a question about the speed of light and electromagnetism

[johnfrancismurray]

TL;DR Summary

an observation that light has both a 'true' and 'apparent' speed.

hello, I am interested in the speed of light as well as electromagnetism.
I understand that time stops at the speed of light, which is approx 300000km/s.
but because time stops at the speed of light it appears to me to have two speeds- those being the speed it experiences which is instantaneous (because time has stopped so all destinations at any distance will be arrived at instantaneously) and the speed a third party experiences it at which is approx 300000km/s (traveling through a vacuum).
this would help explain the infinite and finite characteristics of the speed of light ie. it takes an infinite amount of energy to accelerate an object with mass up to the speed of light, with the amount needed rising exponentially as time slows down to zero exponentially.
It reminds me of wind speeds that a sailing boat experiences, those being 'true' the wind speed for a stationary object in the same place as the boat, and 'apparent' the wind speed experienced across the deck of the moving boat- like light has a 'true' and 'apparent' speed.
please feel free to correct me if I am mistaken in any of my facts.
many thanks
johnmurray

 

[Dale]

Light doesn’t have an experience. I don’t think anything meaningful can come of pretending that it does.

It does have an affine parameter. I am skeptical about the usefulness of any notion of the speed with respect to an affine parameter.

 

[Ibix]

Time does not stop at light speed - that makes no sense, despite its appearance in popularisations of relativity. The correct statement is that proper time cannot be defined along the paths that light follows, so there is no meaning to your "speed it experiences".

 

[johnfrancismurray]

yes Im not trying to anthropomorphize light, I know that wouldn't make sense. Im just talking about time ceasing to exist for something traveling at the speed of light (theoretically).

 

[johnfrancismurray]

yes Im not trying to anthropomorphize light, I know that wouldn't make sense. Im just talking about time ceasing to exist for something traveling at the speed of light (theoretically).

I forgot to add thanks Dale

 

[Dale]

yes Im not trying to anthropomorphize light, I know that wouldn't make sense. Im just talking about time ceasing to exist for something traveling at the speed of light (theoretically).

What does time ceasing to exist mean? When something ceases then it was happening earlier and it stopped happening later. But what does it mean to happen later if it is time itself that stops happening? How does the concept of having previously stopped even make sense without time existing?

I am afraid that this is just a logical dead end. You get tied up in mental knots. It is better just to stick with the standard formulation. It picks a narrow path through some very thorny issues.

 

[FactChecker]

It reminds me of wind speeds that a sailing boat experiences, those being 'true' the wind speed for a stationary object in the same place as the boat, and 'apparent' the wind speed experienced across the deck of the moving boat- like light has a 'true' and 'apparent' speed.

I don't think that the behavior of time and speed in Special Relativity can be likened to anything that is a common experience at low speeds. The geometry of spacetime is not nearly apparent in common experience at low speeds.
That being said, even at low speeds, there are extremely sensitive measurements that agree with SR, as opposed to Galilean relativity. Also, electromagnetic effects are easy to see at slow speeds, but their ties to SR are not obvious.

 

[phinds]

Im just talking about time ceasing to exist for something traveling at the speed of light (theoretically).

But is DOESN'T "cease to exist". It never existed in the first place.

 

[johnfrancismurray]

I don't think that the behavior of time and speed in Special Relativity can be likened to anything that is a common experience at low speeds. The geometry of spacetime is not nearly apparent in common experience at low speeds.
That being said, even at low speeds, there are extremely sensitive measurements that agree with SR, as opposed to Galilean relativity. Also, electromagnetic effects are easy to see at slow speeds, but their ties to SR are not obvious.

thanks FactChecker, I only used the true and apparent analogy to describe that something can be at two speeds simultaneously, it is just a metaphor and not the message. The message that I want to put forward here is that light has an infinite and a finite speed and qualities associated with these two. I think this is all established science but not really acknowledged, it means that things traveling at light speed exist both in time and outside of time.

 

[johnfrancismurray]

What does time ceasing to exist mean? When something ceases then it was happening earlier and it stopped happening later. But what does it mean to happen later if it is time itself that stops happening? How does the concept of having previously stopped even make sense without time existing?

I am afraid that this is just a logical dead end. You get tied up in mental knots. It is better just to stick with the standard formulation. It picks a narrow path through some very thorny issues.

Hey Dale thanks again, what I meant was if something accelerated up to the speed of light (I know that is physically impossible (but isn't that because light speed is also an infinite speed as I was saying) then at that moment time would cease to exist for that object. I see your point Dale if time stopped it could not have a moment in which it started, although is that also problem with the theory of the 'big bang' for you? I can see the mental loop you're referring too

 

[johnfrancismurray]

But is DOESN'T "cease to exist". It never existed in the first place.

isn't that so interesting phinds, it never existed in time and yet it also at a measurable finite speed (speed of course = distance over time), it's another duality of light

 

[phinds]

isn't that so interesting phinds, it never existed in time and yet it also at a measurable finite speed (speed of course = distance over time), it's another duality of light

You are mixing apples and oranges, so it's not surprising that your conclusion is bananas.

 

[DaveC426913]

Hey Dale thanks again, what I meant was if something accelerated up to the speed of light (I know that is physically impossible (but isn't that because light speed is also an infinite speed as I was saying) then at that moment time would cease to exist for that object. I see your point Dale if time stopped it could not have a moment in which it started, although is that also problem with the theory of the 'big bang' for you? I can see the mental loop you're referring too

The speed of light is not an infinite speed.

Since you can't accelerate any object to the speed of light, it is meaningless to pretend you can.

Time doesn't cease to exist for objects.

This is word salad.

 

[PeroK]

isn't that so interesting phinds, it never existed in time and yet it also at a measurable finite speed (speed of course = distance over time), it's another duality of light

The concept of time has two related but distinct meanings in relativistic physics. The first is coordinate time. This is the time as measured in a given frame of reference and used to measure the time that an event took place and, along with spatial coordinates and measurements of distance, to calculate the speed of an object.

In Special Relativity, it is simplest to use inertial reference frames, which are the frames of reference in which Newton's first law of motion holds. Two inertial reference frames may be related by a relative velocity. This relative velocity, however, must be less than $c$, the speed of light in vacuum.

Therefore, there is no inertial refrence frame associated with the rest frame of light. In fact, in every inertial reference frame, the speed of light is measured to be $c$. Which is one of the original postulates of relativity.

The second concept of time, which applies in the theory of relativity, is the proper time of a massive particle. This is the time measured by the particle. You can imagine this as the time recorded by a perfect clock moving along with the particle. Light moves along paths where proper time cannot be defined. The physical consequences of this are well understood.

Popular science sources, however, are often not satisfied with things that cannot be defined (like $\frac 1 0$) and so they like to make a big deal of it. Instead of saying simply: proper time cannot be defined along a light-like trajectory, they prefer to say that "time does not exist" or "the photon experiences no time". This sounds mysterious and of great philosophical interest. Whereas, if you study relativity systematically, then there is no issue at all.

 

[Ibix]

isn't that so interesting phinds, it never existed in time and yet it also at a measurable finite speed (speed of course = distance over time), it's another duality of light

No.

There are two different ways to measure time. One is to establish a network of synchronised clocks at rest with respect to each other and read the timeoff the clock you are currently passing. The other is to carry a clock with you. The former is called coordinate time and the latter proper time. The former is always available and can be used with light - that's how we can measure light speed. The latter cannot be used to measure speed, since the appropriate distance would be the distance you travel in your rest frame which is zero by definition.

All "time is not defined for light" means is that you cannot even in principle build a clock that travels at the speed of light. That is obvious - some parts of a clock travelling at $c$ would have to exceed $c$, which is impossible.