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  4. Why must c be an absolute "speed limit"?
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Why must c be an absolute "speed limit"?

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Offline petelamana (OP)

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Why must c be an absolute "speed limit"?
« on: 20/02/2018 13:44:14 »
I have a simple, and yet nagging question...

Why must the speed of light, c, be an absolute "speed limit"?

Why can't something, anything exceed 299,792,458 m/s?  Why can something go 299,792,459 m/s?
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Offline Kryptid

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Re: Why must c be an absolute "speed limit"?
« Reply #1 on: 20/02/2018 14:17:01 »
Strictly-speaking, it is possible in theory for an entity to move faster than light. Such things are called "tachyons". However, they have the opposite problem that normal matter does: they cannot slow down to below the speed of light. So far, no tachyons have been definitively detected.

Normal matter cannot reach or exceed the speed of light due to energy requirements. The closer an object with mass gets to the speed of light, the more its mass increases and the more energy it requires to move faster. At low, everyday speeds, it isn't noticeable. Very close to the speed of light, the energy requirements explode exponentially. Both mass and kinetic energy approach infinity as you zero in on light-speed. Since there is no method of giving infinite energy to matter, all matter is stuck below the light-speed limit.
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Offline wolfekeeper

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Re: Why must c be an absolute "speed limit"?
« Reply #2 on: 20/02/2018 15:42:17 »
Objects are held together by electrostatic forces, which are mediated by photons that travel at the speed of light. That means if you wobble an electron it takes a tiny moment for the forces on the proton to respond; and also when an object moves the electric field is no longer spherically symmetric, it becomes ellipsoid.

It takes an infinite amount of energy to make an object go faster than light, but if somehow an object found itself going faster than light, the electric fields wouldn't keep up with the electrons and protons, so they would no longer be bound together as atoms and molecules and the object would fall to pieces.
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Offline geordief

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Re: Why must c be an absolute "speed limit"?
« Reply #3 on: 20/02/2018 16:53:08 »
Can the question also be asked "Why is there any maximum speed limit?"

As far as I  have understood , there must be a maximum speed limit and  it looks like c is it since it lies at the heart of all processes that have been observed .

It is the fastest that any object has been observed to go  and since there must be a maximum speed  of some kind the c is the obvious candidate.

I have also understood that c is a function of both the permittivity and the permeability of a vacuum.

So if these observed values were different ,c would also have a different value.

But there would still be a maximum speed limit.
« Last Edit: 20/02/2018 16:55:25 by geordief »
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Offline jeffreyH

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Re: Why must c be an absolute "speed limit"?
« Reply #4 on: 20/02/2018 17:19:08 »
Quote from: wolfekeeper on 20/02/2018 15:42:17
Objects are held together by electrostatic forces, which are mediated by photons that travel at the speed of light. That means if you wobble an electron it takes a tiny moment for the forces on the proton to respond; and also when an object moves the electric field is no longer spherically symmetric, it becomes ellipsoid.

It takes an infinite amount of energy to make an object go faster than light, but if somehow an object found itself going faster than light, the electric fields wouldn't keep up with the electrons and protons, so they would no longer be bound together as atoms and molecules and the object would fall to pieces.

Now that is a very interesting post.
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Offline Janus

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Re: Why must c be an absolute "speed limit"?
« Reply #5 on: 20/02/2018 17:43:13 »
Quote from: petelamana on 20/02/2018 13:44:14
I have a simple, and yet nagging question...

Why must the speed of light, c, be an absolute "speed limit"?

Why can't something, anything exceed 299,792,458 m/s?  Why can something go 299,792,459 m/s?
It boils down to the nature of time and space and their interrelationship to each other.   The speed of c plays an important part of that relationship.      It is the invariant speed for the Universe (the speed everyone measures as having the same value with respect to themselves) Newtonian physics also can be said to have an invariant speed, but it is infinite in value.   c is finite.
Once you have a finite invariant speed, it automatically falls out that it becomes the universal speed limit. 

If you are asking why the universe has an finite invariant speed, then the best I can say is that you should be glad that it does.  Many of the fundamental interactions that allow complex structures, from subatomic particles on up, to even exist rely on Relativity and the fact that this finite invariant speed exists.    In other words, it might not even be possible for a universe without it to have the type of complexity needed for beings capable of asking the question to form in the first place.
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Offline chiralSPO

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Re: Why must c be an absolute "speed limit"?
« Reply #6 on: 20/02/2018 18:36:15 »
I have heard the fact that there is a "speed limit" invoked as evidence supporting the Simulated Universe theory (the idea that are universe is actually a complex simulation--I am not a big fan of this idea, because I am not sure if it is falsifiable, but at any rate, I don't think we have any evidence either way, so I am willing to entertain the notion periodically...)

If I were the Programmer, I would probably have (or need) a maximum speed at which simulated information could move about. That the universe appears to expanding at superluminal speeds at the edges of our observable universe could also be a nice trick invoked to prevent the Processor from needing to crunch infinitely many operations per unit time (of course, once we start thinking about the universe in which our universe exists, who knows if "time" is meaningful.)

Problems with this theory include, "well this doesn't answer anything, it just puts the 'real' universe beyond our observation," and "wouldn't a Simulator need some sort of universal frame of reference?"

(these are the sorts of ridiculous answers that can come up when "why" questions are posed)
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Offline petelamana (OP)

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Re: Why must c be an absolute "speed limit"?
« Reply #7 on: 20/02/2018 18:46:38 »
Quote from: chiralSPO on 20/02/2018 18:36:15
(these are the sorts of ridiculous answers that can come up when "why" questions are posed)

My apologies.  I will endeavor to phrase my post questions more succinctly.
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Offline chiralSPO

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Re: Why must c be an absolute "speed limit"?
« Reply #8 on: 21/02/2018 02:47:38 »
Quote from: petelamana on 20/02/2018 18:46:38
Quote from: chiralSPO on 20/02/2018 18:36:15
(these are the sorts of ridiculous answers that can come up when "why" questions are posed)

My apologies.  I will endeavor to phrase my post questions more succinctly.

I'm mostly ribbing :) But if you haven't come across it yet, this is worth a watch:

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Re: Why must c be an absolute "speed limit"?
« Reply #9 on: 21/02/2018 08:39:42 »
Quote from: petelamana
Why must the speed of light, c, be an absolute "speed limit"?
c isn't an absolute speed limit, absolutely everywhere, absolutely all the time.

If you are in a gravitational well*, your time is slowed compared to points outside this gravitational well.
- It is possible to see things happening outside this gravitational well that are happening slightly faster than the speed of light.
- So the speed of light is an absolute limit here, but it's not necessarily an absolute limit there.
- If you then travel over there (so "there" is now here), you would find that things here are not now exceeding the speed of light.

This is why some aspects of relativity are expressed as being measured in a "small" room - because if you measure on larger scales, the results can be different.

*we are in the Earth's gravitational well, which is in the Sun's gravitational well, which is in the galaxy's gravitational well...
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Re: Why must c be an absolute "speed limit"?
« Reply #10 on: 21/02/2018 09:42:58 »
Well, let's say "infinite speed" is a no go, because according to the "big bang" theory light travelling at infinite speed would be technically unregistrable and completely futile to the idea of an "expanding" universe.

So, let's talk about "variable speed".

"Variable speed" suggests many other factors we well know in physics must also be variable, which gives a "Gooey" understanding of reality for our reference as humans.....like silly-putty.

A constant speed for light can't be as simple as relying on an "expanding" universe, or even our own relativite rigidity as conscious beings.

If I could suggest "space" has a tolerance for light, like it acts as a "wall", seeming to give light "mass" qualities perhaps, like light is stuck in it somehow at a certain rate of progression. Of course we've heard of the mythical "ether", yet, the question remains, why is light stuck at "c".

If we form our theories on the universe using "c".....i just casn't help thinking a steady state universe is what this is...... did light expand at a constant rate from the big bang? Why? It's like the cops already set the speed limit.....how?



« Last Edit: 21/02/2018 10:13:18 by opportunity »
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Offline geordief

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Re: Why must c be an absolute "speed limit"?
« Reply #11 on: 21/02/2018 10:36:34 »
Quote from: evan_au on 21/02/2018 08:39:42
Quote from: petelamana
Why must the speed of light, c, be an absolute "speed limit"?
c isn't an absolute speed limit, absolutely everywhere, absolutely all the time.

If you are in a gravitational well*, your time is slowed compared to points outside this gravitational well.
- It is possible to see things happening outside this gravitational well that are happening slightly faster than the speed of light.

References? I find that hard to believe but ,as they say argument from incredulity is no argument.

(I am aware of  expansion ongoing at superluminary speeds but that is unconnected. Also entanglement does not allow for information transfer at  superluminary speeds either....

Also aware that time passes everywhere at 1 sec per second. What is your scenario exactly in this case? )
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Re: Why must c be an absolute "speed limit"?
« Reply #12 on: 21/02/2018 10:56:03 »

Quote from: geordief on 21/02/2018 10:36:34
References? I find that hard to believe but ,as they say argument from incredulity is no argument.

Also aware that time passes everywhere at 1 sec per second. What is your scenario exactly in this case? )
The reference is GR.
Scenario as @evan_au says is "If you are in a gravitational well, your time is slowed compared to points outside this gravitational well."

PS it is also confirmed by experiment and by operation of GPS
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Offline geordief

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Re: Why must c be an absolute "speed limit"?
« Reply #13 on: 21/02/2018 11:24:47 »
Quote from: Colin2B on 21/02/2018 10:56:03

Quote from: geordief on 21/02/2018 10:36:34
References? I find that hard to believe but ,as they say argument from incredulity is no argument.

Also aware that time passes everywhere at 1 sec per second. What is your scenario exactly in this case? )
The reference is GR.
Scenario as @evan_au says is "If you are in a gravitational well, your time is slowed compared to points outside this gravitational well."

PS it is also confirmed by experiment and by operation of GPS
Well how does that affect the measurement of c? How much faster than c  do or can  (information bearing ?)  processes seem to happen outside a gravitational well for an observer inside it?

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Re: Why must c be an absolute "speed limit"?
« Reply #14 on: 21/02/2018 12:01:29 »
I thought the gravitational well is currently held by the Planck scale? Shouldn't light consider a blockade anything lower than that? Apparently there's a lot of energy per cubic metre below that which light clearly bounces off, doesn't get into, right?
« Last Edit: 21/02/2018 12:09:22 by opportunity »
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Re: Why must c be an absolute "speed limit"?
« Reply #15 on: 21/02/2018 12:11:19 »
Quote from: opportunity on 21/02/2018 12:01:29
I thought the gravitational well is currently held by the Planck scale? Shouldn't light consider a blockade anything lower than that? Apparently there's a lot of energy per cubic metre below that which light clearly bounces off, doesn't get into, right?

When I talk about light considering a blockade there, I'm  giving light some type of "wow, I'm at the Plank scale, and according to humans I can't go deeper" thing.

That's a wall, right? Why is the speed of light consequential of the Planck scale?

If I was light, I'd be happy with electron shells.

We can theorise things to connect dots, but we can't, shouldn't screw around badly, not too much, with how nature shows itself to us. Maybe? What if we're wrong about the sub-elemetary particle realm, you know, "not quite right yet". Can we have that discussion?

It's underatandble. On the small scale there's is a volcano of energy available on the Planck scale, and on the large scale we can't work out where all the forces comply? That's so stupid, apologies for saying that. Doesn't the large scale imply the small scale and vice-versa?
« Last Edit: 21/02/2018 12:35:55 by opportunity »
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Offline geordief

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Re: Why must c be an absolute "speed limit"?
« Reply #16 on: 21/02/2018 12:33:23 »
Quote from: opportunity on 21/02/2018 12:11:19
Quote from: opportunity on 21/02/2018 12:01:29
I thought the gravitational well is currently held by the Planck scale? Shouldn't light consider a blockade anything lower than that? Apparently there's a lot of energy per cubic metre below that which light clearly bounces off, doesn't get into, right?

When I talk about light considering a blockade there, I'm  giving light some type of "wow, I'm at the Plank scale, and according to humans I can't go deeper" thing.

That's a wall, right? Why is the speed of light consequential of the Planck scale?

If I was light, I'd be happy with electron shells.

We can theorise things to connect dots, but we can't, shouldn't screw around badly, not too much, with how nature shows itself to us. Maybe?

I don't understand your post (my level of understanding no doubt) but are we not really firstly considering the maximum speed of information?

Does Planck level have any bearing on that?

Do permittivity or permeability  have any role at those levels?
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Re: Why must c be an absolute "speed limit"?
« Reply #17 on: 21/02/2018 12:39:29 »
No, no effect, that's the idea of the Planck scale. It's like if you're light and you dive deep and hit a level, that's the Planck scale. No reflection though, apparently.....only the "bequeathment" of "mass" via equations.....and yet the energy according to equations there is immense. I thought if light could disobey it could do anything?

I'm sorry if that's not making sense. If it's not, just ignore this.

I question the idea of the Planck scale also, and how light and mass has an actual speed of light bearing there.....like it's a "limit".......we talk about limtis.....here's a limit.

I'm hopeless. The subelementary particle realm to the Planck scale is more immense than us to the Kuiper belt, maybe even to Alpha Centauri and beyond, and it seems a question of introversion, looking within...beyond the idea of a fundamental particle? Drink that idea in. Apparently there's no inner universes there either.

As a scale, it's the most vast "nothing", and then we hit the Planck scale. That's an impressive equation to consider, even for light.

Why can't we ask if the Planck scale limits light? Is the Planck scale something of convenience in bridging an absolute abyss itself of mathematical uncertainty, or really something that limits light through such scales with nothing else from the atom to itself to account for?
« Last Edit: 21/02/2018 14:19:53 by opportunity »
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Re: Why must c be an absolute "speed limit"?
« Reply #18 on: 21/02/2018 14:02:06 »
Just to be absolutely, unequivocally clear. There is a mass/energy equivalence and not a matter/energy equivalence. Puppypower is posting nonsense.
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Re: Why must c be an absolute "speed limit"?
« Reply #19 on: 21/02/2018 14:31:32 »
Quote from: jeffreyH on 21/02/2018 14:02:06
Just to be absolutely, unequivocally clear. There is a mass/energy equivalence and not a matter/energy equivalence. Puppypower is posting nonsense.
I’ve removed the offending post to new theories
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