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quick light speed question
- Thread starter Cheeto
- Start date
Cheeto said:
Still equals SOL, but due to Doppler effect its frequency will be much higher (if the flashlight moves toward you). You better wear your heavy radiation suite
.If the flashlight moves away from you the light frequency will decrease and its color became red, or it became invisible (the famous red shift).
The photons emitted by the flashlight will still be travelling at SOL. Btw, we can change SOL by changing the medium properies (electrical permittivity and magnetic permeability).
There is a great episode of the universe that runs on the discovery channel that goes into the speed of light. It's a great intro to understanding the speed of light.
Following my previous post, here is seemingly relevant piece of information loosely compiled from several sources.
Speed of light is = 1/(e u)^1/2. In other words, one divided by square root of the product of e and u.
where e - is the electrical permittivity of the material
u - is the magnetic permeability of the material
We know the Vacuum is not perfect empty. There are virtual particles and Vacuum could be polarised. That is why speed of light in Vacuum is finite.
An increase in vacuum energy density will result in an increase in the electrical permittivity and the magnetic permeability of space, since they are energy related. Since light-speed is inversely linked to both these properties, if the energy density of the vacuum increases, light-speed will decrease. The virtual particles that make up the "seething vacuum" can absorb a photon of light and then re-emit it when they annihilate. This process, while fast, takes a finite time. The lower the energy density of the vacuum, the fewer virtual particles will be in the path of light photons in transit. As a consequence, the fewer absorptions and re-emissions which take place over a given distance, the faster light travels over that distance.
What is the speed of light in a perfect empty space?
If permittivity goes to zero the speed of light goes to infinity.
However, the converse is also true. The higher the energy density of the vacuum, the more virtual particles will interact with the light photons in a given distance, and so the slower light will travel. Similarly, when light enters a transparent medium such as glass, similar absorptions and re-emissions occur, but this time it is the atoms in the glass that absorb and re-emit the light photons. This is why light slows as it travels through a denser medium. Indeed, the more closely packed the atoms, the slower light will travel as a greater number of interactions occur in a given distance. In a recent illustration of this light-speed was reduced to 17 metres/second as it passed through extremely closely packed sodium atoms near absolute zero. It takes hundreds of thousands years for a photon to travel from the center of the Sun to its surface.
Speed of light is = 1/(e u)^1/2. In other words, one divided by square root of the product of e and u.
where e - is the electrical permittivity of the material
u - is the magnetic permeability of the material
We know the Vacuum is not perfect empty. There are virtual particles and Vacuum could be polarised. That is why speed of light in Vacuum is finite.
An increase in vacuum energy density will result in an increase in the electrical permittivity and the magnetic permeability of space, since they are energy related. Since light-speed is inversely linked to both these properties, if the energy density of the vacuum increases, light-speed will decrease. The virtual particles that make up the "seething vacuum" can absorb a photon of light and then re-emit it when they annihilate. This process, while fast, takes a finite time. The lower the energy density of the vacuum, the fewer virtual particles will be in the path of light photons in transit. As a consequence, the fewer absorptions and re-emissions which take place over a given distance, the faster light travels over that distance.
What is the speed of light in a perfect empty space?
If permittivity goes to zero the speed of light goes to infinity.
However, the converse is also true. The higher the energy density of the vacuum, the more virtual particles will interact with the light photons in a given distance, and so the slower light will travel. Similarly, when light enters a transparent medium such as glass, similar absorptions and re-emissions occur, but this time it is the atoms in the glass that absorb and re-emit the light photons. This is why light slows as it travels through a denser medium. Indeed, the more closely packed the atoms, the slower light will travel as a greater number of interactions occur in a given distance. In a recent illustration of this light-speed was reduced to 17 metres/second as it passed through extremely closely packed sodium atoms near absolute zero. It takes hundreds of thousands years for a photon to travel from the center of the Sun to its surface.
fraterS.O.L.
Bill Nye
What I was referring to earlier was a collection of data from several GRB's in which high-energy photons arrived later than low energy photons. Admittedly, this could be from the structure of the event, maybe the high-energy photons are being released after the low-energy photons. There needs to be more data, but it could suggest a variable speed of light.
Here's a link to the study
Here's a link to the study
There is also the concept of group velocity of waves that can move superluminally in special media, however the photons typically do not. wikipedia link.
What would the implications be if there was a variable speed of light?? Under what circumstances is the speed variable?
What would the implications be if there was a variable speed of light?? Under what circumstances is the speed variable?
Enoon said:
Indeed, group velocity can exceed SOL, but signal velocity can't.
Enoon said:
I suggested an idea in my previous post, i.e. by manipulating vacuum properties. The speed of light is related to the electric constant ε0 and the magnetic constant μ0 by the equation c = 1/√ε0μ0.
More interesting ideas could be found here - Variable speed of light - Wikipedia
Speed of light varies in accordance to the medium the lights travels through. c is for vacuum. By using different media for light to travel through scientists have been able to even able to stop the light. This is how the news reported it:Enoon said:
Trickster, it sounds like you really know your stuff, and i do understand what everyone is saying, to science thats the way it is. I have watched elegant universe, along with countless other science shows, but what i have never seen is an example/test where the infact proved this rule(Light cannot exceed SOL in any way).
I don't think reading is going to help me at this point, im at the point where i would ask the teacher this same question. I'm not one who like to just take an answer, i like to understand why this is, or in this case i just want to see the proof, scientists aren't dumb i know that, though it may be foolish, i cannot fully believe this until seeing the proof, i know they had to test out the theory, i want to see the results and know what they did to attempt to prove this.
My concern is because the way they say it is(Weather correct or not still sounds weird) it makes a universe where the same light particle/wave can, not appear to, but actually go 2 speeds at once. Let me change this up to give a better view of what im saying, Say in my flash light bit, i'll put a person on the flash light, me standing still at one point, and a person is going to represent a Photon.
This is just my crazy understanding, the main question is at the bottom.
Now, Flashlight going nSOL, a photon/person is ejected from the flash light at SOL. The person riding the flashlight sees the Photon/Person run away from him at SOL, because science says everyone must clock light at the same speed in a vacuum, then this man riding the flashlight sees the light/person leave at SOL. Now back to me, science says it is not possible for me to clock light faster than SOL, but the flashligh is at a speed the universes allows(nSOL). So i can clock the flash light and the light leaving the flashlight. The problem is what i observe is a different reality from the person riding the flash light. To show you what i mean, put a point(a) in front of the flash light setup. Say point a is far enough away to test this. From the person riding the flashlight, because light must move away from him at the SOL(in a vacuum) he will see light reach point(a) at a different time than i will, actually, it will take twice as long for light to reach point(a) in my view. To make it werider, say this photon explodes when it hits point(a). Say the whole test lasted 4 seconds. The man on the flash light sees the target blow up 2 seconds before i do, Cahnge all observers to computers which record data, and you have within one event, 2. 2 explosions at two different times that the computers log in, which in computer world is an error because in reality there was only one explosion.
Like i said though, i know thats how they say it is, and they are smarter then me, but still, for them to believe this they must have seen some very convincing evidence, thats what i want to see. Hopefully they didn't attempt to prove it by thinking and equations only, hopefully they observed somthing to be able to state this weird shit, and if so, i really would like to observe this phonemena myself, does no one know of things observed that prove beyond doubt this is true, that i can't watch or read?
I don't think reading is going to help me at this point, im at the point where i would ask the teacher this same question. I'm not one who like to just take an answer, i like to understand why this is, or in this case i just want to see the proof, scientists aren't dumb i know that, though it may be foolish, i cannot fully believe this until seeing the proof, i know they had to test out the theory, i want to see the results and know what they did to attempt to prove this.
My concern is because the way they say it is(Weather correct or not still sounds weird) it makes a universe where the same light particle/wave can, not appear to, but actually go 2 speeds at once. Let me change this up to give a better view of what im saying, Say in my flash light bit, i'll put a person on the flash light, me standing still at one point, and a person is going to represent a Photon.
This is just my crazy understanding, the main question is at the bottom.
Now, Flashlight going nSOL, a photon/person is ejected from the flash light at SOL. The person riding the flashlight sees the Photon/Person run away from him at SOL, because science says everyone must clock light at the same speed in a vacuum, then this man riding the flashlight sees the light/person leave at SOL. Now back to me, science says it is not possible for me to clock light faster than SOL, but the flashligh is at a speed the universes allows(nSOL). So i can clock the flash light and the light leaving the flashlight. The problem is what i observe is a different reality from the person riding the flash light. To show you what i mean, put a point(a) in front of the flash light setup. Say point a is far enough away to test this. From the person riding the flashlight, because light must move away from him at the SOL(in a vacuum) he will see light reach point(a) at a different time than i will, actually, it will take twice as long for light to reach point(a) in my view. To make it werider, say this photon explodes when it hits point(a). Say the whole test lasted 4 seconds. The man on the flash light sees the target blow up 2 seconds before i do, Cahnge all observers to computers which record data, and you have within one event, 2. 2 explosions at two different times that the computers log in, which in computer world is an error because in reality there was only one explosion.
Like i said though, i know thats how they say it is, and they are smarter then me, but still, for them to believe this they must have seen some very convincing evidence, thats what i want to see. Hopefully they didn't attempt to prove it by thinking and equations only, hopefully they observed somthing to be able to state this weird shit, and if so, i really would like to observe this phonemena myself, does no one know of things observed that prove beyond doubt this is true, that i can't watch or read?
Cheeto said:
No
The light from the flashlight moving at nSOL will move away from the flashlight at nSOL. If both nSOL (flashlight & light) are about the same, then the cone of light will not reach very far anywhere soon from the perspective of the flashlight(rider). The distance/time/length of lightcone will depend on the difference in speed. The SOL is independant of the speed of the flashlight. It wont take twice as long i think.
I dunno why.
(I dunno if its true either, it is just what ive understood lol)
Virola78 said:
all this talk is in a vacuum.
Now let me point this out to you, this will surely fuck with your mind, as it does mine, and is what this is all about. Science says that light in a vacuum does not know how fast anything is traveling, to make it really simple...No matter the speed of an object, light will pass at the SOL, or near if you want to get technical. That is what science says, not what i think. So by science, there is no way possible for me to gain ground on traveling photons, they will always run from me at nSOL, even if i reach nSOL, light will still run from me at nSOL.
Which brings up another thought or question less important than the main one im asking(link to proof), what do they even base that off of, compaired to what? Meaining, Light will move past any object at nSOL in a vacuum despite speed of object. What if this object where another photon, light always moves away from light at the SOL? Or say the object has mass, to any atom or particle of mass, light will always travel past it at SOL? This all sounds like a retard writing theories, it sounds way off and not even possible. But again, lots of people thought that when it came out, yet converted to believeing that it is a fact, i want to see what they saw, because from this point of view all i can do is trust the answer is right, and sorry...but fuck that! If its been proved, where is the proof, if there is none science is a joke(or can be), put OBE's on the table and all the evidence in the world is needed for it to be worthy of considering, no one really knows of anything they have done to prove this feature of light?
The way I see it and I am not scientist is that if I am on a bike going 90MPH and I throw a ball at 20 mph the ball will move forward at 110 mph as it takes my initial momentum. If I am on a bike at 90mph and I switch on a flashlight the light will not move forward 90+SOL because photons having no mass will not carry the energy of my initial momentum. Also check this out if you are interested in a basic course on physics:
webcast.berkeley.edu
Webcast and Legacy Course Capture | Research, Teaching, and Learning
Quantum loop gravity actually predicted this. It is a theory less well known than string theory, that is competing with string theory to reconcile quantum mechanics and relativity although it could turn out that in the next century the problem will then no longer be to reconcile QM and relativity, but to reconcile QLG and string theory.fraterS.O.L. said:
The theory sugests that space itself (as we know it) is a medium through wich light travels, consisting out of small gravity loops. high energy photons travel through it at a lower speed because they have a higher sort of 'friction' with this 'tisue of space'.
I find this idea apealing, because the light speed problems as stated here show that if any measurement of the speed of light gives the same result at any time, then our traditional way of looking at space and time can not be correct. So space MUST have a completely different nature than we all think. Wich then makes the assumtion that space itself is a sort of medium as well, no longer so improbable. And that would make the assumption that space is not a continuüm no longer improbable either.
shishigami
Rising Star
vovin said:
The baseball will be moving very close to 110 MPH but at a slightly lower speed...
Pulling out my old high school notes, according to special relativity
v' = (u + v)/(1 + (u * v)/c^2)
I believe u and v are the speeds of the objects (not velocities) and c is the speed of light. v' is the final speed of the object. So we plug in 20 and 90 mph for u and v and we get 110. Not actually but both my calculator and google round to 110. Wolfram Alpha gives 109.99999999999955973257480668344710465642204044077125059099...
EDIT: This is for particles with mass. So no plugging in c for u and v or anything like that. Which means u and v can be velocities.
physics envy
Rising Star
jbark - Peter Russell happened to be the guy I watched that converted me from atheist to spiritual. The way he explained light, time, and consciousness helped me see it all in a way I had never thought of, although I honestly hadn't put much time into it...even though I have an aeronautical engineering degree. I just had to see be lead to spirituality from a scientific point of view rather than religious. I'm glad to see his name in this thread!
He explained that light goes nowhere, and takes no time to do it
He explained that light goes nowhere, and takes no time to do it
physics envy said:He explained that light goes nowhere, and takes no time to do it
Yea, i read something latter on that said light isn't as simple as most explain it. There are 2 main theories, one being light will always be clocked at the same speed, the other one he more agreed with is light will always "Appear" to be clocked at the same speed.