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Flying Penguin
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Say a beam of light is cast somewhere - are the photons transmitted at a speed equal relative to one another, or would one photon still perceive the one behind it as moving at light speed?
Flying Penguin said:Say a beam of light is cast somewhere - are the photons transmitted at a speed equal relative to one another, or would one photon still perceive the one behind it as moving at light speed?
marlon said:Photons ALWAYS travel at the speed of light.
Moloch said:Do they now?.. I thought you could slow down a photon if you push it through a space occupied by other particles. Don't photons move slower through the atmosphere, or through a glass prism?
The emitted photon may encounter other lattice ions as it makes its way through the material and this accumulate the delay.
Flying Penguin said:Say a beam of light is cast somewhere - are the photons transmitted at a speed equal relative to one another, or would one photon still perceive the one behind it as moving at light speed?
There no natural way to define the "photon's point of view". See my posts in this thread.anantchowdhary said:If you would see from the point of view of a photon...another photon moves at the speed of light relative to it...for a photon ...there is no conception of space and time
It doesn't. Photons have speed c in all inertial frames, but not in general coordinate systems.marlon said:Photons ALWAYS travel at the speed of light. So, this answers your question, no ?
First a photon cannot "observe" anything- as Fredrick said, it has NO "point of view".ronnie2177 said:if 2 photos are travelling, they would observe each other as 'stationary'.
if a being on one photon fired another photon, the 2nd photon would travel the same speed as the 1st photon i.e the 1st photon will observe the 2nd photon traveling at the same speed, and the 2nd photon observing the being on the 1st photon trAvelling together. of course, this situation is possible if the being on the 1st photon was made of mc².
HarryDaniels said:In the theory of Millenium Relativity
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Photons do not detect in any sense at all. Photons do not experience time. Photons do not have a valid frame of reference.ronnie2177 said:By "observe" I meant any form or method of detection. Obviously this won't be sight (using EM waves from the visible spectrum)
Sorry, this is nonsense either way.ronnie2177 said:"made of mc²" means an 'energy being'.
I did not ask for a definition of "observe"- the point is that photons, having no "point of view" cannot observe anything.ronnie2177 said:By "observe" I meant any form or method of detection. Obviously this won't be sight (using EM waves from the visible spectrum)
You cannot measure speed relative to a non-existant frame of reference and photons have NO frame of reference.Relativity of the speeds are to the photons in travel.
In other words, it doesn't mean anything!"made of mc²" means an 'energy being'.
hansw said:I once heard Feynman say something like: ”c is just the mean value, some photons go slower, some faster”.
Do you have a reason to think of those coordinates as the "reference frame of a photon"? And don't just say that a photon is stationary in it. (There are lots of coordinate systems with that property).bobc2 said:It might be a little easier to get a handle on this kind of discussion in the context of Light Coordinates.
http://en.wikipedia.org/wiki/Light_cone_coordinates
Light going in the "wrong" direction isn't stationary in this coordinate system. It moves at infinite speed. More importantly, the method we use to single out the comoving inertial frame as "the reference frame of" a massive particle, doesn't single out this coordinate system. It doesn't even even work for massless particles.pervect said:If you stick to linear transformations of (x,t) where (x,t) are Minkowskian coordinates, I think there's only the one set that keeps light in both directions stationary.
I consider speed to be the absolute value of the velocity in a coordinate system, which of course is "change of position coordinate"/"change of time coordinate". So to even assign a speed to two massless particles going in opposite directions (in the inertial frame that was used to construct this coordinate system), we have to label one of the axes "time" and the other one "position". (Yes, that's pretty weird, as they're both null lines, but how else can we make sense of "speed"?) Now we have a world line that coincides with the t axis (dx/dt=0) and one that coincides with the x-axis (dx/dt=infinite).pervect said:Both x-ct and x+ct are null coordinates - I don't quite get the reference to "infinite speed", I'm guessing that you're interpreting the fact that one null coordinate stays constant and the other varies as an indication of "infinite speed". I would prefer to think of speed as being unrelated to the coordinates used, so that the speed of light is always c.
hansw said:I once heard Feynman say something like: ”c is just the mean value, some photons go slower, some faster”.
The speed of a photon is always constant at approximately 299,792,458 meters per second in a vacuum. This means that the speed of a photon is the same relative to any other photon.
No, the speed of a photon remains constant even when it interacts with another photon. This is because photons do not have mass and therefore do not experience changes in speed due to interactions with other particles.
The speed of a photon is the fastest speed possible in the universe, and is much faster than the speed of other particles such as electrons, protons, and neutrons. It is also equal to the speed of light.
Yes, the speed of a photon can be measured using specialized equipment such as lasers and detectors. This is how the speed of light was first determined.
No, the speed of a photon is not affected by external forces such as gravity or electric and magnetic fields. However, it can be bent or refracted when passing through different mediums with varying densities.