Tau Zero, Chapters 11-23

In Chapter 13 of Poul Anderson's Tau Zero (London, 1973), another crew member of the spaceship Leonora Christine is identified: cook Michael O'Donnell. We now know the names of just over half the crew.

Earlier, in Chapter 11, cosmologist Chidambaran had commented on the idea of a faster than light (FTL) drive:

" 'That fantasy! If you want to rewrite everything we have learned since Einstein - no, since Aristotle, considering the logical contradiction involved in a signal without a limiting velocity - proceed.' " (p. 97)

I have studied philosophy and logic but not physics. The proposition, "This vehicle can move faster than light," is not logically contradictory. Of course it contradicts "Nothing can move faster than light," so that, if the latter is true, then the former is false. Does FTL entail "a signal without a limiting velocity"? Does that mean an instantaneous signal? Why is that contradictory? There is no verbal contradiction between "The signal was transmitted at time t1" and "The signal was received at time t1" or indeed between the former and "The signal was received at time t -1."

Time travel is logically possible but illogical conclusions are often drawn from it, e.g., that, if a time traveller prevents his parents from meeting and thus prevents his own conception, then he will cease to exist. Whatever else preventing someone's conception entails, it cannot possibly entail that he somehow exists into adulthood and then ceases to exist. Why am I discussing time travel again? Because it is a sharp way to clarify the distinctive nature of logical im/possibilities.

The Constable has not only deputies but even secret deputies and eventually might include everyone in the system! It is necessary to devise new instruments to detect habitable environments from a distance while traveling at relativistic speeds. Such projects serve the secondary purpose of keeping crew members busy, focused and sane.

Leonora Christine passes an old red dwarf with planets, and thus possibly with life, in intergalactic space. An inhabited planet of a star in intergalactic space is the setting of Anderson's World Without Stars, which I will reread next.