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C is not a constant?

  1. Oct 14, 2003 #1
    http://www.enterprisemission.com/speedlight.html

    From that I've deducted the following ideas.

    Since photons have no mass, they are the fastest moving "particles".

    The force needed to accelerate a massless particle is zero from Newton's F = ma.

    Light changes speed in different environments. It is 3*10^8 m/s in what we call a "vacuum". The speed of light is slower in, say, glass or water.

    Gravity can bend light easily. This means that gravity has an effect on energy. If we assume that mass is also energy, then gravity could also be viewed as a form of an "energy field". Something like the magnetic field.

    If gravity, or this "energy field" can act upon light to change it's trajectory, couldn't it also slow it down while it is in it's energy field? Since the force needed to accelerate a photon to it's maximum speed is zero, it will regain it's original speed after leaving the energy field.

    Our solar system is basically a blob of mass with gravity. It's a blob of energy. An energy field, to be exact. When a photon enters this field (our solar system) then does it not slow down from the "drag" of this special field? Note that it does not keep decelerating, it just slows down by a certain factor when it enters a gravity field.

    It is the motion of things that we perceive as time. There is no absolute time. According to Einstein, time slows down near bodies with huge mass. Could it just be the "drag" exerted by the gravity field that slows down all particles that have any energy?

    According to my theory and NASA's observations, the speed of light is not a constant. In areas of interstellar void where there are either no or very weak gravity fields, the speed of light should increase significantly.

    Could it be that the current size of our universe is the maximum size where this field of gravity can reach? Beyond that, there would be no "drag" by gravity. That would mean that anything which enters that area is instantly transported to somewhere where there is gravity again. Could it be that this is remotely the reason why the space around our universe supposedly loops back onto itself on the opposite side?

    ----

    This also supports various "ether" theories -- mass supposedly drags "ether" around in space which in turn could cause this "drag". What gravity or this "ether" thing really is, I don't know. Could it perhaps be some extradimensional property of space? "Zero-point" energy flux embedded in space itself? I don't know. I'm not a physicist :)
     
    Last edited: Oct 14, 2003
  2. jcsd
  3. Oct 14, 2003 #2

    jcsd

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    Firstly it's lower-case c, never capital C as that in general means Capacitance or another constant used in maths which name escapes me.

    Basically general relativity covers most of your points and your wrong.

    also:

    a) there is no place where gravity cannot reach, it's reach is infinte

    b) the universe from current observations appears to be open and infinite not finite and closed

    c) Ether theories were rejected almost 100 years ago with the formulation of special relatvity

    c is probably a constant though there are a few non-standard theories
    and a few observations that suggest it might not be constant.
     
  4. Oct 14, 2003 #3

    Nereid

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    Which NASA observations?
     
  5. Oct 14, 2003 #4
    See first link in this thread.
     
  6. Oct 14, 2003 #5
    Yes. The uppercase version looked more appealing as it was the first letter of the title. I'm sure there's a forum somewhere where people argue about spelling and not about physics.

    Which ones and how?

    So what do you say to the folks that are trying to detect gravity particles? That they can't find them because gravity is instant? Some of the brightest minds are working on that gravity detection project.

    Suppose it is infinite. It's strength would still get closer to zero as you move away from the point where it originates from. We do not know much about what gravity is so why not theorise that areas with stronger gravity could indeed slow down photons and other particles with energy? After all, that's basically what happens in a black hole or is it not? When a particle reaches the singularity, it stops moving. Time slows down there as well. Do not view time as a motion of some weird property. Time is just the speed at which particles move from point A to point B. In my humble opinion, this explains it quite well.

    There have been several studies that have shown the universe to be quite finite and possible looping back onto itself. See Slashdot's science section for some of them.

    The Brane theory is a quite fascinating explanation to our universe as well.

    The formulation of Einstein's relativity ideas was the direct result of an experiment in 1905 which "debunked" ether theories. I'm not a big fan of ether but it's yet to be debunked in a sensible way. For example, it did not take into account that matter might be dragging ether around, not moving through a "sea of ether".

    I think c might be a constant but it would only apply to, say, our solar system or so. It is, however, definetly not an universal constant.
     
  7. Oct 14, 2003 #6
    Has any one given serious thought to the notion that light and in fact the universe is in essence 2 dimensional and only achieves the 3 dimensions by folding in on itself thus creating mass.

    If light has no mass but is a particle then it would have to be 2 dimensional I would think. Actually when you look at reflected light it certainly seems to be 2 dimensional. Like it's not something you can peel away is it. It definitely appears to hev no thickness.

    Another point to make is that if light was 3 dimensional then you would actually see it when looked at from the side. Which of course we can't unless it is reflecting of something.

    Just an observation and something we take for granted
     
  8. Oct 14, 2003 #7

    chroot

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    No. Curved spacetime does not slow a photon down. A photon follows a null geodesic, and is moving at c locally everywhere in its path. Since light always follows the "straightest possible" lines in curved spacetime, there is no way for light to move faster, rather by definition.

    As jcsd said, photons do not "enter and leave" gravitational fields. They are always in the gravitational field. Relativity theory actually presumes that spacetime and the gravitational field are the same thing. If it's in spacetime, it's experiencing gravitation.
    Only according to an observer not near the field.
    Gravitational time dilation is a consequence of the conservation of energy, particularly the conservation of gravitational potential energy.
    I'd really like to see these observations, too. Since light follows the straightest possible lines, it goes as fast as it possibly can, all the time.

    The size of the observable universe is defined by the past light cone of earth. No more, no less. As far as the size of the entire universe, well, that's just abject speculation, but I can say rather strongly that it has nothing to do with gravity's "reach," which is, as jcsd said, infinite.
    [zz)]

    - Warren
     
  9. Oct 14, 2003 #8

    Nereid

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    About the content of the page (first link in your first post):
    - the only spacecraft which now show anomalous behaviour are the Pioneers. Since the page you cite was written, much further work has been done, only the one anomaly remains (the effect was not found in the recent Cassini GR test, for example).
    - there are quite a few alternative theories which account for the Pioneer anomaly, MOND is perhaps the most interesting as it also accounts for many other astronomical observations (e.g. galactic rotation curves)
    - LISA will provide more than enough data to resolve this anomaly, at least as far as a variation from GR gravity is concerned
    - your link's proposed explanation for the Pioneer anomaly - a varying c - would require some pretty radical 're-explanations'; just about all astronomical data on objects beyond the solar system would have to be re-analysed and new explanations ranging as far afield as nuclear reactions (e.g. proton collision cross-sections) and atomic transitions (e.g. the H spectrum) found. Good luck!
    - the Dolphin link on the page is dead, so there's no way to check the chart
    - AFAIK, the only serious work that shows c may vary is some observations that alpha (the fine structure constant) may vary over cosmological time; the road from this to a variable c is a treacherous one
    - there are no inconsistencies in observations of G, AFAIK (the reports in your link are out of date)
    jcsd is right; despite many, many attempts in the last ~100 years, no (a)ether theory passes all the serious experimental tests; on the other hand, SR does. As an example (of an alternative idea that fails), take a look at the wisp idea (the subject of a thread in Theory Development).
    Other than what's reported in the link, can you point to solid experimental or observational data to support this claim?
     
  10. Oct 14, 2003 #9
    Many thanks for this good reply, Nereid. I'll make sure to follow up on the info you provided tomorrow. Reading a book right now here and it's not physics related unfortunately. ("Catcher in the rye" by Salinger) Plus planning to catch a good night's sleep in a long time tonight.

    As for links on varying c, just type "speed of light is not a constant" into google. All the links on the first page point to scientific articles and studies. Take a pick.

    If I may ask, what really defines c? Is it derived from some equation? Is it purely experimental?

    And if matter is composed mostly of "nothing" then why does light slow down when it enters another environment such as glass for example?

    Also, a vacuum is never really a vacuum, is it? It should be filled with all kinds of virtual particles which, just as different non-vacuum environments, should slow light down. Could the real speed of light in a true vacuum without any virtual particles be instant? I remember reading something about a theory on space.com (I think) which ended with a conclusion that FTL travel might be possible if we could create a vacuum inside vacuum. Would this apply here? Aha, that theory also suggested that forces such as inertia and mass are just virtual particles colliding with real particles. Does anyone remember that theory?

    And if virtual particles always blink into existance (from a "quantum vacuum") in a form of two opposite particles (electron and positron for example) then wouldn't their annihilation release a photon? Or what if one of them gets sucked into a black hole? (As Hawking suggested, I believe) Doesn't this add energy to the universe rather than maintaining a constant state of energy? (Thermodynamics)

    Oh, here's a good one. If the virtual particles that blink in and out of existance constantly fill the "vacuum" and affect the speed of light, then what if virtual particles were more likely to appear near bodies of mass thereby creating a thicker "cloud" of virtual particle occurance probability around solar systems such as ours.

    If it really was more likely for virtual particles to appear near mass (and energy) then the speed of light would vary in different parts of space. Or would it?
     
  11. Oct 14, 2003 #10

    jcsd

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    It's just a pet peeve of mine, but the difference is important as from the title alone I could not tell what exactly you menat. It is even worse when people are lax with their capitalization of G the graviational constant as lower case g means accelration due to gravity.



    It shows that the speed of light is constant only in local refernce frames, one of the most extreme examples is that for a remote observer light at the event horizon of a S. black hole has an apparent velocity of zero. Basically GR already describes the situations that you are speculating on and offers a much better explantion than your speculation.

    GR suggests gravity propagates at c, the problems with detcting gravtons is thta gravity is the weakest force. The fact that gravity has an infite reach is basic Newtonian physics and this doesn't change in general realtivity.

    No, if slashdot says otherwise then it is out-of-date, there have been several recent studies that have shown that the universe is infite before these took place whetehr the unievrse was finite or infinite was simply unknown.

    I doubt you know what M-theory is.



    The Michelson Morley experiment took place in 1887 and Einstein's rleativty was not directly in repsonse to this. Ether as a theory is long dead.



    As I siad it most probably is a universal constant and is always taken as such.

    10/10 for crackpottery though.
     
  12. Oct 14, 2003 #11
    Say you have sun A that moves at a very high speed through the universe and you have planet B moving around it. If B falls not towards where A *is* and towards where A *was* (if gravity propagates at c) then wouldn't it pretty quickly disrupt the orbit of B?

    Also, are gravity particles supposed to have mass or not? Would photons react with gravity particles? Would they "slow down" due to them? :wink:

    Just can't help it - everything seems to point to the conclusion that vacuum is not really a vacuum after all and is thus slowing down photons. Whether there are areas of space where this vacuum is more "dense" or not is the really intriguing part.

    Oh and I'm not a crackpot. I'm trying to learn more about physics and about the things I've read and thought about over the years. My real main field of study is actually computer science.
     
    Last edited: Oct 14, 2003
  13. Oct 14, 2003 #12

    jcsd

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    There is no such thing as 'moving at a very high speed through the universe' as all speeds are relative, so the obsrved velocity of the sun would have no effect on the orbit of the planet, as it would observe a different speed.

    There are a few things known about gravitons (for example their spin angular momentum and charge) and they have no mass.

    Yes due to the HUP you do get virtual particles, infact most gravitns are virtual as they are the product of static graviational fields, but don't get virtual and real particles confused they are different things and what is true for one is not necessarily true for the other.
     
  14. Oct 14, 2003 #13

    Nereid

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    I did; my limited review showed:
    - many links are to web discussions (like PF!)
    - several links were to articles about c being constant, and *not* varying
    - the source observations for a great many links are those of Webb et al, and refer to possible cosmological variability of alpha; like I said above, it's a stretch from alpha to c (and there's other, very good, observational data that contradicts the work of Webb et al)
    - there are references to theoretical work by Moffat; this is not based on experiment or observation
    - several links to Dolphin (same as your page)

    In summary, nothing in what you provided, so I'll repeat my request: can you point to solid experimental or observational data to support this claim ["speed of light is not a constant"]?
     
  15. Oct 14, 2003 #14

    jcsd

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    There was some indication that the speed of light might of been slower at some earlier stage in the universe (though IIRC it was not NASA but a Japanese team).
     
  16. Oct 14, 2003 #15

    jcsd

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    Thinking on it now, it now c might of been faster not slower according to those observations, I honestly can't remeber.

    Though of course the speed of light would of been slower compared to c in the earlier universe anyway as it was denser.
     
  17. Oct 14, 2003 #16

    FZ+

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    The claim was that it was faster. This allowed some to furnish alternatives to inflation theory.

    Just point out an additional mistake that is usually made here - to shoehorn in the relativistic concept of timed gravitational action directly into Newtonian Universal Gravitation. The gravity of einstein, based on curvature of spacetime is very different from Newton's concept, and of course a rough jamming together of the two will not work.

    No. If we accept relativity, they must not, since only massless particles can travel at c. (otherwise, our little graviton will have infinite energy, making the pull of gravity rather intensely painful.

    A key part of GR is to reconsider that conception of "empty space".
     
  18. Oct 15, 2003 #17

    Nereid

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    Do you have any links? From the tone of this sentence, it sounds as if the idea is now pushing up daisies (obscure reference? Hint: Norwegian blue).
     
  19. Oct 16, 2003 #18

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    Well, who else than the infamous Joao Magueijo? Run a google, and you'll find plenty of stuff on him.

    He isn't dead, as far as I am aware of, though I haven't heard much from his corner recently.
     
  20. Oct 21, 2003 #19
    so your saying c is not a constant in an universal equation, but can be used for other uses?
     
  21. Oct 21, 2003 #20
    I don't claim to have top knowledge of this, but it may be possible to fix a true, single frame of stationary reference within space such that the cosmic background radiation aka blackbody is ( believed to be ) homogeneous and isotropic. Any absolute translation by an object through the universe will cause blue shifted blackbody radiation to be detected at the front of the object and red-shifted radiation at the rear the object.
    I think these velocities are termed as peculiar velocities.

    Also, conjecturing: an absolute frame of reference can be established by accurately determining the rate of cosmic expansion ( assuming someone pulls the calculation off ).An object at rest within expanding universe will observe isotropic recession velocities { edit: at large scales, on average } , but an object translating through the universal stationary frame of reference will have higher recession velocities behind it than in front.Maybe, perhaps? Of course, we don't yet have technologies to measure these velocities accurately enough yet
     
    Last edited: Oct 21, 2003
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