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What if light speed wasn't the limit?

  1. Oct 28, 2011 #1
    I saw the recent report where CERN was able to measure something that traveled a tiny bit faster than light. It made me think that only in exceptional circumstances can that speed limit be passed. But it did prompt other questions.

    If light speed wasn't the limit, how would that affect things like BH formation?
    What other astronomical events might be affected by having no such limit?
    And how has the CERN event affected theories based on this limit?
  2. jcsd
  3. Oct 28, 2011 #2


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    The CERN team reported the possibility of FTL by neutrino's, however it is far from certain that the results are correct. Many many people believe it is either a statistical or measurement error. As far as we know currently light speed is unable to be broken.

    As for your what if questions, how can we answer them if they break the laws of nature? Anything is possible if we do that.
  4. Oct 28, 2011 #3
    Also I might stress it important to consider c not just as the speed of light, but at the speed which all particles with 0 mass travel. Bosons travel at c. Fermions travel <c and require increasing energy to approach c.
  5. Oct 28, 2011 #4
    As I read it, they took a long time to publish, to be as certain as is possible that it wasn't a statistical or measurement error.

    If the scale of possibility on the left end measured as being "far from certain" and on the right end as "as close to certain as we can get", this one sounds closer to the right side of the scale than the left.
  6. Oct 28, 2011 #5
    c isn't the speed limit of much of anything. All massive quanta have phase velocities greater than c. Real quanta light has a phase velocity of c in atificial laboratory conditions but is variable in general. What is limited to less than c?
  7. Oct 28, 2011 #6


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    Perhaps. I have not kept up with the 1000+ posts on the issue here on PF.

    Signal velocity?
  8. Oct 28, 2011 #7
    Keeping it simple for boffins like me and quoting from http://www.guardian.co.uk/science/2011/sep/22/faster-than-light-particles-neutrinos" [Broken]:

    The trip would take a beam of light 2.4 milliseconds to complete, but after running the experiment for three years and timing the arrival of 15,000 neutrinos, the scientists discovered that the particles arrived at Gran Sasso sixty billionths of a second earlier, with an error margin of plus or minus 10 billionths of a second.

    The result is so unlikely that even the research team is being cautious with its interpretation. Physicists said they would be sceptical of the finding until other laboratories confirmed the result.....

    Subir Sarkar, head of particle theory at Oxford University, said: "If this is proved to be true it would be a massive, massive event. It is something nobody was expecting.

    "The constancy of the speed of light essentially underpins our understanding of space and time and causality, which is the fact that cause comes before effect."

    The key point underlying causality is that the laws of physics as we know them dictate that information cannot be communicated faster than the speed of light in a vacuum, added Sarkar....

    Despite the marginal increase on the speed of light observed by Ereditato's team, the result is intriguing because its statistical significance, the measure by which particle physics discoveries stand and fall, is so strong.

    Physicists can claim a discovery if the chances of their result being a fluke of statistics are greater than five standard deviations, or less than one in a few million. The Gran Sasso team's result is six standard deviations...

    Neutrinos are mysterious particles. They have a minuscule mass, no electric charge, and pass through almost any material as though it was not there.

    Kostelecky said that if the result was verified – a big if – it might pave the way to a grand theory that marries gravity with quantum mechanics, a puzzle that has defied physicists for nearly a century.

    "If this is confirmed, this is the first evidence for a crack in the structure of physics as we know it that could provide a clue to constructing such a unified theory," Kostelecky said.[/B]

    The above and other articles I've read suggest that CERN have done everything by the book (statistically and measurement) but are remaining conservative until validated by others. What is interesting is where Kostelecky suggests that the benchmark may shift from light speed to neutrino speed. If so, then "the laws of nature" don't break. And the discovery could aid in the work towards a unified theory.
    Last edited by a moderator: May 5, 2017
  9. Oct 29, 2011 #8


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    Statistics are not valid until all assumptions have been validated. That appears to still be an issue.
  10. Oct 29, 2011 #9
    yes.. the usual process still needs going through
  11. Oct 29, 2011 #10
    c is the limit of information transmission speed.

  12. Oct 29, 2011 #11


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    Last edited by a moderator: Apr 26, 2017
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