A new circle constant is being promoted mainly here. the proposal is to have a new constant $\tau = 2\pi=6.28...$ to replace the familiar $\pi$.
One of the claimed benefits is that it will make reasoning about circles easier for students. Additionally a ratio of the radius to the circumference seems more 'natural' than a ratio of the diameter to circumference.
A numer of viral video like this offer a compelling case for the change, at least to a layman.
Is there any momentum for this change with in the professional community? Will we ever see tau in our textbooks. Who here celebrates Tauday (28th June)?