Is the Speed of Light Limited by the Properties of Matter?

[Jeffrey phalen]

Is it possible that the speed of light exists because we cannot move faster than our particles? I.e. the speed of electrons that create the electromagnetic force that hold matter together.

 

[PeterDonis]

Is it possible that the speed of light exists because we cannot move faster than our particles? I.e. the speed of electrons that create the electromagnetic force that hold matter together.

The speed of electrons is not the same as the speed of light. So I don't see how this idea would make sense.

 

[Jeffrey phalen]

So then it would have to be the speed of the particles our particles are made of?

 

[jbriggs444]

So then it would have to be the speed of the particles our particles are made of?

No. The speed of light is the invariant speed for our space-time. It has nothing to do with particles being made of particles being made of... turtles all the way down.

 

[Nugatory]

The question in the thread title is "Reason for the speed of light".

Light is electromagnetic waves, so the speed of light is the speed at which electromagnetic waves propagate. If you start with Maxwell's laws of electricity and magnetism, you can calculate that speed (Maxwell did that himself, more than 150 years ago).

 

[PeterDonis]

So then it would have to be the speed of the particles our particles are made of?

We already know that the speed of light is not the same as the speed of the particles we are made of.

 

[itfitmewelltoo]

Is it possible that the speed of light exists because we cannot move faster than our particles? I.e. the speed of electrons that create the electromagnetic force that hold matter together.

The speed of light is fixed as a result of the properties of free space. While free space is not a medium in terms of "eather", as was once considered, it is still something in and of itself. It has properties beyond simply the three dimensions of distance. Two of these, in the classical sense, are the fundamental constants of electromagnetic propogation. These are what fix the speed of light.

 

[David Lewis]

The speed of light is fixed as a result of the properties of free space... Two of these, in the classical sense, are the fundamental constants of electromagnetic propogation.

The speed of light depends on the resistance of space to electric flux. This electric constant is only about 8.85 x 10^-12 farads per metre.

 

[PeterDonis]

The speed of light depends on the resistance of space to electric flux.

It depends on $\mu_0$ as well as $\epsilon_0$. I believe those are the two constants that @itfitmewelltoo was referring to. (And this assumes that you are choosing that particular system of units--in other unit systems those constants don't even exist.)

 

[Neil Condon]

Empty space is not a type of medium, yet in many ways it is easier to think in terms of Einsteins India rubber sheet. If you drop an object onto a rubber sheet a "shockwave" spreads out through the rubber at the speed of sound. If you drop an object into empty space the gravity, charge and any other properties that say there has been a change here, all spread out at the speed of the "shockwave" through empty space. We just use the phrase "speed of light", we could use other phrases to describe the speed of this "here is a change shockwave".

There is an interesting addendum to this "nothing travels faster than the speed of light" phrase. According to Encyclopedia Britannica (in refractive index} Xrays traveling through glass are bent towards the normal, suggesting they travel faster than the speed of light through "empty space".

 

[phinds]

If you drop an object into empty space ...

Since this is clearly an impossible thing to do, best to stick with known causes of gravity waves such as merging black holes.

 

[Neil Condon]

Yes clearly it is impossible to just drop an object into empty space, I was speaking metaphorically as an analogy to dropping an object on a rubber sheet. Most people want a simple way of understanding things.

 

[jbriggs444]

Yes clearly it is impossible to just drop an object into empty space, I was speaking metaphorically as an analogy to dropping an object on a rubber sheet. Most people want a simple way of understanding things.

The difficulty is that stacking a counter-physical analogy on top of a questionable analogy may not lead to actual understanding.

 

[Neil Condon]

I'm not sure that your argument is valid. It widely understood that matter-antimatter pairs come into existence and annihilate again shortly after. The question of why is there normal matter in the universe and not an even amount of each, or just the light from a totally annihilated universe. So it is obvious than in some circumstances matter can suddenly appear in empty space. It is also widely understood that the gravitation field of newly created matter can only spread out at the speed of light.

I stand by what I said people want simple answers so that they build more complex answers on as their understanding increases. Someone asking for the reason why light is the speed limit in this neighborhood is not asking for an equation.

It is the anomalies to our simple ideas that really teach us something. For example: all agree that a change in a gravitational field spreads out at the speed of light, but the Earth orbits the Sun where the Sun is now not the position of the Sun eight minutes ago where the Sun appears to be if we look. This suggests that once curvature has established itself it behaves in an "instantaneous" manner, and it is only the change in a local field that is limited to light speed.

 

[PeterDonis]

It widely understood that matter-antimatter pairs come into existence and annihilate again shortly after.

No, it is widely misunderstood that this happens.

So it is obvious than in some circumstances matter can suddenly appear in empty space

No, it is not obvious, it is false. The stress-energy tensor in GR is conserved; that means matter cannot "suddenly appear in empty space".

I stand by what I said people want simple answers so that they build more complex answers on as their understanding increases.

This only helps if the simple answers are correct. Yours are not. Moreover, what you are saying has nothing to do with why the speed of light is what it is, or why there is a finite speed of light at all.

Please do not post this misinformation again; if you do, you will receive a warning.

 

[Neil Condon]

Are you denying that matter came into existence shortly after inflation?

 

[Nugatory]

Are you denying that matter came into existence shortly after inflation?

It's hard to deny or not deny that statement because it can be interpreted in several different ways, some incorrect, some correct, and some too vague to call either way.

The claim about particle/antiparticle pairs appearing is OK as long as you're talking about pair production, which is not an "empty space" phenomenon. It is, as PeterDonis says, a common misunderstanding if you're imagining something involving quantum fluctuations in otherwise empty space.

This is all a digression from the original thread topic, so it would be best to start a new thread to continue this discussion. But before you do... please review our Insights articles on virtual particles.