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faster than light?

Discussion in 'Fred's House of Pancakes' started by hyo silver, Sep 23, 2011.

  1. SageBrush

    SageBrush Senior Member

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    Synthetic experiments on Earth have their place, but the scale of space is hard to beat for timing questions.


    [​IMG]
     
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  2. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    What you described is the visible light (not the entire electromagnetic spectrum) being delayed longer, not traveling slower.

    PS. Since supernovas vary dramatically in there distance from earth but the delay you mention is approximately the same for most supernovas, the delay shows up as a constant offset between the light blast and the neutrino blast. A speed difference would show up as a linear relation between the distance and offset.
     
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  3. fuzzy1

    fuzzy1 Senior Member

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    The sample size of this test is what? One event, SN1987A?

    This test also needs repeats to weed out any interferences. And it has material differences from the terrestrial tests.

    (But if I were to bet money, it would be that the terrestrial test had a yet unidentified error or omission.)
     
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  4. davesrose

    davesrose Active Member

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    I still don't see how this negates the theory of relativity. From my *basic college* understanding of neutrinos...they are subatomic units with virtually no mass (and would always theoritically be bordering on what our idea of light is). I think it's great that we're starting to have some measurements in quantum mechanics...but considering many of the measurements are not really what would occur on Earth...it might just help with our understanding of light itself. Take chemistry: look how many current synthetic elements have been rendered but never observed in nature.
     
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  5. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    Yes, but that one event's metrics have the error bounds for the difference between the speed of light and speed of neutrinos being too small to state a speed difference. More info needed.

    Note that I am not taking a position, but just pointing out what is known from the data we have.
     
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  6. daniel

    daniel Cat Lovers Against the Bomb

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    Neutrinos do have mass. Very little, but some. According to Relativity theory, to accelerate ANY amount of mass to the speed of light would require an INFINITE amount of energy. Thus, if the experiment were valid, it would mean there is an error in Relativity theory. Photons can travel at the speed of light because they have no rest mass.

    ONE experimental observation in favor of superluminal speed, vs. thousands of experimental observations against. The burden of proof is on the anomalous observation to prove that it does not contain an error. In the mean time, it is a good bet that a hundred years of theory AND observation for subluminal speed are correct.

    I believe the first demonstration that neutrinos are subluminal was when it was observed that solar neutrinos change "flavor" in their journey to us from the sun. The thermonuclear reaction in the sun is known to produce only one flavor. Neutrinos are allowed by theory to change flavor, but to do so requires time. Not much time, but some time. Due to time and space dilation, an object traveling at the speed of light experiences zero distance and zero time between its origin and its absorption. Therefore a photon (for example) exists for zero time in its own frame of reference. If neutrinos traveled at the speed of light they woud exist for zero time in their own frame of reference and would have no time to change flavor on route.
     
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  7. Trebuchet

    Trebuchet Senior Member

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    Cite please?
     
  8. daniel

    daniel Cat Lovers Against the Bomb

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    Any cosmology textbook.
     
  9. qbee42

    qbee42 My other car is a boat

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    Tom
     
  10. Trebuchet

    Trebuchet Senior Member

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    Cite please?
     
  11. FL_Prius_Driver

    FL_Prius_Driver Senior Member

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    Yes, according to the theories we have at present. But until there is repeatable experimental data to support this, then it remains just conjecture when it comes to neutrinos.

    Except that there are no conclusive observations for subluminal speed. Seriously, if you try and find some widely accepted experimental data for subluminal neutrino speed you will come up short. Measuring anything about neutrinos is immensely hard and difficult. Why do you think that the Opera experiments were measuring the speed?

    Many theorist would support this contention. ALL experimentalists would ask where is the evidence. Right now, there is nothing, and I mean nothing, supporting the bold statement above. I am NOT taking a position that it is wrong, just that it has not shown to be true.

    Let me give an example in Physics where this thinking occurred in the past. All the laws of physics up to 1957 were the same whether viewed in a mirror or viewed directly. All particle experiments matched this characteristic of no preferred "parity". It was widely accepted as a "fact" until Yang and Lee (formally) asked what experimental test were made. A look at all the experimental data showed that identical mirror/direct behavior was proven for gravity, electro-magnetic, and nuclear experiments. However, No experiments for mirror/direct preference could be found for Beta Decay. Imagine the surprise when the very first test of Beta Decay checked for mirror/direct behavior showed that our universe is right handed. Parity is completely violated by this, and only this interaction.

    As a more interesting note, this violation only occurs when neutrinos are involved.
     
  12. fuzzy1

    fuzzy1 Senior Member

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    I don't have cites available, as the remembered descriptions are more than 20 years old and the hardcopy long since discarded. But I'd describe it a bit differently.

    SN1987A experienced a core collapse, an event lasting just a few seconds. But a star's core diameter is much smaller than its overall surface diameter. The core is obscured by the star's many layers between the core and the radiating surface, the photosphere. For a blue supergiant such as this, the overburden is probably hundreds of thousands of miles thick.

    The light flash does not become visible unlike the shock wave from the core propagates through this overburden and erupts through the photosphere. This is a mechanical process, not a speed-of-light process, so it takes some time.

    A search for 'SN1987A shock breakout' yields plenty of hits.
     
  13. Rokeby

    Rokeby Member

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    xkcd:

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  14. amm0bob

    amm0bob Permanently Junior...

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  15. amm0bob

    amm0bob Permanently Junior...

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    2nd test affirms faster-than-light particles - CBS News

     
  16. hill

    hill High Fiber Member

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    Imagine YOU are the sun. Helo Mr. Sun. And you have the planet Neptune tied to a string ... and like a giant lasso - you are spinning Neptune round and round. Mr Sun calls that an, "orbit". Mr Sun's sun ray takes a long long time to reach Neptune.
    BUT: What do you think would happen if Mr Sun lets go of his string, tied to Neptune? What happens if the Sun instantly disappeared? Do you think that the far away planets would continue on their merry way ... following their rotation of a now non-existent sun?


    The Speed of Gravity - What the Experiments Say

    Let's not mess with people's heads any farther for today ... folks can only handle so many unshakable truth's being stood on their head at a time. Maybe down the road we might consider such crazy ideas of light speed being multiple times faster than it was, just a few thousand years ago ... as was the decomposing speed of uranium into lead.
    ;)
    .
     
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  17. daniel

    daniel Cat Lovers Against the Bomb

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    Relativity tells us that even INFORMATION cannot travel faster than light. Thus if the sun were to disappear, its absence would not be felt until the information of its disappearance, traveling at roughly 300,000 km/s, reached them.

    This may seem to the uninformed like something that might be challenged. But remember that FROM THE POINT OF VIEW OF SOMETHING TRAVELING AT THE SPEED OF LIGHT, due to the dilation of time and space, it takes zero time and travels zero distance. From this perspective, something that travels faster than light would be traveling for LESS THAN ZERO TIME.

    Thus we see that if neutrinos, or the propagation of gravity, or anything else, can indeed travel faster than light, then the entire foundation of relativity collapses. And Relativity has been confirmed in thousands of experiments. You do not dismiss thousands of verified experimental results based on a couple of results which are themselves questionable, and which have not been independently repeated. A repetition by the original team does not constitute independent verification.
     
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  18. Rokeby

    Rokeby Member

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    (Don't know why, but I seem to focus better on the substance when I
    get info aurally. Left to my own devices, I think I tend to read faster
    than I comprehend.]

    OK, just for fun, here is an audio clip of Einstein himself stating his
    fundamental energy/mass equivalence:



    Would it really matter on which of the two equations the CERN
    experiment was based?
     
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  19. fuzzy1

    fuzzy1 Senior Member

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    Quantum mechanics has no such limit. Entanglement, spooky action at a distance, seems to violate Relativity's speed limit with impunity.
    Note also that the main version of quantum mechanics has also been confirmed in thousands of experiments. It is in at least as good standing as Relativity.

    A problem here is that QM and Relativity, taken together with a few other principles, produce some contradictions. Entanglement illustrates one of them, black holes are another. Something has to change, but we don't yet know what that will be. Don't ask me for more details, as I get lost at Bell's Inequality and Alain Aspect.

    This is probably part of the reason we don't yet have a Grand Unified Theory tying together gravity and the other fundamental forces of nature.
     
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  20. Stev0

    Stev0 Honorary Hong Kong Cavalier

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