# Linked Questions

5answers
1k views

### Why is the speed of light arbitrarily the limit? [duplicate]

I know Einstein was great and all. Why is it that exactly at the speed of light is where infinite energy is required to accelerate any object with mass? Is it simply because the math of relativity ...
4answers
5k views

### What's so special about the speed of light? [duplicate]

What's so special about the speed of light? Why do many equations in physics include the speed of light in vacuum $c$? Why do so many thing depend upon it? Why can't it be the speed of sound? ...
4answers
3k views

### Why is light in vacuum so slow? [duplicate]

Accepting the speed of light in vacuum and infinite mass and all that, I wonder why light does not have infinite speed? I know light does not have rest mass, but people use the term infinite mass ...
1answer
5k views

### Why does light travel at finite speed? [duplicate]

We have known for quite some time now that light travels at a finite speed of 3x10^8m/s (approx) through vacuum. But why is that? Why can't the speed be infinite? Or at least higher than the current ...
0answers
482 views

### Is the speed of light the speed limit or does light just happen to travel at the maximum speed? [duplicate]

Just looking for a quick, non-mathematical answer. So the speed of light (c) is the fastest that anything can travel. Is c defined as the speed of light or is c a universal constant that nothing (...
4answers
149 views

### Does spacetime have a “preferred” speed/metric? [duplicate]

I read recently that spacetime has a preferred speed, c, and that all observers would agree on the speed of anything moving at c. In particular, there is nothing unique about light when talking about ...
1answer
192 views

### Universal speed limit [duplicate]

Is there any reason the universe has matter not being able to exceed the speed of light, or why there is a speed limit in the first place? I know why it can't, meaning the basic physics of it. I am ...
0answers
126 views

### $E=mc^2$ what is unique about the speed of light? [duplicate]

What unique property of light, makes it the conversion factor between energy and mass? It has to be more than a coincidence that the speed of light, just happens to be the correct number number to ...
3answers
88 views

### Speed limitation [duplicate]

I was thinking about something and I wish to share this thought with you in order to understand better something that bothers me. Relativity theory says that the speed of light is the highest ...
1answer
79 views

### How do we know the maximum speed of conventional matter is the same as the speed of light? [duplicate]

Is there an argument, apart from experiments, that we know this is true? And if we only know it by experiment, how do we know the experiments are precise enough to conclude this? Stated differently,...
8answers
17k views

### Why does the speed of light in vacuum have no uncertainty?

I could understand that the definition of a second wouldn't have an uncertainty when related to the transition of the Cs atom, so it doesn't have an error because it's an absolute reference and we ...
19answers
4k views

### The origin of the value of speed of light in vacuum

Meaning, why is it the exact number that it is? Why not 2x10^8 m/s instead of 3? Does it have something to do with the mass, size or behavior of a photon? To be clear, I'm not asking "how we ...
6answers
5k views

### Does the speed of light in vacuum define the universal speed limit?

Is light the thing causing the universal speed limit to be $299\,792\,458\,\mathrm{m/s}$? So the universal speed limit would be different if light travelled faster or slower? Or, is \$299\,792\,458\,\...
4answers
5k views

### Do units have to make sense in Physics?

For a lack of a better title and phrasing of my question, I am asking: do units have to make sense in physics? Let me give an example of what I mean. Let's say that I have some arbitrary units (for ...
9answers
3k views

### Would it be possible to develop special relativity without knowing about light?

My understanding of special relativity is that it is fundamentally based on the constancy of the speed of electromagnetic radiation - that this speed is a physical law (or derivable from physical laws ...

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