-3

I was lying awake last night struggling to sleep as one does, thinking about time and Einstein's concepts of relativity and having some fun with thought experiments similar to the one Einstein described with the train and clock tower. While doing this it occurred to me that time doesn't actually speed up or slow down when you approach the speed of light only the observer's perspective of the speed of time would vary. I'm curious if I came to the correct conclusion in this having never formally studied such things.

Thesis The belief that traveling at the speed of light affects the rate at which time passes is an oversimplification and dumbed-down explanation of how we perceive time due to our limited sensory ability and the abstract nature of time being a human construct to define a phenomenon we can't truly observe from outside the system.

My thought process:

It makes sense to me that if I'm sitting still and looking at an object 1 light year away then I'm actually viewing 1 year into the past. If I were to begin to accelerate to the speed of light towards the object that I'm viewing then I would begin to see what appears from my perspective as time accelerating, moving at double the speed it did while I was stationary. This would give me the false impression that during my 1 year of traveling 2 years had passed at my destination when I arrived. Conversely if while traveling at the speed of light I were to turn around and look behind me time would appear frozen as though I had only just left.

From my pespective as the observer the rate at which time moves has doubled going forwards and halted in the opposite. While more accurately the number/density of photons hitting my eyes in a single "moment" is the only thing really changing, not the flow of time itself.

Qmechanic
  • 201,751
Eric Farley
  • 1
  • 1
  • Time dilation can only be defined if you have two different frames of reference. A non-inertial observer wouldn't really be able to feel anything in regards to time dilation; you'd have to compare how their "clock" is affected when viewed from the perspective of a second observer who is (let's say) stationary. – rhomaios Jun 20 '22 at 23:31
  • There is also gravitational time dilation. Time runs slower at the surface of the Earth than it does above it. See Why can't I do this to get infinite energy? – mmesser314 Jun 21 '22 at 02:49

3 Answers3

2

I'm curious if I came to the correct conclusion

You raise a reasonable question - whether the non-intuitive predictions of special and general relativity might be simply due to a time delay in light reaching our eyes - but the answer to that question is no; time dilation, length contraction, etc are all effects which are observed after correcting for any time-of-flight delay in the light reaching our eyes.

To give a concrete example, if you start with two perfectly synchronized clocks in an inertial frame and then take one on a high speed journey, when they meet again the clock which was taken on the journey would be behind the other one. No speed of light delay is relevant to this observation, since you didn't need to watch the clock as it flew around.

J. Murray
  • 69,036
1

No, time really does slow down, and this is established in literally billions of experiments at colliders like the LHC. It's not some kind of optical illusion.

Actually, it's probably not helpful to think of "time" as a thing that "slows down". Rather, time is another direction in the universe (along with 3 spatial directions) and observers moving relative to one another have temporal axes that are rotated.

Suppose you take two x-y coordinate systems and rotate one relative to the other. Then the "y" values marked along the first one will be different from (shorter than) the "y" values marked along the second, and vice versa. Time and space work in a very similar way. A time interval for a "stationary" observer is all time; one for a "moving" observer has some space (the distance it travels during the interval) along with the time, so the time has to change.

Eric Smith
  • 9,064
0

it is not an illusion but for a referential frame. in my frame time has been slowed down for another it wont and thats where youre wrong. the observer in an inertial frame wouldnt experience any time dilation. an amazing and by far the most famous one is the muon experiment. so the lifetime of a muon increases by a factor of 2. it has no senses and we cant view it as well so it is pretty well established that time dilation does exist

MasterOfPhysics
  • 9
  • 2