In the Heavens as It Is on Earth
The collision occurred on February 10, 2009 over Siberia at 0455 GMT at an altitude of 790 kilometers (490 miles) above the Earth. An Iridium communications satellite struck a defunct Soviet-era Cosmos 2251 communications satellite. Scientists estimate that the collision speed of the two orbital objects was 42,120 kilometer per hour (26,172 mph).1 There are no fender benders at this speed. A BB traveling at this speed would rip through the Space Shuttle with the force of a hundred-pound cannon ball traveling at 78 miles per hour.2
The satellite collision generated hypersonic shock waves that turned the two satellites into a cloud of high-speed shrapnel that will orbit the Earth for another 10,000 years. Experts called the collision a â€œcatastrophic eventâ€. We will come back to high-speed orbiting space junk at the end of this essay.
It just so happened on that very day in February, I was participating in a three-day consultation in Mountain View, California hosted by the SETI Institute and NASAâ€™s Astrobiology Program. Fifty scientists, philosophers, theologians, lawyers, artists, and anthropologists had assembled to discuss the societal impact of astrobiology. Scientists are increasingly optimistic that we will soon find microbial life elsewhere in our solar system â€“ Mars, Titan, or Europa being likely prospects. Beyond that, astronomers have now identified 340 â€œexoplanetsâ€ orbiting nearby stars in our galaxy. Soon we will have telescopes that allow us to determine whether any of these exoplanets have any of the telltale chemical characteristics of life.
Astrobiology is exciting, cutting-edge science, â€œmultidisciplinary in its content and interdisciplinary in its execution,â€ that seeks to:
1. Understand the nature and distribution of habitable environments in the universe.
2. Explore for habitable environments and life in our own Solar System.
3. Understand the emergence of life.
4. Determine how early life on Earth interacted and evolved with its changing environment.
5. Understand the evolutionary mechanisms and environmental limits of life.
6. Determine the principles that will shape life in the future.
Microbiologists and geologists are now working in teams with astronomers and engineers at NASA. Of the over forty NASA Science Missions envisioned over the next ten years, half of the launches have some aspect of astrobiology in their objectives.4 Astrobiology has broad societal interests and implications, thus NASA gathered us together at SETI for three days to discuss different religious, philosophical, ethical, legal, and cultural implications of discovering life beyond Earth.
It should come as no surprise that there is no single view about the societal impact of astrobiology. NASA historian Steven Dicks was there to remind us that religions and philosophers have speculated for thousands of years about other worlds and other intelligence in the universe.5 Popular cultureâ€™s enthusiasm for extraterrestrial intelligence can be witnessed in the preponderance of science fiction movies and books. NASA would be ecstatic simply to find microbes elsewhere in the solar system.
There has been a tectonic shift in the scientific community over the last twenty years. Life, once thought to be extremely rare and improbable, may turn out to be rather ubiquitous in the universe. We now know that amino acids are spread throughout our galaxy and have even been detected in other galaxies.6 We also know that life on Earth exists in extreme environments, where it was previously thought to be unlikely. These â€œextremophilesâ€ thrive in extreme cold, extreme heat, multiple atmospheres, high acidity, and high alkalinity. The implications are that the universe may be â€œbio-friendly.â€
Much of the conversation at the astrobiology consultation revolved around issues of planetary protection â€“ the possibility for microbial cross-contamination from Earth ending up on Mars or microbes from Mars brought back to Earth on a future return mission. Because microbes inevitably contaminate the machines we build despite extensive efforts to sterilize them, we have already sent microbes to Mars, starting with the Soviet Mars 2 Lander in 1973. The surface of Mars, however, is exposed to ultraviolet radiation from the sun, so there is not much hope for these terrestrial â€œhitchhikerâ€ microbes gaining a foothold on the surface of Mars. If there is microbial life on Mars, it will probably be found under the surface.
A sample return mission from Mars presents the possibility of back contamination â€“ transporting Martian microbes to Earth â€“ with concerns of how to quarantine materials and thereby avoid contamination by possibly biohazardous Martian life. NASA and other international scientists have thought a lot about the kinds of protective measures needed to prevent the contamination of Earth with Martian microbes. Still there is an unknown risk here, so society should continue to scrutinize the technocrats who will decide whether and how to proceed with a return mission from the surface of Mars. If in the future, astronauts go to Mars and return to Earth, then the microbial containment issue becomes a lot more complicated.6
Meteorites from ancient Mars and elsewhere in the solar system regularly land on Earth. Indeed, the interplanetary delivery of materials is one possibility for the origin of life on Earth. In 1984 a Martian meteorite was discovered in Antarctica. The 4-pound meteorite dubbed ALH 84001 made world news in August 1996, when subsequent analysis of the meteorite suggested that it might contain fossilized Martian bacteria.8
In my understanding, discovering microbial life beyond Earth would not be particularly earth-shattering, unless the chemical composition is distinctly different from our terrestrial microbes. If we discover microbial life chemically different than that on Earth, then scientific prudence would suggest that we not destroy what we do not yet understand. My bet, however, is that the chemistry of life has a kind of internal necessity. Far from being improbable, it is highly probable. The universe is bio-friendly. Given the right conditions, biopolymers will self-assemble into thermodynamically disequilibrious, self-replicating, complex structures, i.e., what we call life. In the habitable zones where liquid water and the right conditions exist in the universe, we are likely to find microbial life. This is the view gaining ground in the astrobiology betting pools.
Given that I am unlikely to ever lose this bet, for reasons I will explain below, I will even wager my right arm that the universe is also filled with convergent evolution.9 In other words, the variety of natural kinds that have evolved on Earth will also be present on Earth-like exoplanets, where the initial conditions and sufficient evolutionary time exists. Evidence to the contrary, some would say, is that we have so far been unsuccessful in catalyzing life from the basic chemical ingredients in our terrestrial laboratories. Note that such research is now also being conducted under the rubric of astrobiology.
I am trained as a scholar of comparative religion, and so in this regard, I often find myself discussing the societal implications of astrobiology for religion. This, of course, is an impossible question given the diversity of religions and religious perspectives. For some, astrobiology will be framed as a continuation of the evolution wars. Mythological literalism cannot be easily reconciled with modern science. In many cases though, our religious myths actually anticipated other worlds in the universe. In a silly, but popular form of concordance-seeking-through-science, many will see astrobiology as confirmation of the literal truth of the Qurâ€™an, the Bible, the Vedas, and so forth, even as they reinterpret those scriptures in new ways.
The questions we posed about religion and astrobiology are especially fun and provocative when we posit contact with extraterrestrial intelligence. Will we be able to translate our languages? Will they have similar mathematics, albeit with different symbolic representation? Do they have moral dilemmas? Very early in the conversation, we are going to have to resolve whether or not they eat humans, remembering that humans eat intelligent mammals and intelligent cephalopods. Once we get that question off the table, we can move on to other interesting questions:
Can extraterrestrials achieve Buddha-consciousness? Did Jesus die for the sins of extraterrestrials? Do extraterrestrials even sin? Do they die? What do they believe about death, afterlife, and reincarnation? Do they believe in â€œGodâ€? If they are more technologically advanced, is their â€œGodâ€ also more â€œadvancedâ€? Will ETI be missionaries who come to Earth to promote their God? The latter, I note, is somewhat how the atheist scientist Carl Sagan ends his science fiction book Contact (1985).
Science fiction is the genre where many of these ideas are explored in thoughtful detail. I have long considered science fiction a form of social criticism and theological exploration. A religious scholar who doesnâ€™t keep up with science fiction is missing a lot.10 As already noted, the first and most important question to get out of the way is whether extraterrestrial life is hostile or benign. In the movie Independence Day (1996), the extraterrestrials are intelligent predatory insects that have come to consume our planet like a plague of locusts (much, in fact, as humans seem to being doing on our own). In the movie ET (1982), the extraterrestrial is a cute and cuddly creature that befriends our children and experiences homesickness. Once we have determined that the extraterrestrials do not eat humans, it should be a lot of fun, assuming that they are technologically superior, and we cannot harm them.
In her Hugo Award-winning science fiction book The Sparrow (1996), and its sequel Children of God (1998), anthropologist Mary Doria Russell explores what it might mean for technologically advanced humans to make first contact with an intelligent, but technologically inferior civilization on another planet. The book is written as an allegory of the Europeanâ€™s discoveries of the Americas during the 16th century. With all of the best intentions, the Jesuit mission to the planet Rakat ends in failure. One tortured and traumatized priest returns from the expedition. In the process, the missionaries have misunderstood the social ecology of the aliens and made a mess of someone elseâ€™s planet, even as life back on Earth has become pretty miserable. Russell helps us explore profound theological, environmental, and anthropological questions and shows how imagining other worlds is a powerful tool for re-imagining ourselves.
Certainly new modes of religiosity have and will continue to develop around the insights and metaphors offered by astronomy and astrobiology. We need not think only of the extremes like UFO cults and the Heavenâ€™s Gate suicides. The popularity of Star Trek is itself a phenomenon that can be analyzed through religious categories and has generated a number of scholarly explorations.11
In general, the category of religion needs to be greatly expanded. For instance, many of the tools of religious studies can be used to analyze and understand the complex dynamics of an organization like SETI Institute or the culture and motivations of NASA scientists. I sensed my hosts would not appreciate this kind of psycho-social-symbolic critical analysis. Scientists often presume to have immaculate perception/conception devoid of the messy world of politics, personalities, and power. The presumption is not wholly without warrant, hence my critical realist enthusiasm for science, but the presumption of immaculate perception/conception tends to make one blind to the impact of metaphors, values, beliefs, rituals, bias, politics, economics, and hierarchies within the scientific enterprise itself.
For instance, many of the scientists at the astrobiology gathering used the term â€œsecond genesisâ€ to describe the discovery of distinctly different life beyond Earth. I found the term unnecessarily loaded with baggage and perhaps problematic in terms of societal impact, thinking in particular of the Muslim and Christian mythological literalists. While we are at it, letâ€™s ban the term â€œcolonizeâ€ from the discourse. Most of our fellow humans do not have fond memories of colonization and would not respond favorably to the notion of our â€œcolonizingâ€ other planets.
While NASA and SETI researchers are not likely to find extraterrestrial intelligence, there is a good chance that we will soon find microbes elsewhere in the Solar System. And if the extraterrestrials are just â€œsimpleâ€ microbes, we should stop and reflect that our bodies are simply a collection of cells, tissues and microbes, which turn out to be fantastically complicated. Somehow scientists need to impact society so as to cultivate a fuller popular appreciation of miraculous microbes here at home as well as those that we may soon discover out there.
Whether or not microbial life exists on Mars, there is the question of whether humans should try to â€œimproveâ€ that planet. NASA scientists have identified terrestrial life forms that might grow in the extreme Martian environment. â€œSeedingâ€ these extremophiles on Mars is well within our current technological capabilities. It would be an irreversible experiment, but one that might yield benefits. For instance, jump-starting photosynthesis on Mars would â€œimproveâ€ the atmosphere. Perhaps this once living planet, if indeed it ever did support life, can be reclaimed through â€œterra-formingâ€ Mars in our own image. What, if any, scientific and ethical restrictions should be placed on such activities. How would we calculate the cost-benefit factors? Who decides and how?
Chris McKay is a planetary scientist working at NASA Ames Research Center. McKay is himself something of a human extremophile, with the appearances of someone just returned from an expedition to Antarctica and about to depart for some deep-sea vent. McKay has thought a lot about these scientific questions and ethical implications. He argued that we should be guided by the principle of enhancing the richness and diversity of life in the universe. Implied in this principle are two potentially conflicting goals: 1) that we should search for and support life on other worlds and 2) that we should expand life from Earth.12 As someone influenced by the process philosophy of Alfred North Whitehead and the evolutionary teleology of Pierre Teilhard de Chardin, I can only applaud the principle, support the goals, and appreciate the inevitable ambiguity.
One of our hosts at the SETI Institute was Frank Drake, who has been involved in searching for extraterrestrial intelligence since 1960. Drake is a thoughtful and elderly radio astronomer. He spent most of his time at our consultation listening to the conversation from the sidelines, no doubt looking for signs of intelligence among the alien philosophers and humanists in attendance. Drake is famous in this community for â€œthe Drake Equation,â€ which estimates the number of planets in our galaxy that might host intelligent extraterrestrial life. The equation reads:
N in this equation represents the number of civilizations in the galaxy with whom communication might be possible. R* is the rate of formation of suitable stars such as our Sun. Æ’p is the fraction of those stars with planets. ne is the number of Earth-like worlds per planetary system. Æ’l is the fraction of those Earth-like planets where life develops. Æ’i is the fraction of life sites where intelligence develops. Æ’c is the fraction of intelligence out there that develops electromagnetic communications technologies that might allow intentional or unintentional detection elsewhere in the galaxy. L is the “lifetime” of communicating civilizations. Drake postulated in the midst of the nuclear arms race that there was a tendency of advanced civilizations to destroy themselves. He called this â€œthe Great Filter.â€
Drakeâ€™s Equation has been much debated and modified over the years. All of the values are open to conjecture and unknown probabilities. Nevertheless, we are making progress in identifying exoplanets and complex chemistry in our galaxy. Even with low probability values assigned, the implications are that there are a lot of communicative civilizations out there somewhere waiting to discover us or be discovered by us.
For practical reasons, SETI focuses it search for communicative civilizations to Sun-like stars within 50 light-years from Earth. Given that the Milky Way Galaxy is 100,000 light-years in diameter and contains over 200 billion stars, we have a lot of searching to do.13
In my mind, the most depressing bit of science ever discovered is the speed of light, known as the â€œconstantâ€ in Einsteinâ€™s famous equation E=mc2. The speed of light is constant at 186,282 miles per second. We know of nothing that goes faster. As matter accelerates towards the speed of light, it also approaches infinite mass. In other words, we cannot send humans or robotic probes out into the universe at anything approaching the speed of light; and even if we did, human lifespan would mean these were one-way trips over many generations through the extremely hostile environment of outer space. It looks like fun on Star Trek, but it ainâ€™t happeninâ€™, not if the fundamental laws of physics really are the last word.
We live in an enormous universe â€“ 13 billion light-years old (i.e., 31,557,600 seconds per year x 186,282 miles per second x ~13 billion = a ridiculously long road trip). Why is this depressing? It is not because we are small; on the contrary, our minds are enormous and able to discover and contemplate this incredible reality. It is depressing because our really big universe is probably full of all kinds of really interesting places and indeed intelligences; but we will have no possibility of traveling across this vast space-time scale, let alone exchanging communications with nearby communicative civilizations in our own corner of the galaxy. Unless the fundamental laws of physics are not the whole story, then we are stuck here in this solar system â€“ forever. So I am not likely to lose my bet or right arm, but I would prefer to be wrong about this very sad state of affairs. For all practical purposes, we are alone in a universe that is full of other life and other intelligence.
Which brings me back to space junk. It is all fine and well to imagine our future beyond the stars, and maybe we will get there. Maybe there will be a revolutionary discovery in fundamental laws of physics leading to new technologies and new possibilities. I also want to enhance the richness and diversity of life in the universe. But if we pollute the orbital space around the Earth much more we will be stuck on the ground for a long time to come. The U.S. military tracks some 17,000 pieces of space trash larger than 2-4 inches in diameter. Most of this is in the zone of 300 to 500 miles above the Earth, where most of the communications satellites are in orbit. There are 905 satellites operating in space orbit at this time, satellites which make possible many of the wonders of global communications technology.14
Space debris includes entire spent rocket stages, slag for solid rocket motors, coolants released by nuclear powered satellites, paint flakes, and dust. Space debris also includes the remains of U.S., Soviet, and Chinese anti-satellite weapon tests. Astronauts have also created space debris by intentionally jettisoning garbage bags from the Soviet Mir space station to unintentionally dropping tools and cameras during space walks. If we are lucky, the debris soon falls into the Earthâ€™s atmosphere where it is burned up. If we are unlucky, the debris will remain in orbit for thousands of years.
There is a lot of space up there to contain all of this junk, but not if it grows exponentially. In 1991, NASA consultant Donald J. Kessler wrote a paper entitled â€œCollisional Cascading: The Limits of Population Growth in Low Earth Orbitâ€. Kessler calculated a scenario in which orbital collisions with space junk would increase in a run away feedback loop rendering the orbital zones extremely dangerous to humans and their machines. The theory is now referred to as the Kessler Syndrome. The February 10, 2009, satellite collision dramatically increased the volume of space junk, generating three-times as much space junk for instance as the January 2007 Chinese testing of an anti-satellite weapon. This means more high-speed shrapnel careening around in Earth orbit with an increased probability of destroying other satellites, which would then increase the probability again in a runaway exponential feedback loop of high-speed trash colliding in Earth orbit. Some day we will reach a threshold event that tilts the whole low orbital space towards this horrifying prospect.
Scientists are beginning to think about ways to clean up space junk, but it is certain to be difficult and expensive. I am reminded of the Pixar animated-movie WALL-E (2008), which depicts Earth orbit as full of this deadly debris, even as the surface of the 29th century Earth is devoid of life and covered with trash. WALL-E is the only surviving trash-compactor robot on Earth. His only companion is a cockroach, who feeds on centuries old Tasty-Kakes that WALL-E finds on his daily rounds through the trash piles. The surviving humans live in outer space in Axiom â€“ a kind of â€œCarnival Cruise Space Shipâ€. All of their needs are taken care of by robots. The humans have devolved into stupid, obese blobs, who float around communicating through video screens, largely dumb and passive in the unfolding drama. The robots have been programmed to support the Prime Directive, finding and restoring life on Earth and returning humans safely, while the humans have all but forgotten what they themselves destroyed. When WALL-E meets the robot EVE, an Extraterrestrial Vegetation Evaluator, come to scan Earth for signs of life, the robotic love story and redemptive adventure begin. WALL-E and EVE are the new Adam and the new Eve. In the end, the spaceship Axiom becomes a new Noahâ€™s Ark, returned to Earth to begin the restoration of the abandoned planet. The optimism of the story is placed centuries in the future, as the authors present our short-term prospects in incredibly grim and depressing terms.
Far from escaping our terrestrial problems, we are taking these problems with us into outer space. If Earthlings make a mess of Earth, then the Earthlings are sure to make a mess of space. Perhaps we will yet take our trash to Mars and elsewhere in our solar system. There will be no escape from being human, all too human sometimes.
As I listened to the presentations and debated the societal implications of astrobiology, I was impressed by the science and the scientists. Their work requires a great deal of intelligence, but also admirable dedication and long-hours. It would be encouraging not just to speculate, but to somehow actually discover that the universe is bio-friendly. The NASA scientists I encountered were certainly bio-friendly, so maybe that is proof enough. I wish them luck and am glad to support this work.
And while I was grateful for the chance to expand my intellectual horizons, I kept thinking back to the L variable in the Drake Equation. What is the lifetime of our communicative civilization? Will our civilization make it through the 21st century intact? Is there a â€œGreat Filterâ€ of self-destruction that limits the life expectancy of intelligent life in the universe? Are we ourselves not approaching just such a â€œGreat Filterâ€ in our own cultural evolution and the history of our planet?
It is not the terra-forming of Mars that keeps me awake at night, but the anthro-forming of Terra that darkens my dreams. Can human civilization be more civil and more bio-friendly? We need to get serious about enhancing the richness and diversity of life of Earth, if we ever hope to do so elsewhere in the universe. Maybe the most significant societal impact of astrobiology is the opportunity to look back at ourselves and to appreciate in new ways the extreme good fortune we have of being able to call ourselves Earthlings.
1 Marks, Paul (2009) Satellite collision ‘more powerful than China’s ASAT test’. New Scientist, DOI: http://www.newscientist.com/article/dn16604-satellite-collision-more-powerful-than-chinas-sat-test.html. See also Iannotta, Becky and Tariq Malik (2009) U.S. Satellite Destroyed in Space Collision. Space.com, DOI: http://www.space.com/news/090211-satellite-collision.html.
2 Kinetic Energy (Joules) = Â½ Mass (kilograms) * Velocity (meters per second)2. A steel BB used in shotguns weighs about .4 grams (25 pellets per 10 grams) or .0004 kilograms. 42120 kph = 11700 mps. Ergo Joules = .5*.0004*117002 = 27378 Joules of Kinetic Energy. A 100 pound cannon ball is 45 kilograms. Doing some simple algebra, I calculated that to equal 27378 Joules of kinetic energy, the 45 kilogram cannon ball would need to be traveling at 34.88 mps or 78 miles per hour..
5 Dick, Steven J. (1982). Plurality of Worlds: The Origins of the Extraterrestrial Life Debate from Democritus to Kant. New York, Cambridge University Press; Dick, Steven J. (1996). The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science. New York, Cambridge University Press; Dick, Steven J. (2000). Many Worlds: The New Universe, Extraterrestrial Life and the Theological Implications. Conshohocken, PA, Templeton Foundation Press; and Dick, Steven J. and Roger D. Launius, Ed. (2007). Societal Impact of Spaceflight. Washington, D.C., NASA.
6 Tenenbaum, David. (2008, 2/18/2008). “Amino Acid Ingredients Found in Distant Galaxy.” Astrobiology Magazine Retrieved 2/20/2009, 2009, from http://www.astrobio.net/news/index.php?name=News&file=article&sid=2623&theme=Printer .
7McKay, Christopher P. (2009). Astrobiology and Society: The Long View. Workshop to Develop an Astrobiology Roadmap of Societal Issues. SETI Institute, Mountain View, CA. See also McKay, Christopher P. (2009). “Biologically Reversible Exploration.” Science 323: 718.
8“Allan Hills 84001.”(2009). Retrieved 2/16/2009, 2009, from http://en.wikipedia.org/wiki/Allan_Hills_84001 .
10 See for instance, Ross Kraemer, William Cassidy, Susan L. Schwartz (2003). Religions of Star Trek. Boulder, Westview Press; Jennifer E. Porter and Darcee L. McLaren, Ed. (2000). Star Trek and Sacred Ground: Explorations of Star Trek, Religion, and American Culture. Albany, State University of New York Press; and Jon Wagner and Jan Lundeen (1998). Deep Space and Sacred Time: Star Trek in the American Mythos. Westport, CT, Praeger.
14 Union of Concerned Scientists (2009). UCS Satellite Database http://www.ucsusa.org/nuclear_weapons_and_global_security/space_weapons/technical_issues/ucs-satellite-database.html
Des Marais, David J., Josepth A Nuth III (2008). “The NASA Astrobiology Roadmay.” Astrobiology 8(4): 715-730.
Dick, Steven J. (1982). Plurality of Worlds: The Origins of the Extraterrestrial Life Debate from Democritus to Kant. New York, Cambridge University Press.
Dick, Steven J. (1996). The Biological Universe: The Twentieth Century Extraterrestrial Life Debate and the Limits of Science. New York, Cambridge University Press.
Dick, Steven J. (2000). Cultural Aspects of Astrobiology: A Preliminary Reconnaissance at the Turn of the Millenium. ASP Conference Series.
Dick, Steven J. (2000). Many Worlds: The New Universe, Extraterrestrial Life and the Theological Implications. Conshohocken, PA, Templeton Foundation Press.
Dick, Steven J. and James Strick (2005). The Living Universe: NASA and the Development of Astrobiology. New Brunswick, NJ, Rutgers University Press.
Dick, Steven J. and Roger D. Launius, Ed. (2007). Societal Impact of Spaceflight. Washington, D.C., NASA.
Emmerich, Roland (1996). Independence Day. USA, 20th Century Fox: 145.
Iannotta, Becky and Tariq Malik (2009) U.S. Satellite Destroyed in Space Collision. Space.com, Retrieved 2/16/2009: http://www.space.com/news/090211-satellite-collision.html
Kessler, Donald J. (1991). “Collisional Cascading: The Limits of Population Growth in Low Earth Orbit”.” Advances in Space Research 11(12): 63-66.
Kraemer, Ross, William Cassidy, Susan L. Schwartz (2003). Religions of Star Trek. Boulder, Westview Press.
Marks, Paul (2009) Satellite collision ‘more powerful than China’s ASAT test’. New Scientists, Retrieved 2/16/2009: http://www.newscientist.com/article/dn16604-satellite-collision-more-powerful-than-chinas-asat-test.html.
McKay, Christopher P. (2009). Astrobiology and Society: The Long View. Workshop to Develop an Astrobiology Roadmap of Societal Issues. SETI Institute, Mountain View, CA.
McKay, Christopher P. (2009). “Biologically Reversible Exploration.” Science 323: 718.
Morris, Simon Conway (2003). Life’s Solution: Inevitable Humans in a Lonely Universe. New York, Cambridge University Press.
Porter, Jennifer E. and Darcee L. McLaren, Ed. (2000). Star Trek and Sacred Ground: Explorations of Star Trek, Religion, and American Culture. Albany, State University of New York Press.
Rummell, John (2009). NASA’s Astrobiology Program: Implementation, Truth, and Consequences. Workshop to Develop an Astrobiology Roadmap of Societal Issues. SETI Institute, Mountain View, CA.
Sagan, Carl (1985). Contact. New York, Pocket Books.
Spielberg, Steven (1982). E.T. – The Extra-Terrestrial. USA, Universal Studios.
Stanton, Andrew (2008). Wall-E. USA, Walt Disney Studios: 98.
Tenenbaum, David. (2008, 2/18/2008). “Amino Acid Ingredients Found in Distant Galaxy.” Astrobiology Magazine Retrieved 2/20/2009, 2009, from http://www.astrobio.net/news/index.php?name=News&file=article&sid=2623&theme=Printer .
Union of Concerned Scientists (2009). UCS Satellite Database http://www.ucsusa.org/nuclear_weapons_and_global_security/space_weapons/technical_issues/ucs-satellite-database.html.
Wagner, Jon and Jan Lundeen (1998). Deep Space and Sacred Time: Star Trek in the American Mythos. Westport, CT, Praeger.
Wikipedia (2000) “Allan Hills 84001.” Retrieved 2/16/2009, from http://en.wikipedia.org/wiki/Allan_Hills_84001
Wikipedia (2009). â€œDrake Equationâ€. Retrieved 2/16/2009, from http://en.wikipedia.org/wiki/Drake_equation .
Zemeckis, Robert (1997). Contact. USA, Warner Brothers: 153.