# Thread: Time Dilation and light

1. If time for the observer actually slows down the quicker he goes, and as he approach the speed of light, time dilation occurs ever more strongly. That is to say on their watch a few seconds would be equal to a few years for any one standing on earth.......Okay my question is.........

As time dilation keeps increasing the closer we get to the speed of light.........Does that mean that for Photons which can and do (obviously) travel AT the speed of light, does time stop completely in their frame of reference ?

2.

3. try this; if traveling at 93k mps, the photons heading your direction would be moving at 186k mps and those coming at you will be going 186k mps.
your concept, if possible, would be (one half) and (one and a half) times you actual speed. why would the second (time) change and should still be the full second.

4. Originally Posted by jackson33
your concept, if possible, would be (one half) and (one and a half) times you actual speed. why would the second (time) change and should still be the full second.
i have no idea what this means.... jackson could you repeat this for me? Leohopkins, your correct photons do not experience time.

5. Okay; jackson I kind of understand what you are saying. And yes; I do know that this is an observable affect of relativity.

Put into simpler terms what you are saying is that photons will appear to move at 186,000 miles per second relative to your frame of reference.

e.g. Two trains passing each other from opposite directions; both travelling at 40mph; their velocity relative to each other would actually be 80mph. But this doesnt happen with light. whether you are headed away from the direction of the photon stream or headed towards it; however fast you are travelling; your relative speed will always remain at 186,000 miles per second.

Okay..........Now on to my next wondering......If, just as I suspected; photons do not experience time, (which common sense tells me they do not due to time dilation) then.....how can a photon change is wavelength from gamma rays to microwaves over distance; if they do not have the time to make this change?

6. how can a photon change is wavelength from gamma rays to microwaves over distance; if they do not have the time to make this change?
Interesting question I wonder that too, although I did not know light changed wavelength midway.

Doesnt the wavelength also depend on our own relateive speed and heading?

Could it be that the photon interacts with stray atoms and paticles in the void of space discharging energy and change wave length?

7. Originally Posted by leohopkins
If time for the observer actually slows down the quicker he goes, and as he approach the speed of light, time dilation occurs ever more strongly. That is to say on their watch a few seconds would be equal to a few years for any one standing on earth.......Okay my question is.........

As time dilation keeps increasing the closer we get to the speed of light.........Does that mean that for Photons which can and do (obviously) travel AT the speed of light, does time stop completely in their frame of reference ?
I think this makes sense, this could explain why photons can appear in two different places at once...

8. erm.......I think you could be on to something there!!

All we need now is to build the mathematical model

9. Originally Posted by leohopkins
If time for the observer actually slows down the quicker he goes, and as he approach the speed of light, time dilation occurs ever more strongly. That is to say on their watch a few seconds would be equal to a few years for any one standing on earth.......Okay my question is.........

As time dilation keeps increasing the closer we get to the speed of light.........Does that mean that for Photons which can and do (obviously) travel AT the speed of light, does time stop completely in their frame of reference ?
By George he's got it!

Now consider you are the photon, leaving a galaxy say 12 billion years ago, and you suddenly crash into the earth here, your watch shows no time has elapsed, from your point of view, one minute you were minding your own business watching the big bang, and the next it's all over, 12 Bn years have elapsed and there's these things called planets!

You've just travelled across the universe in '0' time, and 'transported' yourself 12 billion years into the future!.

So the next time your chicken catches fire on the barbeque and leaves only a trace of carbon, you'll know it'll eventually crash into a galaxy somewhere in the future...

10. Originally Posted by Megabrain
Originally Posted by leohopkins
If time for the observer actually slows down the quicker he goes, and as he approach the speed of light, time dilation occurs ever more strongly. That is to say on their watch a few seconds would be equal to a few years for any one standing on earth.......Okay my question is.........

As time dilation keeps increasing the closer we get to the speed of light.........Does that mean that for Photons which can and do (obviously) travel AT the speed of light, does time stop completely in their frame of reference ?
By George he's got it!

Now consider you are the photon, leaving a galaxy say 12 billion years ago, and you suddenly crash into the earth here, your watch shows no time has elapsed, from your point of view, one minute you were minding your own business watching the big bang, and the next it's all over, 12 Bn years have elapsed and there's these things called planets!

You've just travelled across the universe in '0' time, and 'transported' yourself 12 billion years into the future!.

So the next time your chicken catches fire on the barbeque and leaves only a trace of carbon, you'll know it'll eventually crash into a galaxy somewhere in the future...
chicken yes, and what about all those socks that go missing in our dryers lol :wink:

11. Oh that's easy, YOu know that photon I was talking about, well he's got mates see, and well....

12. because the photon does not have a consious, how can it be aware of the passing of time at all?

13. if you were to travel at C time would stand still

14. Originally Posted by Zelos
if you were to travel at C time would stand still
And you would not know about it, you would not know how far you had travelled. One minute you are all excited that you are about to travel at the speed of light, as you get there time stops, no more fuel being used, the on-board navigation kit has stopped as have all the clocks - and this state will continue until you either hit something or the universe ends.

Time travel - Bah humbug!

15. So then in theory.....

In our frame of reference light travels at a finite speed (C)
If, however you were sitting on a beam of light; you would judge your speed (if you could) as being infinate. As time stops for you, you would get there at the same moment you left, right ?

16. You got it in one, photons exist in their own universe which overlaps with ours, they have a different set of laws though.

17. Originally Posted by Megabrain
You got it in one, photons exist in their own universe which overlaps with ours, they have a different set of laws though.
They dont have a different set of laws they behave different just cause they have no restmass and their universe is our universe

If, however you were sitting on a beam of light; you would judge your speed (if you could) as being infinate. As time stops for you, you would get there at the same moment you left, right ?
if you were on a photon traveling with it you would cease to exist since realtive to you it would instantly go a infinite amount of time and the universe would end

18. I of course meant different dimensions...

19. Originally Posted by Megabrain
I of course meant different dimensions...
They have the same amount of spatial and temporal dimensions as we do.
You have to have timedilation that is imaginary for the dimensions to change into eachother

20. But time dilation is not imaginary; it is a REAL effect.

So basically a photon is like a "ghost" particle that will live forever.

Thats...um, interesting.

21. with imaginary i dont mean as in a imaginary friend but rather a imaginary number

like i²=-1 as i hope youre familiar with

22. He's not into maths so just for him take a (metric :wink: ) ruler it's marked along it's length in cm or mm, but what about off to the side? it's one of the most useful tools of mathematics, without it we'd be still living in caves (Metaphorically speaking).

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