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Theory Challenging Einstein's View On Speed of Light Could Soon Be Tested (theguardian.com) 244

mspohr writes: The Guardian has a news article about a recently published journal entry proposing a way to test the theory that the speed of light was infinite at the birth of the universe: "The newborn universe may have glowed with light beams moving much faster than they do today, according to a theory that overturns Einstein's century-old claim that the speed of light is a constant. Joao Magueijo, of Imperial College London, and Niayesh Afshordi, of the University of Waterloo in Canada, propose that light tore along at infinite speed at the birth of the universe when the temperature of the cosmos was a staggering ten thousand trillion trillion celsius. Magueijo and Afshordi came up with their theory to explain why the cosmos looks much the same over vast distances. To be so uniform, light rays must have reached every corner of the cosmos, otherwise some regions would be cooler and more dense than others. But even moving at 1bn km/h, light was not traveling fast enough to spread so far and even out the universe's temperature differences." Cosmologists including Stephen Hawking have proposed a theory called inflation to overcome this conundrum. Inflation theorizes that the temperature of the cosmos evened out before it exploded to an enormous size. The report adds: "Magueijo and Afshordi's theory does away with inflation and replaces it with a variable speed of light. According to their calculations, the heat of universe in its first moments was so intense that light and other particles moved at infinite speed. Under these conditions, light reached the most distant pockets of the universe and made it look as uniform as we see it today. Scientists could soon find out whether light really did outpace gravity in the early universe. The theory predicts a clear pattern in the density variations of the early universe, a feature measured by what is called the 'spectral index.' Writing in the journal Physical Review, the scientists predict a very precise spectral index of 0.96478, which is close to the latest, though somewhat rough, measurement of 0.968."
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Theory Challenging Einstein's View On Speed of Light Could Soon Be Tested

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  • Nature varies (Score:3, Interesting)

    by MrKaos ( 858439 ) on Wednesday November 30, 2016 @05:20AM (#53391309) Journal

    Why would anything in the universe be constant? Maybe the variability is beyond our ability to observe.

    • Re:Nature varies (Score:5, Insightful)

      by abies ( 607076 ) on Wednesday November 30, 2016 @06:13AM (#53391457)

      Anti-arbitrage rule. E = mc^2. If c varies, then you could find a moment where converting energy to matter and later matter to energy would produce surplus energy, allowing you to perform arbitrage against laws of thermodynamic, producing perpetual motion/free energy.

      • This is a circular argument. To quote GP, why would energy be constant? Maybe the variability is beyond our ability to observe. Maybe thermodynamics is wrong, and free energy can be produced but only in very small quantities.
        • This is a circular argument. To quote GP, why would energy be constant? Maybe the variability is beyond our ability to observe. Maybe thermodynamics is wrong, and free energy can be produced but only in very small quantities.

          To an extent, it is circular argument as science does have some basic assumptions. One being that the laws of physics work everywhere and another being that they do not change, thus experiments are repeatable in any location. These are like the axioms of mathematics. They have served us well and have held up when we make predictions using them. It could be that they might not be quite true. In that case, it's not like everything we've known will cease to work, we'll just have to redefine some things. An exa

      • You miss understand what E=mc^2 means - it has nothing to do with converting mass to energy or energy to mass. It is stating the fact that energy has mass, and that the majority of the mass of an atom comes from incredible amounts of potential energy in the nucleus (and thus nuclear energy). If c varies it would just mean the mass of a given amount of energy would vary with it, assuming E=mc^2 holds true.
      • ... E = mc^2. If c varies...

        Slashdot's quote on the bottom of the page: "In any formula, constants (especially those obtained from handbooks) are to be treated as variables."

        • Perhaps the exponent of 2.0 is just an approximation .. an average

          And it seems to me that if space isnt perfectly flat (and we know it isnt) then assuming "2" could be wrong.
          • by lgw ( 121541 )

            Not, that's just unit conversion stuff. Anyhow, real physics is done in units where c=1, so the exponent doesn't matter (as you'd expect, if it's just about the unit of measure).

      • The varying of c could change the energy content of matter in the affected space, preventing the creation of "Free Energy" - or, there may be layers of the Universe of which we are not fully aware, and when the first successful perpetual motion machine is demonstrated, its "apparent free energy" may be being drawn from there.

        Without Einstein's theories, a nuclear explosion certainly would look like the magical creation of large quantities of free energy.

      • by shess ( 31691 )

        Anti-arbitrage rule. E = mc^2. If c varies, then you could find a moment where converting energy to matter and later matter to energy would produce surplus energy, allowing you to perform arbitrage against laws of thermodynamic, producing perpetual motion/free energy.

        Doesn't sound like the Big Bang at all!

    • ...Maybe the variability is beyond our ability to observe.

      Uh yeah. This.

      Even with all of our technological advances we can observe what, a sliver of a fraction of our galaxy? That's like predicting the temperature across the entire history of Jupiter's existence based off a single weather report from central Kansas last Tuesday.

      Oh, and one more thing. Since we has defined the 'spectral index' down to the numerical gnats ass here presumably for accuracy, exactly how fast is "infinite" again?

      • exactly how fast is "infinite" again?

        It's considerably faster than half infinite.

        • exactly how fast is "infinite" again?

          It's considerably faster than half infinite.

          So, I would assume somewhere between Ludicrous and Plaid, then?

          Sorry to be such a bother, just trying to figure out if I need to change the combination on my luggage.

      • Even with all of our technological advances we can observe what, a sliver of a fraction of our galaxy?

        Um, no. Much larger than that - more like a considerable way back to the Big Bang.

        • Even with all of our technological advances we can observe what, a sliver of a fraction of our galaxy?

          Um, no. Much larger than that - more like a considerable way back to the Big Bang.

          Mapping our historical universe is a bit different than defining our observable universe.

          We're still doing a lot of this work in the dark, both figuratively and literally.

          • by lgw ( 121541 )

            Much of the observable universe is the historical universe. "Long ago" and "far away" are two ways of saying the same thing. We can directly observe the universe at different stages of history back to about 300k years old (everything before that, including everything inflation-related, is indirect guesswork).

            • Much of the observable universe is the historical universe. "Long ago" and "far away" are two ways of saying the same thing. We can directly observe the universe at different stages of history back to about 300k years old (everything before that, including everything inflation-related, is indirect guesswork).

              This is true, but since 300K years is essentially a sliver of a fraction of the age of the universe, I think we've both observed how much of this is in fact guesswork.

      • We have some observational constraints on the speed of light.
        11 billion years ago (when the universe was 2 billion years old), the speed of light was about the same as it is now. https://arxiv.org/abs/1609.087... [arxiv.org]
        Otherwise, the light crossing certain objects would be different. This result is essentially independent of cosmology.

        I guess that the cosmic microwave background also places limits. If the speed of light had been infinite at that time, I suspect the last scattering would be affected. This is ~300.0

    • by ledow ( 319597 )

      Pi is constant.

      Zero is constant.

      Both appear in the natural world an awful lot.

  • I read his book back in the 90s when I was in school. Was an interesting enough idea, but going up against Einstein and Inflation at the same time - it's a looooong shot.

    The summary crediting Hawking for inflation is a complete joke. Goes to show if you get a bit of fame in a field you get credited with everything.

  • Is interesting to remember that may be possible that there has not even been a big bang to start (and therefore the answer may be that the universe has always been more or less uniform).
    • Is interesting to remember that may be possible that there has not even been a big bang to start (and therefore the answer may be that the universe has always been more or less uniform).

      To quote 'Forrest Gump'; "Maybe...maybe it's a little bit of both?...both happening at the same time?"

      Maybe there was a 'Big Bang' but what actually happened was that it exploded into tiny bits of space-time+matter+energy which, being essentially pieces of space-time, had no limits regarding 'velocity', and then some time later coalesced into a single fabric forming our universe. In fact, it may still be coalescing and is responsible for what we interpret as 'expansion'.

      Strat

      • It's also possible, true
      • Maybe there was a 'Big Bang' but what actually happened was that it exploded into tiny bits of space-time+matter+energy which, being essentially pieces of space-time, had no limits regarding 'velocity', and then some time later coalesced into a single fabric forming our universe. In fact, it may still be coalescing and is responsible for what we interpret as 'expansion'.

        Apologies, don't normally respond to my own posts, but it also occurred to me that these pieces of space-time that have not yet joined may be where scientists find that 'missing mass'/'dark matter'. It's out there, it just hasn't joined the rest of us yet in this meta-bubble of space-time. There are likely other cosmological/astrophysical/physics phenomena, observations, and properties of the universe this might explain as well.

        Strat

    • Is interesting to remember that may be possible that there has not even been a big bang to start

      Only in the same sense that it's possible dinosaurs never really existed and all the bones were put there by God.

  • by dltaylor ( 7510 ) on Wednesday November 30, 2016 @06:11AM (#53391451)

    If the speed of light is dependent on the strength of the gravity field, as we seem to measure today, then the early universe, with all of the matter/energy (yes. that is redundant) should have had such a deep gravity well that the speed of light should have been about 0 for the first few milliseconds of the universe' existence, if not longer.

    • And one reason why it was so hot - no radiation of heat until the energy overcame the massive gravity well.

    • If the speed of light is dependent on the strength of the gravity field

      It's not. Speed of light is a constant. Gravity affects its trajectory but not its speed [nasa.gov].

      should have had such a deep gravity well that the speed of light should have been about 0 for the first few milliseconds of the universe' existence

      All that matter would affect its path but (so far) there is no evidence that gravity affects the speed of light at all or that it ever did. The reason light cannot escape a black hole isn't that gravity is pulling on the photon so hard but rather because gravity warps spacetime so much that there is literally no path for light to take which can get beyond the event horizon. It's kind of like being in a maze with no

  • by wonkey_monkey ( 2592601 ) on Wednesday November 30, 2016 @06:21AM (#53391475) Homepage

    according to a theory that overturns Einstein's century-old claim that the speed of light is a constant

    Did Einstein ever make any claims about the speed of light being constant over time, or has a journalist just assumed he must have in order to shoe-horn his name in?

    • No, because relativity is more about the measurement of the speed of light being constant between observers in different places/states regardless of how fast/what direction you're moving relative to each other. I don't recall ever reading about an observer in the future and the past being a consideration, but I've been out of the loop for a while.

      So unless this article is claiming that two observers in the initial universe would measure two different speeds of light I don't see this overturning 'Einsteins V

      • Exactly. Einstein was simply saying that observations were always consistent for any one observer in very certain ways (and not necessarily consistent in other ways we might naively expect). Many of his thought experiments used two observers, in order to elucidate the consistencies and apparent inconsistencies. But the underlying physics is about what is true about any one observer.

        There is actually nothing in physics that says so-called physical constants were always the same over time. In fact, there h

    • by lgw ( 121541 )

      Did Einstein ever make any claims about the speed of light being constant over time, or has a journalist just assumed he must have in order to shoe-horn his name in?

      There's simply no difference between saying the speed of light changes over time, and saying the universe expands or contracts, except to make the math harder.

      It much like how the "tired light" idea turns out to be mathematically equivalent to existing physics, just expressed in a way that makes the math harder.

  • Christians often get criticized for saying evolution is only a theory.
    When a theory is really very well supported by evidence, as evolution is.
    But can we really complain when something like this, which is clearly an hypothesis, is called a theory.
    "String theory" seems the biggest offender to me.
    No wonder people tend to describe any idea they have as a theory.
    • Christians often get criticized for saying evolution is only a theory.
      When a theory is really very well supported by evidence, as evolution is.
      But can we really complain when something like this, which is clearly an hypothesis, is called a theory.
      "String theory" seems the biggest offender to me.
      No wonder people tend to describe any idea they have as a theory.

      Huh?

      "Theory" is simply the name given to the second step of the Scientific Method. That's it.

      Christians are criticized because they don't understand that the method doesn't stop there, that there's still a couple of steps to go ("prediction" and "experiment"). It's these other two steps that make the difference between proper science and woo-woo.

    • I partially agree, but the underlying issue is that many words have multiple definitions and which meaning should be clear from context. Scientists cannot police every journalist's and every layman's language, or they will get dinged for being even more highfallutin' than they already are. In this case, the meaning is adequately clear, even if the language is imperfect.

      In this context, String Theory and Fast Light Theory are understood as speculative theories, that are more developed than simply a hypothe

  • 1bn km/h (Score:3, Insightful)

    by Overzeetop ( 214511 ) on Wednesday November 30, 2016 @07:13AM (#53391631) Journal

    Of course, because when I think of physics and the speed of light km/h is the unit I work with the most. And yet we wonder where Brexit and Donald Trump came from.

  • It always struck me (even as an undergrad 25 years ago when we were talking about SR and GR) that this could be the case - that c could be "instanteously" or "episodically" constant, but need not have been the same value for ever. It's not unreasonable to suppose that the value of c could look like a decay curve, or some function whose value tends to the limit we are now seeing over time from some earlier maximum. I just never got around to asking anyone why not at the time - pity. I suppsoe it goes back
  • If light and other particles could travel and infinite speeds during the creation of the universe....wouldn't that throw off all methods of dating the universe? In fact, wouldn't that make Biblical creation very plausible?
    • In fact, wouldn't that make Biblical creation very plausible?

      No. There is nothing that would make creation as "described" in the bible plausible. The bible is a man made fable with no evidential support whatsoever made in a time when man lacked the technological capacity to make necessary observations. The bible makes no testable predictions nor does it describe any observed events. Any similarity to actual observations and scientific theories is purely coincidental.

    • My first thought was that yes, it would throw off pining down a date for the Big Bang.

      As for Biblical creation, do keep in mind that the story starts with "the face of God moving over the deep". The earth, formless and void though it be, existed before day 1. The universe was created, and was in place for an undetermined period of time before the 7 days of creation.

      If you consider the frame of reference, the surface of the earth, the 7 days of creation play out logically. You can't see the sun or moon un

      • Creationist nutter detected. No, it wouldn't throw off anything. They are saying that the speed of light was temporarily infinite for a VERY SMALL FRACTION of a second. Just f*ck off.
  • I'm trying to understand how this affects the redshifting of extremely distant objects.

    Pretty much any distant stars / galaxies we look at from earth are redshifted, which indicates they are moving away from us. However we know we aren't the center of the universe (where the big bang happened), but that any observer at any other point would see the same affect we see - everything far away is redshifted. This is why we think the universe is expanding - because everything distant is redshifted. Further, the

    • Assuming you are serious: only Creationist nutters believe that the speed of light is slowing down. The theory here is that the speed of light was infinite at the start of the Big Bang, not that it is slowing down. The speed of light is not slowing down, and this has already been proven.
      • The theory here is that the speed of light was infinite at the start of the Big Bang, not that it is slowing down. The speed of light is not slowing down, and this has already been proven.

        So the speed of light was infinite, but now it is not. That is the very definition of "slowing down" is it not? At which point did it slow down I suppose is my question. If this theory can replace the concept of expansion, then it also must explain the acceleration of the expansion, which is what dark energy is theorized to do. So this theory must somehow take into account dark energy as well, which infers that the speed of light must still be changing since expansion is still accelerating.

        Another part of

        • However if you spread a finite amount of energy / matter over an infinite distance, the density would approach zero, thus we would not even perceive that it exists.

          This assumes an even distribution of mass / matter / energy. If the distribution weren't even (because another unstable force, like gravity, caused it to collect together) you would see vast swaths of "empty" space and clumps of matter / energy as it collected together.

          Also consider that "speed" is a function of distance over time and "time" i

    • However we know we aren't the center of the universe (where the big bang happened)

      In the Big Bang picture, the universe has no center, and the Big Bang did not happen in it. The Big Bang happened everywhere in space at once.

    • The big differences in the speed of light presumably occurred in the first picoseconds of the universe, long before there was anything like a galaxy (or even a stable atom). Very likely, almost all the slowing down of the speed of light occurred within seconds of the beginning of the universe. But the redshift numbers we seen from the most distant galaxies galaxies record events from a several billion year old galaxy.

      BTW, there has been some ambiguous data about very distant galaxies that could be interp

  • So a black hole forms when matter is condensed into a sufficiently small space so that even light cannot escape because gravity bends spacetime so much that there is no path to get outside the event horizon. Assuming the big bang theory is plausible, early in the universe the universe would (presumably) be incredibly dense with matter for some period of time. So how is it that having all that matter so close together didn't results in nothing but a bunch of black holes? How does the big bang theory get a

  • by NEDHead ( 1651195 ) on Wednesday November 30, 2016 @09:25AM (#53392371)

    Always safe to credit Hawking for cosmological theory, but a gratuitous mention might have better used Alan Guth

  • Science is about consensus, not challenging dogma?

    • Science is about consensus, not challenging dogma?

      If you look at Maguejo's theory, you will find that it is consistent with everything we knew before about relativity. It is not: "ZOMG! Einstein was WRONG!", rather "We noticed it is possible to extend relativity theory in a way which accommodates a variable speed of light, yet reproduces other known physics perfectly." Look up dilaton theories, for example.

  • by bfpierce ( 4312717 ) on Wednesday November 30, 2016 @10:28AM (#53392837)

    c as a constant is derived from Maxwell's equations, held as invariant in a vacuum.

    If that were true everywhere we wouldn't be looking at trying to find a GUT.

    Would not in the least surprise me that relativity doesn't hold at the beginning of the Universe, considering I can't imagine Maxwell's equations used in that derivation being true there either.

  • What if the speed of light is related to the size of the universe? However perception and size is also related.

    So the universe is expanding. What affect does that have on perceived speeds?

    What if the speed of light is relational to size of the universe? Would it cover more distance in a smaller universe? If so, does that mean C was faster? This is where the normal brain starts to spin wheels a bit.

    But it's a lot of fun. And I'll be highly amused if their experiment bears support for their theory. As I first

  • by s122604 ( 1018036 ) on Wednesday November 30, 2016 @01:16PM (#53394439)
    How else could the universe be more than 6000 light years across when it was all created 6000 years ago by YHWH

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