# Is it possible that “$c = 1$?” [duplicate]

Can

c = 1

and if so, what does this mean for Physics?

If you were to take any Physics equation, and let c = 1, will it work?

## marked as duplicate by StephenG, Community♦Jul 17 at 6:54

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## 1 Answer

When $$c=1$$ is choosen in any equation in theoretical physics, this doesn't mean that the value of the speed of light is unity. Rather it has to do with dimensional analysis.

In relativistic physics, space and time are chosen to be in equal footing. Now note that the dimensions of 'c' is $$[c]=\frac{[length]}{[time]}$$ So, $$c=1$$ actually means $$[c]=1$$, i.e., $$[length]=[time]$$. This is only a mathematical way of expressing the equivalence of space and time in relativistic physics.

NOTE: The same is true for $$G=1$$ and $$\hbar=1$$ and you can easily find their meaning using dimensional analysis.