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Speed Limit of the Universe reduced.

Discussion in 'The Pub' started by cjvfr, Jun 25, 2014.

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  1. MUARC had a hand in this, I'll bet. :mad::giggle:
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  2. Apparently the state government has put up point to point speed cameras and in the first week alone billions of photons were booked for exceeding the speed limit
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  3. Does this mean that the universe is slowing down and I get to ride my bike longer?
  4. If all those photons are being booked, who is collecting the fines?

    and on a slightly disconnected note...

    "Why do all the winners of the Miss Universe contest come from Earth"
    Rich Hall
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  5. "Speed kills" campaign is working better than expected :)

    Seriously though. This is roughly 4 hour discrepancy over period of some 168,000 years - I can't be bothered to calculate what percentage that would be, but I'll go with "small".
    Also, so what they are saying is that light doesn't travel at the speed of light, but neutrinos do?
  6. That's no excuse under the Victorian 3km/h tolerance! (n)
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  7. Have you seen what the creatures from other plants look like? Of course the babes from this planet win all the contests.
  8. Ok so I'll ask the question - who set up the far side of the universe camera then, a faster than light traffic cop?
  9. Actually, I've heard there is some evidence that the speed of light may not be constant, but could actually actually be reducing over time / getting slower, so Einstein may have been right about the speed when he recorded it. Don't diss the man too soon! ;)
  10. Well that'll bugger the 'C' in E=MC²
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  11. Actually, it would seem the speed of light is still the same, he's just figured out that it slows down a little bit in built up areas.

    Basically, in space photons occasionally turn into something else for a while, and the Something Else* has mass. Because it has mass, it is affected by gravity. So while the light is Something Else, gravity slows it down, before turning back into a photon. Over short distances, like here to our sun, that makes PFA difference, but if the light is traveling across half the galaxy... it still makes PFA difference, but it becomes measurable.

    Neutrinos, however, don't do that. They do something similar, but are only affected by much weaker forces. So they're speed along at (effectively) full pelt regardless.

    *As good a term as "electron-positron pair" for the porpoises of this explanation :p.

    But I haven't studied physics since high school, so I'm happy to bow out in favor of anyone who actually knows shit.
  12. Great. Next there's going to be reduced light speed zones around schools and random arbitrary variations crossing the Blue Mountains.
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  13. Don't you know? Cops are exempt from the speed limit
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  14. Yeah... but they got six boobies :)
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  15. Not necessarily. Apparently one of the reasons it's been missed is that more recently is because we've gone to using atomic clocks and comparing light with those - which has remained at a constant. (So energy must also be reducing).

    Of course it could be that neither is slowing down - but if that is the case, then the comparison would be that the orbits of the planets are speeding up which would break another theory. Personally it seems more plausible to me that the speed of light is changing than the speed of orbits is accelerating, but either way very interesting stuff.
  16. It seems even more plausible to me that the difference between predicted and observed speeds is simply too small to measure experimentally - as I was saying, they were able to observe an event 168,000 light years away and even then, the difference was only 4 hours at most. That's probably below the error margin of any instruments we can use for experiments over distances that are accessible to us.
  17. Alternatively, the speed of light in vacuum (c) is about the same as it always was, and this is just one of the ways you can slow down a given load of photons (changing the speed of some light rather than changing c). In the same sense that the boiling point of water is 100°C, but water will boil at lower temperatures at higher altitudes or at higher temperatures if you add salt.

    None of the light you have ever seen has been traveling at c, as even passing through air is enough to slow it down (by ~88km/s) and transparent materials like glass slow it even more (your average pane of glass'll drop its speed by about a third).

    EDIT: In fact, even the subject of the article we're discussing relies on c not being different, as otherwise the neutrinos would not have been able to get here before the photons.
  18. Kerrrrist, thought I had given up physics back in Uni.....
  19. Physics and motorcycling go together like confectionery and chemistry.