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I think you mean "What gives a photon its velocity?". Unfortunately, I cannot provide an answer.

Hi All!I wonder if some sharp heads can explain what is the driving force behind the movement of electromagnetic radiation - why does light move - if it does. Does light use some energy to move it self or it does not move any resistance?Thanks!Manjit_{<Mod edit - Formatted the subject as a question - please do this to help keep the forum tidy and easy to navigate - thanks!>}

There is only one driving force for everything. It is energy who changing to not so density energy!

Could c be different if spacetime were dramatically curved or warped? I'm thinkng of some of the extra-dimensional models such as RS2.

Thus the photons are stationary. Only space moves.

Quote from: DoctorBeaver on 28/09/2008 09:14:15Could c be different if spacetime were dramatically curved or warped? I'm thinkng of some of the extra-dimensional models such as RS2.I guess it could be but I suspect that 'c' is always the same within it's space-time frame, although that space-time frame could be distorted and, when viewed by a distant observer, could appear to be different. For example, if we could somehow distort a 1x1x1km volume of spacetime so that it fitted in to a 0.5x0.5x0.5km volume of space and then consider a photon of light passing from 'normal' space, through the 'compressed' region and then back into normal space, to a distant observer the distorted region of space would only appear to be 0.5 km across and light would seem to slow down when it traverses it. The photon of light itself, however, has actually had to travel a full 1km of distance to cross the 0.5km gap between the two regions of 'normal' space.This would be akin to the pair of clocks that end up recording different periods of time when one is moving and the other is not except that the two differing viewpoints record a different distance instead of time.

The only difference I can see between compression and warping is when the compression is linear across a region. If the degree of compression changed over distance then I'd say it was curved. I think []

A photon is mass/energy

The answer to this is simple.Photons do not contain rest mass. I would show you the math, but i can't be arsed doing all the math, but i will if you ask. It means, that rest mass is what stops a particle from displaying a speed which is similar to tht of the speed of light, because it would need an infinite amount of energy to do so, and even if it could the laws of conservation state it would require more than what the universe could yield, as i said in another thread. You can also say, according to relativity theory, a photon has no rest-inertia, where it can decelerate under a force. This was different to a mass who's acceleration can differ under material influence.

Instead, if you could see life from a photons point of view, it experiences no time whatsoever...

and if we are to trust relativity here, this MUST ALSO MEAN space as well, so a photon doesn't really go anywhere, according to theory.

In fact, because a photon can't move anywhere, it suggests that even if it did move at light speed (as in Dirac's Hole theory), it could go no where!!!! It would travel in jagged paths that soon converge on themselves again.

Quote from: Mr. Scientist on 24/12/2008 19:09:13The answer to this is simple.Photons do not contain rest mass. I would show you the math, but i can't be arsed doing all the math, but i will if you ask. It means, that rest mass is what stops a particle from displaying a speed which is similar to tht of the speed of light, because it would need an infinite amount of energy to do so, and even if it could the laws of conservation state it would require more than what the universe could yield, as i said in another thread. You can also say, according to relativity theory, a photon has no rest-inertia, where it can decelerate under a force. This was different to a mass who's acceleration can differ under material influence. Ok.QuoteInstead, if you could see life from a photons point of view, it experiences no time whatsoever... A photon's point of view doesn't exist.Quoteand if we are to trust relativity here, this MUST ALSO MEAN space as well, so a photon doesn't really go anywhere, according to theory.Incorrect. Think about it another time.QuoteIn fact, because a photon can't move anywhere, it suggests that even if it did move at light speed (as in Dirac's Hole theory), it could go no where!!!! It would travel in jagged paths that soon converge on themselves again.Did you smoke strong stuff? []

It meant that if something does anything in time, it must do it in space

QuoteIt meant that if something does anything in time, it must do it in spaceThis is not so. While the temporal dimension can be considered to be the same as the spatial dimensions, it does have different characteristics.For example...Think of a number.Divide it by two.Right - there we have created and then changed something in the temporal dimension without involving any of the spatial dimensions. The value that we were working with occupies zero spatial size and any numerical operation we perform upon it will have no effect in any spatial dimension.

Don't patronize me. I can assure you what i said was true.

For starters, according to Lorentzian Geometry, rotations in space are time dependant. This is what allowed Minkowski to develop a mathematical ntheory based on Einstein's Special Relativity Theory, making space time, and time space. They where the same, being called the ''four dimensions of space,'' with time being the ''imaginary space dimension.'' It meant that if something does anything in time, it must do it in space. This is a basic law of relativity.

And your latter comment only shows how ignorant you are of phsyics.

Diracs Hole Theory, was his prediction of positron, a positive anti-electron. If two electrons woud be created from one place, would experience entanglement. But it also meant, that when the electron was created from the vacuum, its birth created an anti-partner: This meant the real particle left behind a hole. His theory worked so well, it corrollated strongly with Pauli's Exclusion Principle, where electron must obey energy patterns of cancellation, was in fact, the grail, and meaning of why we have the materials we have today.

Inelegance of Dirac seaDespite its success, the idea of the Dirac sea tends not to strike people as very elegant. The existence of the sea implies an infinite negative electric charge filling all of space. In order to make any sense out of this, one must assume that the "bare vacuum" must have an infinite positive charge density which is exactly cancelled by the Dirac sea. Since the absolute energy density is unobservable—the cosmological constant aside—the infinite energy density of the vacuum does not represent a problem. Only changes in the energy density are observable. Landis also notes that Pauli exclusion does not definitively mean that a filled Dirac sea cannot accept more electrons, since, as Hilbert elucidated, a sea of infinite extent can accept new particles even if it is filled. This happens when we have a chiral anomaly and a gauge instanton.The development of quantum field theory in the 1930s made it possible to reformulate the Dirac equation in a way that treats the positron as a "real" particle rather than the absence of a particle, and makes the vacuum the state in which no particles exist instead of an infinite sea of particles. This picture is much more convincing, especially since it recaptures all the valid predictions of the Dirac sea, such as electron-positron annihilation. On the other hand, the field formulation does not eliminate all the difficulties raised by the Dirac sea; in particular the problem of the vacuum possessing infinite energy.

You are kidding yes?

I can't believe this around here

What knowledge of this subject do you possess? Because it sounds right now like you know very little...

LeeE?Isn't this called 'spacetime'.

LightarrowI was speaking about the electron moving at lightspeed, was i not? This is a consequence of wedding relativity and quantum mechanics together; and whilst there are inelegences of the Dirac Theory, it is however a theory with most of its components with good experiemental and observational qualities to that of reality, such as the prediction of an existence of an opposite electron. Right, you want me to go over the comments:Can you explain better what means: "In fact, because a photon can't move anywhere" "Instead, if you could see life from a photons point of view, it experiences no time whatsoever""it suggests that even if it did move at light speed" (why, a photon does NOT move at light speed? )1] A photon, from its frame of existence, makes it a null path through the four dimensions of space. This means, because moving at the speed of light freezes all moments passing outside, it can't go anywhere! If you could travel up to the speed of light, you would notice movement outside slowing down, and upon reaching lightspeed, it stops completely, including your trajectroy along a given distance. 2] If it doesn't move through a distance in space, Minkowskian Geometry of Relativity leaves the experience of time as well obsolete. Because you cannot have a rotation in spacetime without a movement in time, it makes both space and time not only complimentary, but also invaraint under being the same thing, hence ''spacetime.'' So if you move through no space at lightspeed, you also experience no time.3] No the point was, ''despite knowing it moved at lightspeed,'' because from our point of view (the only point of view which remains valid), is that a photon does travel across distances. But from its point of view, it goes no where.

Mr S you say that " upon reaching lightspeed, it stops completely, including your trajectory along a given distance. "I kind of like it Even though my headache now reaches Gigantic proportions...Because what you are introducing here is what our 'thinking photon' would notice.If time is bound to acceleration/'uniform motion' and those other three dimensions that give us what we call 'distance'.But I would first expect this proof to work out mathematically as well?We use three spatial dimensions for defining our 'place' in a 'uniform' space.The fourth is for relating that point in and to, you guessed it, 'time'.But as LeeE described, one could 'look away' from time by define our object to the exact same spatial references not caring for the time passing.Even though it's 'impossible' to do as I see it (for now:), if we could, then motion and distance would become something else.If this statement is correct then either 'time' is something we don't describe right, or those other 'coordinates' we use is a direct outgrowth of 'time'.Or is there some better way to look at it?

Now I don't know what to say Mr. S.To me time seems to be crucial for my understanding?(for now, and always:) I think I can follow what you write here.And the most interesting idea you lift forward, to me, is the one about "I could show some Cardesian Coordinates as highlighted by special relativity, we would see that space is entangled with the time variable. It acts just like an space dimension, and so, is irremovable from space itself. So time becomes, ''spacetime.''"It's very elegant, and if one consider a photon, then there can be no 'travel' if it's considered a 'particle. The problem seems ( at the very least two folded.Either it is 'double-edged' and somehow choose/becomes 'forced' to express its wavelike attributes while traveling?Or it is 'us' that somehow makes it express 'one' of those attributes by observing.Our experiments define/locks the outcome so to speak.But when you come to 'time' you lose me?You write"As for describing time, we have a theory, the only vague interpretation of Minkowskian Geometry, is the Neuroscientific Theory of Consciousness concerning the psychological arrow of time, and various concepts thus relating the physical and the subliminal."I absolutely agree to that we will need to explain/understand consciousness as that is 'the observer' and without a observer, our questions (and therefrom answers) wouldn't 'be'.Also in some QM phenomena it is very 'visible' that our observing do have an 'effect'.But the theory you are considering?"the Neuroscientific Theory of Consciousness concerning the psychological arrow of time, and various concepts thus relating the physical and the subliminal." It is new to me, and 'subliminal'.Below the threshold of conscious perception?I will have to know a lot more on how it treats spacetime to even dare to have a view there:)But I do not doubt that you have thought about for quite some time.Is there any experimental evidence for those thoughts that you could lift forward?No offense meant here.It's just new to me.