Time

AFTERWORD

I owe Kent Joosten of the Johnson Space Center, NASA, even more gratitude than usual for his contribution to the cephalopod sections. Thanks also to Eric Brown and Simon Bradshaw for reading manuscript drafts.

* The idea that squid and other cephalopods may be intelligent is real. A recent reference is New Scientist of 1 June 1997; Cephalopod Behaviour by R. T. Hanlon and J. B. Messenger (Cambridge University Press, 1996) was a valuable source.

* The riches available to us from the asteroids and other extraterrestrial resources, and plans to exploit those riches, are real. A good recent survey is Mining the Sky by John S. Lewis (AddisonWesley, 1996).

* The probabilistic doomsday prediction called here the “Carter catastrophe” is real. It has been well expressed by John Leslie in The End of the World (Routledge, 1996).

* The “Feynman radio” idea of using advanced electromagnetic waves to pick up messages from the future is real. This has actually been attempted, for example by I. Schmidt and R. Newman (Bulletin of the American Physical Society, vol. 25, p. 581, 1979). And the extension of the idea to quantum mechanics (the “transactional interpretation”) is real. See John Cramer, Reviews of Modern Physics, vol. 58, p. 647,1986.

* Cruithne, Earth’s “second Moon,” is real. Its peculiar properties were reported in Nature, vol. 387, p. 685,1997.

* The “quark-nugget” idea of collapsed matter, with its potentially disastrous implications, is real. It was proposed by E. Witten in “Cosmic Separation of Phases,” Physical Review A vol. 30, p. 272,1984.

* The physics of the possible far future drawn here is real. A classic reference is “Time without End: Physics and Biology in an Open Universe,” F. Dyson, Review of Modern Physics, vol. 51, p. 447,1979.

* The idea that our universe is one of an evolutionary family is real. A recent variant of the theory has been developed by L. Smolin in his book The Life of the Cosmos (Oxford University Press, 1997).

* The notion of vacuum decay is real. It was explored by P. Hut and M. Rees in “How Stable Is Our Vacuum?” Nature, vol. 302, p. 508,1983.

The rest is fiction.

Stephen Baxter

Great Missenden

February 1999