From Mark Hardy
I applaud Michael Hartl’s efforts to promote tau (which is 2 pi, or 6.28318…) as the definitive circle constant (8 January, p 23).
He advises that we use the necessary factor of 2 when converting between tau and pi, which seems straightforward enough. I do wonder, though, how many Mars probes may be lost during the inevitable transition period.
Aurora, Illinois, US
