Time Dilation & Length Contraction: Does Relativity Work for Mediums?

[Mohammed Ayaz Quadri]

Hello I am new here and I am just Junior college student. So please use simpler terms. I need to know that does relativity work for mediums like air and water. I mean the equations of time dilation and length contraction, do they work for other mediums. If so shall I take C as the speed of light in vacuum or thr speed at that particular medium? Thank You.

 

[Dale]

Hi Mohammed, welcome to PF!

Relativity still works in a medium, and the c that you use is the speed of light in vacuum. The invariant speed is not changed inside a medium.

In fact, inside a medium, particles may exceed the speed of light in the medium as long as they do not exceed c.

 

[Ibix]

To expand slightly on what Dale said, the quantity c in the Lorentz transforms and length contraction and time dilation formulae is an invariant quantity that is the same everywhere for everyone. It also happens to be the speed at which light travels in a vacuum. That's not actually a coincidence, but as far as relativity is concerned it's just an interesting fact.

So that means you always use c in the Lorentz transforms, not whatever the speed of light is in whatever medium you happen to be in.

 

[Mohammed Ayaz Quadri]

Ty everyone. I didnt expected so quick answers. Can you help with this: I have heard that very few things found are traveling at a speed more that c. How far is this true? Ty

 

[Ibix]

Nothing travels faster than c.

There was some brief confusion about neutrinos, but it turned out that there was a loose cable in the experiment's time recording apparatus. And there are purely hypothetical particles called tachyons, but they've never been detected. I should point out that I don't even know if there's a respectable theory that predicts tachyons, or if they're just science fiction. You do sometimes see them mentioned, though.

Edit: as Dale said, things can exceed the speed of light in a medium (look up Cerenkov radiation, which is a side-effect of this). But nothing exceeds c.

 

[phinds]

Ty everyone. I didnt expected so quick answers. Can you help with this: I have heard that very few things found are traveling at a speed more that c. How far is this true? Ty

NOTHING travels at more than c. Period.

EDIT: Ibix beat me to it.

 

[Ibix]

EDIT: Ibix beat me to it.

My reply speed gets close to c.

 

[Orodruin]

My reply speed gets close to c.

You can increase it by dieting until you are massless! ;)

 

[phinds]

My reply speed gets close to c.

And my brain is often in a vacuum, so together we've got it covered.

 

[Mohammed Ayaz Quadri]

Ty. Everyone is very helpful here. Some interesting conversation going on, eh?