Over the next million years, a descendant of the Internet will maintain contact with inhabited planets throughout our galaxy and begin to spread out into the larger universe, linking up countless new or existing civilizations into the Universenet, a network of ultimate intelligence. (updated)
July 4, 2010 by Amara D. Angelica
Original link: http://www.kurzweilai.net/communicating-with-the-universe
Originally published in Year Million: Science at the Far Edge of Knowledge.
The Earth has already input information to the Universenet. Whenever microwave towers or satellites send Internet traffic, some of the energy leaks off, transmitting data unintentionally into space. The first email messages transmitted via microwave towers in 1969 by the predecessor of the Internet, ARPANET, have (theoretically) traveled thirty-nine light-years so far, way past the nearest star system, Alpha Centauri, four light-years away. In practice, such feeble signals are probably buried in cosmic radio noise.
Now NASA plans to do it intentionally. The Interplanetary Internet (IPI) should allow NASA to link up the Internets of Earth, spacecraft, and eventually Moon, Mars, and beyond.[1] By the Year Million, billions of “smart dust” sensors will be connected to a distant descendant of the IPI, exchanging data in real time or via store-and-forward protocol or wireless mesh (a network that handles many-to-many connections and is capable of dynamically updating and optimizing these connections), on planets and in spacecraft.[2]
Meanwhile, one important near-future use will be for tracking asteroids, comets, and space junk, exchanging three-dimensional position location and time data (similar to GPS on Earth) via multiple hops between sensors. Once affordable personal space travel is available, the IPI could serve as the core of an interplanetary version of air traffic control. The IPI scheme could also become the standard communications protocol as we expand out beyond the solar system’s planets, and then beyond the stars and to other galaxies. We could start with possibly habitable planets beyond the solar system, such as Gliese 581d, the third planet of the red dwarf star Gliese 581 (about twenty light-years away from Earth), if we detect signs of intelligent life there.
But using radio waves or lasers to communicate with civilizations around other stars, let alone in other galaxies, requires huge amounts of energy. Exactly how much energy? That depends mainly on distance, frequency, directional efficiency of antennas, and assumed ability of the receiving civilization to detect signals amid the extreme electromagnetic noise of space. In 1974, the Arecibo telescope beamed a 210-byte radio message aimed at the globular star cluster M13, some twenty-five thousand light-years away. It was transmitted with a power of one megawatt-enough energy to power about one thousand homes, using a narrow beam to achieve an EIRP (effective isotropic radiated power) of 20 trillion watts. That made it the strongest human-made signal ever sent. (It has gone 0.14 percent of the way, so far.)
Arecibo uses a large dish. Another way to create a narrow beam of high-power microwave radio energy is to build a phased-array antenna with multiple dishes spread out over a large area. These could be located on the Moon or at a Lagrange point (one of the stable locations in the Earth-Moon-Sun axis). Or a high-powered laser could be used. How highly powered? Looking toward the Year Million, as we reach out to communication nodes orbiting more distant stars, or in other galaxies, we will need to use a lot of power-as much as the entire power of the Sun. A civilization able to do that kind of cosmic engineering is referred to as Kardashev Type II, or KT-II.
By modest contrast, our civilization used about fifteen terawatt-hours in 2004 (a terawatt-hour is one billion kilowatt-hours) of electrical power.[3] New York University Physics Professor Emeritus Martin Hoffert and other scientists calculate that if our power consumption grows by just two percent per year, then in just four hundred years we will need all the solar power received by the Earth (1016 watts = 10,000 terawatts). And in a thousand years, we’ll require all of the power of the Sun (4×1026 watts).[4] Hoffert and other scientists propose space-based solar power as one major future solution. Solar flux is eight times higher in space than the surface average on cloudy Earth and available 24 hours a day, unlike solar energy panels on Earth. Power satellites located in geosynchronous orbit (like communication satellites) would use a bank of photovoltaic receptors to convert the Sun’s energy to radio waves. This energy would be beamed wirelessly down to a large “rectenna” or rectifying antenna where the incoming microwave energy is rectified (converted) for use in the electrical power grid on Earth, turning it to electricity for distribution. Alternatively, laser beams could replace radio-frequency signals.[5] Once the infrastructure is in place for economically launching space-based solar power satellites, the same types of microwave or laser systems could be aimed at the stars for communicating elsewhere.
Eventually, when we have become first a KT-I and then a KT-II civilization, we will reach even farther out to supergalaxies and even to clusters of supergalaxies, which could require a Type III civilization-one capable of controlling the power of an entire galaxy, some 1036 watts. The communication latencies (transmission delays) for such a system would be millions or even hundred of millions of years. (Two-way latency is already a problem for astronauts in the solar system, increasing as we transmit information to places farther from the Earth, or wherever humans and posthumans end up, perhaps uploaded into a Matrioshka brain that will have replaced the existing solar system.) Even the nearest star, Alpha Centauri, could not reply to a message sooner than eight years after it was sent. Talk about bad netiquette.
Possibly the denizens of the Year Million will solve this time lag with extreme cosmic engineering feats such as wormholes, or even communication via parallel universes.[6] One intriguing possibility is the use of quantum entanglement-that is, allowing an entangled atom or photon to carry information across a distance, theoretically anywhere in the universe (once the initial photons have been received), or “spooky action-at-a-distance,” as Einstein called it.[7] An experiment testing the possibility of communication using this principle is in progress in the Laser Physics Facility at the University of Washington by professor John G. Cramer.[8] Cramer astonished physicists at a joint American Institute of Physics/American Association for the Advancement of Science conference in 2006 by presenting experimental evidence that the outcome of a laser experiment could be affected by a future measurement: a message was sent to a time fifty microseconds in the past.[9] This leads to an even more bizarre idea: retrocausal communication-the future affecting the past, as theoretical physicist Jack Sarfatti (the inspiration for Doc in the movie Back to the Future) has proposed.[10] So in principle, perhaps one could bypass the speed-of-light limitation and have messages show up in a distant galaxy long before they could have been received by radio or laser transmission, or even before they were sent!
Web to ET: Download This
Humans might not be the first technological species to explore the galaxy. Suppose alien probes await us in orbit or on the Moon (like the obelisk in Arthur C. Clarke’s “The Sentinel” and its movie version, 2001: A Space Odyssey) or at Lagrange points.[11] If so, we might only need to respond with the right signals to trigger a connection-similar to logging on to an FTP server with the right IP address, user name, and password. Such probes might even now be scattered around the solar system as smart dust particles that we haven’t yet analyzed. IBM has developed a prototype of a molecular switch that could replace current silicon-based chip technology with atom-based processors, making it theoretically possible to run a supercomputer on a chip the size of a speck of dust. IBM is also developing technology to store a bit on a single atom, portending hard drives that can pack up to a thousand times as much information on a hard disk as current technologies.[12]
Instead of transmitting via radio or laser, sending a physical data spore might be a simpler and more effective alternative. Rutgers University electrical engineer Christopher Rose has shown that for long messages conveyed across long distances (where transmitting a signal would be extremely expensive, have limited range, or be too hard to find), it is more effective to send physical messages than transmit them. That was one rationale for sending the greeting plaque on Pioneer 10 and 11 in 1972 and 1973, and a more complex inscribed disk on the Voyager probe in 1977. Rose thinks there could be such inscribed objects now orbiting planets in our solar system, or on asteroids.[13]
But transmitting information into space still fires up the imagination of several scientists. SETI senior astronomer Seth Shostak has proposed that rather than sending simple coded messages, why not just feed the Google servers into the transmitter and send the aliens the entire Web? It would take about half a year to transmit the Web in the microwave region at one megabyte a second; infrared lasers operating at a gigabyte per second would shorten the broadcast time to no more than two days.[14] Transmitting the Web into space could also serve as a backup for civilization. William E. Burrows has suggested creating a self-sufficient colony on the Moon where a “backup drive” could store the history and wisdom of civilization in case a calamity strikes Earth.[15] To achieve this, Burrows set up an organization, Alliance to Rescue Civilization (ARC), subsequently absorbed by the Lifeboat Foundation, which is developing solutions to prevent the extinction of mankind. Acquiring knowledge from ancient extraterrestrial civilizations could be critical to our long-term human survival, says Lifeboat Foundation president Eric Klien. “The Universenet could give us the final signals of a civilization right before it destroyed itself,” he wrote in a Skype message. “We could use this information to avoid our own destruction, perhaps the most important reason to continue the SETI project. If we learned that a civilization was destroyed by, say, nanoweapons, we could start creating defenses against this situation.”[16]
Such signals might not be obvious. For example, pulsars, discovered in 1967, are rotating neutron stars that emit electromagnetic waves. Their rapid rotation causes their radiation to become pulsed. Could this radiation be modulated deliberately to form a sort of cosmic transmitter? Astronomers at first thought the pulses meant they might be ET; so far, they haven’t found any evidence of an actual message. Or are there encoded messages too subtle to detect? And pulsars are far from the most powerful possible signal sources from space. Quasars can release the energy equal to hundreds of average galaxies combined, equivalent to one trillion suns. Could they be galactic Web sites run by Type III civilizations? (Unlikely, since most quasars are very far away, which means distant in time, and seem to have been formed not long after the emergence of the universe from the Big Bang.)
Computer scientist Stephen Wolfram believes current methods used in SETI are inefficient and unlikely to produce reliable results because our detection methods seek to detect only regular patterns. A more efficient method would use sophisticated, noise-immune coding, producing something similar to spread spectrum signals. To SETI’s present system of analysis this kind of signal sounds and looks like random noise, and would be overlooked and discarded.[17] Wolfram suggests we need more sophisticated software-based signal processing. Maybe we need someone like Hedy Lamarr, the brilliant actress who famously said, “Any girl can be glamorous; all she has to do is stand still and look stupid,” and then went on to invent spread spectrum technology. Could ET be using it? There’s no way to know with the current SETI technology. Complex artifacts made by an advanced civilization could look very much like natural objects, Wolfram argues. Could the stars themselves be extraterrestrial artifacts? “They could have been built for a purpose,” says Wolfram. “It’s extremely difficult to rule it out.”[18]
Is Alien Intelligence Hidden in Junk DNA?
Cardiff University astronomer and mathematics professor Chandra Wickramasinghe, a long-time collaborator with the late cosmologist Sir Fred Hoyle, has suggested that life on this planet began on comets, since their combination of clay and water is an ideal breeding ground for life. He believes that explanation to be a quadrillion times more likely than Earth’s having spawned life.[19] If that’s the case, then comets and asteroids could be carrying physical messages, a sort of “sneakernet”-physical file sharing in the interests of added security-for the Universenet.
Astrobiologist Paul Davies, now at Arizona State University, suggests that ET could embed messages in highly conserved sections of viral DNA-most likely in its so-called “junk” sections-and send them out as hitchhikers on asteroids or comets. (Genomics researchers at the Lawrence Berkeley National Laboratory in California, who compared human and mouse DNA, have reported millions of base pairs of highly conserved sequences of junk DNA, meaning they have a survival value).[20] These messages could even have been incorporated into terrestrial life, Davies thinks, and lurk in our DNA, awaiting interpretation. (There could be an interesting d-mail-DNA-mail-waiting to be discovered as we search through the decoded genome.) Rather than beaming information randomly in the hope that somewhere, someday, an intelligent species will decode them, this method would use a pre-existing “legion of small, cheap, self-repairing and self-replicating machines that can keep editing and copying information and perpetuate themselves over immense durations in the face of unforeseen environmental hazards. Fortunately, such machines already exist. They are called living cells.”[21]
Transmitting People to the Stars
Futurist/inventor Ray Kurzweil has suggested that once the intelligent life on a planet invents machine computation, it is only a matter of a few centuries before its intelligence saturates the matter and energy in its vicinity. At that point, he suggests, nanobots will be dispersed like the spores of plants. This colonization will eventually expand outward, approaching the speed of light (as discussed in Robin Hanson’s Chapter 9).[22] In Fred Hoyle and John Elliot’s 1962 novel A For Andromeda, a radio signal from the direction of the galaxy M31 in Andromeda gives scientists a computer program for the creation of a living organism, adapting borrowed human DNA. They name this young cloned woman Andromeda, and through her agency the computer tries to take over the world.[23] Author James Gardner has seriously suggested a version of such “interstellar cloning”: an advanced civilization could transmit a software program to us with instructions on replicating its own inhabitants-even an entire civilization.[24]
Dr. Martine Rothblatt, who founded Sirius Satellite and other satellite companies, has suggested a related method for connecting with Universenet: sending bemes or units of being-highly individual elements of personality, mannerisms, feelings, recollections, beliefs, values, and attitudes. Bemes are fundamental, transmittable, mutable units of being-ness in the spirit of memes (Richard Dawkins’s term for the replicators of cultural information that a mind transmits, verbally or by demonstration, to another mind). The main difference is that memes are culturally transmittable elements that have common meanings, whereas bemes reflect individual characteristics.
Rothblatt suggests that a new Beme Neural Architecture (BNA) will outcompete DNA in populating the universe. “At any moment, and certainly at some moment, a giant star in our general stellar neighborhood will blow up and thereby fry everything in its vicinity,” she points out. Some of these explosions, known as gamma-ray bursts, are so violent that they damage everything within hundreds of light-years. Yet there are two or three gamma-ray bursts somewhere in the observable universe every day and about one thousand less-explosive but still life-ending supernovae every day throughout the galaxies (that we can observe). One explanation for the Fermi Paradox-why is there no evidence of ET, although the galaxy seems capable of so many extraterrestrial civilizations-is that sooner or later a supernova nabs everyone’s life zone. “Perhaps the only way we can survive the risk of astrobiological or mega-volcanic catastrophe is to spread ourselves out among the stars,” Rothblatt suggests. And as self-replicating code, bemes are much more quickly assembled, replicated, and transported than genes strung along chromosomes and transmitted by sex. Computer technology is vastly more efficient than wet biology in copying information. Expressed in digital bits rather than in nucleotide base pairs, information can be transported farther (beyond Earth to evade killer asteroid impacts) and faster (at the speed of light).
DNA is not well suited for space travel. It can replicate effectively only within bodies. Humans require vast quantities of life-preserving supplies and besides, at the moment, we don’t live long enough to make the journey to other stars (a factor, as Pamela Sargent notes in the previous chapter, that is subject to change). On the other hand, by replicating our minds into BNA and storing them in a computer substrate, we can travel far longer and far faster, since we would be traveling with minimal mass in seeds or spores. Arriving at a promising planet, our BNA can be loaded into nanotech-built machine bodies to prepare a new home. Once that home flourishes, human (and other) DNA can be reconstructed from either stored samples or digital codes and basic chemicals, which can be nurtured into mature bodies free to develop their own minds or to receive a transfer of a BNA mind.
Alternatively, Rothblatt suggests that just by spacecasting your bemes, you can already achieve a level of immortality, and so can all of humanity. In March 2007, Rothblatt’s CyBeRev Project began experimentally spacecasting bemes in the form of digitized video, audio, text, personality tests, and other recordings, of attributes of a person’s being, such as memories, mannerisms, personality, feelings, recollections, beliefs, attitudes, and values.[25] These bemes are transmitted out into the universe via a microwave dish normally used to communicate with satellites. Any spacecast signal, she speculates, has a chance of being decoded from the background cosmic noise in the same way a cellphone’s CDMA (spread spectrum) encoded signal is decoded out of random electromagnetic noise. Your bemes could then be interpreted, and yourself recreated from the transmission. This requires interception by an advanced, intelligent civilization that would receive and decode the signals, then instantiate the bemes as either a regenerated traditional cellular or a bionanotechnological, body. (If this happened, we might find by the Year Million that the galaxy is swarming with other humans downloaded by far-flung extraterrestrials or their machines.)
Each spacecast of an individual’s bemes is accompanied by an informed-consent form authorizing that individual’s re-instantiation from the transmitted bemes. The CyBeRev project is based on the hypothesis that advanced intelligence will respect sentient autonomy and be capable of filling in the blanks of a person’s consciousness via interpolation of the spacecast bemes, using background cultural information transmitted from Earth. The project’s backers do not believe extraterrestrials will unethically revive persons such as television personalities whose images, behavior, and personal information have been telecast, but who have not authorized their re-instantiation. Still, such cultural transmissions will be useful in the aggregate, providing revived spacecasters with a familiar environment. “Given the vast amount of television and Internet information streaming into space, the revivers of our spacecasters will have abundant contextual information with which to work,” concluded Rothblatt.[26]
Programming the Universe
By converting matter into what some futurists call computronium (hypothetical material designed to be an optimized computational substrate), Year Million scientists could create the beginnings of an ultimately powerful computer.[27] Taking it to the extreme, MIT scientist Seth Lloyd has calculated that a computer made up of all the energy in the entire known universe (that is, within the visible “horizon” of forty-two billion light-years) can store about 1092105 computations/second.[28] The universe itself is a quantum computer, he says, and it has made a mind-boggling 10122 computations since the Big Bang (for that part of the universe within the “horizon”).[29] Compare that to about 2×1028 operations performed over the entire history of computation on Earth (“because of Moore’s law, half of this computation has taken place in the last year and a half,” he wrote in 2006). What’s more, the observable horizon of the universe, space itself, is expanding at three times the speed of light (in three dimensions), so the amount of computation performable within the horizon increases over time.
Lloyd has also proposed that a black hole could serve as a quantum computer and data storage bank. In black holes, he says, Hawking radiation, which escapes the black hole, unintentionally carries information about material inside the black hole. This is because the matter falling into the black hole becomes entangled with the radiation leaving its vicinity, and this radiation captures information on nearly all the matter that falls into the black hole. “We might be able to figure out a way to essentially program the black hole by putting in the right collection of matter,” he suggests.[30]
There is a supermassive black hole in the center of our galaxy, perhaps the remnant of an ancient quasar. Will this become the mainframe and central file sharing system for galaxy hackers of the Year Million? What’s more, a swarm of ten thousand or more smaller black holes may be orbiting it.[31] Might they be able to act as distributed computing nodes and a storage network? Toward the Year Million, an archival network between stars and between galaxies could develop an Encyclopedia Universica, storing critical information about the universe at multiple redundant locations in those and many other black holes.
Clash of the Titans
Far beyond the Year Million, our galaxy faces a crisis. The supermassive black holes in our galaxy and the Andromeda galaxy are headed for a cosmic collision in two billion years. Will they have incompatible operating systems-a sort of Mac-versus-PC confrontation? (Of course, they might just pass by each other-or be steered past by hyperintelligent operators.)
In The Intelligent Universe, James Gardner adapted a bold notion originally proposed by cosmologist Lee Smolin. For Smolin, Darwinian principles constrain the nature of any universe such that new baby universes produced via black holes will resemble their parent cosmos, and will be surprisingly life-friendly as well. Gardner extends this idea into a fundamentally radical (but falsifiable) hypothesis called the Selfish Biocosm-the cosmological equivalent of Richard Dawkins’s selfish gene. The idea is that eventually intelligent life must acquire the capacity to shape the entire cosmos. In addition, the universe has a Smolin-style “utility function”: propagation of baby universes exhibiting the same life-friendly physical qualities as their parent-universe, including a system of physical laws and constants that enables life and intelligence to emerge and eventually repeat the cycle.
Under this scenario, the mission of sufficiently evolved intelligent life in the universe is to serve as a cosmic reproductive organ-the equivalent of DNA in living creatures-spawning an endless succession of life-friendly offspring that are themselves endowed with the same reproductive capacities as their predecessors. (Rothblatt’s BNA might well be the fundamental mechanism for this evolutionary process-veteran physicist John Wheeler’s legendary IT from BIT, things arising from information rather than the other way round).
Gardner believes that we’ve already received a message from ET: the laws and constants of our universe, including the inexplicable cosmological constant which at this time is accelerating cosmic expansion. His hypothesis makes sense of the observation that the constants seem rigged in favor of the emergence of life. For example, they are improbably hospitable to carbon-based intelligent life-an unlikely and as-yet unexplained anthropic oddity that some scientists have identified as the deepest mystery in all of science. As Gardner claims:
We are likely not alone in the universe, but are probably part of a vast-yet undiscovered-transterrestrial community of lives and intelligences spread across billions of galaxies and countless parsecs. . . . We share a possible common fate with that hypothesized community: to help shape the future of the universe and transform it from a collection of lifeless atoms into a vast, transcendent mind.In the Year Million, such a cosmic community will be linked up by the Universenet.
Notes
[1] In the late 1990s, Dr. Vint Cerf, who co-designed the Internet’s TCP/IP protocol, designed the Interplanetary Internet (IPN, http://www.ipnsig.org) to link up the Earth with other planets and spaceships in transit over millions of miles. Cerf’s clever scheme solved a big problem. With interplanetary communication delays-the average two-way latency (delay time) between Earth and Mars, 228 million km apart, is 25 minutes 21 seconds-the Internet TCP/IP protocol we use today would simply time out. Who has half an hour to wait for a carriage return? So Cerf and his team came up with a store-and-forward architecture-a sort of relay race. Transmit messages to an Earth-orbiting satellite, let’s say, and store them there until the next local pass of the Moon, which then transmits them to Mars.
[2] Tomas Krag and Sebastian Büettrich, “Wireless Mesh Networking,” O’Reilly Network, Jan. 22, 2004: http://www.oreillynet.com/pub/a/wireless/2004/01/22/wirelessmesh.html
[3] Energy Information Administration , U.S. Department of Energy: http://www.eia.doe.gov/emeu/international/electricityconsumption.html. The world electrical power generation is increasing by 2.4 percent per year (see http://www.eia.doe.gov/oiaf/ieo/electricity.html) and is expected to grow to thirty terawatt-hours in the year 2030.
[4] Martin I. Hoffert, et al, “Advanced Technology Paths to Global Climate Stability: Energy for a Greenhouse Planet,” Science, Vol. 298 (2002): 981-987. As Dougal Dixon notes in Chapter 2, we are running out of oil, and what is worse, many countries, especially China, are burning huge amounts of coal, increasingly polluting the atmosphere with toxins and carbon dioxide and accelerating global warming. It can only get worse: 850 new coal-fired power plants are to be built by 2012 by the United States, China, and India. Terrestrial solar installations, biofuel, wind power, and geothermal power will help, but they all have limitations (ground-based solar panels don’t work at night, for example) and, says Hoffert, can’t economically provide the amount of power needed, especially in Africa and Asia.
[5] Martin Hoffert, “Energy from Space,” Marshall Institute, Aug. 7, 2007, http://www.marshall.org/article.php?id=550
[6] John G. Cramer, “Wormholes and Time Machines,” Analog Science Fiction and Fact, June 1989, communication access via parallel universes, or retrocausal and faster-than-light (FTL) signaling John G. Cramer, “EPR Communication: Signals from the Future?,” Analog Science Fiction and Fact, December 2006, http://www.analogsf.com/0612/altview.shtml; Max Tegmark, “Parallel Universes,” Scientific American, May 2003.
[7] Seth Lloyd, Programming The Universe (New York: Knopf, 2006): 165.
[8] John G. Cramer, “An Experimental Test of Signaling using Quantum Nonlocality,” http://faculty.washington.edu/jcramer/NLS/NL_signal.htm.
[9] John G. Cramer, “Reverse Causation and the Transactional Interpretation of Quantum Mechanics, in Frontiers of Time: Retrocausation-Experiment and Theory,” in AIP Conference Proceedings, Vol. 263, ed. Daniel P. Sheehan (Melville, NY: AIP, 2006): 20-26; John G. Cramer, “Reverse Causation-EPR Communication: Signals from the Future?,” Analog Science Fiction and Fact, December 2006, http://www.analogsf.com/0612/altview.shtml; B. Dopfer, PhD Thesis, University of Innsbruck (1998); A. Zeilinger, Rev. Mod. Physics, 71, S288-S297 (1999).
[10] Jack Sarfatti, Super Cosmos (Author House, 2006): 20.
[11] Robert A. Freitas Jr. and Francisco Valdes, “The search for extraterrestrial artifacts (SETA),” Acta Astronautica, Vol. 12 (1985): 1027-1034.
[12] Peter Liljeroth, Jascha Repp, and Gerhard Meyer, “Current-Induced Hydrogen Tautomerization and Conductance Switching of Naphthalocyanine Molecules,” Science, Vol. 317. no. 5842, pp. 1203 – 1206, http://www.sciencemag.org/cgi/content/abstract/317/5842/1203
[13] Christopher Rose and Gregory Wright, “Inscribed Matter as an Energy Efficient Means of Communication with an Extraterrestrial Civilization,” Nature, Vol. 431, September 2004. http://www.winlab.rutgers.edu/~crose/papers/nature.pdf
[14] Seth Shostak, “What Do You Say to an Extraterrestrial?” SETI Institute News, December 2, 2004, http://www.seti.org/news/features/what-do-you-say-to-et.php
[15] William E. Burrows, The Survival Imperative: Using Space to Protect Earth (New York: Forge, 2006).
[16] Personal communication, September 3, 2007.
[17] Stephen Wolfram, A New Kind of Science (Wolfram Media, 2002): 1188, http://www.wolframscience.com/nksonline/page-1188b-text
[18] Marcus Chown, “Looking for Alien Intelligence in the Computational Universe,” New Scientist, November 26, 2005, http://www.newscientist.com/channel/fundamentals/mg18825271.600
[19] Hazel Muir, “Did Life Begin on Comets?” NewScientist.com news service, http://space.newscientist.com/channel/astronomy/astrobiology/dn12506, August 17, 2007.
[20] Mark Peplow, “ET Write Home,” Nature News, http://www.nature.com/news/2004/040830/full/040830-4.html, September 1, 2004.
[21] Paul Davies, “Do We Have to Spell It Out?” New Scientist, August 7, 2004, http://www.newscientist.com/article/mg18324595.300.
[22] Ray Kurzweil, The Singularity Is Near (Viking 2005).
[23] Fred Hoyle and John Elliot, A For Andromeda (Harper & Row, 1962), adapted from the 1961 BBC TV serial, now lost: http://www.imdb.com/title/tt0054511/
[24] James Gardner, The Intelligent Universe (New Page Books, 2007).
[25] In Chapter 7 of this book, Wil McCarthy estimates that people could store most of their memories in about two terabytes, which could be transmitted via satellite in just a few hours.[26] CyBeRev, Terasem Movement, Inc., http://www.cyberev.org
[27] http://en.wikipedia.org/wiki/Computronium
[28] Seth Lloyd, Programming The Universe (New York: Knopf, 2006): 165.
[29] Based on the Margolis-Levitin theorem: take the amount of energy within the horizon (1071 joules), multiply by 4, and divide by Planck’s constant. What has the universe computed? Itself. Seth Lloyd, Programming The Universe (New York: Knopf, 2006): 165-167.
[30] Maggie McKee, “Black Holes: The Ultimate Quantum Computers?” NewScientist.com news service, March 13, 2006, http://space.newscientist.com/article.ns?id=dn8836&feedId=online-news_rss20%3E
[31] “Chandra Finds Evidence for Swarm of Black Holes Near the Galactic Center,” January 12, 2005, http://www.sciencedaily.com/releases/2005/01/050111114024.htm
* http://www.amazon.com/Year-Million-Science-Edge-Knowledge/dp/1934633054/
© 2008 Amara D. Angelica
