# What happens if you go faster than light?

by mathlete
Tags: faster, light
 P: 151 Let's say you are in water where light travels at a speed of $$\frac{c}{n_w}$$ where $$n_w = 1.5$$ and you travel faster than this speed - what happens? What do you see?
 P: 2,219 The laws of the speed of light apply to any medium, not just vacuum. If the speed of light were 1m/s in a certain material, that speed would be unattainable in that same medium.
Emeritus
PF Gold
P: 29,239
 Quote by whozum The laws of the speed of light apply to any medium, not just vacuum. If the speed of light were 1m/s in a certain material, that speed would be unattainable in that same medium.
Yes, it can. That's the whole principle behind the Cerenkov radiation - charged particles moving in a medium at a faster velocity than light in that medium. Huge detectors are used to detect neutrinos this way.

Zz.

 P: 166 What happens if you go faster than light? you will die, no seriously, you will. you will be of infinite weight and will require infinite energy to move, and will die. talk about letting yourself go. it is impossible to go faster than light, no matter what (unless you are a universe that just happens to be expanding, then, i read, it is possible. i don't know exactly how, but i will trust my reading skills Fibonacci
Emeritus
PF Gold
P: 29,239
 Quote by 1,1,2,3,5,8,13,21 you will die, no seriously, you will. you will be of infinite weight and will require infinite energy to move, and will die. talk about letting yourself go. it is impossible to go faster than light, no matter what (unless you are a universe that just happens to be expanding, then, i read, it is possible. i don't know exactly how, but i will trust my reading skills Fibonacci
This is a faulty application of relativistic mass. Take a look at how it is applied with respect to ANOTHER observer. Pay attention to the fact that a person does NOT see his/her mass increasing since he/she is always in the same proper frame and does not observe his/her mass moving.

Zz.
P: 166
 Quote by ZapperZ This is a faulty application of relativistic mass. Take a look at how it is applied with respect to ANOTHER observer. Pay attention to the fact that a person does NOT see his/her mass increasing since he/she is always in the same proper frame and does not observe his/her mass moving. Zz.
you didn't get that 'physics guru' for nothing, did you Zz.

Fibonacci
 Emeritus Sci Advisor PF Gold P: 10,428 Fibonacci, Please refrain from responding to question unless you are quite sure you are giving a correct answer. - Warren
P: 2,219
 Quote by ZapperZ Yes, it can. That's the whole principle behind the Cerenkov radiation - charged particles moving in a medium at a faster velocity than light in that medium. Huge detectors are used to detect neutrinos this way. Zz.
Isn't that more of an exception than the rule?
 P: 82 offcourse it's an exception
 P: 2,219 Then my answer to the OP is more or less correct. :D
Emeritus
PF Gold
P: 10,428
 Quote by whozum Then my answer to the OP is more or less correct. :D
No, it wasn't. It was completely wrong.

- Warren
 P: 2,219 Care to explain why?
 Emeritus Sci Advisor PF Gold P: 10,428 You said that objects cannot exceed the speed of light in a medium. That is completely false. - Warren
 P: 2,219 Wont argue with you. How do objects go faster than the speed of light in a medium?
 P: 949 By covering a greater distance in the same amount of time. I suspect you are looking for a good reason why they 'can'. Well, there is simply nothing that prevents something (often an electron) from doing so. Laws of physics are generally written according to what restricts movement or any other characteristic. It's just the way we interpret them - if it's not restricted to move a certain way, then it can. Cerenkov radiation does not need to be explained here - http://en.wikipedia.org/wiki/Cerenkov_effect and scroll to "Physical Origins"
 P: 2,219 Isn't it restricted by the same reasons its restricted in vacuum?
 Emeritus Sci Advisor PF Gold P: 10,428 whozum, No. The speed of light in vacuum is a universal 'speed limit,' but the speed of light in an arbitrary medium is not. - Warren
P: n/a
 Quote by whozum Isn't it restricted by the same reasons its restricted in vacuum?
"in our world" there exists a universal speed limit c. From the Maxwell's equations we see that in vacuum light wave propagates with c. In the media this velocity is reduced due to existing wave impedance, but this doesn't mean that a universal constant is changed ;) just the EM wave propagates slower.

 Related Discussions General Physics 5 Special & General Relativity 13 Special & General Relativity 7 Special & General Relativity 2 General Physics 2