended and if now change also would be a description of a arrow?