Search for Extraterrestrial Life - Essay Example

Astronomy Research and the Search for Extraterrestrial Life Human beings, designed to be the most rational of all the higher animals in this planet, have always tried and explain life by defining its purpose and existence or merely by trying to scientifically explain its basis. Scientists see life as something that has the ability to reproduce and develop. Profound ideas point out life as an indefinable concept that ironically can be explained in various contexts and subjective to the person describing it. It is very confusing enough that defining life as the opposite of death makes it more puzzling. Physicists describe living opposed to non-living in terms of the molecules that constitute the entities. Forrest Gump even likens life to a box of chocolates! This gives us a lasting notion that it is very difficult to define life in a single dictionary meaning. There are efforts that try to delineate life from non-life to give us a clear perspective. In fact, the only planet that is capable of supporting life is the big blue one we are living in right now. What does earth possess that other planets, stars and cosmic bodies don't Is there yet an undiscovered life outside of earth Gradually, we can try and analyze the answers to these questions through an intense exploration of life and its characteristics. Properties of Life There are no definite properties of life. Authors have tried and listed ten or more observable properties that seem to adhere to the principles of physics, chemistry and mathematics. Harold J Morowitz pointed out six features on what life is simply based on. Living things are capable of "(1) reproduction; (2) growth; (3) metabolism; (4) movement; (5) responsiveness; and (6) adaptation" (242). It is indeed likely that these six characteristics are possessed by all living things because plants and animals reproduce following the law that reproduction only occurs within a species. Inanimate rocks do not reproduce instead they split up or break down to make smaller pieces. Even the littlest bacterium has a mechanism of splitting itself or combinatorial joining with another bacterium. Special plants can reproduce by budding their leaves to produce another organism separate from the original. Certainly, reproduction will not make sense if the progenies do not develop into a mature individual so it is very certain that development should follow. With growth, there is differentiation of the different cells into the supposed make-up of the whole organism. Every structure corresponds to its specific function. For example, the human eyes will develop into something capable of seeing and the legs into resilient limbs capable of running and balancing the whole body. Metabolism is defined as the "totality of an organism's chemical processes" (Campbell 83). This is a fusion of the chemical, physical and biological processes that occur within the organism to sustain life. In animals, this can include the digestion of food that would later be converted to energy, the breathing process, and the blood flow along the veins and arteries. For plants though, metabolism can be observed in the production of food from light energy termed as photosynthesis. Movement is a property is visibly manifested in animals and hardly noticeable in plants. This property can easily be misinterpreted because movement is not exclusive to living things. While animals move about freely to search for food, plants on the other hand make their own food so movement is unnecessary except for internal processes such as the exchange of food within cells. All living things also share the same property of responsiveness to a certain stimuli. This can be used as a mechanism of defense or a simple reaction to a chemical attractant. This property is very important for the living organism's to respond to the different changes in the environment. Lastly, living organisms that have the ability to reproduce, develop, move, use up energy and respond to the environment must learn how to adapt in various conditions to allow them to survive in the rapidly changing natural world. On the chemical basis, there are a few elements required to sustain life. These include oxygen, carbon, hydrogen and nitrogen (Campbell 23). Water is also one basic requirement in supporting life that human beings can only live for three days without water. Possibilities of Extra-terrestrial Life Does the planet earth allow for these properties to transpire Are there planets other than earth that are capable of doing so The earth is the third planet from the sun giving it enough heat tolerable for life to occur. If the planet were to be placed nearer or farther than the sun, the temperature would not be suitable for living organisms to survive. Also, since water is very abundant on the surface of the earth, life is maintained. Today, the population of human beings is exponentially increasing making resources for food scarce and has now become a major global problem. Are the natural resources now depleted that in the future, the earth will be called a "has-been" There is a possibility that the earth be exhausted of its reserves that living things cannot survive anymore. This speculation can become a reality, so scientists all over the world explore other ways to find food and manage the use of the earth's resources. Ideas are coming everywhere to save the planet with advocates of recycling and anti-pollution coming to the streets to campaign. There is also one plausible option that is now undertaken by scientists that study the outer space; to find a suitable planet for life to carry on. Based on how we specified the properties of life, we can check if there really is a possibility of extra-terrestrial living. There have been numerous space missions to nearby cosmic bodies, such as Mars and the earth's moon that aims to find an evidence of life. Reaney reported that in the 1990s, NASA has reportedly found life in meteorites from Mars from evidences of bacteria and chemical compounds. An earlier expedition also reported life through findings of the presence of organic materials. Until today, these reports remain to be full of loopholes and still open to doubt especially in the scientific community. Recently, another tuft of a certain bacteria was found in the outer atmosphere of the earth that may be related to bacteria in the earth's land yet have no reason to be found in the limits of the earth. Life itself may have begun in the outer space so there is a chance that life can be found in neighboring planets. Recently, organic molecules were found in gaseous stars in the outer space. One particular molecule discovered that is stirring controversy is acetamide which contains an amino acid linked to another amino acid. This finding is the first time ever an amino acid was found evident in outer space (Garfield). While some search for the presence of molecules for the basis of life, others search for clues that says life has occurred in outer space. This is through the use of searching remnants or relics such as bones, fossils and imprints. Instead of excavating the surface of Mars to search for evidences, these set of scientists started with the inner component of the earth's surface. ("Finding life," 2006) They are working on the principle that we can investigate earth's extreme environments similar to that of Mars thus understanding if and how life exists there. For example, the scientists are working on an evaporative lake in California that is almost similar to a lake in Mars. There are living microbes there able to support life in harsh conditions having an alkaline pH, high salt concentration, and high temperatures. If the studies can understand how this phenomenon occurs, search for life on Mars and other planets can be easier. Life-bearing Planets The solar system is composed of the sun, as the star, and all the other planets circling around it. There has yet been no evidence of life in the solar system other than on earth which makes us alone in the solar system. But are there other stars and solar systems capable of supporting life similar to the condition in our own solar system A recent discovery has found a close neighbor of stars and planets called the 55 Cancri (Britt) . This includes 4 planets wherein one of them can be similar to earth. The scientists have created models that suggest the presence of water in this planet which coincidentally has an almost similar dimension and orbital distance like the earth to the sun. The studies are only simulations and models so this remains to be a possibility and still inconclusive. Our solar system is composed of the central star, which is the sun, a type of yellow star. G types of stars are just in the right temperature which is similar to the sun and can radiate heat into planets around it. Cooler stars may not produce enough radiation and energy to sustain the cosmic bodies near it. Our galaxy, aptly termed the Milky Way is spiral and is composed of stars of different types suspended in dust and gas ("Types of stars"). Alpha Centauri is a neighboring star that scientists believe to be the closest possibility to extra-terrestrial life since it passed a certain test ("Alpha Centauri," 1997). It is also a yellow star and uses helium and hydrogen to produce heat just like the sun. It has the exact spectral type needed to allow water to exist in the planets and again, the right temperature. Alpha Centauri is as stable as and even older than the sun which makes it possible for planets to evolve and start to mature. Lastly, Alpha Centauri has enough metals and other elements that life needs. It seems like this nearby star is as close to the sun as we think it is but again, there are still problems underlying this discovery. Until now, no planets are known to be around Alpha Centauri's orbit and thus possible for the existence of life. Further studies, observations and simulations can be done to address this concern. Extra-terrestrial Intelligence Pop culture has instilled in our minds that alien life forms are more advanced than earthly technology through films released in the early 90s. Aliens fly using fast and disc shaped spaceships and kill "earthlings" using laser guns. We also see aliens looking like monsters with long limbs, large, round eyes in eccentric shapes. But is there truth to any of these Humans discovered the use of radio waves to communicate to people in different places. There have been some speculations that aliens from other galaxies can also be using this technology. We still have no proof that they are more intelligent than us or the other way around. It is ironic that in this age of technology, there is still no evidence of life outside our planet. From the properties we have discussed earlier, we can acquire information that only with the presence of these properties is life capable of existing. Yet, silicon can be a substitute to carbon and even ammonia for water. There could exceptions to the rule. Even if life was found to be existent outside of earth, it could result in an alteration in our own definition of life since we characterize life as how we see it on earth and not otherwise. Being rational beings, there were attempts to find extra-terrestrial activity and to contact them. A radio signal was sent into outer space containing information on the human species, the earth and other facts. This attempt may be far-fetched but it is another step towards something more conceivable. The SETI or Search for Extra-Terrestrial Intelligence has funded dozens of researches and expeditions in their mission to search for outside life. These include radio, optical and probe experiments. An example is the Arecibo message, mentioned above as the radio signal sent into the outer space. Another breakthrough is the establishment of an "all-sky optical survey system" that minimizes error from noise and provides a system that detects automatically signals along the line of the system ("SETI"). The Future of Extra-terrestrial Investigations For the past half-century, the existence of extra-terrestrial life still remains to be a question for all. Is there truth to the urban legends, UFO sightings, crop circles and alien abduction Does this still remain to be fiction or fact There is no one to blame why we still have no answers to these questions. The first-world countries like the United States and USSR have made their attempts to find a solution to the greatest mystery humankind has ever encountered. Astronomy remains to be a field of science that lures student's imaginations because of the still unanswered questions. It has evolved and branched into different specialized fields like observational astronomy. Modern astronomy is a million times different from the archaeoastronomy known in the ancient times. NASA or the National Aeronautics and Space Administration has been doing explorations for the past 50 years and still remain to be the leading group of scientists that provide solutions to the mysteries. They continued doing researches only aiming to answer the simplest questions and providing services like the weather satellites. They also reached Mars in 1997 and usually made researches that are useful information for further studies. * The SETI is more specialized as it only aims to find existing life in the outer space. They have been clouded with controversy on their existence because their projects are too expensive and the results seem to find no success for their mission. Also, there is no proof that extra-terrestrial intelligence exists so efforts from this organization could only be useless information instead of advancement. Still, SETI is evolving and they have even launched a taskforce committee that can answer the public's questions without compromising the intelligence measures of the organization. Even with the controversy over the organization, I still think it is not an issue to have established SETI since in a way, it gives light to some of the questions working hand-in-hand with NASA and other organizations. Evidences provided for by the earlier researches were inconclusive and do not leave a definite answer. The continuous researches funded for by these organizations still try to answer the most basic questions although the answers elude them. This is proof that although the answers are not available yet, the human race still has the capacity and drive to still search and continue discovering new things and finding possible explanations. We can expect in the future that more will be done and further information will be available. WORKS CITED "Alpha Centauri: A Candidate for Terrestrial Planets and Intelligent Life." 15 October 1997. July 13, 2007. http://homepage.sunrise.ch/homepage/schatzer/Alpha-Centauri.html Britt, Robert Roy. "Star system should hold habitable planet." 1 August 2006. July 13, 2007. http://www.msnbc.msn.com/id/14142549/ Campbell, N., Reece, J. and Mitchell Lawrence. Biology. 5th edition. USA: Benjamin Cummings Pub.1999 "Finding life on Mars and outer space begins by examining Earth's inner space". 1 February 2006. July 13, 2007. http://www.physorg.com/news10464.html Garfield, Kathryn. "Did Life Begin In Space" 13 July 2007. http://discovermagazine.com/2006/nov/life-begin-space Life on Mars. July 13, 2007. http://www.astrocentral.co.uk/lifeonmars.html Morowitz, Harold J. "Life". World Book Encyclopedia. 1982. p. 242. Reaney, Patricia. "Scientists Claim Evidence of Life in Outer Space." 9 November 2006. 13 July 2007. http://www.space.com/searchforlife/bacteria_space_010731.html "SETI". July 13, 2007. http://en.wikipedia.org/wiki/SETI#Where_are_they.3F "Types of Stars and Star Groups". July 13, 2007. http://www.innvista.com/science/astronomy/types.htm Read More