Time travel non sequiturs annoy me most, e.g., a time traveler prevents his own parents from meeting, therefore he immediately ceases to exist:
in a single continuous timeline, the fact that he exists means that his parents were not prevented from meeting;
in a single discontinuous timeline, a time traveler arriving from nowhen, like a macroscopic quantum event, can prevent the man and woman who would otherwise have been his parents from meeting but there is no reason why he should then cease to exist;
in a multiple timelines scenario, the time traveler can be born in timeline 1 and prevent his own birth in timeline 2 and should continue to exist;
in no timeline can a potential person whose parents did not meet exist into adulthood, then cease to exist.
See The Logic of Time Travel, Part I.
Poul Anderson either avoids such non sequiturs completely, e.g., in There Will Be Time, or conceals them carefully, i.e., in his Time Patrol series. The classic sf howler is getting the science wrong. Examples can be cited from other authors' works.
A few posts ago, here, I referred to Edmund Cooper's Seed Of Light. I borrowed this book as well as Anderson's Guardians Of Time and Robert Heinlein's Orphans Of The Sky, from the Public Library in Penrith, Cumberland (now Cumbria) in the early 1960s. Remembering that I had appreciated Cooper's combination of interstellar travel with time travel and also motivated by nostalgia, I have ordered a copy from Amazon and have also reread Damon Knight's review in In Search Of Wonder. Knight highlights howlers that can help us to compare Cooper with Anderson.
3 comments:
Kaor, Paul!
I think I recall some where Anderson writing about how he came to have doubts about the practicality of using Bussard ramjets as a means of STL interstellar traveling. But, at the time he used that concept for stories like TAU ZERO, Anderson was as scrupulously accurate as the knowledge and science available to him at the time he wrote that novel as was possible.
Sean
Some time after Anderson wrote "Tau Zero", calculations on the Bussard Ramjet idea found that the magnetic scoop would produce more drag than the fusion rocket would produce thrust. IIRC Robert Zubrin was involved in this research. So the next idea is to use such a magnetic field as a sail or a parachute to slow a spacecraft relative to the motion of interplanetary or interstellar plasma.
Some variants of this idea are named 'magsail' and 'M2P2'.
Kaor, Jim!
And I also read how Anderson was not entirely satisfied with the final text of TAU ZERO. But his publisher was pressing for the manuscript, which he turned in despite his dissatisfaction.
I've read two of Robert Zubrin's books and may have read of similar being written about at the CENTAURI DREAMS website.
Far better, of course, would be a real FTL drive that works!
Ad astra! Sean
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