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Jack Oughton - SETI And A Brief History Of The Search For Extra Terrestrial Life.doc
 

Jack Oughton - SETI And A Brief History Of The Search For Extra Terrestrial Life.doc

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    Jack Oughton - SETI And A Brief History Of The Search For Extra Terrestrial Life.doc Jack Oughton - SETI And A Brief History Of The Search For Extra Terrestrial Life.doc Document Transcript

    • Jack Oughton SETI There are few subjects to inspire the mind as much as the idea of finding intelligent life amongst the stars. What would a being from another world look like? What characteristics would we recognize in it? Would it have a personality? What could we learn from each other? Throughout human history, the belief in life beyond the creatures of the earth has been consistent, but harder to define. Ancient superstitions of supernatural beings, clearly identified as intelligent, though not so commonly believed in today, could be perceived as ‘alien’. Long before the modern and well developed idea of aliens that we identify with today; influenced by new media and films, some ancients wrote of men on other worlds. Indeed, many new age spiritual practices blur the line between spirituality and science on the matter, with many unorthodox belief systems such as Scientology taking hold in a more liberal intellectual climate. Some with more radical views look back retrospectively and believe that many of our prophets and old Gods where actually alien beings, arguing that such complicated creations as the pyramids could not have been created so early without outside assistancei (Daniken, 1990). The first known Western thinker to argue for a universe full of other planets and therefore, extraterrestrial life (the plurality of worlds) is the ancient Greek philosopher Thales. However, opponents to his theory, Plato and Aristotle, argue that the Earth is unique and that there can be no other systems of worlds. Eventually their views win this philosophical war, becoming remembered and seen as more credible, their belief in a unique earth endures. When their philosophy is adopted by the Church as religious dogma in the early first millennium, the unique earth theory is given a new centuries long lease of life, and arguments against it, effectively made illegal. Giordano Bruno, an Italian priest and cosmologer is burnt at the stake for heresy on February 17, 1600. His crimes include arguing that an infinitely large universe could contain an infinite number of planets, some which harbour life. Lucian, 800 years after Thales, writes of aliens on the moon in his work, A True Storyii, but only from what we would consider a fictional perspective. The spread of the telescope allows people to observe moons orbiting Jupiter, suddenly people realise that the dogma could be wrong. The subsequent overcoming of the geocentric theory undermines the premise which the Church has clung to for hundreds of years, and soon esteemed astronomers such as Kepler begin to suggest the possibility of alien life; “Each planet in turn, together with its occupants, is served by its own satellites. From this line of reasoning we deduce with the highest degree of probability that Jupiter is inhabited.”iii After this, the possibility of extra terrestrial life and intelligence is once again considered in the West. Thus, the belief in the idea of extra terrestrial intelligence, loosely defined, has persevered (even in the face of adversity) in some form for far longer than the organized scientific search of today. The historic debate continues, modern sceptics; proponents of the Rare Earth hypothesisiv claim sentient life is rare or nonexistent in the universe, while simple microbial life is more common. SETI scientists and supporters through their actions and arguments have more faith in finding extra terrestrial intelligence and could be described as modern pluralists. What? The Search For Extraterrestrial Intelligence (SETI) is the collective name for a number of activities to detect intelligent extraterrestrial life. The aim of the SETI projects is to detect extraterrestrial life,
    • and if possible, communicate with it (Communication With Extraterrestrial Intelligence – CETI, a branch of SETI’s research). Probably the most well known SETI organization of today is the SETI Institute, a non-profit Corporation founded in 1984, and based in California; “The mission of the SETI Institute is to explore, understand and explain the origin, nature and prevalence of life in the universe”v. However, SETI is established globally, for example, the SETI League is another non profit corporation based in New Jersey, and founded in 1994. It has branches worldwide, including a UK divisionvi, which co-ordinates the research efforts of British amateur radio astronomers. The hugely successful SETI@Home program has participants with the software installed from over 200 countriesvii. The origin of the modern SETI era can be placed to 1959. Cornell University physicists Giuseppi Cocconi and Philip Morrison published an article in Nature, “Searching for Interstellar Communications” in which they suggested the potential use of microwave signals for interstellar communication. ETI, they argued, would most likely broadcast at 1420 MHz; the emission frequency of hydrogen – the most abundant element in the universe. Soon after, in 1960, little known Cornell University astronomer Frank Drake performed the first modern SETI experiment; Project Ozma. Drake used the 25 meter radio receiver, the National Radio Astronomy Observatory at Green Bank, West Virginia, to examine the stars Tau Ceti and Epsilon Eridani at around 1420 MHz, he picked them because of their relative proximity of 11ly and similar ages to Sol. Though he found no alien signals he did accidentally detect a secret military transmission. Later that year Frank Drake wrote his now famous Drake Equation, which allows it’s user to speculate on how many communicable alien civilizations there may be, which he then presented to the first SETI meeting, held at Green Bank, in 1961. That same year, a paper was published which was the blueprint for future optical SETI research. (Dr. R. N. Schwartz, 1961)viii. SETI finally had established itself, with operating procedures to follow and scientific credibility. Arguably the only success SETI had was in 1977 with the ‘Wow Signal’. A strong, narrowband radio signal detected by Big Ear radio telescope at Ohio State University. It lasted 72 seconds, but despite recent efforts to find it has not been detected again. Project SERENDIP (Search for Extraterrestrial Radio Emissions From Nearby Developed Intelligent Populations): A ‘parasitical’ program that ‘borrows’ the radiotelescope at the National Radio Astronomy Observatory from other radioastronomical projects. It is able examine 168 million channels every 1.7 seconds. This parasite operating template has been modelled by other radio SETI programs, such as SETI Australia based at the 64m Parkes radioscope and Project Starvoice, based at the 32m Medicina radio observatory, in Italy. NASA Microwave Observing Program and Project Phoenix: In 1992, the U.S. government funded NASA’s "Microwave Observing Program (MOP)". MOP was planned as a long-term effort, performing a search of 800 specific nearby stars, along with nonspecifically directed "Sky Survey", unfortunately MOP was canceled by congress a year after its start. In 1995 the SETI Institute resurrected it under the name of Project Phoenix, funded by private sources. Project phoenix ended in 2004, after completing its scan of 800 stars, but found nothing promising. How? The SETI process can be broadly divided into 3 parts, the actual detection of evidence of alien life (‘intelligent’ or not), the analysis of the massive amounts of data involved, and the practical ways of
    • communicating with this yet undiscovered life. Detection of ETI: These methods are directly applied to discover possible extraterrestrial intelligence, either by intentional communicational broadcast, or as a biproduct of their technological activities. Radio: Currently the most widely used detection technique used. Radio receivers located at different points on the earth’s surface scan the skies in search of unusual signals, these signals are then recorded and sent for analysis to determine if they are worth pursuing further. Optical: Optical telescopes watch the skies for concentrated pulses of laser light in the visible spectrum, which could be thousands of times brighter than background starlightix. Determining suitable planetary candidates for alien life: These are methods used more by astrobiologists, who are not looking specifically for evidence of alien intelligence, just life. But, using them in tandem with SETI can give researchers a better idea of where to point their receivers. Spectroscopic: Though we don’t yet possess the optical ability to observe extrasolar planets directly, spectroscopic analysis would allow us to determine the conditions upon the planet, and to see if it was theoretically habitable. Exoplanetary Wobbles: Minute gravitational influence of planets upon distant stars allow us to detect the presence of these planets (Struve, 1952).x The distance of these planets from their stars calculated by this information allows us to decide whether they could be candidates for sentient life. Communicating: A purely hypothetical field so far, as no alien civilizations have been discovered, nevertheless a number of messages have been sent in an attempt to make our presence known to anyone listening. These included the famous 1974 Arecibo Message. A number of communicational languages are in development: mathematical languages, pictorial systems such as the Arecibo message, and even algorhythmic computer messages which could be run as self explanatory codes on alien software. Why? There are reasons to seek out alien life, beyond the inherent human need to explore and learn. The indirect benefits of SETI so far have been significant, the SETI Institute itself has a significant outreach element, engaging people of all ages in a fascinating branch of science, far removed from unappealing dusty classrooms and chemical formulaexi. SETI is at the bleeding edge of applied astrobiology and radio astronomy, and through the internet and mass media, SETI has a well established public presence, with educational cruises, internet podcasts and TV specials. More directly, SETI is involved in formal education, it has it’s own curriculum at high school level, Voyages Through Time. SETI researchers also have written textbooks used in classrooms, such as Life in the Universe, a national best-seller for introductory astrobiology, and Perspectives on Astronomy, a widely adopted text for introductory astronomy. SETI also trains teachers through Astrobiology Summer Science Experience for Teachers (ASSET), giving them the knowledge and physical tools to teach a detailed astrobiology curriculum. SETI encourages undergraduate scientists also with its Astrobiology Research Experience for Undergraduates (REU) program, in which especially promising candidates get the chance to work hands on with research institute scientists. SETI’s work as a member of the NASA Astrobiology Institute (NAI) sees the organization supporting public science talks, and contributing to the design of science museum exhibits. The SETI Institute understands the benefits of publicity, and has leveraged its interesting subject matter as a way of capturing public
    • imagination. Admittedly this is an advantage it has over more ‘academic’ organizations, which do not take much of an active role in public outreach, and therefore have less public engagement. Compared with other research subjects, SETI is cheap, it costs the American taxpayer nothing, as it is entirely privately funded, since 1992, when the American congress ceased it’s funding of the Microwave Observing Program. SETIs use of ‘grid computing’ means that computational loads greater than any super computer ( 27.24 teraflops xii)can be processed, without the multimillion dollar operating costs a supercomputer would bring. By nature, the research costs of most of SETI are low due to it’s thrifty ethos. Parasitical research programs and public initiatives such as the SETI league keep costs as low as possible. The implications of discovering or communicating with alien life would be far reaching, and would mark one of the most monumental points of human history. From the philosophical stance, it may bring us closer to an understanding of who we are as a species, our origin and our place in the vast universe we inhabit. The useful discoveries to be gained from communicating with a species that could possess technology and knowledge that we do not are limited only to the imagination; answers to questions that we haven’t been able to answer yet? The insights that could be gained from interacting with completely alien minds could cause a paradigm shift on the very way humans perceive everything; questions that we haven’t even asked yet? As technologist and Microsoft co- founder Paul Allen said while commissioning the new telescope that bears his name, "I like to call SETI the longest of long shots. But if this array picks up a signal, that would be an amazing thing – a civilization-changing event." Problems with SETI At the moment, one of the main problems facing SETI is the distances involved. The transmission of the Arecibo, will take 25,000 years to arrive at the stars it was directed at, and a return signal would take another 25000 years. The immensity of the universe means that any communication, if theoretically established would literally take years, as the distances between stars are measured in light years; wave information travelling at the speed of light (which at this time we cannot find a way to exceed) would take 4.2 years to reach the next nearest star to us (after Sol), proxima centurai. And by astronomical measures this distance is next to nothing, the Milky Way is thought to be 100,000 light years across, and the ‘nearby’ galaxy, Andromeda, is 2.5 million light years away. Even if we were to receive a message, there would be no assurance of the continued existence of the civilization or star system it originated from, and if we could establish communication, it would be awkward and slow, in the time lag waiting for responses. Another fundamental, but rather subtle problem SETI faces is the inherent bias we as humans will have, in searching for alien life, only on the criteria for life which we know about or can imagine. Carbon chauvinism is a term used by Carl Sagan to describe itxiii, It describes the limits that humans have in our imagination or perception of alien life, based on our preconceptions born of our earthly environment. At a philosophical level, an alien species may not fit the criterion for our definition of life, we may not even recognise it. A sufficiently advanced species may choose not to make itself known to us, or we may not be fully able to understand or comprehend itxiv. On the flipside of this, on our planet of the total estimated twenty million different speciesxv, only humans are capable of interstellar communication. If we do find life on other worlds, are the odds of it being sentient completely stacked against us?
    • The radio astronomers make a broad assumption that the alien communicational medium would be through wave based information, but since it appears that this is essentially impractical for communication over the distances involved, perhaps an alternate and more efficient technology is used, that we are not yet aware of and cannot receive.. The human definition of ‘habitable’ is predicated around carbon based life, and the search criterion for habitable worlds is ones where liquid water could exist. However, astrobiologists are beginning to propose alternate mediums that life could develop in. These include and are not limited to ammonia, silicon and hydrogen fluoride. Extremophile life has been discovered on earth happily subsisting in extremely hostile environments; such as acidic, extremely hot or areas of high pressure that ‘normal’ life could not survive. This indicates that our search criteria could be completely wrong, is it possible that life could live anywhere? Research has proven that certain hardy terrestrial bacteria are able to survive for extended periods of time when exposed to space. (R. L. Mancinelli, 2008)xvi Another problem with SETI is the fragmented nature of the human race. Since the invention of the radio at the end of the 19th century, humanity has been sending out radio transmissions in a variety of different languages and contexts. The first messages received by hypothetical aliens would make very little sense and would not communicate in any form an appropriate introduction or first impression of humans as a species. Do we really want an alien race’s early impressions of us to be based on the gibbering of the mass media? Have we already presented a terrible first impression? Although commercial radio signals are relatively weak in comparison with concentrated signals beamed for interstellar communication, perhaps other civilizations have the technology to listen. This idea was explored in the film Contact, based on a book written by Sagan, in which an alien signal to humanity is sent back encoded into Hitler’s opening speech at the Nuremburg Olympics. If contact is then made with extra terrestrial intelligence, the problem arises of who speaks for earth. As a species which has not yet outgrown its old habits of tribal warfare and in which the prospect of self annihilation still remains, would we be ready to communicate reasonably with another species? We have always reacted badly to new important discoveries that threaten to shake up our well entrenched world views. A question taken less seriously asks, is revealing our location safe?xvii Would they be benign or hostile? The lessons of our own history have taught us that when a more advanced civilization communicates with a more primitive one, the social implications for the less developed civilization can be disastrous. It’s people and government struggle to come to terms with a bewildering new technology gap to which they have not had enough time to gradually adapt to. Also, if the more advanced civilization decides to make war on the weaker, inevitably it prevails. An example is the Spanish-Aztec wars, in which a few hundred gun wielding, steel armoured Conquistadores overthrew the most militarily powerful Mesoamerican civilization in less than 2 years. The Future of SETI: There have been significant advances in technology over the last 40 years, especially in processing power. Chances of success today are greatly higher, for example Project Ozma’s detection ability was 1 trillion times less sensitive than the average SETI radiotelescope used today.xviii Moore’s law states that processing power doubles every 18 months, this combined with a greater distribution of the SETI@Home project as more people own personal computers, paints a bright future for SETI’s capacity to both detect and analyse new information. Specific new developments in the SETI
    • program itself appear promising. In November 2008 NASA will launch the Kepler space telescope, which will for the first time allow us to detect earth sized exoplanets. As Morrison and Cocconi argued, in their influential paper; "The probability of success is difficult to estimate, but if we never search, the probability of success is zero." Though we may be alone, at least we can say we tried.
    • i Daniken, E. V. (1990). Chariots of the Gods : Was God An Astronaut?. Souvenir Press Ltd. ii http://www.sacred-texts.com/cla/luc/wl2/wl211.htm [accessed 08/04/08] iii The Internet Encyclopaedia Of Science - http://www.daviddarling.info/encyclopedia/K/KeplerJ.html [accessed 08/04/08] iv Ward, Peter D., and Brownlee, Donald, 2000. Rare Earth: Why Complex Life is Uncommon in the Universe. Copernicus Books (Springer Verlag). ISBN 0-387-98701-0 v http://www.seti.org/about-us/ [accessed 08/04/08] vi http://www.jsquared.co.uk/seti-uk/ [accessed 08/04/08] vii McConnell, Brian; Chuck Toporek (2001). Beyond Contact: A Guide to SETI and Communicating with Alien Civilizations. O'Reilly. ISBN 0-596-00037-5 viii Dr. R. N. Schwartz, P. C. (1961). Interstellar and Interplanetary Communication by Optical Masers. Nature , 205-208. ix A. Howard et al., "Optical SETI at Harvard Smithsonian," in Bioastronomy '99 - A New Era in Bioastronomy, G. Lemarchand and K. Meech, eds., ASP Conference Series 213, pp. 545-552, 2000 x Struve, O. (1952). Proposal for a project of high-precision stellar radial velocity work. The Observatory , 199-200. xi http://www.seti.org/epo/index.php [accessed 08/04/08] xii McConnell, Brian; Chuck Toporek (2001). Beyond Contact: A Guide to SETI and Communicating with Alien Civilizations. O'Reilly. ISBN 0-596-00037-5 xiii Sagan, Carl (1973). The Cosmic Connection. Anchor Press / Doubleday: New York xiv Baird, John C. (1987). The Inner Limits of Outer Space: A Psychologist Critiques Our Efforts to Communicate With Extraterrestrial Beings. Hanover: University Press of New England. ISBN 0-87451-406-1. xv - The Department of Biochemistry and Molecular Biology; biodiversity http://www.bmb.psu.edu/courses/bisc002_summer03/biodiversity.pdf [accessed 08/04/08] xvi R. L. Mancinelli, M. R. (2008). Biopan-survival I: Exposure of the osmophiles Synechococcus SP. (Nageli) and Haloarcula SP. to the space environment. Advances In Space Research , 327-334. xvii David Brin(2006) Shouting at the cosmos http://lifeboat.com/ex/shouting.at.the.cosmos [accessed 08/04/08] xviii Horizon – are we alone in the universe? (2007) BBC2