## Why is there a universal speed limit, c, and why is it what it is?

Some may find this link interesting - http://www.phys.unsw.edu.au/einstein...well.htm#light

Take this brother and may it serve you well,

Q
 Hi all, On the moment i'm learning about special relativity in College and there is a fairly good explanation for the cosmic speed limit, indeed caused by causality (which comes from second law of thermodynamics). I included 3 photo copies of my textbook that explain the relevant part. After reading i think you will understand why nothing can travel faster than the speed of light, and so why it is the cosmic speed limit. On the other hand there is one thing i don't understand, and that is why we would not be able to travel at the speed of light, since the book tells we can only travel at near the speed of light and only information can travel at the speed of light. But on the otherhand it says that we could be the information. If somebody understand out of this text why we cannot travel at the speed of light, please post. The page come from Six ideas that shaped physics Unit R by T.A. moore Very good step by step explanation of special relativity. happy reading, Thanks. Attached Thumbnails

 Quote by zyap Hi all, On the moment i'm learning about special relativity in College and there is a fairly good explanation for the cosmic speed limit, indeed caused by causality (which comes from second law of thermodynamics). I included 3 photo copies of my textbook that explain the relevant part. After reading i think you will understand why nothing can travel faster than the speed of light, and so why it is the cosmic speed limit. On the other hand there is one thing i don't understand, and that is why we would not be able to travel at the speed of light, since the book tells we can only travel at near the speed of light and only information can travel at the speed of light. But on the otherhand it says that we could be the information. If somebody understand out of this text why we cannot travel at the speed of light, please post. The page come from Six ideas that shaped physics Unit R by T.A. moore Very good step by step explanation of special relativity. happy reading, Thanks.
Thanks, it's a nice text; but as you already discovered, one weakness is that it fails to explain why we cannot travel at the speed of light. For that you need to look at other, more physical explanations - and probably that has already been done earlier in this thread.

Harald
 Light is Electromagnetic so if light travels at diffrent speeds in different frames then Laws of Electromagnetism will also vary giving different results in different frames..but thats not possible so c is constant!!

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 Quote by sahil_time Light is Electromagnetic so if light travels at diffrent speeds in different frames then Laws of Electromagnetism will also vary giving different results in different frames..but thats not possible so c is constant!!
Okay, so no explain why it is trivial (more obvious than the fact that c is constant) that the Laws of Electromagnetism can NOT give different results in different frames.

 Quote by sahil_time Light is Electromagnetic so if light travels at diffrent speeds in different frames then Laws of Electromagnetism will also vary giving different results in different frames..but thats not possible so c is constant!!
sahil_time, why is that not possible?

 Quote by bobc2 sahil_time, why is that not possible?
Because doing so may change the whole concept of Forces!!Like if C was different for different observers then epsilon/permeability would be different and hence the electric field and magnetic pheneomenon would be different for different observers!!Like Electric field at a point could have infinite possible values!!
Well thats what i think!!