ملاحظات
تمهيد
(1)
Paul Davies, The Eerie Silence: Renewing
the Search for Alien
Intelligence (Boston: Houghton
Mifflin Harcourt, 2010),
2.
(2)
There is, however, a lively
debate under way about whether ‘Oumuamua, a
large interstellar object that passed through
the inner solar system in the fall of 2017,
might have been a light sail or some other
kind of craft built by an extraterrestrial
civilization. See chapter 5 for more
discussion of
‘Oumuamua.
(3)
Carl Sagan, The Cosmic
Connection (New York: Doubleday,
1973).
(4)
Quoted in Wade Roush, “Spielberg
Finances E.T. Search,” Harvard Independent, October
3, 1985.
(5)
Carl Sagan, Contact (New York:
Random House, 1980).
مقدمة
(1)
For the story of Eratosthenes’s
measurement, see, for example, Nicholas
Nicasro, Circumference: Eratosthenes and the
Ancient Quest to Measure the
Globe (New York: St. Martin’s
Press, 2008).
(2)
For a more serious treatment of
Native American culture in the pre-Columbian
moment, see Charles Mann, 1491: New Revelations of
America before Columbus (New
York: Knopf, 2005).
(3)
The account here comes mainly
from the Harvard physicist and SETI
scientist Paul Horowitz, who heard it from
York. See “The Fermi Paradox,” late 1998,
http://seti.harvard.edu/unusual_stuff/unpublished/fermi.htm.
But there are several other versions; in
some, the conversation took place in 1943,
not in 1950. See David Grinspoon,
Lonely
Planets: The Natural Philosophy of
Alien Life (New York: Harper
Collins, 2003),
311.
(4)
Milan M. Ćirković, The Great Silence: The
Science and Philosophy of Fermi’s
Paradox (Oxford: Oxford
University Press, 2018),
2.
(5)
Peter Ward and Donald
Brownlee, Rare
Earth: Why Complex Life Is Uncommon in
the Universe (New York:
Copernicus, 2000).
(6)
Stephen Webb, If the Universe Is
Teeming with Aliens … Where Is
Everybody? Seventy-Five Solutions to
the Fermi Paradox and the Problem of
Extraterrestrial Life, 2nd
ed. (New York: Springer,
2015).
(7)
NASA Exoplanet Archive, https://exoplanetarchive.ipac.caltech.edu/docs/counts_detail.html, data retrieved April
30, 2019.
(8)
Michael H. Hart, “An
Explanation for the Absence of
Extraterrestrials on Earth,” Quarterly Journal of the
Royal Astronomical Society
16 (1975): 128–135.
(9)
Quoted in Joel Achenbach, and
Peter Essick, “Life beyond Earth,”
National
Geographic Magazine,
January 2000.
الفصل الأول: أحلام بوجود كائنات غير أرضية
(1)
Barbara Duncan, The Origin of the Milky Way
and Other Living Stories of the
Cherokee (Chapel Hill:
University of North Carolina Press,
2008).
(2)
Karl Taube, Aztec and Maya
Myths (Austin: University of
Texas Press, 1993),
45–47.
(3)
Karl Popper, Conjectures and Refutations:
The Growth of Scientific
Knowledge (New York: Routledge,
2014), 186.
(4)
Richard McKirhan, “Anaximander’s
Infinite Worlds,” in Essays in Ancient Greek Philosophy VI:
Before Plato, ed. Anthony Preus
(Albany: State University of New York Press,
2001), 49–66.
(5)
Bertrand Russell, “The Atomists,”
in History of Western
Philosophy: Collectors Edition
(New York: Routledge, 2009), chap.
9.
(6)
This version of the Metrodorus
quote comes to us via Aetius and the unknown
authors grouped under the name
“Pseudo-Plutarch.” See Plutarch, Morals, chap. 5,
https://ebooks.adelaide.edu.au/p/plutarch/nature/book1.html#chapter5.
(7)
Epicurus to Herodotus, in
Epicurus, The Epicurus
Reader: Selected Writings and
Testimony, ed. Lloyd P. Gerson
(Indianapolis, IN.: Hackett, 1994),
8.
(8)
Lucretius, De rerum
natura, ed. William
Ellery Leonard (1916),
http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.02.0131%3Abook%3D2%3Acard%3D1048.
(9)
Plato, The Timaeus, trans. Benjamin
Jowett (1892), http://classics.mit.edu/Plato/timaeus.html.
(10)
Aristotle, On the Heavens,
trans. J. L. Stocks (Adelaide, Australia:
University of Adelaide, 2016), book I, chap.
8, https://ebooks.adelaide.edu.au/a/aristotle/heavens/index.html.
(11)
William Whewell, Of the Plurality of Worlds:
An Essay, Also a Dialogue on the Same
Subject (London: Parker, 1855),
144.
(12)
Benjamin D. Wiker, “Alien Ideas:
Christianity and the Search for
Extraterrestrial Life,” Crisis, November
4, 2002, https://web.archive.org/web/20030210140752/http://www.crisismagazine.com/november2002/feature7.htm.
(13)
Wiker, “Alien
Ideas.”
(14)
Stephen Greenblatt, The Swerve: How the
World Became Modern (New
York: Norton,
2011).
(15)
Johannes Kepler, Kepler’s Conversation
with Galileo’s Sidereal
Messenger, trans. Edward
Rosen (New York: Johnson, 1965),
42.
(16)
Galileo Galilei, Letters on
Sunspots, in Discoveries and Opinions
of Galileo, trans. Stillman
Drake (New York: Doubleday, 1957)
137.
(17)
One valuable book that does
attempt such a comprehensive overview is
Steven J. Dick, Plurality of Worlds: The Origins of
the Extraterrestrial Life Debate from
Democritus to Kant
(Cambridge: Cambridge University Press,
1984). For another thorough tour of
discussions of extraterrestrials in the
seventeenth, eighteenth, and nineteenth
centuries, see Michael J. Crowe, The Extraterrestrial
Life Debate, 1750–1900
(Cambridge: Cambridge University Press,
1986).
(18)
Bernard le Bovier Fontenelle,
Conversations
on the Plurality of Worlds,
trans. H. A. Hargreaves (Berkeley:
University of California Press, 1990), 49,
60.
(19)
Christian Huygens,
The
Celestial Worlds Discover’d; or,
Conjectures Concerning the
Inhabitants, Plants, and
Productions of the Worlds in the
Planets (London: James
Knapton, 1698) 149,
151.
(20)
Whewell’s arguments are
summarized in Crowe, Extraterrestrial Life
Debate, chap. 6, sec.
3.
(21)
Whewell, Of the Plurality of
Worlds, 330–331, emphasis
added.
(22)
Giovanni Schiaparelli,
La via sul
pianeta Marte: Tre scritti di
Schiaparelli su Marte e i
“marziani,” ed. Pasquale
Tucci, Agnese Mandrino, and Antonella
Testa (Milan: Mimesis, 1998), 76;
translation courtesy of Paola
Rebusco.
(23)
Percival Lowell, Mars (Boston:
Houghton, Mifflin, 1895),
149-150.
(24)
Lowell, Mars,
209.
(25)
A. R. Wallace, Is Mars
Habitable? (London:
Macmillan and Co., 1907),
38–77.
(26)
A hundred million of millions
to one is 1014
to 1: small odds indeed. See the appendix
to A. R. Wallace, Man’s Place in the
Universe, 4th ed. (London:
Chapman and Hall, 1904).
(27)
Here I must thank Carl Sagan
for introducing 13-year-old me to the
story of Percival Lowell in “Blues for Red
Planet,” episode 5 of the television
series Cosmos, PBS, October 26,
1980. In the book version, Sagan wrote:
“Lowell always said that the regularity of
the canals was an unmistakable sign that
they were of intelligent origin. This is
certainly true. The only resolved question
was which side of the telescope the
intelligence was on” (Cosmos,
110).
الفصل الثاني: تحوُّل البحث عن ذكاء خارج الأرض إلى علم
(1)
Guiseppe Cocconi and
Philip Morrison, “Searching for
Interstellar Communications,”
Nature, September 19,
1959, 846, emphasis
added.
(2)
Cocconi and Morrison,
“Searching for Interstellar
Communications,”
845.
(3)
For the details of Drake’s
Project Ozma, see Grinspoon, Lonely
Planets, 163; Sarah Scoles,
Making
Contact: Jill Tarter and the Search
for Extraterrestrial
Intelligence (Berkeley, CA:
Pegasus Books, 2017), 60–64; and Davies,
The Eerie
Silence,
1.
(4)
Frank Drake and Dava Sobel,
“The Origin of the Drake Equation,”
Astronomy
Beat 46 (April 5, 2010): 1.
Drake’s statement that only 10 people in
the world were thinking about
extraterrestrial life in 1961 was a bit of
an exaggeration. For a thorough look at
the debate at that time, see Steven Dick,
The Biological
Universe: The Twentieth-Century
Extraterrestrial Life Debate and the
Limits of Science
(Cambridge: Cambridge University Press,
1996).
(5)
Drake and Sobel, “The
Origin of the Drake Equation,”
2-3.
(6)
Drake and Sobel, “The Origin
of the Drake Equation,”
3.
(7)
David Grinspoon, Earth in Human Hands:
Shaping Our Planet’s Future
(New York: Grand Central Publishing,
2016), 299–305.
(8)
L. M. Gindilis and L. I.
Gurvits, “SETI in Russia, USSR, and the
post-Soviet Space: A Century of Research,”
Acta
Astronautica 162 (September
2019),
https://doi.org/10.1016/j.actaastro.2019.04.030.
(9)
I. S. Shklovskii, and Carl
Sagan, Intelligent
Life in the Universe (San
Francisco: Holden-Day, 1966),
359-360.
(10)
NASA, Project Cyclops: A Design Study of a
System for Detecting Extraterrestrial
Intelligent Life, NASA
Report no. CR 11445 (Washington, DC: NASA,
1971), 1.
(11)
NASA, Project Cyclops,
4.
(12)
Scoles, Making
Contact,
65.
(13)
Quoted in Grinspoon,
Earth in Human
Hands,
313.
(14)
Quoted in Bill Steele, “It’s
the 25th Anniversary of the First Attempt
to Phone E.T.,” Cornell Chronicle,
November 12, 1999,
http://news.cornell.edu/stories/1999/11/25th-anniversary-first-attempt-phone-et-0.
(15)
Quoted in Steven Johnson,
“Greetings, E.T. (Please Don’t Murder
Us),” New York
Times Magazine, June 28,
2017.
(16)
Quoted in Alan Penny, “The
SETI Episode in the 1967 Discovery of
Pulsars,” European
Physical Journal, February
2013, 6.
(17)
Robert Krulwich, “Aliens
Found in Ohio? The ‘Wow’ Signal,”
Weekend
Edition Saturday, National
Public Radio, May 28, 2010,
https://www.npr.org/sections/krulwich/2010/05/28/126510251/aliens-found-in-ohio-the-wow-signal.
(18)
Scoles, Making
Contact, 67. Scoles’s book
was my main source for the details of
Tarter’s work.
(19)
Paul Horowitz, “A Search for
Ultra-narrowband Signals of
Extraterrestrial Origin,” Science 201
(August 25, 1978):
733–735.
(20)
Roush, “Spielberg Finances
E.T. Search.”
(21)
Quoted in Zeeya Merali,
“Search for Extraterrestrial Intelligence
Gets a $100-Million Boost,”
Nature, July 20, 2015,
392-393.
(22)
NASA, Project Cyclops,
64.
(23)
Anita Heward, “LOFAR Opens Up
the Low-Frequency Universe—and Starts a
New SETI Search,” Phys.org, April 14, 2010,
https://phys.org/news/2010-04-lofar-low-frequency-universe-seti.html.
(24)
T. Joseph W. Lazio, Jill
Tarter, and D. J. Wilner, “Cradle of
Life,” Science
with the Square Kilometer
Array, 2004,
https://www.skatelescope.org/cradle-life.
(25)
Hillary Lebow, “Search for
Extraterrestrial Intelligence Expands at
Lick Observatory,” UC Santa Cruz
Newscenter, March 23, 2015,
https://news.ucsc.edu/2015/03/lick-niroseti.html.
(26)
SETI Institute, Technosearch,
https://technosearch.seti.org.
(27)
Quoted in SETI Institute,
“New Search for Signals from 20,000 Star
Systems Begins,” press release, March 30,
2016, https://www.seti.org/seti-institute/press-release/new-search-signals-20000-star-systems-begins.
(28)
Breakthrough Initiatives,
“National Astronomical Observatories of
China, Breakthrough Initiatives Launch
Global Collaboration in Search for
Intelligent Life in the Universe,” press
release, October 12, 2016,
http://astrobiology.com/2016/10/national-astronomical-observatories-of-china-breakthrough-initiatives-launch-global-collaboration-in.html.
(29)
Jason Daley, “In the Search
for Aliens, We’ve Only Analyzed a Small
Pool in the Cosmic Ocean,” Smithsonian,
October 2, 2018, https://www.smithsonianmag.com/smart-news/search-aliens-weve-only-examined-cosmic-hot-tub-180970447.
(30)
Jason T. Wright, Shubham
Kanodia, and Emily Lubar, “How Much SETI
Has Been Done? Finding Needles in the
n-Dimensional Cosmic Haystack,” Arxiv.org
astro-ph, September 19, 2018,
https://arxiv.org/abs/1809.07252.
الفصل الثالث: الكائنات المُحبة للظروف القاسية والكواكب الخارجية
(1)
Davies, The Eerie Silence,
25.
(2)
Davies, The Eerie Silence,
32.
(3)
For the story of Carl Woese,
see David Quammen, The Tangled Tree: A Radical New
History of Life (New York:
Simon and Schuster,
2018).
(4)
David Toomey, Weird Life: The Search
for Life That Is Very, Very Different
from Our Own (New York:
Norton, 2013),
4–11.
(5)
Toomey, Weird Life,
28.
(6)
Douglas Fox, “Lakes under the
Ice: Antarctica’s Secret Garden,”
Nature, August 21, 2014,
244–246.
(7)
Catherine Offord, “Life
Thrives within the Earth’s Crust,”
The
Scientist, October 2018,
https://www.the-scientist.com/features/life-thrives-within-the-earths-crust-64805.
(8)
US National Research Council,
The Limits of
Organic Life in Planetary
Systems (Washington, DC:
National Academies Press, 2007),
31.
(9)
Leonard David, “NASA’s Mars
Rover Curiosity Had Planetary Protection
Slip-up,” Scientific American,
December 1, 2011,
https://www.scientificamerican.com/article/nasas-mars-rover-curiositt/,
and Jyoti Madhusoodanan, “Microbial
Stowaways to Mars Identified,” Nature, May
19, 2014, https://www.nature.com/news/microbial-stowaways-to-mars-identified-1.15249.
(10)
Melissa Gaskill, “Space
Station Research Shows That Hardy Little
Travelers Could Colonize Mars,” NASA
Johnson Space Center news release, May 2,
2014,
https://www.nasa.gov/mission_pages/station/research/news/eu_tef.
(11)
Using modern data-analysis
software, Levin’s allies say they have
found evidence of circadian rhythms in the
LR experiment’s radiation measurements,
another possible signal of life. See Ker
Than, “Life on Mars Found by NASA’s Viking
Mission?” National
Geographic News, April 15,
2012,
https://news.nationalgeographic.com/news/2012/04/120413-nasa-viking-program-mars-life-space-science.
(12)
NASA, Viking 40th Anniversary: Life on
Mars, EDGE video,
https://www.nasa.gov/mission_pages/Viking.
(13)
Davies writes: “Gil wanted to
run the LR experiment with two broths, one
having left-handed amino acids and
right-handed sugars, the other using their
mirror forms. Thus, had the Mars soil
fizzed equally for both, a simple chemical
reaction would be the most likely
explanation—the one most scientists now
back. But if biology had been responsible,
then there would have been a marked
difference in response between the two
forms of broth” (The Eerie Silence,
39).
(14)
Mike Wall, “Signs of Life on
Europa May Be Just beneath the Surface,”
Scientific
American, July 23, 2018,
https://www.scientificamerican.com/article/signs-of-life-on-europa-may-be-just-beneath-the-surface.
(15)
US National Research Council,
Limits of
Organic Life in Planetary
Systems,
30-31.
(16)
James Stevenson, Jonathan
Lunine, and Paulette Clancy, “Membrane
Alternatives in Worlds without Oxygen:
Creation of an Azotosome,” Science
Advances, February 27,
2015,
http://advances.sciencemag.org/content/1/1/e1400067.
(17)
See chapter 3, “A Shadow
Biosphere?,” in Davies, The Eerie
Silence,
42–65.
(18)
US National Research
Council, Limits of Organic Life in
Planetary Systems,
74-75.
(19)
Donald Goldsmith’s book
Exoplanets:
Hidden Worlds and the Search for
Extraterrestrial Life
(Cambridge, MA: Harvard University Press,
2018) is a wonderful source on the
exoplanet story.
(20)
NASA Exoplanet Archive,
https://exoplanetarchive.ipac.caltech.edu/,
data retrieved July 27, 2019. The archive
offers up-to-date information about the
exoplanet hunt.
(21)
Seth Shostak, “This Weird
Planetary System Seems Like Something from
Science Fiction,” Mach, NBC News, February
22, 2017, https://www.nbcnews.com/mach/space/weird-planetary-system-seems-something-science-fiction-n724136.
(22)
See the Habitable Exoplanets
Catalog maintained by the Planetary
Habitability Laboratory at the University
of Puerto Rico at Arecibo, http://phl.upr.edu/projects/habitable-exoplanets-catalog.
(23)
Sara Seager, William Bains,
and Janusz Jura Petkowski, “Toward a List
of Molecules as Potential Biosignature
Gases for the Search for Life on
Exoplanets and Applications to Terrestrial
Biochemistry,” Astrobiology 16 (2016):
465.
(24)
US National Research Council,
Limits of
Organic Life in Planetary
Systems,
84.
الفصل الرابع: حل مفارقة فيرمي
(1)
I’m referring mainly to Milan
Ćirković, who considers the Drake Equation to
be not just outmoded but also dangerous: “In
the SETI field, invocation of the Drake
equation is nowadays largely an admission of
failure … to develop a real theoretical
grounding for the search” (The Great
Silence,
95).
(2)
Matthew Cobb, “Alone in
the Universe: The Improbability of
Alien Civilisations,” in Aliens: The World’s
Leading Scientists on the Search
for Extraterrestrial
Life, ed. Jim al-Khalili
(New York: Picador, 2016),
166.
(3)
“On the Shores of the Cosmic
Ocean,” episode 1 of Cosmos, PBS, September 28,
1980.
(4)
NASA Exoplanet Archive,
https://exoplanetarchive.ipac.caltech.edu/docs/counts_detail.html.
(5)
Webb, If the Universe Is Teeming with
Aliens,
230–234.
(6)
Michael Hart, “Habitable
Zones about Main Sequence Stars,”
Icarus 37, no. 1 (January
1979): 351–357.
(7)
Erik Petigura, Andrew Howard,
and Geoffrey Marcy, “Prevalence of
Earth-Size Planets Orbiting Sun-Like
Stars,” Proceedings of the National Academy
of Sciences 110, no. 48
(November 26, 2018):
19273–19278.
(8)
Ward and Brownlee, Rare Earth,
190–220.
(9)
Webb, If the Universe Is Teeming with
Aliens, 288–290. To be
clear, although Ward and Brownlee were
aware of the Mars hypothesis, it wasn’t a
big part of their
argument.
(10)
Ward and Brownlee, Rare Earth,
243.
(11)
Ward and Brownlee, Rare Earth,
250.
(12)
US National Research Council,
Limits of
Organic Life in Planetary
Systems,
1.
(13)
David J. Darling, Life Everywhere: The
Maverick Science of
Astrobiology (New York:
Basic Books, 2001),
103.
(14)
Ćirković, The Great
Silence,
152.
(15)
John G. Cramer, “The Pump of
Evolution,” Analog
Science Fiction &
Fact, January 1986,
https://www.npl.washington.edu/av/altvw11.html.
(16)
Ćirković, The Great
Silence,
172.
(17)
This is known as the
Adaptationist or Permanence Hypothesis,
after a story by science-fiction author
Karl Schroeder. See Ćirković, The Great
Silence,
158–162.
(18)
Ross Andersen, “What the Crow
Knows,” Atlantic, March 2019,
https://www.theatlantic.com/magazine/archive/2019/03/what-the-crow-knows/580726.
(19)
Sagan, Cosmos,
301. Note that Sagan’s version of
the Drake Equation was slightly
different from the standard one. He
used
(the absolute number of stars in
the galaxy) instead
of
(the rate of star formation), and (“the
fraction of a planetary lifetime
graced by civilization”) instead of . But
the math comes out the same. Note
also that Earth will become
uninhabitable in about one billion
years, long before the sun
dies.
(20)
The Light-Cage Hypothesis:
see Webb, If the
Universe is Teeming with
Aliens,
101–103.
(21)
The Galactic Stomach Ache
Hypothesis: see Ćirković, The Great
Silence,
222–228.
(22)
The Thoughtfood-Exhaustion
Hypothesis: see Ćirković, The Great
Silence,
163-164.
(23)
The Deadly Probes Hypothesis:
see Ćirković, The
Great Silence,
187–193.
(24)
The Astrobiological Phase
Transition Hypothesis: see Ćirković,
The Great
Silence,
174–178.
(25)
Nick Bostrom, Anthropic Bias:
Observation Selection Effects in
Science and Philosophy (New
York: Routledge,
2010).
(26)
Nick Bostrom, “Where Are
They? Why I Hope the Search for
Extraterrestrial Life Finds Nothing,”
MIT Technology
Review, April 22, 2008,
120.
(27)
Robin Hanson, “The Great
Filter—Are We Almost Past It?” September
15, 1998,
http://mason.gmu.edu/~rhanson/greatfilter.html.
(28)
David Deutsch, The Beginning of
Infinity: Explanations That Transform
the World (New York:
Penguin Books, 2011),
446.
(29)
Ćirković explores the Hermit
Hypothesis and finds it wanting (The Great
Silence, 27–30). It assumes
that every individual in a hermit species
feels the same way and that the species
has figured out how to avoid leaking any
transmissions or other information about
themselves.
(30)
Webb, If the Universe Is Teeming with
Aliens,
183–185.
(31)
The Sustainability or Aliens
Are Green Hypothesis: see Ćirković,
The Great
Silence, 220–222, and Webb,
If the
Universe Is Teeming with
Aliens,
106–109.
(32)
The Resource-Exhaustion
Hypotheses: see Ćirković, The Great
Silence, 185, and Webb,
If the
Universe Is Teeming with
Aliens,
103-104.
(33)
Webb, If the Universe Is Teeming with
Aliens,
111–113.
(34)
The Distance-Learners
Hypothesis: see Webb, If the Universe Is
Teeming with Aliens,
187–189.
(35)
Ćirković calls this the
“Introvert Big Brother” Hypothesis: see
The Great
Silence,
182–185.
(36)
The Persistence Hypothesis,
also known as the Percolation Hypothesis:
see Ćirković, The
Great Silence, 212–214, and
Webb, If the
Universe Is Teeming with
Aliens,
92–98.
(37)
Jonathan Carroll-Nellenback,
Adam Frank, Jason Wright, and Caleb Shaw,
“The Fermi Paradox and the Aurora Effect:
Exo-civilization Settlement, Expansion,
and Steady States,” ArXiv preprint,
February 13, 2019, https://arxiv.org/pdf/1902.04450.pdf.
(38)
The average distance between
any two communicating civilizations is
calculated using a standard formula for
the number of spheres of a given volume
that fit into a space of a given volume.
The formula is ((space-volume/sphere-volume)/packing-density), where
the packing density is the optimal 0.74048
for cubical or hexagonal packing. We know
the number of spheres, 16,875 in this
case, and the volume of the galaxy, so we
can solve for sphere volume and hence the
sphere radius. The distance between any
two communicative civilizations in this
idealized scenario will be twice this
radius.
(39)
“Kepler-1229b,” Wikipedia, n.d., https://en.wikipedia.org/wiki/Kepler-1229b.
(40)
Douglas Adams, The Hitchhiker’s Guide
to the Galaxy (London: Pan
Books, 1979), chap.
8.
(41)
Ćirković calls this the
“Eternal Wanderers” Hypothesis: see
The Great
Silence,
214–220.
(42)
This is sometimes called the
Berserker Hypothesis: see Grinspoon,
Earth in Human
Hands, 348–351, and Webb,
If the
Universe Is Teeming with
Aliens,
122-123.
(43)
Mark Buchanan, “Searching for
Trouble?” Nature
Physics, August 2016,
720.
(44)
Quoted in Johnson,
“Greetings, E.T. (Please Don’t Murder
Us).”
(45)
John A. Ball, “The Zoo
Hypothesis,” Icarus 19 (1973):
347–349.
(46)
The nonexclusivity principle
is one of the most powerful ideas in Milan
Ćirković’s book The Great Silence
(85–90).
(47)
Stephen Baxter, “The
Planetarium Hypothesis—a Resolution of the
Fermi Paradox,” Journal of the British Interplanetary
Society, 54 (2001):
210–216.
(48)
Jason Koebler, “Elon Musk
Says There’s a ‘One in Billions’ Chance
That Reality Is Not a Simulation,”
Motherboard, June 2, 2016,
https://motherboard.vice.com/en_us/article/8q854v/elon-musk-simulated-universe-hypothesis.
(49)
J. Richard Gott,
“Implications of the Copernican Principle
for Our Future Prospects,” Nature, May
27, 1993, 315–319.
(50)
For more discussion of the
Delta-T argument, see Webb, If the Universe is
Teeming with Aliens,
178–183. For a recent book on Gott’s idea,
see William Poundstone, The Doomsday
Calculation: How an Equation That
Predicts the Future Is Transforming
Everything We Know about Life and the
Universe (Boston: Little,
Brown Spark, 2019).
(51)
Webb, If the Universe Is Teeming with
Aliens,
208–211.
(52)
The Transcension Hypothesis:
see Ćirković, The
Great Silence, 195–199, and
Webb, If the
Universe Is Teeming with
Aliens,
196–198.
(53)
Ćirković, The Great
Silence,
133.
الفصل الخامس: الانضمام إلى المحادثة
(1)
Thomas Levenson, the head of
MIT’s science-writing program, tells the
Vulcan story in compelling detail in The Hunt for Vulcan … and
How Albert Einstein Destroyed a Planet,
Discovered Relativity, and Deciphered the
Universe (New York: Random
House, 2015).
(2)
Ćirković calls this the
“Paranoid Style in Galactic Politics”
Hypothesis; see The Great Silence,
124–126.
(3)
Webb, If the Universe Is Teeming with
Aliens,
160.
(4)
Marek Abramowicz, How to Search for a
Signal from an Alien
Civilization, video,
December 4, 2018,
https://www.youtube.com/watch?v=P-XE7DOFLo0.
(5)
A double-size DVD-RAM disk
holds 9.4 gigabytes of data. Assume that
it flies for one second in a small room.
You have just sent data at 9.4 gigabytes
per second or 75,200 megabits per second.
Compared to a maximum download speed for
most home broadband services (circa 2020)
of 300 megabits per second, the flying
disk offers a 250-times
improvement.
(6)
Webb, If the Universe Is Teeming with
Aliens,
161–163.
(7)
Shmuel Bialy and Abraham
Loeb, “Could Solar Radiation Pressure
Explain ‘Oumuamua’s Peculiar
Acceleration?” accepted for publication in
Astrophysical
Journal Letters, November
6, 2018; Abraham Loeb, “6 Strange Facts
about the Interstellar Visitor ‘Oumumua,”
Scientific
American, November 20,
2018,
https://blogs.scientificamerican.com/observations/6-strange-facts-about-the-interstellar-visitor-oumuamua.
(8)
Quoted in Josh
Swartz, “Harvard Astronomer on Why
Aliens Aren’t Science Fiction,”
WBUR, January 30, 2019,
https://www.wbur.org/endlessthread/2019/01/30/oumuamua-alien-probe-avi-loeb.
(9)
Andreas Hein, Nikolaos
Perakis, T. Marshall Eubanks, Adam
Hibberd, Adam Crowl, Kieran Hayward,
Robert G. Kennedy III, et al., “Project
Lyra: Sending a Spacecraft to 1l/‘Oumuamua
(Former A/2017 U1), the Interstellar
Asteroid,” ArXiv.org, October 19, 2018,
https://arxiv.org/ftp/arxiv/papers/1711/1711.03155.pdf.
(10)
Quoted in Oded Carmeli, “If
True, This Could Be One of the Greatest
Discoveries in Human History,” Haaretz,
January 16, 2019, https://www.haaretz.com/us-news/.premium.MAGAZINE-if-true-this-could-be-one-of-the-greatest-discoveries-in-human-history-1.6828318.
(11)
Nathalie Cabrol, “Alien
Mindscapes—a Perspective on the Search for
Extraterrestrial Intelligence,” Astrobiology
16, no. 9 (2016): 663,
667.
(12)
Cabrol, “Alien Mindscapes,”
669.
(13)
Four of my favorites films
that focus on postcontact outcomes include
2001: A Space
Odyssey (1968), Close Encounters of the
Third Kind (1977),
Contact (1997), and
Arrival
(2016).
(14)
See Carl Jung, Flying Saucers: A Modern
Myth of Things Seen in the
Skies (Princeton, NJ:
Princeton University Press,
1979).
