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Theory Challenging Einstein's View On Speed of Light Could Soon Be Tested (theguardian.com)
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."
Why would anything in the universe be constant? Maybe the variability is beyond our ability to observe.
My ism, it's full of beliefs.
Well, it says "cosmologists including Stephen Hawking", so this time the summary is not that wrong.
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.
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?
systemd is Roko's Basilisk.
This was my thought... a photon is a particle, that travels in a wave. It has some pressure when it shines on an object (see light sails, NASA). If light were to travel at an infinite speed, anything it encounters would be given an infinite amount of energy in the form of momentum. We can then deduce that this was not the case, since most of the sky is black and not full of stars (see Olbers' Paradox). An infinitely fast beam of light would have come into contact with "stuff", and given off an infinite amount of mass/energy (matter), and generated an infinitely dense universe with an infinite amount of energy.
E=MC^2 is dead. Long live E=MC^2!
It's 2016, not reading the summary is the new 'not reading the article'.
Temperature is a measure of the vibration rate of particles - it's not found in vacuums. I suspect the article/summary is oversimplifying or just using temperature as a convenient layman's analogue for heat (unless it refers to the vibration rates of particles in the early universe).
EIther way - do you have any idea how much energy it would take to build a beam that could heat anything up that much ? The amount of energy needed to heat something up depends on the specific heat of the substance, the amount you are heating up and the starting temperature. The last one doesn't much matter considering how huge the heat-up here is - it will be immeasurably small a factor. If we use water then 1g takes 1 calorie to heat up by 1 celcius. A calorie is 4.2 joules of energy.
So you would need 42 thousand trillion trillion joules of energy to raise just one gram of water that high. Just about any other substance - the number goes up.
As of 2012 Humanity produced 155105 TW/H of energy. That is just over 5 .5 trillion joules.
No problem, we just need to multiply the total energy production on earth by about ten thousand trillion times and we can do the experiment you're proposing.
But as the summary explains - we don't need to. The theory makes predictions about the universe which will be true if it holds, and false if inflation is correct - all we need to do is develop sufficiently good measurement technology to see if the prediction is true or not - which we should have fairly soon, and the fact that we are close to being able to do sufficiently accurate measurements to test it is literally the story you are commenting on.
Unicode killed the ASCII-art *
This was my thought... a photon is a particle, that travels in a wave. It has some pressure when it shines on an object (see light sails, NASA). If light were to travel at an infinite speed, anything it encounters would be given an infinite amount of energy in the form of momentum. We can then deduce that this was not the case, since most of the sky is black and not full of stars (see Olbers' Paradox). An infinitely fast beam of light would have come into contact with "stuff", and given off an infinite amount of mass/energy (matter), and generated an infinitely dense universe with an infinite amount of energy.
E=MC^2 is dead. Long live E=MC^2!
No. A photon is a quantized amount of energy which can exhibit particle like and wave like properties under different observations. It is not "a particle" that travels "in a wave"
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.
Is it just my observation, or are there way too many stupid people in the world?
So you would need 42 thousand trillion trillion joules of energy to raise just one gram of water that high.
I knew there was something special about that number being the answer . . .
Next you will tell me that the energy can be generated by a guitar amplifier that goes up to 11 . . .
Schroedinger's Brexit: The UK is both in and out of the EU at the same time!
God placed lamps everywhere in the universe so he could see as he was building it.
Temperature is a measure of the vibration rate of particles - it's not found in vacuums.
The early universe was not a vacuum. It was an extremely dense, high-temperature plasma.
In any case, vacuum can in fact have a temperature, due to virtual particle production.
>The early universe was not a vacuum. It was an extremely dense, high-temperature plasma.
Agreed, but I was referring to the GP's suggestion to heat up a beam and send photons through a vaccuum.
I can see how my post could be ambiguous though.
>In any case, vacuum can in fact have a temperature, due to virtual particle production.
True again, but not really relevant to the point I was making. I am NOT going to try and calculate the energy required to heat up a vaccuum's virtual particles to the temperature of the big bang...
Unicode killed the ASCII-art *
Just curious, do we ever pear actions to them? Or even apricot actions to them?
No. Pears and apricots aren't suitable for actions against infinities due to the extra cost associated with shipping them.
Do you Gentoo!?
Is this the young earth creationist wet dream, that would make it possible for the earth to be 5000 years old?
Definitely not new. I remember reading an article back in the late '80s that followed that line of thinking: that C is constant now, but was faster when first measured, allowing a magical curve that placed earth's age between 5,700 and 10,000 years old.
This was my thought... a photon is a particle, that travels in a wave.
Stop right there. Your understanding of particle wave duality is incomplete. Go back and study before you continue. MinutePhysics has some excellent videos on the topic.
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 until the atmosphere is cleaned up and put to into a usable-for-life state, for example.
$0.02. Opinions on the topic are many and varied.
Always safe to credit Hawking for cosmological theory, but a gratuitous mention might have better used Alan Guth
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 this theory doesn't make sense. If the speed of something is infinite, then the size of the universe must also be infinite to accommodate it, otherwise it would "bunch up" as it hits whatever the "every corner of the cosmos" means (which implies there is a finite size to the universe).
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. So I guess this theory assumes there is a finite size to the universe that is independent of the amount of distance or expansion that could happen at the speed of light.
Better known as 318230.
Crediting Hawking for inflation is yet another example of the Matthew Effect.
More specific credit could have gone to Guth, Linde, and Starobinsky who won the Kavli Prize for "pioneering the theory of cosmic inflation" but who's heard of them?
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.
> a photon is a particle, that travels in a wave
No. This is just wrong. Completely. You need to make your brain unlearn this.
Here is a toy model you can use on your journey... Think of the photon as a cheshire cat. You cannot see the cat, if you try to perceive it completely, it will vanish. You can, however, ask it questions. If you ask it "what is your gizifa", it will say "10". Or in this case, you can ask "what is your momentum", and it might say "5".
Asking certain questions will upset the cat and cause it to change all the other values just to piss you off. So if you ask it what its momentum is, the answer you *might* have got for its gizifa will now change. These values also change on their own over time. So even if you know that its location is 2,7 now, when you ask it again later you will get a different answer. No, this is not *because you asked* (another common misconception), this is inherent to the way the cat works. Some of these values are conserved (like electric charge), others are not (like location) and others are linked together (like momentum and location).
Photons are not particles. There are no particles. "Particles" is the term we use when we refer to these things when you keep asking them what their location is. If you do that, they will give you nice answers like 2,7 and then 3,7 and then 4.7, and you'll go "oh, this thing is travelling along positive X, and it's a point, so it must be a particle!". But the problem is that if you ask it different questions, like its position and the location, then any semblance of particle-like behaviour will vanish. You were fooling yourself, ITS NOT A PARTICLE. Neither is an electron or a proton, or anything else. They're just quanta. It's all quanta.
> It has some pressure when it shines on an object
This is also incorrect.
Newton thought momentum had something to do with mass because he only had large objects to work with. Shotputs have a lot of momentum, and so do planets. But in the "real world" of quantum, momentum is just a number. It's a number like any other, like energy. It's not related to mass. You ask a quanta a question and it will give you an answer. If you ask a photon its mass it will say zero. And if you ask it its momentum it will say 5. These questions are orthogonal, they don't have anything to do with each other.
So why does it LOOK like momentum has something to do with mass? Because the momentum of any one quanta is tiny, so in order to be measurable at macro scales, you need a WHOLE LOT OF QUANTA. It's very easy to make a ball of protons and electrons, because they attract each other. So you put a bunch together and call it a shotput and notice that it has a lot of momentum. But the fact that it has a lot of momentum isn't because it has a lot of mass - it has a lot of mass AND momentum because it *has a lot of quanta*.
It is much harder to make a big ball of photons, they don't attract each other. If you did such a thing, you'd find it had just as much momentum as a ball of matter, but still has no mass.
> and given off an infinite amount of mass/energy
No. Energy is also a measurement of the same sort, it's just a number you can ask for. It has nothing to do with "speed". Some of these values you ask for are more interesting than others because they are concerned, but that's not due to quanta, that's due to the shape of the universe.
How else could the universe be more than 6000 light years across when it was all created 6000 years ago by YHWH
The thing your post misses is, why is a quanta not a particle? You say that repeatedly and effectively, but you don't say why.
Because it doesn't behave like a particle.
Using the previous poster's question analogy, you ask a quanta particle-based questions, and you get answers that look like a particle. And those answers make it impossible for that quanta to be a wave.
But if you ask that same quanta wave-based questions, you get answers that look like a wave. And those answers make it impossible for that quanta to be a particle. (For example, the classic double-slit experiment.)