Tau Zero

by Poul Anderson

I’m outward bound with no regrets and no pain that won’t heal. The luck is mine,

It would take her thirty-one years to cross interstellar space, and one year more to decelerate as she approached her target sun. But that is an incomplete statement. It takes no account of relativity. Precisely because there is an absolute limiting speed (at which light travels in vacuo; likewise neutrinos) there is an interdependence of space, time, matter, and energy. The tau factor enters the equations. If v is the (uniform) velocity of a spaceship, and c the velocity of light, then tau equals The closer that v comes to c, the closer tau comes to zero.

Aw, it didn't highlight the equation: http://www.tauzero.net/

‘A sound physique helps keep a sound mind. If you go to bed tired, you don’t lie awake brooding.’