/sci/ - Science & Math

>>8852915
Space has something like density and compressibility that defines the speed of light.

[math]
\displaystyle
c = \frac{1}
{ \sqrt{ \varepsilon_0
\mu_0
}
}
[/math]

>>8853060
O-ok.

>>8853060
yeah but what defines the density and compressibility? Those two are just constants also, right?

>>8853060
Ah, of course

https://www.youtube.com/watch?v=kr_CFydcBZc

Watched this couple of hours ago.
How legit is it?
Basically he is saying it's tided to time, so when you hit speed of light, time stops and if you would go faster it would run backwards.
Which sounds logical to me, as a brainlet.

>>8853297
measured to work like that

>>8853297
My guess is it's defined by the exact structure of our universe's Calabi-Yau manifolds.

source: my ass

>>8852915
What's so special about it? Well nothing really, it's no more special than any other constant of nature.
>Is there some hidden variable which makes it the limit of spreading?

Not really. I guess in some "deep" sense it all comes from requiring that the interval [math] ds^2 = c^2 dt^2 - d \vec { x }^2 [/math] is invariant. But from there you might ask "what makes that so special?" And I've no idea, just is.

>>8853627
>so when you hit speed of light, time stops
Well there's some issues with talking about what happens at the speed of light, since light doesn't have a rest frame. But what you can say is that as you go faster time passes relatively slower for you than for someone in relative stationary frame.

>if you would go faster it would run backwards.
Completely wrong. Relativity doesn't say anything about what happens beyond the speed of light, as far as relativity goes it's a completely unphysical region.

The real reason you can't go faster then light is because [eqn] E = \frac { m c^2 } { \sqrt { 1 - \frac { v^2 } { c^2 } [/eqn] so your energy diverges as v tends to c, which means you'd need and infinite amount of energy to accelerate to a massive object to the speed of light.

>>8853627
>>8853676
>E = \frac { m c^2 } { \sqrt { 1 - \frac { v^2 } { c^2 }

Funny thing I actually know this equation since maybe 16 years now.
So knew about the limit because of higher mass, which diverges to infinity and therefor required infinite energy.
But it did not occur to me that higher values than speed of light just breaks the equation. so relativity simply doesn't cover these areas. Thanks for clearing this up for me.

He actually says the time would stop for a photon since it has no mass and travels with the speed of light. But does the time only stops for a relative stationary observer, or for the photon itself?

>>8852915
Don't listen to these ridiculous hypothesis based on crackpot general relativity misconceptions. Time is an after effect of the loss of inertia. Quite literally a human contrivance. Einstein was wrong about a lot of things but especially the supposed speed of light limit. In fact light should not even be thought of in terms of speed but rather resistance and capacitance. Light is a coaxial CIRCUIT, its so called speed limit is nothing other than the rate of induction due to the capacitance of the ether.

>>8852915
C is the speed of causality. The maximum speed by which information itself can travel through space.
Light happens to go at c, so it is often referred to as the speed of light.

>>8853060
"speed of light"
don't you mean the speed of causality anon? More than just photons can travel at this speed.

>>8853844
which can look pretty nice.
>Cherenkov radiation

>>8852915
You want the truth you have to start over and read the greats like tesla and Oliver heavyside and James Maxwell. You'll cry when you realize the real physicists are electricians while everyone else is off chasing leprechaun farts and virtual particles. Maxwellian field equations is all it takes to understand both light and gravity but no amount of college taught me that.

>>8853830
>Light is a coaxial CIRCUIT
framing the world in terms of what you learned in a high school physics class is not the worst I've heard honestly

Nah, its just the anthropological constant.

>>8853676
>Relativity doesn't say anything about what happens beyond the speed of light

Come on, anon. If a particle was always faster than light it doesn't hurt the relativity. It's not likely that there are particles like this but in theory it is perfectly coherent.

>>8852915
It's connected to the geometry of spacetime. There can't be a time dimension without a maximum speed.

>>8853848
Cherenkov radiation actually is trvaelling at speeds lower than c. This is why we see the blue color coming from.

If the speed was the same as c, we wouldnt see anything because it would blue shit towards infinity.

>>8853627

square root ( 1 - (v2/c2) )
faster than light doesn't turn the passage of time negative, it's the square root of a negative number, which isn't the same thing.

>>8852915
c is just a constant, it's not really that important, it just appears on relativity becouse relativity measures things using light. If you get your information form say sound waves, and you still want to use relativity for it, you'll have to change c for the speed of sound (besides some other things since sound waves don't work exactly the same than electromagnetic).

Also, he might be right >>8853860

>>8854376
That doesn't make sense. It also doesn't work.

>>8853860
>Tesla
Didn't think light was a wave. He didn't take Maxwell seriously either.

>and gravity
God no. Electromagnetism is a U(1) gauge theory, that's pretty simple. Gravitation is much more complicated than that.

>>8853848
He was talking about bosons like gluons and
*cough
Gravitons

>>8852915

I think it's important to separate the fact that light in a vacuum just happens to travel at c. c would still be important, even if that were not true.

Basically, c is the value such that if you travel at this speed in one inertial frame, you will travel at the same speed in any other inertial frame. In other words, there is a speed that everyone agress upon, no matter how fast they are going - if you try to measure the speed of something moving at c in your frame, someone else in another frame will get exactly the same answer regardless of how they are moving relative to you. For us, that value, which we call c, is about 300,000,000 m/s. However, that large number is purely a function of how we define a metre and/or second, not something fundamental.

It turns out that photons travel at this speed. Other (hypothetical) massless particles should also travel at this speed.

The value itself is just a constant of nature. You might as well ask why the mass of the electron is what it is, or why Boltzmann's constant has the value it does. Maybe there is some deeper theory that connects it all, but for the moment, these are just verifiable constants.


>Consequence of geometry
Not really
More correctly, c determines the invariant interval around which everything is built. If anything, c forces the geometry of space to exist as it does by saying that the spacetime interval cdt^2 - dx^2 is invariant. So you can see c as the artefact of our geometry, or that c sets the geometry - it comes to the same thing.

>>8852915
it's just the clock of the PC

>>8852915
Electromagnetism is everything
You have to think of it as the smallest building block, there doesn't exist another element that would travel faster, so because this is what exist, this is the limit of everything that exists

They explain it with a lot of mumbo jumbo but it's pretty simple

They are beginning to invent new particles, like graviton, and say that travels faster, which represents gravity itsself even though forces don't actually have particles like that, I don't know what to think of it

>>8852915
assuming that a maximal speed exists, we would expect massless particles like photons to travel at the maximal speed.

>>8855544
Oh yeah that they are massless also plays a role in how fast they can travel, because there is no friction. If photons had mass then the speed of light would be variable because of the friction in different conditions