# Speed of sound in vacuum

I am not a scientist but I have a question about speed of sound in vacuum. All I know is that the speed of sound $v$ in a medium is given by formula $$v= \sqrt{\frac E\rho},$$ where $E$ is elasticity and $\rho$ is density.

And according to a scientist, vacuum is a medium which has elasticity highest comparison to other and it's density is so less it is nearer to zero. Then, from above, the value of velocity of sound in vacuum should be the greatest among all other medium? Am I wrong?