Light - What exactly is happening?

[Drakkith]

Well said.

I agree!

 

[bobc2]

Well, that being the case, I'd have to accept that the photon would be considered to form at-once ... whatever "at-once" means at the quantum level. If the electron jumps the bands in zero time, then it stands to reason the photon should be formed at-once. Difficult to swallow, but QM is a rock solid theory, so.

GrayGhost

Perhaps the closest we could get to instantaneous would be within a Planck time.

 

[Drakkith]

Perhaps the closest we could get to instantaneous would be within a Planck time.

Closest we could get to measuring it, or calculating it, or what?

 

[bcrowell]

Yes, I was referring to the actual published theory, in 1915. I do realize that Einstein deliberated over a medium for the years thereafter.

No, this is incorrect. Einstein wrote a 1924 paper in which he made the philosophical point that although relativity killed off the luminiferous aether as the supposed medium of electromagnetic vibrations, it still imbued the vacuum with specific physical characteristics, such as curvature and energy. The basic point of the paper is that we can't decide, purely based on philophical ideas like Mach's principle, whether the vacuum has its own properties; we actually have to go through the usual scientific cycle of theory and experiment in order to find out the answer. Internet kooks love to misinterpret and overinterpret this paper, or to misrepresent it by saying that Einstein referred to GR in general, throughout his career, as an aether theory.

A. Einstein, "Über den Äther," Schweizerische naturforschende Gesellschaft 105 (1924) 85

original text - http://www.wikilivres.info/wiki/Über_den_Äther

English translation of [Einstein 1924]- http://www.oe.eclipse.co.uk/nom/aether.htm

commentary by John Baez on [Einstein 1924] - http://web.archive.org/web/20070204022629/http://math.ucr.edu/home/baez/RelWWW/wrong.html

 

[GrayGhost]

No, this is incorrect. Einstein wrote a 1924 paper in which he made the philosophical point that although relativity killed off the luminiferous aether as the supposed medium of electromagnetic vibrations, it still imbued the vacuum with specific physical characteristics, such as curvature and energy. The basic point of the paper is that we can't decide, purely based on philophical ideas like Mach's principle, whether the vacuum has its own properties; we actually have to go through the usual scientific cycle of theory and experiment in order to find out the answer.

Yes, I see I used the word "deliberated", which was a mistake on my part. I meant that he "debated" its existence over the years thereafter (in favor of). My point was that "aether or medium" was not mentioned in the original published theories of Maxwell or Einstein, even though they both believed one existed (of sort) at that time. Einstein's medium (of course) not being the traditional classical aether Maxwell had assumed.

Wrt your reference ...

http://www.oe.eclipse.co.uk/nom/aether.htm" :Now, it might be claimed that this concept covers all objects of physics, for according to consistent field theory, even ponderable matter, or its constituent elementary particles, are to be understood as fields of some kind or particular ‘states of space’. But it must be admitted that such a view would be premature, since, thus far, all efforts directed toward this goal have foundered.​

Thanx for this reference bcrowell. I happen to be one of these folks, those who have the opinion that all objects are some state of the medium. I do agree that any opinion is premature in the lack of enough proof. Nonetheless, everything is premature until proven true, or otherwise. I must say though, it is very surprising IMO that in the past 96 years, it remains premature.

GrayGhost

 

[harrylin]

Post 28 deals with the historical information you mentioned and posts 28 - 64 deal with the semantics of the word "medium" in this context.

OK I see - yes indeed, that refers to a different but similar remark by GreyGhost, and it already contains part of my reply. Note that my reply was just about a historical fact related to the OP's question, it's not about semantics.

Cheers,
Harald

 

[harrylin]

Yes, I was referring to the actual published theory, in 1915. I do realize that Einstein deliberated over a medium for the years thereafter.

GrayGhost

Ah yes OK, his theory as first published only discusses observables and not possible (meta)physical explanations. That's the safest thing to do.

PS. I see nothing wrong with "deliberated": his 1920 discourse may certainly be called a "thoughtful, careful, or lengthy consideration". - dictionary.com

 

[harrylin]

[..] I happen to be one of these folks, those who have the opinion that all objects are some state of the medium. I do agree that any opinion is premature in the lack of enough proof. Nonetheless, everything is premature until proven true, or otherwise. I must say though, it is very surprising IMO that in the past 96 years, it remains premature.

GrayGhost

A century isn't much if you think of other things like that: didn't atoms take more than a millennium to be proven beyond reasonable doubt?

Cheers,
Harald

 

[GrayGhost]

A century isn't much if you think of other things like that: didn't atoms take more than a millennium to be proven beyond reasonable doubt?

Given we've already been thru the dark ages, consider me anxious :)

GrayGhost

 

[GrayGhost]

Roger Penrose seems to believe that particle wave functions are the realities of nature, whereas many other physicists feel there is no objective reality for a particle until the wave function collapses. This all makes for difficulty in imagining the details of how a photon is created.

I've always thought Sir Penrose believed in the infinite quantum simultaneous states of the wavefunction. Given such, it would seem that he does not disagree with non-objectivity at the quantum realm. If I recall properly, he is trying to determine why uncertainty vanishes at some level just above the size of some certain small molecules (ie a mass threshhold). At said size threshhold, the wave nature of particles vanishes in the double slit experiments. Penrose seems to think that the collective (local) gravity field of a particle system (at said threshhold) becomes unstable, collapsing the wavefunction into a single state. If's he's right, and establishes the theory accordingly, he believes he might merge GR with QMs.

GrayGhost

 

[GrayGhost]

Perhaps the closest we could get to instantaneous would be within a Planck time.

Theoretically, and in relation to any physical meaning, I'd agree. All we need to do is increase the accuracy of the http://en.wikipedia.org/wiki/4Pi_Microscope" some 1 x 10²⁸ times over, then we're good :)

GrayGhost