"Picking on Einstein" Article

[davidgow77]

I've just read thePicking on Einstein article on the TOEQuest Homepage, and found it very interesting. However, I would like to try and dispell one of the myths that it presents as fact. Newton did not believe that space and time were absolute, and in fact states very clearly ion Principia that time and motion are "relative".

"For from the positions and disatances of things from any body [object] considered as immovable, we define all places; and then with respect to places we estimate all motions considering bodies as transferred from some of those places into others. And so instead of absolute places and motions, we use relative ones; ... for it may be that there is no body really at rest, to which the places and motions of others may be referred."

(pg 8, Defintions, Principia, Isaac Newton)

In light of this, it must be realised that although Einstein may have come up with the notion of relativity by himself, it was by no means an original thought. Newton was very aware of the philosophical problems of absolute space, motion and time, and it has been the subsequent arguements of lesser physicist s that have landed the term "Newtonian Space-time" as meaning absolute motion, space and time. Nweton was probably only prevented from researching this field further by the limitations of technology of his time, although it must be said that he found the question (is space and time absolute or relative) a largely incosequential notion.

DG

[AntonioLao]

Newton did an experiment called the rotating bucket of water. He was trying to understand the absoluteness of acceleration. This experiment was commonly interpreted to be an experiment of absolute space and time.

in modern quantum theory of radiation physics, the photons cannot be accelerated. It is always moving at a constant speed of about 186,000 miles per second. While moving through matter, the speed of the photon can be less than the speed of charge particles. This phenomenon is known as Cerenkov radiation discovered in 1934 by the Russian physicist pavel Cerenkov.

[davidgow77]

I would say that there is a reason why photons cannot be accelerated, and that they must always travel at the speed of light. They can however, be slowed somewhat by the refractive index of the medium through which they pass. This means that where there is no medium (as in the near perfect vacuum of space) the speed of the photon is constant, but that the speed of light through water (for example) would appear to be slower due to the refactive effect that the water has upon light.

What I would like to know is that, given the Hesinberg uncertainty principle, is it possible that photons are incapable of having location.... is this why they always travel at the maximum possible speed?

DG

[AntonioLao]

.... is this why they always travel at the maximum possible speed?

According to the relativistic formulation of energy in quantum mechanics given as

[math]E^2=c^2\mathbf{p}^2+m^2c^4[/math]

when m=0, as that for all photons, then their absolute momenta are given by

[math] p=\frac{E}{c}[/math]

it's the momentum of a photon that keeps it constantly moving.

[davidgow77]

I would say that the fact that a photon cannot accelerate (i.e it is always travelling at the speed of light) is an indicator of the heisenberg uncertainty principle in action. We should look at the photon as a particle that cannot have location.... in this way the uncertainty principle is clearly manifestsed. We know exactly the speed of the particle/wave, but we now nothing about it's location. Put another way, if something is to have no location, then it must have the absolute maximum amount of speed possible, and that this fixed speed (299792458 m/s) is determined as being the speed at which something must travel in order to be constantly in motion at the Planck time scale.


DG

[Omni]

@davidgow77: "is it possible that photons are incapable of having location". That's not possible. Everything at a certain moment in time has a certain location.

[davidgow77]

[QUOTE=Omni

"is it possible that photons are incapable of having location". That's not possible. Everything at a certain moment in time has a certain location.[/QUOTE]
This is exactly what I propose. If you try to evaluate the position of a photon at any given moment, you must define a moment. The smallest definable unit of time is Planck-time, and it is at this time scale that the locality of the photon in indiscernable. It has something to do with the Compton Wavelength.... but you'd need to ask someone Like AntonioLao if you want a more detailed explanation in terms of physics.

From a philosophical perspective however, this idea makes perfect sense. A maximum velocity (such as the speed of light) is wholly dependant upon a minimal measure of time (planck time).

DG

[Omni]

I understand the problem determining the location at a certain time, but if you can't localize it it doesn't mean it's not there. It's an interesting problem which I will think about. Btw the speed of light isn't the max. speed.

[davidgow77]

The problem of locality of the photon is that if you froze time it would look like an oscillating wave rather than a particle (wave/particle duality). And I absolutely guarantee you that nothing made up from energy can travel at super-luminous speed. Anything faster than light speed would, at very short distances, resemble teleportation, and would jump from one location to the next.

What is your reasoning for thinking that super-luminal speeds are possible?

[Omni]

If it looks like an oscillating wave then you didn't freeze time.