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Basic metascience questions in theoretical physics

  1. Sep 10, 2003 #1
    i have a few questions of the scientists out there. i'm looking for scientific answers to questions on the philosophy of science, though i'm not sure scientific answers can answer questions on the philosophy of science.

    here goes nothing...

    is it assumed that the laws of nature are constant throughout the universe? if so, what evidence is there that the laws of nature are not just constant within the confines of labs on planet earth? is there astronomical observational evidence that the laws of physics are constant throughout the universe? if not, how can we investigate the laws of physics and what would be the point? a related question is, in newtonian gravitational theory (which has been proven to be incomplete, i will add), what if the gravitational "constant" actually gets warped by matter?

    now a question about the speed of light being the speed limit of the univese...

    in radioactive half-life decay theory, the mathematical MODEL would suggest that the sample of element 92 would NEVER fully decay, that there would always be some mathemematically measurable quantity of the substance left, however infinitesimal. but experiments would seem to indicate that the sample of uranium would eventually all decay, in a detectable sense, contradicting the mathematical model that it would only asymptotically approach zero quantity. my analogy is this: the mathematical model dictates that the speed of light is the maximum speed of anything in this universe but what if it was only a mathematical model and not complete? in other words, is it concievable that once a high enough speed is reached that one actually goes at the speed of light?

    a related question is this: what does the universe appear to be (time like and space like) from the point of view of a photon, if it were to possess an awareness of time and the universe (i know that's a big assumption, but let's just suppose)?

    thank you for considering my questions. that's all my questions for now.

    may your journey be graceful,
    phoenix
     
  2. jcsd
  3. Sep 10, 2003 #2

    Janus

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    Well yes, there are a number of astronomical observations that support the notion that the Laws of Physics are the same everywhere:

    We see the same spectral emission and absorption bands from the stars as we see on Earth. More massive stars burn hotter than less massive stars, as we would expect if this were true. Binary stars follow the orbits we expect, etc.

    These observations taken together with many more, paint a convincing picture of a universe that follows the same rules as those in the lab.

    The difference is that radioactive decay is a statistical model based on random events. As such, it only works when you have a large enough sample to work with. It can't tell you, for example, how long it would take for a single U238 atom to decay, it can only tell you what probability there is that it will have decayed after a given time.
    So it is well understood why the model's accuracy drifts as the number of atoms decrease.

    As far as The Lorentz transformations go, they aren't based on statistical models, so the same problem doesn't apply. They are expected to, and in every test so far have, hold all the way up to c
    This is one of those questions that is hard to answer properly. Because the very conditions it relies on are ones that violate the laws it is meant to investigate.

    The best answer I can give that the universe would be frozen in time and squished to zero dimension along the axis of motion. The photon would exist at it's origin point and destination at the simultaneously.
     
  4. Sep 11, 2003 #3
    thanks. those answers are satisfying enough for now.

    cheers,
    phoenix
     
  5. Sep 11, 2003 #4

    selfAdjoint

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    a related question is this: what does the universe appear to be (time like and space like) from the point of view of a photon, if it were to possess an awareness of time and the universe (i know that's a big assumption, but let's just suppose)?

    Einstein and his coworker Rosen wondered how the Schwartzschild spacetime of a gravitating masspoint would look to a photon. So they made a change of variables from the spherical-like coordinate system in which that spacetime is usually expressed to one in which two of the axes are lightlike. And you know what they found?

    A wormhole. No kidding, it's called the "Einstein-Rosen Bridge". It was the first example of a wormhole solution in the theory of GR.
     
  6. Sep 11, 2003 #5
    very cool.

    so does that mean there's a wormhole around every photon? does every photon offer a gateway into the whole universe of space and time, existing beyond time and space somehow?

    what about tachyons? is there a whole universe operating with a LOWER speed limit of c?

    cheers,
    phoenix
     
  7. Sep 12, 2003 #6
    These wormholes, black holes and pardoxes of relativity make of it more mathematical theory than a physical one. One should not trust a theory that allows infinite mass increase and thus sets limits to God with respect to velocity or anything else.
     
  8. Sep 12, 2003 #7

    selfAdjoint

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    Phoenixthoth, the wormhole is he way a photon sees a gravity field. The wormhole is not a part of the photon but an aspect of the field.

    Clicky, God hasn't yet complained about the speed of light.
     
  9. Sep 12, 2003 #8
    here's a probably dumb question.

    suppose there are wormholes.

    the starship enterprise enters a wormhole and ends up ten trillion trillion light years away in a nanosecond.

    from the observer using a telescope on earth (or at least to God), aware of the entrance and exit of the starship into and out of the wormhole, the starship has exceeded the speed of light. however, from the perspective of the starship, the speed of light was never exceeded. so has it been exceeded or not?

    cheers,
    phoenix
     
  10. Sep 12, 2003 #9

    selfAdjoint

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    In getting from point A to point B in less time than it would have taken light to get there, the spaceship did encroach on spacelike separation. From this all the consequences (time travel, causality violation) can be made to happen.

    Whether it "violated the speed of light" in doing this is a semantic question.
     
  11. Sep 13, 2003 #10
    "From this all the consequences (time travel, causality violation) can be made to happen."

    could this be evidence that there are, in fact, no wormholes except in theory? we wouldn't want to live in a universe with causality violation, would we?

    cheers,
    phoenix
     
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