It turns out that a number of physicists have proposed that the speed of light varies. The idea that the speed of light in the past cone of the universe was many multiples of c, seemed to remove many cosmological problems. One that I can think of off the top of my head, is the time it requires to allow light to reach all four corners of the universe. In order to create a balance in the equations with observational evidence of the background temperatures, an inflationary period was introduced. This moment which allowed the universe to expand faster than light itself, allowed light to reach all four corners of the universe, and create a homogeneous background of gamma particles. If we did not have this inflationary period, we would see clumps of the background radiation showing different temperatures, but this is not the case. Immediately, one can deduct, that if light speed was many more times c, it would remove this problem, and without need of some phenomenal inflationary period that occurs around \(-33-35s\) after big bang. The scientists I refer to at the beginning of the post, include V.S. Troitskii [1] who proposes that the speed of light was initially \(10^{10}\) times the general speed of c, Moffat [2] who proposed it be a value which has dropped over the billions of years since big bang, Albrecht and Magueijo [3] who agreed with Moffat and proposed a whopping value of c that was \(10^{60}\) times the value of c, and John Barrow [4] who agreed with that value, who proposed it dropped over the lifetime of the cosmos, instead of proposing it be immediately after big bang. [1]. V S Troitskii, Astrophys. & Space Science 139 (1987) 389. [2]. J Moffat, Int. J. Mod. Phys. D 2 (1993) 351 and Int. J. Mod. Phys. D 23 (1993) 411. [3]. A Albrecht, J Magueijo,Phys. Rev. D 59:4 (1999) 3515 . [4]. J D Barrow, Phys. Rev. D 59:4 (1999) 043515-1.
The speed of light is a set speed for EMR and gravity. It suggests that if visible light could travel as fast as you claim, it would have the impact of hard gamma rays and molecules, even atoms would not survive under such impacts. Hard gamma rays would be like high intensity cosmic rays. As to gravity, would that be hugely intensified too? If so, everything would collapse into black holes. If not, then EMR would escape black holes so they would deteriorate as they lost all their energy, becoming the brightest things in the universe as they did so. Of course, light slows in a denser medium and until the universe became optically transparent, light would have travelled at slower speeds.
From a wiki article, dubbed ''speed of light...'' interesting stuff. Things that can travel faster than c [edit] Wave velocities and synchronized events It has long been known theoretically that it is possible for the "group velocity" of light to exceed c.[15] One recent experiment made the group velocity of laser beams travel for extremely short distances through caesium atoms at 300 times c. In 2002, at the Université de Moncton, physicist Alain Haché made history by sending pulses at a group velocity of three times light speed over a long distance for the first time, transmitted through a 120-metre cable made from a coaxial photonic crystal.[16] However, it is not possible to use this technique to transfer information faster than c: the velocity of information transfer depends on the front velocity (the speed at which the first rise of a pulse above zero moves forward) and the product of the group velocity and the front velocity is equal to the square of the normal speed of light in the material. Exceeding the group velocity of light in this manner is comparable to exceeding the speed of sound by arranging people distantly spaced in a line, and asking them all to shout "I'm here!", one after another with short intervals, each one timing it by looking at their own wristwatch so they don't have to wait until they hear the previous person shouting. Another example can be seen when watching ocean waves washing up on shore. With a narrow enough angle between the wave and the shoreline, the breakers travel along the waves' length much faster than the waves' movement inland. [edit] Light spots and shadows If a laser is swept across a distant object, the spot of light can easily be made to move at a speed greater than c.[17] Similarly, a shadow projected onto a distant object can be made to move faster than c. In neither case does any matter or information travel faster than light.
Can i also add, a little bit of stuff i already knew. If we consider sine waves, and neglecting a little math, but just cutting straight to the solution of a sine wave, \(v=\frac{b}{a}=\sqrt{(c^{2}+\frac{w}{a}^{2})}\) Are wave solutions that propogate at superluminal speeds. These are normal equations for any wave form or particle. The problem can be removed, by distinguishing this velocity which is known as the phase velocity \(v_{pr}\) from another velocity known as the group velocity \(v_{gr}\) which is given by, \(v_{gr} = \frac{c}{v_{ph}}\) Now, this basically means that a wave packet will have a velocity at the value of ''c'' when in a group.
What i would also like to add, it that the idea of thing moving faster than light should not surprise us. The photon is a particle that flooded spacetime only a handful of years after big bang, and since then, it floods our corner of the universe. However, there is a massive amount of spacetime we don't know about, and faster than light objects may very well exist. Einstein developed his idea of the ultimate speed, in only one corner of the universe, where different measuring rods may hold different surprises in other parts of this infinitely vast universe.
None of your references are from this century, and it appears that there remain serious problems with this idea which has been picked up by only the smallest handful of researchers. While they inflame the imagination, right now they are little more than ideas. Example: Troitskii, V. S. "Physical constants and evolution of the universe" Astrophysics and Space Science 139 (2), 389-411 (Dec. 1987) http://adsabs.harvard.edu/full/1987Ap&SS.139..389T Compare: Youm. D. "Variable-speed-of-light cosmology and second law of thermodynamics" Phys. Rev. D 66, 043506 (2002) http://arxiv.org/abs/hep-th/0203145 Moffat, J.W. "Variable Speed of Light Cosmology: An Alternative to Inflation" http://arxiv.org/abs/hep-th/0208122 Moffat, J. W. "Variable Speed of Light Cosmology and Bimetric Gravity: An Alternative to Standard Inflation" Int. J. Mod. Phys. A20 1155-1162 (2005) http://arxiv.org/abs/gr-qc/0404066 Ellis, G.F.R. "Note on Varying Speed of Light Cosmologies" http://arxiv.org/abs/astro-ph/0703751 http://en.wikipedia.org/wiki/Variable_speed_of_light#The_varying_speed_of_light_cosmology
You mean 'instantly'. Light speed being the ultimate speed wasn't developed as the result of experiment but from the singular premise "The speed of light is the same in all inertial frames". Learn some relativity.
Don't patronize me Alphanumeric. For starters, light didn't flood the universe until after a good 180,000 years. There is some delay to when light appeared in the cosmos when relatively speaking about expansion. And i made no mention about the ultimate speed as some kind of mistake. I was hinting that if the overall density of the universe is not homogeneous, then lightspeed is different. Learn some relativity? As i said, don't patronize me. I've completed two relativity courses.
Photons (as we know them today) flooded the universe after the electroweak unification was broken. This happened at about \(10^{15}\) Kelvin -- about a trillionth of a second after the Big Bang. Prior to this, the bosons of electoweak interations had a different game plan. Thanks to a generic statement about thermodynamics called equipartition, we know in detail what the photonic makeup of the early universe was long before Recombination. That's a statement about the fermions of the universe, not the photons. There were photons long before the event known as Recombination (which is when electrons and nuclei paired up for the first time and neutral gas condensed from the electrically charged plasma, which since it was electrically charged, coupled to photons). Our telescopes cannot see further back in time than this Recombination since the universe was opaque prior to it, but that is not the same thing as saying there were no photons. http://www.astronomy.ohio-state.edu/~pogge/Ast162/Unit5/early.html http://hyperphysics.phy-astr.gsu.edu/Hbase/astro/bbcloc.html http://en.wikipedia.org/wiki/Timeline_of_the_Big_Bang http://en.wikipedia.org/wiki/Graphical_timeline_of_the_Big_Bang
No, it was after 300,000 or so years that recombination occured, which allowed the sea of photons in existence, being emitted and absorbed by all the free electrons and nuclei, to travel further than a few micrometres. Light was there, it just couldn't travel very far. Why? Departures from homogeneity and isotropy are observed in the CMB and there's no evidence the speed of light changes. Infact, it's been searched for and it's been constrained to have not varied by any more than something like a million of a percent in the last 10 billion years. Anywhere. Really? Where?
Rpenner Actually, the time delay varies quite a bit -- from 30 years to about 180,000 years... i think it more or less depends on which theory you use. But photons certainly DID NOT appear instantaneously with the big bang, which alphanumeric appears to say. Alphanumeric What makes you think i would give out personal details like that? Are you mad or something?
Do you think I could work out who you are if you gave me the university you studied at? Given I don't know any other personal details about you, it would be impossible. If you don't want to say something as anonymous as "Michigan" or "York", how about I ask you a few relativity questions then? Are you saying that the enormously energetic charged particles created by vacuum fluctuations immediately after the big bang didn't radiate photons? You do realise hot things give off radiation, right? Didn't they teach you that during your physics course?
I'm possibly guessing, but I suspect that Saxion is referring to free photons that are no longer interacting. At those higher energies the 'photons' were all interacting, and had no effective transit distance. However, there were other interactions as well, and in particular it is believed that neutrino interactions quit interacting as the expansion proceeded and acquired an effective transit distance before the photons did so, and that we should have a neutrino background comparable to the red-shifted CMB. We just can't detect it because of their low interaction capability, particularly when at an effective low speed [presuming they have mass and therefore are initially emitted at barely sub-relativistic speeds] in our cosmic neighborhood.
Well, in that case, where he is talking about long-mean-free-path propagation of radiation, he is free to talk about "light" or more precisely the transparancy of the universe. But when he talks about the genesis of photons, which mediate the force between electromagnetically charged particles of all types, then his misappropriation of technical language has rendered his statement incorrect. Photons existed before the universe was transparent because what rendered it opaque was the plasma of free charged particles. Now prior to that first trillionth of a second, the fundamental forces weren't in the familiar state in which we find them today, so I reckon you could quibble a lot about whether the bosons found then were "photons" or not.
Then that's sorted. I can assure that whatever timeline you give it, photons did not appear instantaneously. Rpenner, if it is how i worded it which causes me to be wrong, at least my perception of the theory is not. Alphanumeric, I won't give in, and i am not going to get into silly quabbles and exchanging homework questions, for your pleasure.
Now, could we discuss the artical i posted in the OP, or are we going to endlessly debate on the nature of the photogenesis?
