Of course there had been plenty of speculation on the
possible effect of the overdrive on the subjective time of the
pilot, but none of it had come to much. At any speed below
the velocity of light, subjective and objective time were
exactly the same as far as the pilot was concerned. For an
observer on Earth, time aboard the ship would appear to be
vastly slowed at near-light speeds; but for the pilot himself
there would be no apparent change.
Since flight beyond the speed of light was impossible
although for slightly differing reasonsby both the current
theories of relativity, neither theory had offered any clue as
to what would happen on board a translight ship. They would
not allow that any such ship could even exist. The Haertel
transformation, on which, in effect, the DFC-3 flew, was
nonrelativistic: it showed that the apparent elapsed time of a
translight journey should be identical in ship-time, and in the
time of observers at both ends of the trip.
But since ship and pilot were part of the same system,
both covered by the same expression in Haertel’s equation,
it had never occurred to anyone that the pilot and the ship
might keep different times. The notion was ridiculous.
One-and-a-sevenhundredone, one-and-a-sevenhundredtwo,
one – and – a – sevenhundredthree, one – and – a – sevenhundred
four . . .
The ship was keeping ship-time, which was identical with
observer-time. It would arrive at the Alpha Centauri system
in ten months. But the pilot was keeping Garrard-time, and
it was beginning to look as though he wasn’t going to arrive