Finding Life on
Other Planets: Easier by Theory, Harder by Application
By Sharon Cornet
Science and Culture LIB 332
Professor: Jennifer Cramer
February 22, 2010
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Finding Life on Other Planets: Easier by Theory, Harder by Application
Life on other planets why look? Could it be that we humans, who are among a great diversity of other forms of life on this planet, may not be on the only habitable planet in the universe? If earth systems were to fail one day, and/or humankind decided to pioneer space and colonize another planet in our solar system, or in our galaxy, would it even be possible? The greatest question has been, first, to find such a habitable planet meaning a planet that could support life as we know it, whether human or alien. The possibility for life on other planets appears to be greater than originally thought; however, the chances of getting there to study or colonize a planet that could sustain human life would be nearly impossible to reach. An exploration of this concept will be discussed in this paper.
A scientific breakthrough for two possible life-harboring planets near the Habitable Zone (HZ) around a red dwarf star (Gliese 581) was discovered (see: http://www.wired.com/science/discoveries/news/2007/12/YE_10_breakthroughs) by Stéphane Udry and his colleagues, and lies about 20 light years away in the constellation of Libra. Udry works for the Geneva Observatory in Switzerland as an astronomer and is a member of the International Astronomical Union (http://www.iau.org/administration/membership/individual/1418/); according to that site Udry is also the Chair of Division IX Commission 30 WG Radial-Velocity Standard Stars, Organizing Committee Member of Division III Commission 51 Bio-Astronomy, and a Member of Division III Planetary Systems Sciences (IAU, 2010, Section: Affiliation(s) within the IAU).
Udry discovered the slightly-larger-than-earth sized planet in 2007, although another planet has also been acknowledged and debated. The first of the planets that are called super-earths is Gliese 581c, which is being contested due to being outside of the HZ. Nonetheless, other researchers are also favoring Gliese 581d because it is within the HZ. A paper by W. von Bloh, C. Bounama, M. Cuntz, S. Franck (2007) detailed the study of the long-term possibility of photosynthetic biomass production on a dynamically active planet and determined that [t]he super-Earth Gl 581c is clearly outside the habitable zone, since it is too close to the star. In contrast, Gl 581d is a tidally locked habitable super-Earth near the outer edge of the habitable zone. Despite the adverse conditions on this planet, at least some primitive forms of life may be able to exist on its surface (Abstract). These four researchers researched in tandem on the possibility of life being on these two planets. Their backgrounds are in astrophysics and their expertise is complementary regarding the data from Udrys original discovery.
Werner von Bloh was born in 1963 in Oldenburg, Germany and works at the Potsdam Institute for Climate Impact Research. His diploma is in physics, and his PhD is in Theoretical Physics, with his thesis in Geophysiological modelling of the interaction between climate and biosphere (Curriculum Vitae: http://www.pik-potsdam.de/~bloh/homepage/cv.html). Von Blohs research fields include: Geophysiological modeling, Long-term evolution of the geosphere-biosphere system, Astrobiology, and Scientific computing, plus he has over 50 publications in books and journals. Finally, he is a member of the American Geophysical Union (AGU).
Christine Bounama nee Gillert, born in 1964 in Stralsund, Germany, also works at the Potsdam Institute for Climate Impact Research Development and has assisted on the "WIP project group for general geophysics at Potsdam UniversityAnalysis of seismograms Development and programming of thermal evolution models for the Earth," as well as having been a "Research engineer at the Central Institute for Physics of the Earth in Potsdam Analysis of core phases of teleseismic events in seismograms for the investigation of the core-mantle-boundary" (Curriculum Vitae: http://www.pik-potsdam.de/members/bounama/curriculum-vitae). Bounamas diploma is in geophysics, and her PhD is in Astrophysics, thesis on Thermal evolution and habitability of terrestrial exoplanets.
Manfred Cuntz is an Associate Professor of Physics at the University of Texas at Arlington. He is the Co-Director of Astronomy, and received his PhD at the University of Heidelberg, Germany. His research group is in astrophysics and his research interests include the topics: Solar and Stellar Physics, Magnetohydrodynamics, Stellar Surface Structure, Extra-Solar Planets, Stellar Habitable Zones and Astrobiology, Observational Programs, and Future NASA Missions. Like Udry, he is a member of the IAU, among other associations dealing with astrophysics (Faculty CV: http://www.uta.edu/physics/main/faculty/cuntz/).
Dr. Sigfried Franck was born in 1952 in Annaberg-Buchholz, Germany. He is a Research scientist at the Potsdam Institute for Climate Impact Research. His degrees are in Physics, and his research interests include: Internal structure of planets, Planetary evolution, Earth system science, Global carbon cycle, Extrasolar planets, and Astrobiology. Franck has been involved in numerous national and international committees concerning physics, seismology, and geophysics (Curriculum Vitae: http://www.pik-potsdam.de/members/franck/curriculum-vitae). He, like his colleagues named above, has many publications in books and peer-reviewed journals.
Like countless other professionals around the world, these scientists use their knowledge and expertise to inquire and test hypotheses concerning the world (or worlds) around them/us. Formal scientific knowledge is a daily part of their paradigm, and social constructs can also include truth or facts within the standard account (Erickson, 2005, p. 78). For example, the entire premise of the HZ is based on earth-centric criteria. Just as early seafaring explorers were ethnocentric due to the cultural lens that they used to view the world, they judged small-scale societies they discovered as not being civilized or as too primitive because they were based on a European scale of prejudice, fear, or ignorance (rather than extracultural or indigenous knowledge). Similarly, the possibility exists that Udry, or even von Bloh, Bounama, Cuntz, and Franck, may be judging Gliese 581d as being able to hold at least some primitive forms of life [that] may be able to exist on its surface because of a lack of scientific knowledge, rather than what they think they know (2007, Abstract). Their comments may merely be a conservative gesture, however, since it is unconfirmed if life exists there, let alone advanced forms of life. The real question then becomes, what are the chances of life being on this planet? Or even more importantly, what are the chances of life being out there within our galaxy or universe at all?
Franck, von Bloh, and Bounama (2007), together in a separate paper, have taken a complex problem and partially reduced or limited HZ criteria to being linked to the photosynthetic activity of the planet and is thus strongly influenced by the planetary geodynamics (para. 3). Is it that simple, or do factors of chance come into play? According to Dr. Miniot (1997), Associate Professor of Physics at Fordham University, the chances based on an equation he said was developed by Paul Wrey are mathematically very small that life or alien civilizations could ever exist (for details see: http://www.columbia.edu/cu/augustine/arch/frear/rutler97.htm). However, it was the famous Professor of Astronomy, Dr. Carl Sagan, who made this 1961 Drake equation even more well known through his writings in popular science by quoting its originator, Frank Drake (whom established SETI (the Search for Extraterrestrial Intelligence), see: http://www.seti.org/Page.aspx?pid=336). The formula is as follows:
R* fp ne fl fi fc L
N = The number of civilizations in The Milky Way Galaxy whose electromagnetic emissions are detectable.
R* =The rate of formation of stars suitable for the development of intelligent life.
fp = The fraction of those stars with planetary systems.
ne = The number of planets, per solar system, with an environment suitable for life.
fl = The fraction of suitable planets on which life actually appears.
fi = The fraction of life bearing planets on which intelligent life emerges.
fc = The fraction of civilizations that develop a technology that releases detectable signs of their existence into space.
L = The length of time such civilizations release detectable signals into space.
Although the equation has variables that are yet unknown, the chances for intelligent life on other planets can be estimated at between less than one to over a billion, depending. The most conservative is less than one, but we humans are aware of our own existence, so it stands to reason that one could be the minimum predictor, while more information on the variables is needed to predict anything higher with any degree of certainty. Basically, it is anyones guess. Gregory Georgiou (2008) attacks it from a different perspective based on observation:
Astronomers now believe that most stars have planets, and recent research concludes that worlds with the potential for life might even be more common than originally thought. Using a space-based telescope, scientists have determined that at least 20%, and possibly 60%, of stars similar to the Sun are candidates for forming rocky planets similar to Gliese 581c or Earth. SETI scientists generally agree that any alien race that would contact people is probably far more advanced than they are, both technologically and morally.
It should be noted, however, that there are other criteria than mathematical equations that can be used as predictors. One of the questions posed by scientists and lay people alike is whether or not life on earth was seeded. The term seeded implies an extraterrestrial source. Popular science and certain religious groups (especially YECs (Young Earth Creationists) who hold to a Biblical literalist interpretation of scriptures and insist that the earth and the cosmos were created only a mere 6-10kya) decidedly push a faith-based view that if life on Mars is ever absolutely confirmed it will be because it was earth-seeded, rather than any possibility of it being the other way around. It is common knowledge that when a meteor hits the surface it becomes a meteorite many pieces are exploded out, and some may escape the planets atmosphere. If they land on a nearby planet, and any microbes actually survive the process, then it is possible for life to be seeded, or transferred from one place to another through natural means, provided the life takes hold in the new environment. However, the view by YECs that life could only exist on earth, as God created it, is highly ethnocentric, and is based on an enculturated view and blind faith, rather than scientific observation or testing. Technically, the chances of either planet being seeded from outer space should be equally viable since earth and Mars are not closed systems they are open systems (Cornet, 2010, para. 6). Whether or not such possible source seeds (whether microbial or as intelligent life) would take hold in a new environment is a different question altogether, and is what we will talk about soon; in the meantime, these so-called seeds would still require a compatible environment to live.
The HZ is based on a set of parameters or criteria, also called the goldilocks zone. According to the Absolute Astronomy Encyclopedia the HZ is also called the goldilocks zone because it's neither too hot nor too cold, but just right (http://www.absoluteastronomy.com/topics/Habitable_zone). Many times the goldilocks zone has a prerequisite of liquid water in order to sustain life, or other features such as temperature ranges, or distance from a sun. As stated before, the goldilocks/HZ area may be like the story of Goldilocks and the Three Bears, where it is equally simplistic. For instance, scientists used to think that life could not exist outside of the typical day/night temperature ranges found in nonpolar latitudes on earth. Life, however, has been found at the deepest depths of the ocean, much deeper (and darker) than the required sunlight exposure range of the goldilocks zone. This life thrives in the heat of underwater volcanic vents, not to mention life that has been found deep under the ice in the Arctic (see: http://www.arctic.noaa.gov/essay_vogt.html). Just when people (professionals and lay people alike) think that the limits have been met (set/constructed), nature calls them a liar. Nature, we must remember, extends outside of mere earth and does indeed include every atom, speck of dust, asteroid, planet, sun, super nova, and galaxy of the cosmos. The socially constructed ranges of what is possible are shattered, and then widened, the parameters reset, and minds opened to new possibilities.
This same phenomenon of setting parameters back has occurred throughout the history of science. Human evolution and archaeological dates of the earliest or first human accomplishments in cave art have been moved back (see Appendix A). Spirituality of hominids, and specifically Neandertal, was discovered, altering the view of scientists worldwide on the nature of the concept of the so-called human spirit, (see Appendix B). Bipedalism in human evolution was considered to be a fairly new physiological feature, but paleoanthropologists then discovered the Laetoli footprints in an ancient volcanic ash bed, which are 3.6 million years old (see Appendix C). Looking further back, long before hominids, and into the angiosperm (flowering plants) category, evidence has surfaced in geology and microbiology that has completely turned over the decades-long Cretaceous school of thought (paleobotanical thought communities) on flowers that are now known as having Triassic origins (see Appendix D). In all of these cases, and where it is certainly probable that at least hundreds more exist in other fields of science, the dates have been pushed back on what we know to be true according to the standard account of science.
The standard account has left us with a view that science is progressive, and that new information builds on older information, and essentially updates it, expands it, and brings more light to our understanding. Where some of this may be true, it by no means indicates that all of the previous knowledge is not replaced. According to Erickson (2005) it was T. S. Kuhn who challenged the standard account of scientific progress and introduced a discontinuous history of knowledge (p. 106). Kuhns model suggests that after a scientific revolution a huge chunk of the old science will be abandoned as it is incompatible with the new science (p. 106). This model is supported by the trend or pattern where what we know today has turned over the old information in the past; or better, where what we think today may be overturned by new information tomorrow. This would include the possibility of finding planets in the HZ (or not).
Scientists today are looking at the planet Gliese 581c and Gliese 581d. A popular science website (Anonymous, 2007), still hooked on 581c instead of the now-favored 581d, admits that alien life forms could have years of evolutionary advantage on us as its ancient star may have supported life for longer and that the Gliese planet(s) will be a key target for future space missions and by 2020 scientists hope to have sent powerful telescopes to search out signs of extra-terrestrial life. Despite the 13-year wait for more detail, bookmakers William Hill have slashed the odds regarding the existence of intelligent extra-terrestrial life from 1000/1 to 100/1. This account has, interestingly enough, picked up on the probability of not only accepting the notion of alien life in space, but in the possibility of finding it. Also noted, more favorably toward intelligent life being more advanced than us, is that we may find more than microbes.
How would we know that a planet would have intelligent life? We can look through a massive telescope, and by using instrumentation and technology we can determine what type of sun we are seeing, or what size planet, what its orbital path and how long its year is, or even whether it is rocky or gaseous, and so on. Physically reaching a planet light years away is nearly impossible by todays space travel standards, however. Gliese 581ds 20.5 light years distance is equal to 120,511,820,150,263 (120.5 trillion) miles. Even Cornet and Stride (2003) and their out-of-the-box-thinking telescope array proposal for SETI is limited to being within our own solar system, at less than 50 AU, so such a system would never reach as far as Gliese 581d (Abstract). An AU stands for Astronomical Unit, and is equivalent to the distance between the earth and our sun (93 million miles), which is an earth-centric value (http://neo.jpl.nasa.gov/glossary/au.html).
Even if scientists could locate a habitable planet, that fit in the earth-centric goldilocks/HZ range, other problems arise in visiting such a planet to verify the data, or to colonize it. We do not have the capability of warp speed like in the Star Trek science fiction TV shows or movies. Considering the speed of light, and the theory of relativity, we would likely need another science-fiction-based-on-science-fact type of traveling media: wormholes! Also, according to Cornet (2010) there are inherent problems with rerouting humans (or other earth life) to an other world, even if it is Mars, or the moon; she said it stands to reason that when designing a model for living in earth-like conditions on another world, the scientist must alter his/her perception to another place entirely so that the context is applicable. Mars conditions are not to be implemented with earth-centric bias! (p. 4). Herein lies the problem, because even if the conditions on such a planet could harbor life as we know it, there would be differences such as gravity, oxygen-nitrogen-carbon dioxide ratio and levels, light spectrum radiation, cosmic rays (for instance, can we count on an ozone layer being present?), and so on.
All of these things, including how long the days/nights are (remember that Gliese 581d is tidally locked, so one side gets sun all of the time, while the other side is perpetual night) will have an effect on natural systems, including cosmic ray-induced genetic mutations, not to mention unknown variables in the environmental conditions that would ultimately affect human life once there. Speciation might be something that happens slowly, or very quickly. Adaptations in the life forms (including ourselves, or any intelligent life forms discovered) might cause new species to form and if that species that was changing were us, would we still be human? How many changes would it take before one could not have viable offspring with earth-born/raised people? The same goes for space travel, where long-term problems arise in loss of bone density, muscle tone, aging rates, and other health issues. If the trends in hominid evolution (based on the fossil record) of a flatter face, reduced sinuses, smaller dentition, and a larger brain case were to continue, but in lesser gravity (causing reduced musculature, for instance), we might wind up looking like the extraterrestrials (ETs) promoted in popular science called the grey alien beings.
If somehow science was able to utilize SETI models, or other methods for finding extraterrestrial life within our solar system (or beyond), and we actually met an alien civilization (outside of alleged covert abduction scenarios), then who is to say that they would be more advanced? For that matter, who is to say we would be more advanced? Popular science depicts ET as having technology beyond our present capabilities, but typically not more than 20-200 years ahead. According to Theoretical Physicist Michio Kaku, who quoted Carl Sagan on the level of advancement of ET compared to humans, an advanced civilization millions of years old is as much beyond us as we are beyond a bush baby or a macaque (http://mkaku.org/home/?page_id=246). At that point we would be reliant on ET (provided they were friendly, and cross-cultural barriers and challenges were overcome) to take us, or teach us how to go to other worlds successfully, how to live and survive, learn about different types of travel methods, how to slow or reverse mutation rates, and on and on.
the variable of super intelligent ET into the equation of space travel and finding HZ
planets adds an entire new dimension and dynamic, and without such help, or some
tremendous advancements in science and technology on our own, the problem of going to such
a planet, so very far away, is much harder than the theory or practice of finding it in
the first place (long distance, as we are doing presently).
The possibility for life on other planets appears to be greater than
originally thought; however, the chances of getting there to study or colonize a planet
that could sustain human life would be nearly impossible to reach. Evidently, with all of our scientific knowledge
and achievements to date, the standard account of so-called progress is hardly
worth talking about, and our level of attainment is still in its infancy. Based on the trends of new paradigms and theories
replacing (vs. adding on to) old ones, and the dates for evolutionary firsts
being pushed back, it appears that we humans are not as advanced as we think we are, and
have not been evolving as quickly as previously thought.
People of the world have a long way to go (both literally and figuratively)
before intrasolar or extrasolar planets can be inhabited by our species, or before we can
meet any possible (intelligent?) alien species on HZ (or not) planets that we find. Of course, tomorrows next discovery could
very well overturn everything we think we know.
Anonymous. (2007, April 25). Sister Earth Found 20 Light Years Away. Sky News. Retrieved on February 7, 2010 from http://news.sky.com/skynews/Home/Sky-News-Archive/Article/20080641262484
Cornet, W. Bruce, & Stride, Scot L. (2003, April 28). Solar System SETI Using Radio Telescope Arrays. Retrieved on February 21, 2010 from http://contactincontext.org/cic/v1i2/s3eti-ata/s3eti-ata.htm
Cornet, Sharon. (2010, February 1). Learning from Failure: Biosphere 2. Retrieved on February 21, 2010 from http://sunstar-solutions.com/biosphere2.htm
Erickson, M. (2005). Science, culture and society: Understanding science in the 21st century. Malden: Wiley.
Franck, S., von Bloh, W., & Bounama, C.. (2007). Maximum number of habitable planets at the time of Earth's origin: new hints for panspermia and the mediocrity principle. International Journal of Astrobiology, 6(2), 153-157. Retrieved February 5, 2010, from ProQuest Biology Journals. (Document ID: 1459295261).
Georgiou, G. (2008). The Real Life Search for E.T. Heats Up. The Futurist, 42(6), 17-23. Retrieved February 5, 2010, from Research Library. (Document ID: 1570227981).
Von Bloh, W., Bounama, C., Cuntz, M., Franck, S. (2007). The habitability of super-Earths in Gliese 581. ArXiv: Physics: Astrophysics. Abstract retrieved February 21, 2010 from http://fr.arxiv.org/abs/0705.3758