The Speed of Light

[Grandliseur]

You know what I find so incredible, besides everything you wrote making sense, the ideas you put forth are so far from the mind of the average human being that they would think you are crazy.

I just love physics. Used to read a lot about it, black holes, Schrodinger's Cat, and what not.
Probably a bit nutty. It improves the flavor with age, as with Whiskey!

 

[sayak83]

I am just a bit ornery, perhaps.

That is why, I am wondering if in the propagation of photons, since we have the space-time field where we have the probability quantum effect of particles popping in and out of existence, a question of where this photon, wave of electromagnetic energy, needs to work its way through this 'sea of probability matter' (sorry for the poor phrasing) and that this activity might be affecting the top speed of light in a vacuum.

I think I am going to quit now.

Also note that calling "c" the speed of light is actually a misnomer. Rather, this universe has a fundamental upper speed limit that light happens to attain(just as we also have a fundamental lower temperature limit at 0 Kelvin). Suppose we have a signal that moves from A to B faster than the speed of light. Then it can be shown that certain observers will see that the signal reaches B before it starts from A, violating all kinds of things. Thus the speed at which light travels is not just about the physical constraints of how photons are interacting with space-time.

 

[Polymath257]

Thank you. That was fun.

There has to be some reason for the speed limit?!

Well, there are actually two questions here:

1) Why is there a speed limit?

2) Why is that speed limit the speed of light?

The first seems to be an aspect of the geometry of spacetime and is related to causality: we can only influence events that we can reach by going slower than a certain speed. That speed seems to be built into the actual geometry.

The second is a bit easier: anything massless will move at the speed limit and photons are massless. So light is just what we noticed first going at that speed.

 

[Grandliseur]

Ref #42

this universe has a fundamental upper speed limit that light happens to attain

I have never heard this assumption before. I have always thought of the speed of light as being its own limitation kind of like me having a limit to how fast I can run, rather than the universe telling me that nobody else can exceed my speed.
Or, kind of like a boat with x horsepower that only can go so fast through the water. If it had a bigger engine it would be able to go faster.

In your statement, a bigger engine would not permit the boat to go faster, i.e., if the speed limit is built into the universe.
In this you are saying that the limit is not light's, but the universe's. I find that an interesting twist to what I have perceived until now.

Then it can be shown that certain observers will see that the signal reaches B before it starts from A, violating all kinds of things.

But, if we have worm holes in which we imagine we might travel through, that is exactly what will happen. I might start out in my spaceship at time origin. I arrive a B. and see myself start out from A since light takes so long to come to B. That does, however, not affect time; it only affects what is perceived by those who ignore the events having taken place.

 

[Polymath257]

Ref #42

I have never heard this assumption before. I have always thought of the speed of light as being its own limitation kind of like me having a limit to how fast I can run, rather than the universe telling me that nobody else can exceed my speed.
Or, kind of like a boat with x horsepower that only can go so fast through the water. If it had a bigger engine it would be able to go faster.

In your statement, a bigger engine would not permit the boat to go faster, i.e., if the speed limit is built into the universe.
In this you are saying that the limit is not light's, but the universe's. I find that an interesting twist to what I have perceived until now.

Yes, that is correct. Light is special because its particles (photons) are massless, so they naturally move at the universal speed limit.

We have found *nothing* that goes faster than light.

But, if we have worm holes in which we imagine we might travel through, that is exactly what will happen. I might start out in my spaceship at time origin. I arrive a B. and see myself start out from A since light takes so long to come to B. That does, however, not affect time; it only affects what is perceived by those who ignore the events having taken place.

If wormholes exist, then the speed *through* the wormhole will still be light speed or slower. it is just that there is a shortcut through the wormhole. The speed limit still applies.

 

[Grandliseur]

Well, there are actually two questions here:

1) Why is there a speed limit?

2) Why is that speed limit the speed of light?

The first seems to be an aspect of the geometry of spacetime and is related to causality:

That speed seems to be built into the actual geometry.

The second is a bit easier: anything massless will move at the speed limit and photons are massless. So light is just what we noticed first going at that speed.

Has it not been theorized that the inflation at the very first milliseconds of the BB happened at FTL.
And, that this was supposedly possible since matter wasn't involved?

we can only influence events that we can reach by going slower than a certain speed.

I am not sure I follow this logic, understand it.
If I knew that a sun 100 light years distant would be going supernova and destroy the planet in 20 years, it would by conventional means take me centuries even a 1/2 light speed to get there. But, if I could go through a wormhole and get there in 10, and save Miss Universe, I would have influenced events despite light having a speed limit I couldn't exceed.

Maybe I am misunderstanding your statement, and sprouting nonsense.
Well, as long as we are having fun.

 

[Polymath257]

Has it not been theorized that the inflation at the very first milliseconds of the BB happened at FTL.
And, that this was supposedly possible since matter wasn't involved?

Space itself was expanding very rapidly at that point. So there was no motion *through* space.

I am not sure I follow this logic, understand it.
If I knew that a sun 100 light years distant would be going supernova and destroy the planet in 20 years, it would by conventional means take me centuries even a 1/2 light speed to get there. But, if I could go through a wormhole and get there in 10, and save Miss Universe, I would have influenced events despite light having a speed limit I couldn't exceed.

Maybe I am misunderstanding your statement, and sprouting nonsense.
Well, as long as we are having fun.

Think of it like this. if you take the normal highway, and go at the speed limit, it might take you 15 minutes to get to your destination. But, if you knew a shortcut, you might get to your destination in 5 minutes while still going at the speed limit. Wormholes (if they exist) provide a shortcut, but don't change the speed limit.

 

[Thief]

Thank you. That was fun.

There has to be some reason for the speed limit?!

YES!

but I don't have the answer

 

[Grandliseur]

The speed limit still applies.

I agree with that naturally, but I would still arrive at B before they saw me depart from A.
If am not sure if that would create a paradox or not in the way it is being spoken of. I don't see why it should.

 

[Grandliseur]

Ref 47

Space itself was expanding very rapidly at that point.

When you say space, you are addressing a point I have an opinion about -- namely, that this space being expanded is the space-time field.
If you imagined being outside that field, I think of such place as null-space, imagining it to be a place where light cannot propagate in. Wonder if you have an opinion on what would be outside this envelope of expanding space-time?

 

[Grandliseur]

YES!

but I don't have the answer

We can always imagine what it might be, and try to falsify it, if possible. If not possible, go to the nearest pub to drown our sorrows deeply for an hour or so. That might make us see the light at the end of the tunnel.

 

[Polymath257]

Ref 47

When you say space, you are addressing a point I have an opinion about -- namely, that this space being expanded is the space-time field.
If you imagined being outside that field, I think of such place as null-space, imagining it to be a place where light cannot propagate in. Wonder if you have an opinion on what would be outside this envelope of expanding space-time?

Some care is required in this subject. Space-time is NOT expanding. Space is. Space-time just 'is'. Furthermore, the expansion of space isn't 'into' something beyond.

And, yes, if you regard the 'space-time field' as being the metric, then the metric determines the distances in spatial 'cross sections' and thereby how much expansion there is.

An analogy:
If we think of latitude on the Earth as representing time with north being 'into the future', then we can think of longitude as space.

In this analogy we have several key things going on:

1) At any point in time (any latitude), space is finite (and in this analogy space is circular).

2) The Big Bang corresponds to the South Pole. There is literally no 'south of the South pole' just as in the simplest version of the BB scenario, there is no 'before the Big Bang'.

3) There is a 'singularity' at the South pole: all the longitude lines converge there and we cannot go any further south.

4) As we move north from the South pole (i.e, we watch things after the Big Bang), we initially see space 'expanding': the latitude lines that represent space get larger as we move north.

5) Space-time is curved with a definite geometry. In the analogy, space-time is spherical.

Now, the aspects of this model that may not correspond to reality (based on current data):
6) Once we pass the equator going north, 'space' starts to contract. The latitude circles get smaller as we go north from the equator.

7) There is a 'Big Crunch' at the North pole.

8) There is a singularity at the North pole (all longitude lines converge and we cannot go any further north).

9) There is no 'after the Big Crunch' (i.e, no north of the north pole).

One obvious aspect of this analogy is that it is *two* dimensional with 'space-time' being the surface of the Earth. Actual space-time is at least four dimensional (and in some theories up to 26 dimensional).

 

[Tmac]

I just love physics. Used to read a lot about it, black holes, Schrodinger's Cat, and what not.
Probably a bit nutty. It improves the flavor with age, as with Whiskey!

I'm just happy that you can see these things and then are able to illustrate it in your words, thanks. The last time I saw what you can see was an LSD experience.

 

[Thief]

there is always a 'point' of origin
movement has no meaning without it

 

[Grandliseur]

Some care is required in this subject. Space-time is NOT expanding. Space is. Space-time just 'is'. Furthermore, the expansion of space isn't 'into' something beyond.

And, yes, if you regard the 'space-time field' as being the metric, then the metric determines the distances in spatial 'cross sections' and thereby how much expansion there is.

An analogy:
If we think of latitude on the Earth as representing time with north being 'into the future', then we can think of longitude as space.

In this analogy we have several key things going on:

1) At any point in time (any latitude), space is finite (and in this analogy space is circular).

2) The Big Bang corresponds to the South Pole. There is literally no 'south of the South pole' just as in the simplest version of the BB scenario, there is no 'before the Big Bang'.

3) There is a 'singularity' at the South pole: all the longitude lines converge there and we cannot go any further south.

4) As we move north from the South pole (i.e, we watch things after the Big Bang), we initially see space 'expanding': the latitude lines that represent space get larger as we move north.

5) Space-time is curved with a definite geometry. In the analogy, space-time is spherical.

Now, the aspects of this model that may not correspond to reality (based on current data):
6) Once we pass the equator going north, 'space' starts to contract. The latitude circles get smaller as we go north from the equator.

7) There is a 'Big Crunch' at the North pole.

8) There is a singularity at the North pole (all longitude lines converge and we cannot go any further north).

9) There is no 'after the Big Crunch' (i.e, no north of the north pole).

One obvious aspect of this analogy is that it is *two* dimensional with 'space-time' being the surface of the Earth. Actual space-time is at least four dimensional (and in some theories up to 26 dimensional).

Thank you. If you have other posts, I haven't seen.

But, the forth and back was enjoyable. Won't take up more of your time with it.

 

[Grandliseur]

I'm just happy that you can see these things and then are able to illustrate it in your words, thanks. The last time I saw what you can see was an LSD experience.

Only coffee and a tiny bit of alcohol at times. Those are the only drugs I use unless in the hospital, and except for a little bit of Metphormin.

Yeah, my wife never could take my discussions about math and physics, I gave her headaches! No wonder we only had 3 kids.

 

[Polymath257]

Thank you. If you have other posts, I haven't seen.

But, the forth and back was enjoyable. Won't take up more of your time with it.

If you have any questions, feel free to ask. I am a mathematician by profession and have been studying physics at the graduate level for quite some time. I am always willing to help answer serious questions.

 

[Terrywoodenpic]

If my understanding is correct, the maximum speed of light is independent of physical motion or frames of reference, therefore the velocity of the train would have nothing to do with it. There is the velocity of the train, and the velocity of light, separately. Did I get that right?

The problem is easier to think about when you know time is not a constant.
The time experienced by the speeding train and the time experienced by the observer are different.
As you move faster time slows.....
In the same way, mass increases.

 

[Grandliseur]

If you have any questions, feel free to ask. I am a mathematician by profession and have been studying physics at the graduate level for quite some time. I am always willing to help answer serious questions.

Well, I once heard Professor Michio Kaku speak on time travel. Without wanting to be disrespectful - I thought it a lot of baloney. I do not believe time travel to be possible. (except forward by approaching the speed of light, thus reducing the rate you age relative to those who do not move this way)

If you should want to engage in this subject, let me know. It is not that my claim is that long btw.

 

[Thief]

Well, I once heard Professor Michio Kaku speak on time travel. Without wanting to be disrespectful - I thought it a lot of baloney. I do not believe time travel to be possible. (except forward by approaching the speed of light, thus reducing the rate you age relative to those who do not move this way)

If you should want to engage in this subject, let me know. It is not that my claim is that long btw.

just occurred to me....

if you gain the speed of light...... hold to it for a while.....
your return to the starting point would be everyone else's future
(everyone you left behind would continue forward)

and you would be the past