Naked Science Forum
On the Lighter Side => New Theories => Topic started by: mikeh. on 13/11/2011 08:58:05
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I'm responding to a previous question but the last response seems to have been in 2009.
Time does stop for photons - travelling at the speed of light, but if it does then the very idea of 'distance' must too. If 'distance' were a 'real' quantity, it would always take time to traverse it. No time, no distance. For a photon then, and in a Kantian spirit, existence itself must be devoid of time and space. This suggests that from a photon's 'point of view' existence is a featureless singularity of an infinitesimally short duration.
These conditions hold within only the frame of reference of movement at the velocity of light. But if photons, - which move at the velocity of light, exist in a timeless and dimensionless frame of reference, by definition velocity or movement of any kind cannot exist. How can velocity decrease as it increases?
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Hi Mikeh (is that Mike H or Mikeh - just curious) - SR which is the basis of these thoughts does not allow for the frame of reference of photon. Good question - but very complex and difficult, if not impossible to answer.
Not sure about why you mention Kant - I think of Kant in terms of necessity of experience; all of our physics states that nothing capable of experience or even of change (ie massive / non fundamental) can ever travel at the speed of light. we can experience and experiment and through logic move from subjective senses to objective theories - nothing that is able to travel at c can do this and to criticise the theory from this angle seems unjust
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Everything moves at the speed of light through the spacetime continuum, but the faster it moves through space, the slower it moves through time (and vice versa).
So time only stands still for photons moving through a vacuum, where their speed through space equals c (the speed of light in vacuum) and thus their speed through time equals 0. As soon as a photon travels through another medium, ie air or water or glass, it's speed through space will be a very small amount lower than c and that very small amount will be converted to "speed through time", so a photon, in my opinion, does age whenever it's not traveling through vacuum. Therefore, from the point of view of a photon, existence is not a featureless singularity of an infinitesimally short duration, but more like: "The big bang? Oh, wasn't that the day before yesterday?"
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Everything moves at the speed of light through the spacetime continuum, but the faster it moves through space, the slower it moves through time (and vice versa).
So time only stands still for photons moving through a vacuum, where their speed through space equals c (the speed of light in vacuum) and thus their speed through time equals 0. As soon as a photon travels through another medium, ie air or water or glass, it's speed through space will be a very small amount lower than c and that very small amount will be converted to "speed through time", so a photon, in my opinion, does age whenever it's not traveling through vacuum. Therefore, from the point of view of a photon, existence is not a featureless singularity of an infinitesimally short duration, but more like: "The big bang? Oh, wasn't that the day before yesterday?"
hmmm - not sure about that Nizzle. Whilst the propagation of a signal will be slower through a medium - at no point will you be able to catch a photon doing anything apart from c. Heuristically the signal delay is down to absorption and re-emission of quanta by the atoms of the medium - but the travelling of individual photons is always at c between interactions. there is no bit of the spacetime metric to put the time spent in interaction to calculate the spacetime interval. and if this was the case you would have the problem of photons accelerating and decelerating and the concomitant forces etc.
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These conditions hold within only the frame of reference of movement at the velocity of light. But if photons, - which move at the velocity of light, exist in a timeless and dimensionless frame of reference, by definition velocity or movement of any kind cannot exist.
If space length and time duration cannot be defined for photon, how then a frame of reference for photon (i.e. a frame of reference moving at speed of light) would work?
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If time stops for photons, how do they red or blue shift?
Photons like electrons are unchanging so essentially ageless. You could as easily say time does not exist for electrons.
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Time stopping for photons is a popular misreading of special relativity. SR determines time dilation for massive particles travelling at below c - to extend the equations of time dilation to photons which are masslss and travelling at c is just not correct; ie there is no such thing as the local frame of a photon.
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Time stopping for photons is a popular misreading of special relativity. SR determines time dilation for massive particles travelling at below c - to extend the equations of time dilation to photons which are masslss and travelling at c is just not correct; ie there is no such thing as the local frame of a photon.
Isn't that just a way of saying the math breaks down so SR can't provide an answer?
There is some empirical evidence that photons are "immune" to time. While everything else seems to decay, it seems that photons don't.
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Time stopping for photons is a popular misreading of special relativity. SR determines time dilation for massive particles travelling at below c - to extend the equations of time dilation to photons which are masslss and travelling at c is just not correct; ie there is no such thing as the local frame of a photon.
Isn't that just a way of saying the math breaks down so SR can't provide an answer?
There is some empirical evidence that photons are "immune" to time. While everything else seems to decay, it seems that photons don't.
It's not just that the maths breaks down - although no one ever likes trying to divide by zero; but the theory has limits - it deals in flat space and massive, thus, sub luminal particles. photons might not decay because of a time thing, or because they are truly elementary, or because we just haven't noticed it happening.
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or because we just haven't noticed it happening.
Oh, I think we would. They would be redshifted, so everything would look like it was retreating from us
(thinking)
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- wait a minute!
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Mike, as far as I know 'photons' know where to go. And if they do, then they 'navigate' inside our time, as observed by us. To ask what a 'photon' sees is another thing. According to main stream definitions they propagate at 'c', which is a unchanging constant no matter from where you measure it, or how fast.
If you think of it then that is a very strange property. As far as I know nobody can answer why radiation behaves that way. You might refer it to 'time' possibly, which is another weird property according to the theory of relativity. Both time and 'c' stays the same for you, as measured locally. And your relative motion doesn't matter for that, neither does what mass you are on, as a neutron star.
It's the rules of the game. And trying to see why those rules exist, and what one would see when at that 'edge' of reality is very difficult. We know what we expect mass to see, when gaining a relativistic velocity, near lights speed. But that is mass, not bosons.
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or because we just haven't noticed it happening.
Oh, I think we would. They would be redshifted, so everything would look like it was retreating from us
(thinking)
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- wait a minute!
protons are expected to decay, are certainly not travelling at such a speed that "they are frozen in time" (hateful concept), and we have never noticed one of them decaying
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or because we just haven't noticed it happening.
Oh, I think we would. They would be redshifted, so everything would look like it was retreating from us
(thinking)
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- wait a minute!
protons are expected to decay, are certainly not travelling at such a speed that "they are frozen in time" (hateful concept), and we have never noticed one of them decaying
Yes - protons are difficult to observe, but photons seem to be able to travel trough all of time without any difficulty at all.
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Of course, gluons (the only other massless particle we know about) decay so quickly that none have ever been observed. We detect them through their decay products.
So half the massless particles we know about seem "immune" to time, while the other half seem to grow old and die very quickly.
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Photons maintain information over billions of light years, such as red or blue shift and luminosity. Which is why we have information from type 1A supernova. If this information was not 'frozen' then the expansion of the universe would be undetectable.
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"time" does not "stop" per se, for photons. Time is an observation of progression or expansion.
A photon leaves a distant star, say 1 million light years distance from observer, 1 million years later Photon arrives at observer.
progression of said photon, never stopped. Hence "time" per se, never stopped for the Photon.
If a photon experienced "time stop", then basically it stops moving, instantly....of course this is not observed....
Time is a funny thing, and may not even be anything at all, but an observation...
Of course all of this, make no sense at all..........but it is reality......ha ha
if you think about "time stopping" hence progression or expansion stopping, then at a "time stop", then time stops.....nothing moves, electrons stop orbiting protons n neutrons, elements stop spinning, energy ceases to exist, all particles stop moving, spinning, etc.etc.....
if "time" ever did stop, per se......existence stops at that point also............end of all progression and expansion
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What we cannot tell is if the photon is actually flat-lining until we detect it. It may only express its wavelength and other properties at the point it is absorbed. Like schrodinger's cat we may have to open the box to see it's state. The fact that matter undergoes time dilation until, if it was ever possible to reach light speed, it goes into a state of infinite dilation where time has no meaning, points to a frame where time does actually stop in THAT frame of reference.
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The fact that matter undergoes time dilation until, if it was ever possible to reach light speed, it goes into a state of infinite dilation where time has no meaning, points to a frame where time does actually stop in THAT frame of reference.
If time actually "stopped" for that frame of reference, then inside of that frame of reference, movement is not possible, nor is energy, nor is mass, nor is gravity, nor is any force operating in a frame of reference that time has "stopped" inside of.
I do not believe it possible for "time" ( progression, expansion/decay, etc )to stop and then have all these things and others to "stop" all at once.
In a state of time stop.....time stops.....you can not escape from no time, into time,
if you are in time stop.....
then for you.............................. time stops,
and you break down into elementary particles, and you cease to exist......as all stop spinning and orbiting, etc.....
time stop is infinite.....................for the frame of reference that it happened in...hence not possible for a photon to have "time" stop ( per se ) for it......mainly because time is not a thing, but an observation,
and the main, and key point...
a photon can not observe, so in essence "it" has no frame of reference....
and nothing that observes can travel at the speed of light to observe the effects anyways....
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I believe that the statement you made about breaking up into elementary particles at light speed is very interesting. Simply because the elementary particles would be unable to travel at this speed. They are not photons and have mass. Length contraction is of interest in this case though, as a particle seen as infinitely contracted (there's that infinity again) would not exhibit mass. It may well be expressed simply as energy where this has swapped places with mass. I know that is a bizarre concept but aren't quantum physics and relativity bizarre?
In the mass of a photon topic you posted the relationship p = E/c. Maybe it is momentum that has interchanged with mass. Interestingly this equation would give c=E/p showing that how fast the object travels affects the energy and shows a direct proportionality.
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By the way the relationship p=E/c indicates that a rest frame is impossible just like light speed travel is as nothing can ever truly be at rest with respect to the rest of the universe. This relationship also appears to show the impossibility of reaching absolute zero. As photons reach light speed, which is impossible for other particles, could another undiscovered particle only exist at absolute zero?
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yes a photon is a funny thing, it makes the rule, then seems to break the very rule it made, lol..
unfortunately no one can ever travel at the speed of light to observe exactly the effects this has, but maybe one day there can be a experiment to "observe" this frame of reference, but I doubt it.
here is an article that explains it better then I ever could.
( link for this article on precious post )
Does the photon have mass? After all, it has energy and energy is equivalent to mass.
Photons are traditionally said to be massless. This is a figure of speech that physicists use to describe something about how a photon's particle-like properties are described by the language of special relativity.
The logic can be constructed in many ways, and the following is one such. Take an isolated system (called a "particle") and accelerate it to some velocity v (a vector). Newton defined the "momentum" p of this particle (also a vector), such that p behaves in a simple way when the particle is accelerated, or when it's involved in a collision. For this simple behaviour to hold, it turns out that p must be proportional to v. The proportionality constant is called the particle's "mass" m, so that p = mv.
In special relativity, it turns out that we are still able to define a particle's momentum p such that it behaves in well-defined ways that are an extension of the newtonian case. Although p and v still point in the same direction, it turns out that they are no longer proportional; the best we can do is relate them via the particle's "relativistic mass" mrel. Thus
p = mrelv .
When the particle is at rest, its relativistic mass has a minimum value called the "rest mass" mrest. The rest mass is always the same for the same type of particle. For example, all protons, electrons, and neutrons have the same rest mass; it's something that can be looked up in a table. As the particle is accelerated to ever higher speeds, its relativistic mass increases without limit.
It also turns out that in special relativity, we are able to define the concept of "energy" E, such that E has simple and well-defined properties just like those it has in newtonian mechanics. When a particle has been accelerated so that it has some momentum p (the length of the vector p) and relativistic mass mrel, then its energy E turns out to be given by
E = mrelc2 , and also E2 = p2c2 + m2restc4 . (1)
There are two interesting cases of this last equation:
If the particle is at rest, then p = 0, and E = mrestc2.
If we set the rest mass equal to zero (regardless of whether or not that's a reasonable thing to do), then E = pc.
In classical electromagnetic theory, light turns out to have energy E and momentum p, and these happen to be related by E = pc. Quantum mechanics introduces the idea that light can be viewed as a collection of "particles": photons. Even though these photons cannot be brought to rest, and so the idea of rest mass doesn't really apply to them, we can certainly bring these "particles" of light into the fold of equation (1) by just considering them to have no rest mass. That way, equation (1) gives the correct expression for light, E = pc, and no harm has been done. Equation (1) is now able to be applied to particles of matter and "particles" of light. It can now be used as a fully general equation, and that makes it very useful.
Is there any experimental evidence that the photon has zero rest mass?
Alternative theories of the photon include a term that behaves like a mass, and this gives rise to the very advanced idea of a "massive photon". If the rest mass of the photon were non-zero, the theory of quantum electrodynamics would be "in trouble" primarily through loss of gauge invariance, which would make it non-renormalisable; also, charge conservation would no longer be absolutely guaranteed, as it is if photons have zero rest mass. But regardless of what any theory might predict, it is still necessary to check this prediction by doing an experiment.
It is almost certainly impossible to do any experiment that would establish the photon rest mass to be exactly zero. The best we can hope to do is place limits on it. A non-zero rest mass would introduce a small damping factor in the inverse square Coulomb law of electrostatic forces. That means the electrostatic force would be weaker over very large distances.
Likewise, the behavior of static magnetic fields would be modified. An upper limit to the photon mass can be inferred through satellite measurements of planetary magnetic fields. The Charge Composition Explorer spacecraft was used to derive an upper limit of 6 × 10−16 eV with high certainty. This was slightly improved in 1998 by Roderic Lakes in a laboratory experiment that looked for anomalous forces on a Cavendish balance. The new limit is 7 × 10−17 eV. Studies of galactic magnetic fields suggest a much better limit of less than 3 × 10−27 eV, but there is some doubt about the validity of this method.
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I believe that the statement you made about breaking up into elementary particles at light speed is very interesting.
I said they break down in a "time stop", but I do not believe a stop of progression is possible..
here is my quote.
In a state of time stop.....time stops.....you can not escape from no time, into time,
if you are in time stop.....
then for you.............................. time stops,
and you break down into elementary particles, and you cease to exist......as all stop spinning and orbiting, etc.....
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Which theories predict massive photons? I have been looking around for that and haven't found anything.
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A quick thought on the absolute zero particle idea. If a particle can be emitted that has a continuous absolute zero state then this could explain singularities.
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Which theories predict massive photons? I have been looking around for that and haven't found anything.
here you go. The so-called Proca action describes a theory of a massive photon
http://en.wikipedia.org/wiki/Proca_action
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The Feynman Diagram on that link shows an electron/positron annihilation. Is that an illustrative or functional representation? If this relates to annihilation then does this mean only those types of photons are massive?
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I know that electron/positron pairs can be produced by high energy photons.
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I appreciate the posters comments that refers to photons as 'unchanging so essentially ageless" as well seemingly 'immune to time."
I believe that the photon represents the original innate state of all that is. The photon(s) represents the innate energy that existed solely by 'itself' before it began to express itself in ways that could be viewed as less ageless or even as radioactively decaying or ceasing to exist...by relative observers. Photons are eternal in duration. The infinite state of the photon goes both directions, backward in "time" or forward in "time. Everything else that is not the true nature of the photon represent energy or mass that is afforded energy or mass from the ever present photon. This would mean that all energy and mass that we perceive, though receiving their mass or energy from this source proton state, are dependent upon this source for the experience of or duration of ...time. This would at least seem to bespeak that the proton state is a a state of intelligence with the prerogative of either increasing or decreasing the time allotment given to each photon.. representation. We may go as far as saying that entropy is afforded to the borrower of the photons energy, and as the one side makes choices ( side A= photon) the other side is allowed to make choices as well. An entropic energy exchange.
While the mass or energy is afforded "time"( by "the" photon side) the experiences of that time and how long that time lasts is determined by the equally as scientific realization. That of the presence of entropy in the system. This would dictate that the photon side is immune to any and all changes ( good or bad entropy) and can adapt instantaneously and efficiently to all changes in the system. This would not be true of all other energy or matter that is not innately photon.
I think that ...Entropy... should be considered more so when discussing this quirky thing called: Time. What is it about the photon that establishes and seems to drive or maintain the ebb and flow or flux of radioactive decay..while itself remaining perfectly intact and seemingly inexhaustible?
Time does not stop for the photon..no matter what medium it enters. I believe this is a wrong perception. Rather time starts for whatever product or existential results from when photon enters a medium or even reflects from the surface of a medium in the path of light. We do know what happens when pure light enters into a prism and is refracted. We know that a light source can also be communicated from one point to another via the principles of reflection. Though the light( or photon..necessarily) has its established place ..it can be represented at any point outside of its place via refraction and reflection. In essence the photon can be in two places at one time though separated by huge distances. As it concerns our universe full of many points taking on myriad of different forms and attributes...we see that "the" photon could be communicated to any or every point and thus the universe be comprised of photons being refracted and reflected and thus the result describing the qualities of the photon. This would seem to imply that the photon has an infinite number of ways of expressing itself.
I will try to explain how the 'very idea of distance" as stopping is not necessary just because time is perceived as stopping relative to the photon. Imagine that the photon is a light and energy source ( as it is). Imagine that the source light ray is traveling through space. Imagine that the light hits a reflective substance and thus its light and energy communicated to the plane surface. Has the light photon stopped its progression. No. Its light is reflected off of the surface. As well its energy and light is refracted. Would we say that the photon ceases it's progression? We may be tempted to draw such conclusion. However if we introduce another reflective plane into the equation and face it toward the first plane surface then the photon that seems to stop its forward progression at the surface of the first mirror ..now is communicated to the surface of the second mirror. This represents the light photon actually reproducing verses stopping or ceasing progression. As well we must consider a very interesting other phenomenon that occurs. Once the innate energy of the photon is 'planted' on the first mirror it is then planted on the second mirror due to the relativity surface reflections of both mirrors. What occurs next? When these 3 factors ( 3 vectors come into relativity..one photon..2 reflective planes receiving the image of the same proton upon its surface) occur then a strange sort of instantaneous photon propagation happens. That is when two mirrors facing one another receive the same image of the photon they then begin to copy the photon and continually reproduce the photon back into the mirrors. This sort of continual symmetry will further multiply as another or other mirrors perspectively are placed into the scenario ..where all faces of the mirrors are at least facing one of the preceding mirrors. Thus photons in this way...already Infinite in nature continue to expand itself and continue to be represented. In this way...ONE REALLY BIG PHOTON..could represent itself at any and all points in a universal ( or universes) system.
Thus the only distance that would be real would be the distances between mirrors or the distance between each perspective mirror to the photon source. If we are looking at a universe and concluding that all distances between all masses objects represent true distance we may be forgetting that ..if the scenario I am explaining were indeed occurring..many of the perceived distances represent the reproduction effect that happens when two reflective surfaces face each other. That is to say. Which masses that we see are occurring on the surface..and which are occurring because two mirrors facing each other reproduce the same image over and over. This would seem to say that their is a horizon to our universe ( a surface) and the space of the universe ..filled with mass spots ...is behind the surface and represent merely continual symmetries being reproduced from said surface. The horizon of the universe would represent where the entire universe is receiving information on its surface ( A circumference or a plane) ..recieving ALL information bits from a source outside its reflective skin/membrane/circumference/wall
If this were so this would preclude any idea that the photon is limited in its ability to communicate itself to any and all points.
If I place a ball between two mirrors then we would have to admit that only the ball is really and truly a ball. We could go as far as saying that the first ball that appears in mirror one and 2 is more accurately representative of the ball ( photon). Yet all of the other successive balls that appear get farther and farther away from representing the ball accurately. Most certainly we should conclude that the only true distance that is relevant and perhaps really occurring would be:
1) The distance from the ball to the SURFACE of the first mirror
2) The distance from the ball to the surface of the second mirror.
All other distances that occur between each successive reproduced ball is merely reproducing the real established distance between the ball and the surfaces of both mirrors.
In this illustration true distance as a "real quantity"` ( verses perceived due to the illusion of the expansion of mass and space and distance) should only be relevant from ball to each mirror surface. A distance that can be measured accurately. After this distance is measured..any further attempts as measuring would not be so disambiguous.
If this were so it would only take enough time to 'traverse" the distance between ball and surface..every other illusion of distance would be precluded from relevance. Yet this illusion is what may be exaggerating the human comprehension and making it harder to "traverse" the implications intellectually. While the photon exists innate and not constrained by time..Its light as received at other points does indeed take time. Yet this "traversing" in no way implicates the photon as time dependent. In fact it is the future creation that is time dependent and must wait for the time when the photon begins to reflect at their point. Once the photon( no time) reaches the reflective plane then "time" starts at that point. Time continues at that point ..or expires at that point...contingent upon whether or not the photon remains relative to that point or departs from relativity.
Yet may it not be said that the photon as communicated to reflective points..is "featureless." The existence of our universe is proof that the photon is infinitely full of ''features." However when the light of the photon is transferred to another point( through reflection/refraction) then a singularity is born at that point. That is the singularity between the photon and the photons image represented upon the plain or through ann aether. In comparison to the innate existence( never had a beginning nor will have an end) of the photon..no reflected point can ever say that they can compare to this infinite time existence. So Indeed! All reflective points that have, do and will..reflect light photon( and qualitative energy of photon) are merely a 'short duration."This would be true even if a particular reflective point was maintained forever. Though this forever mass or energy would not have an end..it DID have a beginning. Such cannot be said of the origin of or actual personification of photon.
As for the commenter's next statement( very astute).."But if photons, - which move at the velocity of light, exist in a timeless and dimensionless frame of reference, by definition velocity or movement of any kind cannot exist. How can velocity decrease as it increases?
I will attempt to explain using the same reasoning and methodological approach..utilizing the principles of reflection.
A photon may move at the velocity of light in a forward progression. True. However a photon need not move at all to appear to constantly maintain the speed of light. So long as reflective mediums are relative to the motion or non motion of photon the mirror as well mirror to mirror reflection can create the perception of motion as well speed increased.
If I place a motionless ball in between two mirrors then move one mirror face away from the face of the other mirror..the ball as reproduced in either mirror will move. The faster I move the mirror away from the other the faster all reproductive images will move. I can move the mirror to the right and the reproduced continual symmetries ( super symmetry?). I can move the mirrors up and down and all points move either consistent with or exactly reversed. But we are talking about the IMAGES moving at such and such speed or such and such speed or direction. The ball between the mirrors( the photon being reflected ) is motionless! As well when one conducts these experiments they will see that the distance between each successive continual ball symmetry as reflected can either be expanded or contracted by moving either or mirror toward one another or up and down.
Is the source PROTON motionless. Is all the perceived motion and mass and energy that we perceive animated forms or representations of a single and motionless photon. Or is the PHOTON comprised of energy parts and its parts communicated to form and motion throughout the universe.
Big bang! A infinite light and energy source.. SUDDENLY... begins to reflect. Instantly when it reflects its representation quality and energy..forms..appear!
And yes! Photons " know" ( "smacks of intelligence) where to go.
Perhaps! The photon also knows where not to go..or how not to act if being observed in an inordinate way. 2 slit experiment?
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If the forward progression of a light photon seems to slow ..or is slowed due to entering a medium...if this medium is reflective and reflects to another mirror the light and speed communicated to a relative observer will seem to imply that though the light ray ( or foraward progression) has altered as to speed..the resultant reproduction of speed on the mirror surfaces will seem to say that there is an .."increase."
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well, photons don't need to 'move', as you point out Miro. We can assume a network of causality effects simulating a motion, creating a probabilistic reference mesh on a minimalistic plane that then according to some logic present what we call motion. That's quite acceptable to me, but then we have matter and its 'relative motion' inside SpaceTime? Matter fulfill all demands I can set upon measuring a motion, relative or not. And in a acceleration you assumingly won't need any other reference frame than your rocket for finding that 'motion'.
If I now, as all radiation according to my first statement do not 'move' but is a result from some other logic principle, simplified as 'motion' for us in our four 'degrees of freedom', meaning the arrow and our other three dimensions. How would radiation translate the 'motion' of matter? One can assume that as all mediation we have is through radiation it then becomes a simple problem, but it's not simple at all. Something would need to represent 'matter' in such a logical universe, but how would it do that? And why would it differ 'matter' from radiation as they all in this view becomes expressions of a same 'hidden' reality. And then we have the way the arrow act too.
=
Another thing complicating matter is that we find other 'forces' acting on/with particles than just EM. And they are there because of a reason as I understands it, they will not break down to radiation, although you may fit them to 'energy'.
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SR which is the basis of these thoughts does not allow for the frame of reference of photon.
If a frame of reference exists which would allow a rocket to travel in a single second (as recorded by its clocks) a distance which appears to most of the inhabitants of the universe to be a lightyear, then the distance for that rocket would be very short indeed - I make it 32 millionths of a lightyear, which means a mere hundred and eighty thousand miles (which is less than the distance to the moon). Such a frame of reference certainly does exist. The distance a photon would travel on the same route would be shorter than that. Ramp the speed of the rocket up and the distance it has to go reduces further, thereby further limiting the distance for the photon, so if the rocket did the trip in a millionth of a second by its clocks (and again there is a real frame of reference for that), then the distance of travel is reduced to a fifth of a mile. Ramp it up further such that the rocket is doing the trip in a trillionth of a second (which again has a very real frame of reference for it) and the distance is reduced to about a third of a millimetre. Clearly if you carry this on forever, you must end up with a photon covering zero distance for the trip, and doing it in zero time.
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A similar logic would claim that 1/0 is infinity - but it isn't; it is undefined in the realm of real numbers. In a similar way - within the auspices of Special relativity you cannot evaluate v/c as the simple limit according to common sense and an understanding of what it should be.
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Well, I've already taken a lightyear down to a third of a millimetre and the time for the journey being a trillionth of a second. There are ever more extreme frames all the way towards 0, so it would be easy enough to find one for any situation which (given that the photon is travelling faster) guarantees that the trip for the photon is, if you attempt to put a time and distance on it, so close to zero as to make no practical difference in any case you wish to explore. Some of the self-proclaimed experts on SR (who certainly know be capable of fooling me) who I've spoken to elsewhere do assert that photons do travel everywhere in zero time and covering zero distance - they step straight off one object and directly onto another which to us may appear to be billions of lightyears away, and then they can step straight back again, taking a shortcut billions of years into the future in the process. This appears to be a credible view of SR because a near identical case can certainly fit the theory where something moves a fraction slower than the speed of light, thereby covering the same trip in a distance and time too short to measure.
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I just got around to reading this thread, now cold for 9 days.
Physics in general and SR in particular refuse to address the ontological question, "What is time?" but go ahead and talk about it as if we all know what it is. Likewise "for this frame" describes one circumstance (not called 'reality', as there is no such thing, they say) while "for that frame" describes another... what... paradigm.
So the confusion proceeds as in claiming that "for a photon" there is no time or distance traveled. Yet we all know that it takes over 8 minutes for light (photons) to travel from Sun to Earth and 4.37 years (that's orbits of Earth around Sun, for those who may have forgotten) for light to travel from Alpha Centauri to Earth.
But not everyone here is so confused.
Emc2, reply 15:
A photon leaves a distant star, say 1 million light years distance from observer, 1 million years later Photon arrives at observer.
Yes, if a light source is a million light years away from an observer (a LY is a standard measure of astronomical distance), it will in fact require a million years (time) for those photons to travel the *distance* between source and observer.
(Yes, there is distance between things in space, not varying with how it is variously observed.)
"For those photons" no time elapsed and no distance was traveled??
This is another case of "science" going off the deep end into total nonsense in service to a dictum that insists that all frames of reference "see and measure" time and distance with equal validity... or in this case, make "time stop" and distance "shrink" to zero.
There is no paradox, just confused SR theorists who deny a "real world" and insist that each frame of reference creates its own "reality."
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just got around to reading this thread, now cold for 9 days.
Only 9 days! How about 120?
This is another case of "science" going off the deep end into total nonsense in service to a dictum that insists that all frames of reference "see and measure" time and distance with equal validity... or in this case, make "time stop" and distance "shrink" to zero.
Point taken, but this doesn't address David's reasoning in Reply #32.