[geuis]

I'm going to be the odd man out here. There are several statements made in the article that are incorrect, and then other arguments are based on them.

In particular, the tying together of speed and time.

"By 'world line' we mean a curve traced out in the four dimensions of space-time". Time is not a dimension. Time is a human concept. Clocks don't measure a physical dimension or force called time, they repeat mechanical motions at regular intervals that we label as time passing. Same for atomic clocks. We measure the spin rates of cesium atoms but that isn't any different than mechanical clocks. Time is not a force that figures into physics equations.

Further, time doesn't exist. Not in the classical sense. What we experience as time is the entropy of energy in the universe winding out. We remember things that happened before and imagine things in the future, but since there is no physical "time" dimension there is no traveling forward and back.

If you are on a ship traveling close to c, the rate of entropy in the matter and energy on your ship is lower than the outside universe. That's why time seems slower.

There's a classic thought experiment that you can build a time machine by putting one end of a wormhole on a ship, send it out for 20 years near c, then bring it back. At this point you would have a wormhole with ends in two different times. It doesn't work like that though. Passing through it will just put you wherever it opens to, and you'll just end up in whatever local entropy rate is going on.

[bermanoid]

I'm not entirely sure what you're really trying to say overall, but you're accusing the article of making several incorrect statements and then in the next breath saying a whole bunch of stuff that completely and utterly contradicts any mainstream interpretation of physics. You might be making a philosophical argument about the definition of "time", in which case I'd say "fine, whatever" (metaphysics is probably the grandest waste of time and effort that humanity has ever dreamed up), but I still don't see what makes anything in the article wrong - what tangible physical predictions does it make that are incorrect, in your opinion?

In physics, time is a dimension in all but the most obscure and fringe formulations - whether you're talking about classical theory, special relativity, quantum mechanics, general relativity, quantum field theory, string theory, M-theory, there's always a timelike dimension that shows up somewhere in the formulation.

Are you actually arguing that all of standard physics is in some way measurably wrong, or are you merely trying to make a philosophical point about the definition of the word "time"?

[Chirono]

Further, time doesn't exist. Not in the classical sense... If you are on a ship traveling close to c, the rate of entropy in the matter and energy on your ship is lower than the outside universe. That's why time seems slower.

Not trying to be facetious, this is a genuine question, but rate of change in entropy with respect to what?

[felipemnoa]

I suspect with respect to the frame of reference from where the measurement is being done. If the frame of reference is the ship itself then you will not notice any change in entropy. Hence why you won't be able to tell that time is actually slower. However, from a frame of reference outside the ship you will notice the difference in rate of change.

So really what you are really measuring is the difference in change of entropy from your local frame of reference to the frame of reference of the ship. There is no such thing as absolute rate of change. All is relative.

With respect to time, if you could somehow reverse all the motions of every single subatomic particles in a particular frame of reference then you would essentially be moving back in time in that specific frame of reference. To reverse time you have to reverse the motion of every single particle, sub-particle. Is almost the same thing as simply playing a movie in reverse. Now the real issue with this methodology is that the particle movements are not being recorded anywhere as far as we can tell. So we need to first find a way to record the movement of all the particles in a frame of reference and then find another way to run the entire recording in reverse. I wonder if exceeding the speed of light would actually reverse the motion of particles. That would imply that the motion is somehow being recorded? Who knows, just thinking out-loud.

Another really good question that I've been wondering about is why does entropy decreases when you move faster? What is it that causes entropy to decrease? Is it some sort of "friction" with space-time? Anybody have any good suggestions? It may have to do something with conservation of energy. Or conservation of something. The faster it moves the slower the particles move. Something is being compensated for.

[geuis]

In regards to your last question, I have had similar thoughts. I no longer like using the phrase "speed of light" because it's most commonly used to reference the maximum speed anything observed can attain. It's very clear this has nothing to do with light itself but is derived from the medium itself, space-time.

One analogy that occurrs to me is movement through a fluid. There is almost always a terminal velocity. We can transmit waves via a fluid, and particles through it as well.

I would like to know what vacuum looks like at the Planck scale. Perhaps entropy increases slower or faster based on interactions at the smallest scale between light/matter and whatever space-time is. Movement through the medium at higher speeds decreases these interactions, maybe by skipping over them. Less interactions, slower entropy, slower apparent time.

Perhaps c is the terminal velocity of space-time. The air/water analogy breaks down easily, since we can travel faster than terminal velocity in air. But it's a different way of looking at the question.

[felipemnoa]

Terminal velocity is a really good analogy. Light is just a ripple in space. The ripple will continue forever until it gets absorbed by other matter. Space-time does seem to be an actual substance. Perhaps the proponents of the Ether were right except that now we call it space time. Space-time seems to be made up of super tiny particles were all other particles ride on.

One more thing, if we were to discover that light actually accelerates to c when it is first released by an electron then that would be strong evidence that the upper limit on light velocity is just something intrinsic of space-time. Nothing is ever instantaneous and I have a feeling that neither does light go from zero to c in zero time.

[dkersten]

If we were to discover that light accelerates to c when it is first released, the next step would be to discover that c isn't actually the maximum possible velocity of light at all, but rather the maximum naturally occurring velocity (terminal velocity) and that through some as yet undiscovered means, it actually is possible for light to be artificially accelerated above the value of c.

The terminal velocity analogy makes sense to me. It would be pretty interesting is it turned out to be more than just an analogy.

[geuis]

Vlad refined this concept well. Let me change "rate of entropy" to his clearer distinction.

[hugh3]

I'm still not sure that makes any sense.

[tel]

Relativity just demands that changes in time are a measurement you could make. Then it talks about the geometry of those measurements. What are you arguing against?

[danparsonson]

That's not an interpretation I've heard before but it sounds very interesting - can you recommend any relevant reading material?

[ignifero]

Time in physics is not the same as the psychological arrow of time that we experience (which in itself may be related to the thermodynamical arrow of time). Time is a dimension of a 4-dimensional geometry and thus a quantity of the physical world independent of our perception. The laws of mechanics don't even distinguish between past and present.