On 29 Dec 2017 at 17:55, Rob O'Connor wrote:

> The energy-momentum relationship is actually:
>
> (energy)^2 = (momentum x c)^2 + (rest mass x c^2)^2
>
> energy = gamma x mc^2
> momentum = gamma x mv
> where gamma is the Lorentz factor 1/sqrt(1-(v^2/c^2))

gamma is 1/tau

And there's a great shortcut for calculating tau

tau = sin(arccos(v/c))

--
Leonard Erickson (aka shadow)
shadow at shadowgard dot com