The Beginning Of Time

Time officially started with the first second of 1970 ;-)

And ends some time in 2106, if you're using 32-bit unsigned integers, or some time in 2038, if you're using 32-bit signed integers.

That would be the dawning of the Age of Aquarius, I would imagine.

A couple of MegaSeconds after the first successful mission to another celestial body, according to DeepnessInTheSky.

UnixWay, LinguaFrancaPattern