EXTRATERRESTRIAL LIFE 10
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Extraterrestriallife has been hypothesized to exist throughout the universe. Thishypothesis is based on the fact that the world is vast and adheres tothe laws that govern the observable physical universe. According toStephen Hawkins and Carl Sagan, both scientists, it is improbable forlife to exist only on Earth and nowhere else. The probability of lifeother than on earth is rooted in the Copernican principle “that theearth does not hold a unique position in the universe,” and theMediocrity principle that “there is nothing special about life onEarth.” 13.8 billion years ago after the Big Bang, life startedforming in the universe this emergence of life on earth may have beenduplicated in other independent areas in the universe(Wickramasinghe, 2015)
ScientificArguments Favoring the Possibility of
In2012, NASA, based on studies done on meteorites that fell on Earth,found out that RNA and DNA constituents may be createdextraterrestrially. The scientists reported that cosmic dustconstitutes organic matter that is complex in nature and they couldbe rapidly and naturally produced by stars. In 2012 in the month ofSeptember, NASA announced that polycyclic aromatic hydrocarbons(PAHs), exposed to interstellar medium (ISM) conditions, aretransformed in the process of oxygenation, hydrogenation to verycomplex organics. This is a step in the course of the formation ofamino nucleotides and amino acids the basics in the formation ofproteins and DNA (Thiel et al., 2014)
InMarch 2015, NASA scientists reported that DNA and RNA components oflife that are organic which include cytosine, uracil, and thyminewere found in a laboratory that mimics conditions in the outer space.This was done by employing chemicals such as pyrimidine found inmeteorites (Thiel et al., 2014)
TheDrake equation calculates the number of civilized lives present inour universe supporting arguments for the existence of other planets.This equation assumes that other civilizations will be able to sendand receive radio signals as per the purpose of SETI (Search forExtraterrestrial Intelligence). SETI was founded in 1984, has itsbase in the Drake equation, focused on contributing to the discoveryof extraterrestrial life (Wandel, 2015).
Theequation states that “N = R* × fp × ne × fl × fi × fc × L,where N=the number of technically advanced civilizations in thegalaxy that are currently capable of communicating with other solarsystems R*=the number of new stars formed in the galaxy each yearfp=the fraction of those stars that have planetary systems ne=theaverage number of planets in each such system that can support lifefl=the fraction of such planets on which life actually exists fi=thefraction of life-sustaining planets on which intelligent lifeevolves fc=the fraction of intelligent life-bearing planets on whichbeings develop the means and the will to communicate overinterstellar distances and L=the average lifetime of such atechnological civilization.” The Drake equation supports theargument that life exists elsewhere in the galaxy and universe(Wandel, 2015).
Thepurpose of this equation is to aid scientists in summarizing all thefactors that need to be considered in the search of life in theuniverse, and it gives life the basis of scientific analysis. Ithelps people understand that life is as a result of cosmic eventsthat are natural. It fits squarely into current scientific theoriesconcerning extraterrestrial life but rejects the supernatural originsof life and embraces the natural path (Wandel, 2015).
TheKepler mission at NASA has played a significant role in the recentdiscovery of 3 planets in the Kepler mission that are located in thehabitable zones of their solar systems, and are known as“Super-Earths.” The presence of other planets as supported by theKepler Mission is a basis for the discovery of other planets thatsupport life (Wandel, 2015).
Thereis a solar system discovered by the Kepler mission named Kepler-62,“a five-planet system about 1,200 light-years from Earth.” Thissystem contains two planets the Kepler 62-e and the Kepler 62-f bothlocated at the habitable zone of their solar system, thought to besupporting life. These planets are larger than Earth, and Kepler 62-eis considered to contain a lot of water, while Kepler 62-f ispresumed to be rocky. Kepler 69-c is another planet that wasrecently found in another solar system, approximately 2,700 lightyears away. It is much larger than Earth, but the star that itorbits is more similar to Earth’s sun than the star of Kepler-62(Wandel, 2015).
Thisplanet is also expected to be a “water world,” like Kepler 62-e,and it is the smallest exoplanet that scientists have discovered inthe “habitable zone” of the orbit of a star so similar to earth’ssun. These arguments work to disapprove the Femi Paradox that isagainst the possibility of alien life in the universe (Wandel, 2015).
Argumentsagainst the Existence of
Theopposing arguments about the existence of extraterrestrial aresupported by Enrico Femi who believed that if other civilizationsexisted, “they should be in our midst by now.” He believed that,with the universe being in existence for over a billion years, it hadprovided more than enough time for other civilizations to grow anddevelop communication abilities. He states that there must be noother civilizations because they would be just as, if not moreadvanced than we now are and that they would have come into contactwith us by this point if they did in fact exist. This belief isknown as the Fermi Paradox and is still considered by some to be alegitimate viewpoint on the question of extraterrestrial life. TheFermi Paradox is a contradiction to the famous Drake equation, whichprovides a theoretical amount of civilizations that exist in theuniverse (Grey, 2015).
Thepercolation theory is another contrasting argument for the existenceof extraterrestrial life and is supportive of the Fermi Paradox. This theory takes into account the creation of “two states: colonizing or non-colonizing, the reason being that while somecultures opt toward exploration and expansion, others develop nonexpansionist values and display minimal interstellar reach.”Parameters, defined as “P (predetermined probability) and N(connectivity of the graph connected the sites)” are used toexplain the distances to which “colonizing colonies can orpropagate offspring to neighboring sites.” If P is lower than itscritical value, it limits the rate of the growth of civilization,and as a result, cultures are restricted to a limited place in thegalaxy (Hair & Hedman, 2012)
Inthe case of Earths civilization, there is very little [probabilitythat we may expand to space, or continue doing so till interstellercolonization is achieved. When the values of N and P are nearcritical they indicate large colonized regions which are actuallylarge empty regions. This argument is in agreement with the FemiParadox because life would not possess the ability to grow to otherworlds. This theory provides complex, concrete mathematical evidenceto prove the unlikelihood of other civilizations in the universe(Hair & Hedman, 2012)
Thesearch for extraterrestrial life has and is being done by employingtelescopic radio. These kinds of telescopes detect low occurrenceradio energies. These low cosmic energies come from sources that arecosmic in nature like planets and stars. These radio telescopes actas a medium to help determine if life exists elsewhere in theuniverse (Gilster, 2015).
Onearth, the radio telescopes employed in the process of determiningwhether other parts of the universe possess life are the ParkesTelescope located in New South Wales Australia, and the AreciboTelescope located in Puerto Rico. There are plans to build the AllenTelescope Array on the Cascade Mountains in Carlifonia. Thistelescope is a joint effort between the University of California andthe Search for Extraterrestrial Intelligence Institute (SETI)(Gilster, 2015).
Othersigns of life in the universe are explored by studying the radioemissions of star systems. These systems are scanned for the chanceof having individual planets that are maybe orbiting. The AllenTelescope will be able to do this many stars at a time, the presentradio telescopes are only able to search one star at a time. With anability to detect a thousand to ten thousand megahertz, scientistswill be able to enhance their capacity to search for life in otherworlds (Gilster, 2015).
Throughouthistory, much of the speculation about extraterrestrial life has beenbased on intelligent life. A living being can be classified asintelligent if it possesses self-awareness, can question itsexistence and come with a hypothesis. Intelligent living organismswill be able to create tools in order to manipulate the environmentso as to make it habitable. It will also be able to employ languageto communicate with other intelligent beings apart from itself thisincludes a civilization too (Galantai, 2016).
Accordingto Galantai (2016), life is a precondition of intelligence at leastat the beginning. It is based on the assumption that evolution leadsintelligence which produces culture, and culture brings aboutnon-biological intelligent entities. One can envision a universe withthe presence of life, after its manifestation, then the appearance ofintelligence is inevitable.
Intelligentlife is to varying extents. On earth, examples of animals thatportray intelligence include Humans, Chimpanzees, and Dolphins. Theseare based on the fact that they possess communication and contactsignals, they have a working and established culture. All markers ofan intelligent life (Galantai, 2016)
Humanbeings are searching for Extraterrestrial life, and these are groupedinto two sets. The first classification is broad, and it constituteslife itself in a process that includes simple forms such asmicrobial. Without technology, life cannot produce signals thattravel through the solar system. Still, scientists are investigatingthe characteristics and atmospheres of worlds across the solar systemin search of life beyond our planet (Redd, 2016).
Inan effort to find extraterrestrial intelligence scientists lookbeyond this category so as to find advanced civilizations. SETIsearches under this category focus on optical or radio signals thatmight hint to an evolved alien life. Due to the fact that on earth,life began over the past 100 million years before the planet washabitable, scientists think that life on planets with similarcharacteristics should have evolved. The stars in the galaxy arethought to contain at least a planet each, making the opportunitiesfor evolved life numerous (Redd, 2016).
Asper SETI, the ways of finding life on other planets are three. Thefirst being to go and look, the second is studying light from otherplanets in order to determine their atmosphere, and the third is tosearch for indicators of intelligence (Redd, 2016).
SETIsearches are focused on radio signals, most of which are radioemissions, narrow-band signals. These but cover only a portion of theradio spectrum. Natural objects block spectrum with signals.Therefore, finding a signal that dominates only a small region willindicate an artificial source. This would serve as a proofintelligent life. The focus of scientists is also focused on opticalsearches, and it involves searching for micro flashes that last ananosecond (Redd, 2016).
Contactfrom other planets could be sent deliberately or by accident. Sincethe Earth has been sending messages into space since World War II,SETI has been searching for intentional messages that have been sentinto space. SETI has also begun looking for communications betweenworlds, other than earth those of which are along earth’s line ofsite. This is because messages beamed towards other worlds maycontinue and cross earth’s path (Redd, 2016).
Theability to understand dispatched messages from space will depend onthe intent of the messages. If an intelligent species is sendingmessages into space, they may need to make it as simple as possibleso that other lives can understand it. However, if the message issent accidentally or it is purposely meant for another world,decoding it might be an impossibility if not a task. According toSETI, the signal might reveal details about a civilization that mightpinpoint to their origin and the information can help determine howthe planet is moving (Redd, 2016).
Lifein Non-Earthlike Conditions
Alternativebiochemists are of the view that certain solvents and atoms couldbring about life. Since carbon has been a source of life on earth, itis thought that that would be the case all over the universe. Inreality, many elements could spawn life (Hawking, n.d.).
Wateris not necessarily essential to life, and other elements such asammonia have many properties such as water making life feasible innon-earth like conditions. Such an example outside the water basedhabitability zone is the moon, Titan. Water replacements such as,hydrogen sulfide, hydrogen fluoride methanol, formamide, and hydrogenchloride have been suggested as possible solvents that could supporta different biochemistry. With these various elements, it isconsidered in a radically different environment there would be anentirely different life. Carbon and water may be the most unlikelyelements to support life in such extreme conditions (Hawking, n.d.).
NASA’sannouncement that it has discovered the possibility of anarsenic-based life in Mono Lake rhymes with its search beyond carbonbased life. As earth did not accumulate oxygen till it was threebillion years old, there might be microbial non-carbon ecosystemsparallel with the evolution of earth indicating a tectonically activeplanet (Hawking, n.d.).
Galantai, Z.(2016). Life, intelligence and multiverse. Budapest University ofTechnology and Economics (Hungary).
Gilster, P.(2015, 24). Searching for extraterrestrial life and intelligence:knowable and unknowable. Retrieved fromwww.centauri-dreams.org/?p=33686
Grey, R. H.(2015). The Fermi Paradox is neither Fermi`s nor a paradox.Astrobiology, 15(3), 195-199.doi:10.1089/ast.2014.1247
Hair, T. W.,& Hedman, A. D. (2012). Spatial dispersion ofinterstellar civilizations: a probabilistic site percolation model inthree dimensions. International Journal of Astrobiology,1-8. doi:0.1017/S1473550412000420
Hawking, S.(n.d.). Life in the Universe. Retrieved fromhttp://www.hawking.org.uk/life-in-the-universe.html
Redd, N. T.(2016, August 2). SETI & the search for extraterrestrial life.Retrieved fromhttp://www.space.com/33626-search-for-extraterrestrial-intelligence.html
Thiel, C. S.,Tauber, S., Schutte, A., Schmitz, B., Nuesse, H.,Moeller, R., & Ullrich, O. (2014). Functional activityof plasmid DNA after entry into the atmosphere of earth investigatedby a new biomarker stability assay for ballistic spaceflightexperiments. PLOS.
Wandel, A.(2015). On the abundance of extraterrestrial life after the Keplermission. International Journal of Astrobiology, 14(3),511-516. doi:10.1017/S1473550414000767
Wickramasinghe, C.(2015). Evidence to clinch the theory of extraterestrial life.Journal of Astrobiology & Outreach.doi:10.4172/2332-2519.1000e107