Proxima

Afretworld

This novel is about life on an “exoplanet”, a planet beyond the solar system. The first such planet orbiting a normal star (as opposed to a pulsar) was discovered as recently as 1995. At time of writing we have discovered thousands of such worlds (for a recent survey see Ray Jayawardhana, Strange New Worlds, Princeton, 2011). The first discovery of a planet in the Alpha Centauri star system was announced in October 2012 (see “An Earth Mass Planet Orbiting Alpha Centauri B” by Xavier Dumusque et al., Nature, 17 October 2012).

Could Per Ardua exist? At the time of writing no planet of Proxima has been detected, but a careful inspection of the star’s apparent movements has put upper limits on the sizes of any possible planets (for a technical paper see Zechmeister, M., Kürster, M., Endl, M., “The M Dwarf Planet Search Programme at the ESO VLT+UVES: A Search for Terrestrial Planets in the Habitable Zone of M Dwarfs’, Astron. Astrophys., vol. 505, pp. 859–71, 2009). The planetary system I have invented for this novel fits these limits. Proxima is a red dwarf—an “M dwarf”. We used to think that only sunlike stars could host Earthlike worlds. Now we suspect that M dwarfs like Proxima could after all host habitable worlds (see “A Reappraisal of the Habitability of Planets Around M Dwarf Stars”, J. Tarter et al., Astrobiology, vol. 7, no. 1, pp. 30–65, 2007).

The idea of starships driven by very lightweight “smart sails” pushed by microwave beams was suggested by Robert Forward (‘Starwisp: An Ultralight Interstellar Probe’, Journal of Spacecraft and Rockets, vol. 22, pp. 345–50, 1985) and revisited by Geoffrey A. Landis (‘Microwave Pushed Interstellar Sail: Starwisp Revisited’, paper AIAA-2000-3337, presented at the AIAA 36th Joint Propulsion Conference and Exhibit, Huntsville AL, July 17–19, 2000). I have extrapolated wildly beyond these respectable works.

The classic work Interstellar Migration and the Human Experience, ed. Ben Finney and Eric Jones (Berkeley, 1985), contains much speculation on the anthropology and ethics of the colonisation of space.

I’m deeply grateful to Professor Adam Roberts for a brief injection of Latin.

Any errors or inaccuracies are, of course, my sole responsibility.

Stephen Baxter

Northumberland

December 2012