Q: If a photon doesn’t experience time, then how can it travel?

Physicist: It’s a little surprising this hasn’t been a post yet.

In order to move from one place to another always takes a little time, no matter how fast you’re traveling.  But “time slows down close to the speed of light”, and indeed at the speed of light no time passes at all.  So how can light get from one place to another?  The short, unenlightening, somewhat irked answer is: look who’s asking.

Time genuinely doesn’t pass from the “perspective” of a photon but, like everything in relativity, the situation isn’t as simple as photons “being in stasis” until they get where they’re going.  Whenever there’s a “time effect” there’s a “distance effect” as well, and in this case we find that infinite time dilation (no time for photons) goes hand in hand with infinite length contraction (there’s no distance to the destination).

At the speed of light there's no time to cover any distance, but there's also no distance to cover.

At the speed of light there’s no time to cover any distance, but there’s also no distance to cover.  Left: regular, sub-light-speed movement.  Right: “movement” at light speed.

The name “relativity” (as in “theory of…”) comes from the central tenet of relativity, that time, distance, velocity, even the order of events (sometimes) are relative.  This takes a few moments of consideration; but when you say that something’s moving, what you really mean is that it’s moving with respect to you.

Everything has its own “coordinate frame”.  Your coordinate frame is how you define where things are.  If you’re on a train, plane, rickshaw, or whatever, and you have something on the seat next to you, you’d say that (in your coordinate frame) that object is stationary.  In your own coordinate frame you’re never moving at all.

How zen is that?

Everything is stationary from its own perspective.  Only other things move.

Everything is stationary from its own perspective.  Movement is something other things do.  When you describe the movement of those other things it’s always in terms of your notion of space and time coordinates.

The last coordinate to consider is time, which is just whatever your clock reads.  One of the very big things that came out of Einstein’s original paper on special relativity is that not only will different perspectives disagree on where things are, and how fast they’re moving, different perspectives will also disagree on what time things happen and even how fast time is passing (following some very fixed rules).

When an object moves past you, you define its velocity by looking at how much of your distance it covers, according to your clock, and this (finally) is the answer to the question.  The movement of a photon (or anything else) is defined entirely from the point of view of anything other than the photon.

One of the terribly clever things about relativity is that we can not only talk about how fast other things are moving through our notion of space, but also “how fast” they’re moving through our notion of time (how fast is their clock ticking compared to mine).

 

The meditating monk picture is from here.

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87 Responses to Q: If a photon doesn’t experience time, then how can it travel?

  1. sumoworm says:

    C does not equal infinite speed, it is a finite number. Therefore isn’t it accurate to say state that C’s time = 0 corresponds to its antithesis that space contraction at C = the plank length? Neither are infinite, both are the maximum/minimims in our universe.

  2. dylan says:

    light from the most distant galaxies has been traveling at 186,000 miles a second for 13.5 billion years, it would take thousands of trillions of years to reach us because it has been traveling at the speed of light, reason being when traveling at speed of light for 30 years 1000 years pass here on earth so the first photon waves to leave those galaxies should not have reached us yet. is this correct, if not, why. two people, one standing on the equator, one traveling around equator at 99….. % speed light, both have flash lights pointing at north star. they switch them on at same moment whose beam will reach the north star first

  3. jiohdi says:

    a photon traveling 13.5 billion years at light speed is just that… it does not take more than 13.5 billion years to arrive at earth from the point of view of a man on earth detecting its arrival… if there were another man traveling on that photon, it would seem like no time had passed at all for him, because he is essentially not moving relatively speaking… but if he were a real man with real mass, he would have become a black hole singularity and would never ever again notice any time at all… hyper-dimensionally speaking he would be precisely where he started in the 4th dimension, even though he would have moved in the other three dimensions… as did the rest of the universe around him, so he is basically down a very very deep gravity well that is now 13.5 billion light years deep.

  4. dylan says:

    very interesting

  5. FD says:

    I still don’t understand.. Let’s focus on length contraction. I am observing a light ray coming in from a distant star. Length contraction tells me that the distance between every pair of photons in the ray should appear to be zero to me, but in fact it doesn’t: I can put a synchronized clock on a spaceship stationary with respect to me, located on the straight line between myself and the star, and I can measure the distance between a pair of photons this way, and it won’t be zero. Where’s the catch?

  6. jiohdi says:

    I am observing a light ray coming in from a distant star. Length contraction tells me that the distance between every pair of photons in the ray should appear to be zero to me…

    1. Length contraction only exists for massive objects that warp space-time.
    2. the reason that length contraction happens at all is to ensure that no object can be observed by anyone as greater than light speed. Photons are traveling at light speed and will be measured as such.

  7. Tracy says:

    Just some thoughts…

    So, from the frame of reference of a photon, the photon as we experience it does not exist. There is only a probablity that energy is transferred from one mass (an atom) to another. The type of energy transferred is characterized by the normal electromagnetic parameters we assign to photons. (Simplified, yes, for the moment let’s not discuss electrons, orbitals, directions, etc.)

    In example, a photon travelling from an atom in a star in galaxy we describe as 13.5 light years away hits a detector on the Hubble Space telescope. The probability of those two masses transferring energy is very low but it happens anyway, and its effect is to lower the energy transferred exponentially (inverse square).

    In the ‘mass world’ the Hubble detects a photon (or a bunch from a very localized area in the blackness of space) with very low energy and we back calculate a distance of 13.5 l/y. Anyway, we assume that si where this really big galaxy is, because that answer is consistent with other measures we have (in other words, it’s not a microscopic low energy mass only 3 miles away, because we could tell the differnce using parallax, etc.)

    Subsequently, if in the photon frame of reference it does not exist, there is no such thing as a free photon just shooting off somewhere. It only exists as a transfer of energy between mass objects.

  8. joey says:

    – The photon does not experience elapsed time and can cover any distance in zero time.
    In effect, a photon can be everywhere at once. This implies that there is no need for more than ONE photon in the universe.

  9. Tracy says:

    Interesting, but pondering what a photon is ‘experiencing’ can only be done when considering the relative frame of reference. In the zero-mass frame of reference: there is no time, there is no distance, energy is transferred between mass objects instantaneously (and all the mass objects are in one place that has no dimension to it), there is not the need for any photons, because they do not exist in that frame of reference.

    However, from the mass world’s frame of reference (where you and I do experience things) photon’s appear to be flinging about everywhere. We perceive the transfer of electromagnetic energy between masses much differently, imparting both dimensions of time and distance between the masses and placing the now existent photon (our definition of the phenomenon) between them.

  10. Ric Adams says:

    Time is a measure of changing relationships. Time tending to zero for massive objects means that the mass tends to infinity and there is no energy or force capable of moving them from that final state. A photon has no mass and so there is no need to say its time is zero. From any perspective you can measure photons do change relationships with the rest of the universe and can always be measured to do so at the speed of light.

  11. Xerenarcy says:

    to help clarify this… if you were to draw the line of simultaneity for a photon on a minkowski diagram (SR only for simplicity), it would be parallel to the photon’s path through spacetime. that easily confirms that the photon experiences a single instant only, what is more difficult to prove is its ‘motion’ whether apparent or physically real.

    well… at rest our notion of ‘simultaneous’ is anything happening parallel along the time axis. since a photon’s time component is zero, its motion (if any) must exist entirely on it’s axis of simultaneity. because photons can travel an arbitrary ‘distance’ and have an observable ‘motion’ (position dependent on or can be a function of time), the path it takes does have to have a ‘length’ or ‘magnitude’ of some sort in all reference frames if you avoid using reference frames that yield singularities (such as zero-distance analogies).

    the motion of a photon, if not space-like, must then be time-like to the point of view of a photon. (to summarize) this is because all apparent motion must have parallels in all reference frames; singularities arise only because of poor choice of coordinate systems, and a zero-distance interpretation implies a singularity has arisen.

    so then to restate the question unrelated to photons specifically – can time-like motion experience time?

  12. Rpahut says:

    It is the perverted corpuscular idea of a photon we get from our daily lives, I have learned, what leads to all the questions about its motion and speed. The answers are not to say simple, but rather questions themselves should have no place if you understand what the photon really is (or what it isn’t).

    Note that the photon is from the bosons family. Photon carries light just as gluon “carries” the strong force, or higgs boson “creates” the mass. They are used in physical models and proved themselves useful as proxies in interactions (for the lack of better alternatives), but outside of the equations they make very little sense.

    No one have ever observed a boson for example. The only way to know there is a photon is to get it absorbed by an electron – but then there is no photon any more, and it is still a question if there was one to begin with. All we know is that one electron somewhere emitted a portion of energy and then another somehow received it. There is definitely no ball of light traveling through the space between them, as was demonstrated by the double-slit experiment all the way back in 1800′s, so the question “how can photon travel” actually became invalid long before it could have come to any of our heads.

  13. Bryan says:

    Photon’s don’t travel. Photons are everywhere at the same time as they are infinitely big.

    If you want to see Einstein’s thoughts on this then google “spooky reaction at a distance”. The misnomer in that name is “distance”, not “spooky”, because there is no distance. As long as you keep that in mind you’ll be able to a) understand “perfectly”, no PhD required, and b) appreciate the genius Einstein really was (well beyond e-mc2).

  14. Orien Rigney says:

    If a photon experiences no time in its travel between objects and is every where at once, doesn’t that make using “red shift” as a means of measuringe distance between stars and galaxies a waste of time? Now I am just a bit confused as to why it isn’t light all of the time? Perhaps my ignorance is causing me to miss something here???

  15. Xerenarcy says:

    @Orien
    redshift is used in conjunction with brightness to determine distance. at first we only had brightness to go on, but after noticing that things appear to be receding from us the further you go (correlation with redshift) we realized we could use this fact backwards – that the redshift indicated the recession velocity and due to the correlation, distance as well.

    after thinking on this for a while i’ve come to believe that ‘photon’ is a label in the same way that ‘wave’ describes a propagating distortion. perhaps a simple way to explain this distinction is conways game of life. specifically gliders (http://en.wikipedia.org/wiki/File:Gospers_glider_gun.gif)

    in the same way a photon is, in one sense, an self-sustaining oscillation of the electric field which due to the nature of the oscillation itself, ends up moving through the field (if it were stationary or could slow down, the oscillation would likely disappear / disperse). what this would imply is the field itself must experience time, since without time-evolution occurring the photon could not propagate to begin with.

    in that respect it makes no sense to talk about ‘the experience of a photon’ for the same reason it makes no sense to talk about the motion of a dot of light from a laser pointer – regular matter cannot hold itself together from exchanges via ripples in a field if it begins moving at the same speed as these ripples. in fact it is academic to show how this slows down time for matter as it speeds up relative to something, without having to touch the rate of time-evolution of the matter or the relative observer.

    basically the rate of time evolution looks to be independent from time dilation of electromagnetic interactions, commonly attributed to actual time passing. due to this it is not impossible for a photon to experience time, however this notion of time is quite abstract – it is not the same notion of time you would ascribe to anything of human experience; if there is a locally absolute time in some form, this would be it.

  16. Orien Rigney says:

    Thanks Xerenarcy! I do get the gist of your statements: But, it seems the deeper I dig, the wetter I get. To me, light is light no matter at what part of the spectrum(freq,) we are looking. Then I see the superluminal properties Einstein speaks of, and knowing nothing of calculus or physics, I’m stuck. Perhaps you might run this by me so I may get a better understanding. Thanks http://www.nature.com/nature/journal/v406/n6793/abs/406277a0.html.

  17. The Physicist The Physicist says:

    @Orien Rigney
    There’s a post here that talks about some of those superluminal experiments. You’ll be happy/disappointed to know that no physical thing actually goes faster than light, even in these bizarre experiments.

  18. Orien Rigney says:

    Thanks again Xerenarcy!
    Am I thrilled that I’m ignorant, of course not! But it does open an even larger can of worms for me to contemplate. In a sense then, we’re earth bound other than visiting our relatively small solar system? Trying to stay within the subject matter, knowing that C is max., how can we even think of traveling to another star system. While I’ve heard of a generational transport ship of some sort getting us possibly to Alpha Centauri B, time wise it reminds me of an old TV series starring Lorne Greene. In just so many words, wouldn’t it be far more conducive for everyone involved to use their knowledge making our planet a more habitable world?

  19. Xerenarcy says:

    yup. so far there has not been a single physical thing conclusively observed to move faster than the speed of light. but in that experiment and in the linked post explaining it, we are not dealing with a physically real thing, so conventional notions of ‘speed’ and ‘position’ (amongst other things) would not always or necessarily apply.

    and for the record our planet is the most habitable we’ve found, after all, we’re on it. we don’t really know how to improve it, and when we think we do, we either screw it up royally or can’t agree on what to do. (im a social cynic, don’t listen to me)

    just thought this section on good old wiki would help explain my argument a bit better – http://en.wikipedia.org/wiki/Maxwell%E2%80%99s_equations#Vacuum_equations.2C_electromagnetic_waves_and_speed_of_light

    the very short version is: if photons couldn’t experience time in some way, they couldn’t have a phase.

    which leads to an interesting perspective – when two things interact, if one experiences time so must the other.

  20. Orien Rigney says:

    It doesn’t take long to see that I’m only a thinker not a scientist, does it? So, let me hit you with what I think is my very best shot ever. Your statement gave me the reason to even consider it. Quote: the very short version is: if photons couldn’t experience time in some way, they couldn’t have a phase. Unquote What is the possibility of a wave or system of waves that link all atoms in the universe? And are systemic, intrinsic, self sustaining and endowed to each sub-particle at inception. Personally I see this as the Holy Grail of nature. If science can even remotely consider such a phenomona, I think they will have begun to understand creation itself.

  21. Xerenarcy says:

    i’m more of a thinker too heh, but i don’t know when to stop digging for an answer either so here we are…

    personally i take one principle to heart with questions like these – whatever the answer it must be the same for everywhere and everywhen. from that i tend to believe things that don’t agree with modern physics nicely or outright contradict it (for one i grow more doubtful of a big bang by the week).

    but in a very hand-waving way, yes, there likely is one huge ‘wave’ or wave equation that can describe everything. the problem is that to work out what this wave is, you need to take into account more or less everything, which is impossible. for practicality then, such a wave (or equivalent representation) doesn’t exist in a useful form. ie, saying (for example) “for all a,b there is a z such that z=a+b” is interesting and (to some) profound, but tells you nothing useful about a or b or whether there is another c out there somewhere; at best it tells you that there is a conserved quantity involved (mass-energy, charge, spin, momentum, etc).

    however, in my mode of thinking i’m leaning on this perspective of how everything ‘fits’ together:

    every object, entity, anything, can only be defined in terms of its relative properties. all systems of measure we use are in relation to some existing / known quantity. the closest to some ‘absolute’ scale we have would be the plank scale / natural units, but these too reduce to ratios / relations from other physical constants – in other words without any reference, an object alone in an empty universe cannot be described except in terms of itself.

    therefore, every object is, in a sense, defined by its relationship to every other object in existence / reality / etc, in both space and time. more profoundly, since empty space itself contains latent energy (vacuum expectation / casimir effect and so on) we can say that the properties of a point in spacetime are defined by the properties at all other points in spacetime.

    from this you can go on to define ‘entities’ or particles or matter, anything really, as a collection of properties maintaining coherence for some time. in a very abstract way, so long as some collection of properties ‘travel together’, they are or could be thought of as a particle endowed with those properties.

    skipping ahead a little to answer your question, intrinsic properties (such as electron charge) are asked the wrong way i reckon – really, for an electron for example, all we are doing is saying that “the behavior with this particle / wave is consistent with a set of properties we attribute to an electron”; if we were to see some properties different but others the same, we know the particle in question is somewhat like an electron but is not an electron (perhaps a muon, or an anti-electron, etc).

    basically anytime i hear a particle by its name (and similar phenomena), i opt to think that we’re naming a known collection of properties at a region of spacetime. hence my view on why a photon experiences time in some form… my personal reason for thinking this is that it is easier to accept the coincidence that all electrons (for example) have the same properties (like charge) if we identify them by their properties instead of trying to follow their paths and identities exactly (quantum weirdness ensues, which electron is which, how do they gain their charge, etc).

    hope that helps

  22. Orien Rigney says:

    I find it fascinating to think “gravitational waves” may have been found even though we are still trying to ascertain with some degree of certainty what gravity is? As we discussed earlier, it’s possible that all sub particles of atoms may be linked in such fashion. I wonder how such waves could be thought of as Gravitational with nothing to compare them? Are they at one, or more frequencies? What strength is the signal? I’m not trying to shot the physicist down, just curious. And thanks again for another good self explanatory reply to my ignorance.
    http://www.jhunewsletter.com/2014/04/20/gravitational-waves-point-to-birth-of-universe-74128/

  23. Xerenarcy says:

    well… that experiment in and of itself is designed to catch artifacts / secondary evidence of propagating spacetime distortions (ie, waves in spacetime). for that reason it is very important to understand what a wave is before diving into spacetime distortions.

    the best / easiest way is a one-dimensional spring. imagine masses of weight/energy M, connected in a chain by springs. naturally, if you displace one mass, it will pull in one direction and push in the other, which in turn causes the effect to propagate. gravitation is (for simplicity) a pull on the weights towards some location, but this can also form stable curvatures (eg, a rope slacking when one end is tied to a higher position and the other to a lower position). in any case, a gravity wave in this example would be any amount of force propagating along the weights / springs due to the source of the pull / slack moving.

    another way to look at it: tie a spring / rubber band lengthwise at level height; when you place a weight in the middle and do so suddenly, the sudden change in the ‘geometry’ of the ‘space’ (the spring / rubber band) would need to propagate to the ends, and this takes time. similarly, moving the weight changes the height at all points with a delay roughly proportional to the distance to the weight from that point.

    whether we are distorting space, time, or both is not terribly important. but we can (and apparently have) proven that there most certainly are displacements / distortions in spacetime that can propagate due to moving masses / energies.

    otherwise they are waves in every respect – they would have amplitude, speed, frequency and so on. just bear in mind that gravity waves are incredibly weak except for frankly, insane conditions such as two black holes in orbit or a non-symmetrical supernova, things like that.

  24. Orien Rigney says:

    As much as I have read about Einstein’s space/time distortion and continuum, I simply can’t wrap my head around it. For the record, I’m just an old Euclidian Dinosaur. To me, a straight line is unending in both directions and extends throughout eternity. What I visualize, is our universe expanding into this endless non-real estate I refer to as the continuum. One problems of mine is failing to see it bending and buckling much like a trampoline. I know, it’s just props to make argumentative a good math theory that is beneficial to the originator. But then, neither do I believe this universe started at the behest of a singularity carving out a swath of some-thingness forty billion light years in all directions in less than a trillionth of a trillionth of a trillionth of a second, thus giving us the Big Bang. My worst enemy is that I believe our universe is cyclic. Wish I could get away from that bugaboo, but it’s too ingrained for me to do anything about it after 80+ years. In trying to read “Weinberg’s first 3 Minutes”, I felt as though I had been subjected to shock treatments. I know this is theory positive in the real world, as to how elements sequentially change over time into other elements. But man! that’s carrying math to the nth.
    I believe our universe began with a gentle nudge, shattering a comparable world of an antithetical crystal constructed from depleted matter, (energy). By the way, dark matter and dark energy fit well into this idea.I don’t have the wherewithal or the time to push this (IDEA), but somewhere there is a person with the knowledge and knowhow, ready for the challenge. Thanks again for not thinking me a fool, just totally unlearned.

  25. socratus says:

    Photons know a few tricks that physicists don’t.
    ==..
    1. Einstein discovered photons *without mass*.
    2. Dirac discovered virtual photons with *imaginary mass*.
    3. Photons take part into photosynthesis and must have *positive mass*
    ( biological physics – quantum biology)
    4. These three kinds of photons should not be imagined as being
    the same kind of photons that we see from a flashlight.
    ==..
    There isn’t *Physics* without *Quantum Physics*.
    There isn’t * Biological Physics* without *Quantum Biology*.
    Physics – - > Quantum Physics — > Biological Physics – - > Quantum Biology
    and photons take part in all these effects. And in all these effects photons
    know a few tricks that physicists cannot understand. Photons are an enigma.
    ===…
    1) Reality is based on particle dynamics (!)
    Newton wrote:
    ” For the basic problem of philosophy seems to be to discover
    the forces of nature from the phenomena of motions
    and then to demonstrate the other phenomena from these forces.”
    / Newton . /

    2) Trying to “simulate photon’s behavior” we are confused because
    a) on the one hand, photon at constant speed c=1 knows a trick
    to have infinite frequency and wavelength.
    b) on the other hand, photon knows a trick to have specific
    frequencies and wavelengths.
    ===========.
    One and the same photon is able to take part in different effects.
    And in these different effects photon knows a few different tricks which
    today cannot be understood and therefore photon is an enigma for us.

    Einstein said:
    ” All these fifty years of conscious brooding have brought me
    no nearer to the answer to the question, ‘What are light quanta?’
    Nowadays every Tom, Dick and Harry thinks he knows it,
    but he is mistaken.’‘

    This situation isn’t changed.
    How can one and the same photon take part in different effects
    and which ” tricks / technique” photon is using – we don’t know.
    ===…
    All the best.
    Israel Sadovnik Socratus.
    ==============..

  26. Matuvo says:

    I understand this, to a degree. but this still doesnt explain to me how can light move 136,000 Mps IF, light does not move or cover distance. because the scientist measuring this didnt measure it relative to themselves. they measured it in general. light cant go around earth 7 times in one second if it doesnt actually cover distance.

    from now on scientist should say; “this thing moves x speed RTH. (Relative To Humans, cause i’m sure animals perceive time differently) or “this thin moves x speed RTI (Relative To Itself)

    confusing stuff, but interesting

  27. Orien tRigney says:

    This may be a little lengthy but it will give you one understanding of how light works. Even before these experiments, scientists and radio techs were bouncing signals off the moon with pretty good accuracy. With lasers it is a mad rush to see just how finite the accuracy can be. A rough estimatr is that light travels at 186,000, 300 mps, give a yard or so. So yes, I also find it hard to understand that a photon is here, there and everywhere at the same time. Either that or I am totally missing the whole point.
    http://en.wikipedia.org/wiki/Lunar_Laser_Ranging_experiment

  28. Steve Bolin says:

    I have a question. I get thrown off when it’s said that your going back in time if one would actually be able to travel at the speed of light, say to another galaxy. I understand the speed of light and the idea of what we see actually being the light that left one such galaxy some time ago, but if one were to travel to such galaxy, as he or she were to get closer the image to them would be that of light, that had reached their present location. Right? So their image would be of a more current status for that planet, right? So they wouldn’t actually be going back in time nor would that specific galaxy be anything other than on current time. I’m no expert but I must say, I feel were missing something, or I’m missing something. I can’t help but believe that every place in time is current as time is an illusion. I get that we could be looking at stars that are technically burnt out, but if you were to travel closer, at some point you would catch up to current. Right? Please help enlighten me. Thanks. I am loving science these days.

  29. Steve Bolin says:

    And then if you were to reach your destination of such galaxy, and looked back at earth, your saying the traveler would see the planet as it was many years ago? Hmm

  30. Jiohdi says:

    going back in time comes from a mis-reading of the Lorenz transformation for speeds beyond lightspeed or C… at that point the formula presents the square root of a negative number… if it were not a square root this would say back in time, however there is no actual whole number which can be said to be a square root of any negative number which means that the actual answer is an imaginary number which does not mean un-real. in Electronics these numbers arise a lot and represent phase shifts of current. So rather than backwards in time, my view is that it means backwards in a phase shifted direction perpendicular to the normal space time, ie, hyperspace. If you think of normal space time represented by a rubber sheet which is moving say upwards… a black hole would attain a certain fixed location and the sheet would keep rising upwards making a whirlpool down to its fixed location, so steep that light itself cannot escape it… if any object were to somehow violate einstein and move faster than light… its speed on the surface of the rubber sheet say right to left would still measure light speed or less but its descent into the whirlpool its excessive relative mass creates would cause it to make that whirlpool deeper than where it began… going backwards into hyperspace if you will. this is not at all the same as going back in time as it will encounter nothing of any past moments… however in their it could encounter the opposite side of the universe if it went deep enough or contacted a whirlpool originating from the other side…. but it would be so thin and stretched it is unlikely that anything could survive other than perhaps a signal.

  31. Orien Rigney says:

    Once a physicist with his head filled with extreme calculations, actually turned a sows ear into a silk purse. At least that’s what I’ve been, (wink) told. Not overly endowed in mathematics beyond trig., it’s hard for me to equate such knowledge. While having a descent understanding of C.,, I’m totally lost when it comes to time travel in either direction. When looking out at stars or galaxies, I can see why C. and spectrophy were so instrumental in Hubble’s calculations. Unfortunately, time travel even approaching C. will likely always be out of the reach of humans.

  32. Orien Rigney says:

    Not to be disrespectful of some great scientific minds that give us so much, but my problem with trying to understand most hypotheticals is that I haven’t the math or brain power to do the research. So, I must “assume” most of what I read and am told. And yes! To me anything that can’t be substantiated as pure hands on fact, is only theory or hypothetical. But even then, some of the hoopla is so far fetched you could beat me over the head repeatedly with it and I would still have my doubts. Einstein’s space fabric is one such theory. With his space/time, gravitational lensing, primordial gravitational waves and now to combine them with the Higgs boson, well; we have a quandary. Since all of these things are happening at approx. t the speed of C. and each in such radical and random direction, how can the four totally conflicting theories have cohesiveness? Take space fabric. Our universe, (matter) according to scientific interpolation; is moving along at approx. 1.3 million mph. (vectorially), spherically if you will. Secondly, galaxies, or at least our Milky Way, is rotating axially at approx. 500,000 per hr. cc. Then we have suns (stars), planets, moons, asteroids and etc. revolving and rotating at different speeds and directions inside all solar systems throughout all galaxies. And all of these maneuvers while zipping along at the initial universal speed of 1.3 million mph. Our solar system alone should be enough to give one pause to reflect when contemplating such. Earth revolves around our sun at approx. 67,108 Mph. while rotating on its axis at approx. 1,000 mph. Then, our moon is circling earth at 22,880 mph while rotating on its axis at approx. 10 mph. So, as for space fabric! I find it very hard to believe. WHEW!!
    And space/time? Even when I read and try to interpret a meaning, I fall flat on my ignorance. So believe me, there are many ways of looking at space time. Some noted scientists seem to visualize it as something of a magical helix that wraps in on itself, thus allowing all heavenly bodies to do whatever is needed to maintain their equilibrium in these movements ? All of these magical movements going on throughout the entire universe down to and including the smallest spec of dust. No! down to and including the smallest sub-particle of matter, this is a “must” happening.
    Now the Higgs Boson, perhaps coupled with gravity and magnetism theoretically, allows matter to be formed into all of the different shapes and sizes we see and find throughout our world, and this, without compromising the integrity of sub-particles. To this, we must include, birds in flight, squirrels scurrying up trees, stones, water, grapes hanging in an arbor, mountains, wind, etc.. Just name it.
    This rambling is not to be considered fact or even melodramatic, but the LHC at CERN is working big time in hopes of finding such a connection with the Higgs. At a cost of nearly $5 billion to construct, 10 years to complete and a billion yearly to operate, I sure hope they find it quickly.

  33. Mark says:

    I thought of a couple of paradoxes concerning light. First one is, if light travels at the speed of light, then time should stop for it and distance should contract to zero. So, what happens of the light (photons) has no place to land? How can something that must continue on move forever also get to its destination instantaneously? This would seem to indicate that in every direction there must be some object for a photon to strike and the universe in not infinite. Second, if time stops from the vantage point of an observer watching an object traveling at the speed of light, then how can we perceive light as having a frequency and color?

  34. jiohdi says:

    time has no meaning to a non-sentient entity other than whether it
    changes or not… a photon having no time simply means it does not change as far as its energy or size when it manifests as a particle… which it only does once it strikes or is absorbed by another object. The wave nature of light has nothing to do with its particle nature and so your question is not a paradox at all. 2ndly the experience of color is the observer who does measure changes around itself and not about the photons.

  35. Orien Rigney says:

    Referring to normal light, not C.”; one have to realize that it is probably the most perplexing of all dichotomies. That is, you’re damned if you do and damned if you don’t; in trying to extrapolate or differentiate the nuance’s (it), light has. People talking about traveling at, or near the speed of light drive me nuts because, even the thought can be no more than a guesstimation. It may be way to discuss or to write a paper talking of “time dilation”, getting younger on a long journey, cocooning for a billion year to get out of our solar system or perhaps, just a bunch of hype? At any rate, day or night; we are subjected as to how light lets us see things. A bright sunny and cloudless morning can take leave you breathless and blind you at the same time. Conversely, an overcast and moonless night will do just the opposite. If light, photons are everywhere all of the time, why is light more prevalent during daylight hours than at night? There are many observations and physical experiments that can be done to still this questioning. Such explanations as black body absorption; sunshine, starlight and moonshine, among others. But, getting down to the nitty gritty, I’ve never found a clear answer yet. Even if so, I probably wouldn’t understand it. But, I certainly hope you find your answers.

  36. Phil Markert says:

    I don’t know if this is entirely on topic and thinking out of the box here, but what if light traveling across the universe very gradually slows, making more distant objects appear to be more red shifted. If this were true wouldn’t this blow apart theories about accelerating universal expansion and dark matter? Perhaps light is cumulatively slowed by gravity over its long journey.

  37. Anders says:

    When we say that the speed of light is the same relative to everything we really mean that the speed of light is the same relative to everything moving slower than the speed of light.

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