When moving at the speed of light time stops

eyad-996

So light takes time to reach between two points because I (the observer) can feel/ measure time differently from the Light ??

DaleSpam

That seems like a good way to put it. In your reference frame you are not moving at the speed of light, you experience time, and in your frame light takes time to go from A to B. And light doesn't have a reference frame of its own.

eyad-996

Thank you all, you have been a great help.
Last post puts it straight and simple.

jk22

the lorentz transformation is singular for the speed of light i.e. Not defined

Moonraker

What about this answer:

The time dilation formula is according to http://en.wikipedia.org/wiki/Time_dilation

T‘ = T * sqrt (1-v²/c²).


Set v=c, the proper time of light T’ will always be 0. The lorentz transformation is not defined for the speed of light, but the time dilation formula above is.

However, time is not frozen, the proper life time of a photon is zero.

ghwellsjr

Here's a thread you should read:

http://www.physicsforums.com/showthread.php?t=661429

bcrowell

I don't think any of the previous posts have really addressed the basic misunderstanding invoved in the OP's question. The OP asked:

(1) The question shows a more basic misunderstanding of frames of reference. Suppose the OP had asked instead:

(2) "If when you're moving close to the speed of light time freezes, why then does it take neutrinos 8 minutes to reach the earth from the sun?"

The answer is that when we talk about the time taken for something to reach the earth from the sun, we're implicitly talking about the time as measured in the frame of the earth. But relativistic time dilation would relate the 8 minutes to the much longer time taken in the frame of the neutrino.

A question that didn't involve this misconception would be:

(3) If when you're moving close to the speed of light time freezes, does that mean that only a very short time passes in the frame of a neutrino that, in the earth's frane, takes 8 minutes to reach the earth?

The answer would be yes.

eyad-996

Thanks, great answer!

Moonraker

Hi ghwellsjr,
which one? are you (mistakenly?) refering to our current thread?
Moonraker

Moonraker

I suppose that neutrino's speed in neutrino's frame is not higher than light speed because the distance sun-earth is diminishing in neutrino's frame as well? (according to Lorentz transformation)

ghwellsjr

It was no mistake.

If you had read this thread you would have read this post:
So then why do you say:
This is a wrong statement because time does not apply to a photon. It doesn't have a proper time or a life time or a proper life time or any other time. You shouldn't say that time for a photon is not frozen or frozen. You should say time doesn't apply to a photon which is different than saying that some kind of time of a photon is zero.

Moonraker

I don’t agree. There is no doubt that each photon is sent and absorbed at a precise time.T_emission and T_absorption. Time applies to photons too. This is one of the very few things we know for sure about photons.

Doc Al

These are not times measured from the (nonexistent) frame of a photon, they are measured from other quite ordinary frames of reference.

DaleSpam

The neutrinos speed in the neutrinos frame is 0.

Moonraker

No, the moment of emission is the same for the observer and for the photon.
At the absorption, the clock of the observer shows 8 minutes (Sun-Earth). The “clock” of the photon shows 0 seconds, according to the above-mentioned time dilation formula:
T‘ = T * sqrt (1-v²/c²),
even if the Lorentz transformation does not apply to photons.

Moonraker

This would mean that the distance is 0 as well in the neutrino's frame.

Doc Al

You do realize that the time dilation formula is just a special case of the Lorentz transformation, don't you? So if the LT doesn't apply, neither does the time dilation formula.