by Chris Impey
9. Spacesuits: The Smithsonian National Air and Space Museum Collection by A. Young 2009. Brooklyn: Power House Books.
10. “The Retro Rocket Look” from The Economist, online at http://www.economist.com/news/technology-quarterly/21603234-spacesuits-new-generation-outfits-astronauts-being-developed-although.
11. NASA’s Ames Research Center in California commissioned the space-colony studies, and they hold the drawings and design studies. To show that the vision hasn’t been abandoned, the website quotes Michael Griffin, former administrator of NASA, as saying, “I know that humans will colonize the Solar System and one day go beyond.” The project continues with an annual design study open to middle and high school students from anywhere in the world. The 2014 competition had 562 entries from 1,567 students in eighteen countries. Online at http://settlement.arc.nasa.gov/.
12. The grim fate of the Biosphere is a reminder that habitable zones evolve on long timescales. A planet is kept habitable by a symbiotic relationship between living organisms and the rocks and oceans, an insight first noted by James Lovelock, who originated the Gaia hypothesis. The fundamental drive of habitability is energy from the parent star. The Sun was 25 percent dimmer 3 to 3.5 billion years ago, when life on Earth was microbial and oxygenic photosynthesis had not yet evolved. In the future, as the Sun uses its nuclear fuel and settles into a more compact configuration, it will “burn hotter,” so the Earth will not remain habitable for the full span that the Sun has nuclear fuel, another 4 to 4.5 billion years. Microbes that live inside rock or far below the surface of the ocean are immune to moderate changes in solar radiation since they live off geological energy. As the Earth becomes intolerably hot, we’ll have to develop Biospheres for the whole population—assuming humans persist that long.
13. Since 2012, the Doomsday Clock has stood at five minutes to midnight, uncomfortably close to disaster. The explanation associated with that judgment is worth quoting in full: “The challenges to rid the world of nuclear weapons, harness nuclear power, and meet the nearly inexorable climate disruptions from global warming are complex and interconnected. In the face of such complex problems, it is difficult to see where the capacity lies to address these challenges. The political processes in place seem wholly inadequate to meet the challenges to human existence that we confront. . . . The potential for nuclear weapons use in regional conflicts in the Middle East, Northeast Asia, and particularly South Asia is also alarming. . . . Safer nuclear reactor designs need to be developed and built, and more stringent oversight, training, and attention are needed to prevent future disasters. . . . [T] he pace of change may not be adequate . . . to meet the hardships that large-scale disruption of the climate portends.” See: http://thebulletin.org/press-release/it-5-minutes-midnight. The Doomsday Clock and its timeline can be seen online at http://thebulletin.org/timeline.
14. Tsiolkovsky quote from a letter written in 1911, online in Russian at http://www.rf.com.ua/article/388. Sagan quote from Pale Blue Dot, p. 371. Niven is quoted by Arthur C. Clarke in “Meeting of the Minds: Buzz Aldrin Visits Arthur C. Clarke,” reported by A. Chaikin on February 27, 2001, on Space.com. Hawking quote from a transcript of a video interview for BigThink, online at http://bigthink.com/videos/abandon-earth-or-face-extinction.
15. Lansdorp is quoted in the article “Is Mars for Sale?” by A. Wills, for Mashable.com, online at http://mashable.com/2013/04/09/mars-land-ownership-colonization/.
16. “Space Settlement Basics” by A. Globus, NASA Ames Research Center website, at http://settlement.arc.nasa.gov/Basics/wwwwh.html.
17. From the collection Tales of Ten Worlds by A. C. Clarke 1962. New York: Harcourt Brace.
18. “What Do Real Population Dynamics Tell Us About Minimum Viable Population Sizes?” by C. D. Thomas 1990. Population Biology, vol. 4, no. 3, pp. 324–27.
19. Bottleneck: Humanity’s Impending Impasse by W. R. Catton 2009. Xlibris.
20. “Biodiversity and Intraspecific Genetic Variation” by C. Ramel 1998. Pure and Applied Chemistry, vol. 70, no. 11, pp. 2079–84.
21. “The Grasshopper’s Tale” by R. Dawkins, in The Ancestor’s Tale: A Pilgrimage to the Dawn of Life 2004. Boston: Houghton Mifflin.
22. “Genetics and Recent Human Evolution” by A. R. Templeton 2007. International Journal of Organic Evolution, vol. 61, no. 7, pp. 1507–19. Other researchers think the bottleneck may have been more drawn out and not due to sudden environmental change, with numbers dropping as low as 2,000 for tens of thousands of years until the Late Stone Age. (See also note 23.)
23. “Population Bottlenecks and Pleistocene Human Evolution” by J. Hawks, K. Hunley, S. H. Lee, and M. Wolpoff 2000. Molecular Biology and Evolution, vol. 17, no. 1, pp. 2–22. The complete story of our evolution from Africa is in “Explaining Worldwide Patterns of Human Variation Using a Coalescent-Based Serial Founder Model of Migration Outward from Africa” by M. DeGiorgio, M. Jakobsson, and N. A. Rosenberg 2009. Proceedings of the National Academies of Science, vol. 106, no. 38, pp. 16057–62.
24. “Legacy of Mutiny on the Bounty: Founder Effect and Admixture on Norfolk Island” by S. Macgregor et al. 2010. European Journal of Human Genetics, vol. 18, no. 1, pp. 67–72. The Tristan da Cunha case study is reported in Population Genetics and Microevolutionary Theory by A. R. Templeton 2006. New York: John Wiley, p. 93. “Amish Microcephaly: Long-Term Survival and Biochemical Characterization” by V. M. Siu et al. 2010. American Journal of Medical Genetics A, vol. 7, pp. 1747–51.
25. “ ‘Magic Number’ for Space Pioneers Calculated,” a report on the work of John Moore by D. Carrington, reported in New Scientist, online at http://archive.is/Xa8I.
26. Interstellar Migration and the Human Experience, ed. by B. R. Finney and E. M. Jones 1985. Berkeley: University of California Press.
27. Do Androids Dream of Electric Sheep? by P. K. Dick 1968. New York: Doubleday. The novel served as the primary source for the 1992 film Blade Runner, directed by Ridley Scott and starring Harrison Ford. Released to mixed reviews, it has since become a cult classic. The Roy Batty quote is in the penultimate scene in the director’s cut of the film.
28. “Cyborgs and Space” by M. E. Clynes and N. S. Kline 1960. Astronautics, September, p. 27.
29. Harbisson founded the Cyborg Foundation in 2010 to help humans become cyborgs. His eyeborg has been enhanced such that he can perceive color saturation as well as 360 different hues. He has a flair for publicity, and a short documentary about him won a Grand Jury Prize at the 2012 Sundance Film Festival. He has done performance art converting colors into music, and his art focuses on the relationship between color and sound; he’s also had experimental theater and dance performances. Using his eyeborg, he has created live sonic “portraits” of celebrities, including Leonardo DiCaprio, Al Gore, Tim Berners-Lee, James Cameron, Woody Allen, and Prince Charles. A 2013 Huffington Post article, “Hacking Our Senses,” features his 2012 TED Global Talk, “I Listen to Color,” and quotes him saying, “I don’t feel that I’m using technology, I don’t feel that I’m wearing technology, I feel that I am technology.” The article is online at http://www.huffingtonpost.com/neil-harbisson/hearing-color-cyborg-tedtalk_b_3654445.html.
30. Warwick’s most influential paper in 2003 begins: “From a cybernetics viewpoint, the boundaries between humans and machines become almost inconsequential.” Published as “Cyborg Morals, Cyborg Values, Cyborg Ethics” by K. Warwick 2003. Ethics and Information Technology, vol. 7, pp. 131–37. See also: “Future Issues with Robots and Cyborgs” by K. Warwick 2010. Studies in Ethics, Law, and Technology, vol. 6, no. 3, pp. 1–20.
31. Article from 2012 in The Verge, online at http://www.theverge.com/2012/8/8/3177438/cyborg-america-biohackers-grinders-body-hackers.
32. Kevin Warwick quote is from an FAQ on his website, at http://www.kevinwarwick.com/. Francis Fukuyama quote is from “The World’s Most Dangerous Ideas: Transhumanism” by F. Fukuyama 2004. Foreign Policy, vol. 144, pp. 42–43. Ronald Bailey 2004 rebuttal to Fukuyama is from Reason
online at http://reason.com/archives/2004/08/25/transhumanism-the-most-dangero. If you want to drink deep from the transhumanist Kool-Aid, see “Why I Want to Be Transhuman When I Grow Up” by N. Bostrom 2008, in Medical Enhancement and Posthumanity, ed. by B. Gordijn and R. Chadwick. New York: Springer, pp. 107–37.
12: Journey to the Stars
1. This particular quote has engendered a lot of speculation and misattribution. For example, it cannot be reliably attributed to baseball manager and purveyor of malapropisms Yogi Berra. It seems to originate in nineteenth-century Denmark and was used but not coined by physicist Niels Bohr. A detailed discussion is online at http://quoteinvestigator.com/2013/10/20/no-predict/.
2. See http://www.scientificamerican.com/article/pogue-all-time-worst-tech-predictions/; and http://www.informationweek.com/it-leadership/12-worst-tech-predictions-of-all-time/d/d-id/1096169.
3. See http://www.smithsonianmag.com/history/the-world-will-be-wonderful-in-the-year-2000-110060404/?no-ist.
4. “An Earth Mass Planet Orbiting Alpha Centauri B” by X. Dumusque et al. 2012. Nature, vol. 491, pp. 207–11. See also “The Exoplanet Next Door” by E. Hand 2012. Nature, vol. 490, p. 323.
5. “Possibilities of Life Around Alpha Centauri B” by A. Gonzales, R. Cardenas-Ortiz, and J. Hearnshaw 2013. Revista Cubana de Física, vol. 30, no. 2, pp. 81–83. The exoplanet simulation paper on the Alpha Centauri system is “Formation and Detectability of Terrestrial Planets Around Alpha Centauri B” by J. M. Guedes et al. 2008. The Astrophysical Journal, vol. 679, pp. 1582–87.
6. “Atmospheric Biomarkers on Terrestrial Exoplanets” by F. Selsis 2004. Bulletin of the European Astrobiology Society, no. 12, pp. 27–40. See also: “Can Ground-Based Telescopes Detect the Oxygen 1.27 Micron Absorption Feature as a Biomarker in Exoplanets?” by H. Kawahara et al. 2012. The Astrophysical Journal, vol. 758, pp. 13–28; and “Deciphering Spectral Fingerprints of Habitable Exoplanets” by L. Kaltenegger et al. 2010. Astrobiology, vol. 10, no. 1, pp. 89–102.
7. “Exoplanetary Atmospheres” by N. Madhusudhan, H. Knutson, J. Fortney, and T. Barman 2014, in Protostars and Planets VI, ed. by H. Buether, R. Klessen, C. Dullemond, and Th. Henning. Tucson: University of Arizona Press.
8. “Detection of an Extrasolar Planet Atmosphere” by D. Charbonneau, T. M. Brown, R. W. Noyes, and R. L. Gilliland 2001. The Astrophysical Journal, vol. 568, pp. 377–84.
9. Web pages on space propulsion and interstellar travel are maintained by NASA’s Glenn Research Center: http://www.nasa.gov/centers/glenn/technology/warp/scales.html.
10. For an overview, see Project Orion: The True Story of the Atomic Spaceship by G. Dyson 2002. New York: Henry Holt. The original paper was “On a Method of Propulsion of Projectiles by Means of External Nuclear Explosions, Part 1,” by C. J. Everett and S. M. Ulam 1955. University of California Los Alamos Lab, unclassified document archived at http://www.webcitation.org/5uzTHJfF7. For more recent technical design work, see “Physics of Rocket Systems with Separated Rockets and Propellant” by A. Zuppero 2010, online at http://neofuel.com/optimum/.
11. “Reaching for the Stars: Scientists Examine Using Antimatter and Fusion to Propel Future Spacecraft,” April 1999, NASA, online at http://science1.nasa.gov/science-news/science-at-nasa/1999/prop12apr99_1/.
12. The Rand Corporation, online at http://www.rand.org/pubs/research_memoranda/RM2300.html.
13. “Galactic Matter and Interstellar Flight” by R. W. Bussard 1960. Astronautica Acta, vol. 6, pp. 179–94.
14. “Roundtrip Interstellar Travel Using Laser-Pushed Lightsails” by R. L. Forward 1984. Journal of Spacecraft, vol. 21, no. 2, pp. 187–95.
15. “Magnetic Sails and Interstellar Travel” by D. G. Andrews and R. Zubrin 1988. Paper presented at a meeting of the International Aeronautics Federation, IAF-88-553.
16. “Starship Sails Propelled by Cost-Optimized Directed Energy” by J. Benford 2011, posted on the arXiv preprint server at http://arxiv.org/abs/1112.3016.
17. Starship Century: Toward the Grandest Horizon, ed. by G. Benford and J. Benford 2013. Lucky Bat Books. This book represents the proceedings of a conference by the same title in 2013, featuring scientists such as Sir Martin Rees, Freeman Dyson, Stephen Hawking, and Paul Davies, and science fiction authors such as Neal Stephenson, David Brin, and Nancy Kress.
18. Frontiers of Propulsion Science by M. Millis and E. Davis 2009. Reston, VA: American Institute of Aeronautics and Astronautics.
19. The 100 Year Starship (100YSS) project was started in 2012 by NASA and the US Defense Advanced Research Projects Agency (DARPA). The website is http://100yss.org/.
20. “Light Sails as a Means of Propulsion” by T. Dunn, unpublished calculations, online at http://orbitsimulator.com/astrobiology/Light%20Sails%20as%20a%20means%20of%20propulsion.htm.
21. “SpiderFab: Process for On-Orbit Construction of Kilometer-Scale Apertures” by R. Hoyt, J. Cushing, and J. Slostad 2013, final technical report to NASA on project by Tethers Unlimited, NNX12AR13G, online at http://www.nasa.gov/sites/default/files/files/Hoyt_2012_PhI_SpiderFab.pdf.
22. “Life-Cycle Economic Analysis of Distributed Manufacturing with Open-Source 3D Printers” by B. T. Wittbrodt et al. 2013. Mechatronics, vol. 23, pp. 713–26. Also “A Low-Cost Open-Source 3-D Metal Printing” by G. C. Anzalone et al. 2013. IEEE Access, vol. 1, pp. 803–10.
23. “A Self-Reproducing Interstellar Probe” by R. A. Freitas 1980. Journal of the British Interplanetary Society, vol. 33, pp. 251–64.
24. The original work is Theory of Self-Reproducing Automata by J. von Neumann, and completed by A. W. Burks 1966. New York: Academic Press. See also “An Implementation of von Neumann’s Self-Reproducing Machines” by U. Pesavento 1995. Artificial Life, vol. 2, no. 4, pp. 337–54.
25. NASA funded a program called Breakthrough Propulsion Physics for eight years. Led by Marc Millis, it resulted in several workshops and a dozen technical publications. The project website says that no breakthroughs appear imminent. It also has this cautionary note: “On a topic this visionary and whose implications are profound, there is a risk of encountering premature conclusions in the literature, driven by overzealous enthusiasts as well as pedantic pessimists. The most productive path is to seek out and build upon publications that focus on the critical make-break issues and lingering unknowns, both from the innovators’ perspective and their skeptical challengers.”
26. “Possibility of Faster-than-Light Particles” by G. Feinberg 1967. Physical Review, vol. 159, no. 5, pp. 1089–1105.
27. “The Warp Drive: Hyper-Fast Travel within General Relativity” by M. Alcubierre 1994. Classical and Quantum Gravity, vol. 11, no. 5, pp. L73–L77.
28. Synopsis at the official Star Trek website: http://www.startrek.com/database_article/realm-of-fear.
29. “Teleporting an Unknown Quantum State via Dual Classical and Einstein-Podolsky-Rosen Channels” by C. H. Bennett et al. 1993. Physical Review Letters, vol. 70, pp. 1895–99.
30. Alice and Bob are two commonly used placeholder names, particularly in the fields of cryptography and subsequently in physics. The practice started because it’s more personal and appealing than talking about A and B. The first use was by Ron Rivest in Communications of the Association for Computing Machinery in a 1978 article presenting the first public-key cryptographic system. Rivest says the choice of names is not a nod to the 1969 movie Bob & Carol & Ted & Alice. Communication of tangled quantum states follows this tradition: “Alice wants to send a message to Bob . . . .” If a third or fourth participant is needed, they’re called Chuck or Dan. Eve is used for an eavesdropper in cryptography, or the external environment in a quantum communication situation. And that is probably more than you need or want to know.
31. “Quantum Teleportation over 143 Kilometers Using Active Feed-Forward” by X. S. Ma et al. 2012. Nature, vol. 489, pp. 269–73. For a report on worldwide teleportation by a University of Tokyo group, see http://akihabaranews.com/2013/09/11/article-en/world-first-success-complete-quantum-telepor
tation-750245129.
32. “Unconditional Quantum Teleportation Between Distant Solid-State Quantum Bits” by W. Pfaff et al. 2014. Science, DOI:10.1126/science.1253512.
13: Cosmic Companionship
1. In any product of numerical terms, the product is as uncertain as its most uncertain component. Having measurements of the incidence of habitable planets in the Milky Way doesn’t mitigate our almost complete ignorance of the terms that related to alien physiology or sociology. Evolution on Earth led to intelligence and the development of technology by one species, but natural selection doesn’t predict this as a necessary outcome; to argue that it does is to fall prey to anthropic bias. The counterexamples are the many species that did not become noticeably more complex, or evolve large brains, after hundreds of millions of years of evolution.
2. An anthropocentric way to estimate L is to use the average of human civilizations on Earth. Doing this historically gives an average of 300 to 400 years. See “Why ET Hasn’t Called” by M. Shermer 2002, in Scientific American, online at http://www.michaelshermer.com/2002/08/why-et-hasnt-called/. It’s also possible that there may be many civilizations that are unstable or evanescent, with low L, but some that are essentially immortal, with very large L. David Grinspoon has discussed the implications of this for the Drake equation; see Lonely Planets: The Natural Philosophy of Alien Life by D. Grinspoon 2004. New York: HarperCollins.
3. Contact by C. Sagan 1985. New York: Simon & Schuster. Sagan and his wife, Ann Druyan, wrote the outline for the 1997 film, which was directed by Robert Zemeckis.
4. The Dispossessed: An Ambiguous Utopia by U. K. Le Guin 1974. New York: Harper and Row. This novel was something of a breakthrough for Le Guin, earning her literary recognition as well as the Nebula, Hugo, and Locus Awards for science fiction.
5. “Nikola Tesla and the Electrical Signals of Planetary Origin” by K. L. Corum and J. F. Corum 1996. Online Computer Library Center, Document no. 38193760, pp. 1, 6, 14.