The discussion revolves around the concept of the speed of light and its relationship to time, particularly questioning how light can have a speed while being described as not moving through time. Participants explore the implications of light's speed in different reference frames and the nature of time as it relates to light.
Participants express differing views on whether light can be said to have a rest frame, with some asserting it cannot while others explore the implications of such a concept. The discussion remains unresolved regarding the interpretation of light's speed and its relationship to time.
Participants highlight limitations in understanding the nature of light's speed and time, particularly the dependence on reference frames and the implications of relativistic effects. There are unresolved mathematical aspects related to the Lorentz transformation when considering light's speed.
)I think you misheard. It isn't relative to us that it doesn't move through time - it is in its own reference frame (i.e. one moving at c relative to us).daniel_i_l said:How can we say that light has speed but at the same time say that relative to us it doesn't move through time? (sorry if this is a stupid question
daniel_i_l said:
No, as derz said, light does not have its own rest frame. One of the postulates of relativity is that the laws of physics should work the same in all inertial reference frames, and this would be violated if you gave light a rest frame, since clearly the laws of electromagnetism could not work the same in this frame. Also, the Lorentz transformation for transforming between the coordinates of different frames moving apart at velocity v gives infinities if you try to plug v=c in.El Hombre Invisible said:
If you have a clock that is approaching the speed of light in your frame, the length of the ticks of the clock approaches infinity. You can test this with natural clocks like particles that have a characteristic decay time--the closer to light speed they're moving, the longer the decay time as measured in your frame. So whichever author said that light doesn't travel through time relative to us, this is presumably what they meant.daniel_i_l said:
And also what I meant when I said: "i.e. one moving at c relative to us". I was not assessing the feasibility of constructing such a frame, merely where the idea of a photon being emitted and absorbed instantly comes from: i.e., for v = c, /\T' = 0.JesseM said: