Introduction

Scientists and governments have invested more resources in searching for the existence of life in the universe outside of earth. The question that keeps on popping in people’s mind is that will they succeed with their research? However, over the past years, science has propelled heated debates regarding the existence of extraterrestrial life. Researchers from NASA have conducted comprehensive investigations, and they claim to have conclusive evidence. According to NASA, a certain meteorite that was believed to have landed in Antarctica from Mars exhibits forms of life. The ‘Mars fever’ has ignited researchers all over the world to carry out several studies. On the other hand, the topic of extraterrestrial intelligence has been in circulation in both scientific investigation and speculation. Extraterrestrial life refers to the life that is thought to exist and originates in the universe outside of earth (Caumette, Lebaron, Matheron, Normand, & Sime-Ngando, 2015). Besides, it is the only place known by humans to support life. The paper will analyze various arguments concerning life outside earth, methods used and what they were researching. Also, it will encompass the difference between life and intelligent life, and the existence of life in non-earthlike conditions.

Scientific Arguments Favoring the Possibility of Life

According to scientists, the planet Mars has features that are similar to Earth; therefore, it appears to be the best candidate that could support life. For instance, in 1976, the Viking Mars Landers performed a test on Martian soil and detected chemical evidence of life. They tested for radioactive methane gas by mixing soil with radioactive carbon nutrients (Caumette, Lebaron, Matheron, Normand, & Sime-Ngando, 2015). The test showed a positive result. Besides, they have searched for other candidates such as Europa. It is the moon of Jupiter and has been backed by scientists to support life. Although the moon has a high temperature, scientists still believe it can support life (Hanslmeier, 2013). Scientists have supported their research by referring to hot regions and vents found on planet earth that sustain life. The preconditions for life include sources of water and energy and according to scientists, they claim that Europa as an extraterrestrial body has those prerequisites (Hanslmeier, 2013). Similarly, they have based their argument on the concept that the heat present in the extraterrestrial body is warm enough to support life and water under the ice layers can do the same.

Moreover, in 2003, Sulphur traces were detected on Europa and the Italian scientists hypothesized that the traces might be excretions from underground bacterial colonies. According Hanslmeier (2013), the Sulphur signature on Europa resembled the waste products of bacteria that were found beneath the ice layers in Antarctica. Therefore, if those bacteria could thrive below the water, the same bacteria might survive below the surface of Europa. The current findings from scientists reveal that some regions in the universe are habitable and can support extraterrestrial life. Such regions are found in planets with temperatures that range between zero and a hundred degrees Celsius (Hanslmeier, 2013). Besides, the NASA scientists released a report that detailed three planets that offer room for habitation. Although scientist came up with planets Mars, Europa and Kepler as the possible candidate that could support life, no one has ever come up with conclusive findings concerning life beyond planet Earth.

Arguments against the Possibility of Life Based on Scientific Hypothesis

First, extraterrestrial life is non-existent. Scientists who argue against the possibility of life outside the planet Earth base their argument on the fact that the conditions required to support the evolution of life are unique to the planet Earth. They have used the rare earth hypothesis to support their argument whereby the evolution of biological complexity occur in situations that exhibit galactic habitable zones, a terrestrial planet with the right size, environment conducive to plate tectonics and magnetosphere and circumstellar habitable zones. Moreover, scientists have visited the moon many times, satellites have been sent to Mar and other planets, but we have never seen any physical evidence of life forms (Jakosky, 2006). Although scientists have received radio telescope signals, they have not come up with conclusive evidence that shows that the aliens sent the signals (Jakosky, 2006).

Second, researchers argue that there has been no case of a risen intelligent species. None of the remote sensing techniques has ever revealed whether the detected life is intelligent even after finding life-bearing planets. Third, intelligent alien species use technology that is incompatible with ours (Jakosky, 2006). If they exist, then their technological advancement has not reached the level that they can communicate with us. It would be difficult for humans to detect such civilizations since they are primitive and cannot communicate (Jakosky, 2006). Moreover, according to life history, only one civilized species can develop space flight and radio technology. Therefore, the evidence adds credibility to the idea that it is rare to find technologically advanced civilizations in the universe.

Fourth, the existence of natural events would periodically destroy extraterrestrial life. New life would get extinct because of heating and cooling that occurred on their planets. For instance, the earth experienced extinction events that killed complex species. Such events are thought to have resulted from volcanic eruptions and impact of a meteorite. Therefore, such extinction events might be common throughout the universe, and there will be no chance for the survival of intelligent life. Similarly, since aliens would not be able to evolve faster enough to control the greenhouse gases and surface temperatures, they would rapidly go extinct. Fifth, experts argue that if extraterrestrial life exists and have the technological knowledge for interstellar communication, then they would have already sent their spaceships in our solar system (Jakosky, 2006). Therefore, this proves that extraterrestrial life does not exist.

Methods Used in this Search

Scientists are yet to discover life beyond the planet Earth. Although the search for extraterrestrials life is hard, scientists have thought of using advanced technology to detect intelligence in the other extraterrestrial bodies. The first method involves searching for microbial extraterrestrials or their potential remains. The search includes sending robots to Mars. For instance, the Curiosity and Opportunity Mars rovers are still searching for signs of life on the red planet. Scientists suspect that Mars could have once had the potential to provide a habitable environment (Redd, 2014). Moreover, astronomers say that they do not only target Mars, but there are other potentially habitable environments. For instance, Jupiter’s Europa moon is said to have hidden surface oceans while Saturn’s moon Titan contain lakes that have methane.

The second technique will involve conducting a research of the atmosphere of planets that orbit around other stars (Redd, 2014). The objective would be to try to find if there are traces of gases such as oxygen or methane. Such gases would be an indication of the presence of biological processes. For example, NASA’s Kepler mission. It was designed to survey and discover planets that are Earth-size and smaller in our Milky Way galaxy near the habitable zone. Third, scientists involve in searching for intelligent life, and the project is conducted by Search for extraterrestrial intelligence (SETI). SETI seeks electromagnetic signals from extraterrestrial civilization by trying to search the universe for any signs of intentional or accidental signals (Gary, 2014).

Scientists in SETI Institute use the radio search method such as the radio telescopes to search for extraterrestrial life. Since humans cannot see radio waves with their naked eyes, the special telescopes will detect the transmission of low energy waves emitted by stars and planets. Some of the radio telescopes used in the search include the following. The Allen Telescope Array (ATA) is situated at Hat Creek Observatory, Northern California and has 42 antennae, which enables it to map the whole galaxy in search of new radio signals. The telescope has a larger field view than any other. It has significantly expanded the Search for Extraterrestrial Intelligence. Second, SETI uses optical searches such as optical telescopes to survey the sky (Gary, 2014). Scientists believe that extraterrestrial civilization could be using laser beams for communication, and that is why they have come up with laser detector to search for potential extraterrestrial signals.

What we are looking for

Scientists are looking for bacteria and any possible signs of bacteria in the extraterrestrial bodies. Considering the earth’s history, it is with no doubt that, bacteria are the predominant form of life. Therefore, scientists are trying to find whether there are signs of bacteria beyond the planet earth and if there is, do they behave and evolve the same way they do on earth (Linde, 2016). For instance, since water is an essential form of life, scientists have carried research on planets that show or have shown sign of water. Similarly, they have examined organics that are part of life’s building block to find carbon molecules. Since life is carbon based, it would be logical if they use the search for carbon to look for life. Moreover, experts have made discoveries on planets orbiting stars found in the solar system and similar to the earth.

For example, In 1976, the U.S made its first mission to land on Mars with Viking Lander 1 and 2 and conducted three experiments to find Martian life (Linde, 2016). From the biological test, unexpected chemical activity was discovered in the Martian soil. However, the operation did not find any evidence of living organism. Second, NASA first launched the Phoenix Lander for a scout program in Mars to verify whether the place possessed habitable conditions. The device landed in the Artic plains of Mars where scientists suspected to have sub-surface water ice. The Hobble Telescope has been in operation since 1980, and it is positioned above the atmosphere (Linde, 2016). The device detected an organic molecule containing methane in the atmosphere of Jupiter-size planets orbiting another star. The molecule could play a critical role in chemical reactions required to support life.

The Differences between Life and Intelligent Life

Life refers to the condition that differentiates plants, animals and humans from inorganic matter. These conditions include the capacity for functional activity, reproduction, growth and continual change after death. For life to flourish, it requires a suitable environment (Ulmschneider, 2003). Life changes its environment in a process known as bio-signature. Similarly, when ozone and water vapor are present in the atmosphere, they indirectly indicate the evidence of life. The life on earth is mostly made up of microbes. Animals and humans contribute only 1% of life on earth. What do animals, plants and humans need for life? They need food, shelter, protection from features or creatures that might interfere or kill them and fuel to provide the energy necessary for life (Ulmschneider, 2003). The energy that supports life is chemical based. Precisely, it has carbon elements, water and nitrogen as ingredients.

To complete the chemical reaction, we need the help of an outside source of energy. The earth has two sources of energy that include sunlight that provide plants with life and hot springs from the undersea that emit chemicals. Some of the things that might interfere or kill life include extreme weather conditions such too hot or too cold temperatures that will distort the chemistry of life. In addition, energy stars emit high radiations such as ultraviolet radiations and cosmic rays, and this will disrupt the living cells. Therefore, when you break the energy chain, you will starve life to death.

Although animals and plants have life, they lack the intelligence humans possess. It is believed that the only place that intelligence exists is here on earth. In addition, intelligence exists in the forms of human animal. If there is a possibility to find places where human life could grow, then those are the right place to search for intelligence. According to Cranford (2014), intelligent life entails the ability to possess self-awareness, think about the future, use tools and language to solve problems. Dolphins are intelligent, but since they lack limbs that would have helped them create, improve and integrate technology into the society, they cannot exceed humans in intelligence. Humans have used their intelligence to organize the ecology to the extent that it is beneficial and convenient. Humans have visited the moon and sent robots to Mars (Cranford, 2014). Moreover, they are planning to go there by themselves. Being intelligent has helped humans to organize the society to implement and execute their grand plans to something real and adorable (Ulmschneider, 2003). After gaining awareness of what genetics entails, human have developed ability to conduct genetic sequencing.

How Life might exist in Non-Earthlike Conditions

According to the results of researches done by several scientist all over the world, there are non-earth conditions outside the solar system that could support life. Most individuals find it difficult to imagine a living thing surviving somewhere else outside the planet Earth. For other planets, it is not necessary for them to have similar requirements to that of the earth for them to inhabit life. Organisms can survive in different weather patterns, temperature conditions, radiations and chemicals (Hanslmeier, 2013). Some of the reasons to support the idea of the existence of life in non-earthlike conditions include the following.

First, scientists have discovered creatures or microbes who live around the superheated volcanic vents without oxygen. The oldest fossils have proved that Sulphur-based fossils lived on earth some 3.4 billion years ago (Hanslmeier, 2013). There were no plants or algae to produce oxygen through photosynthesis; therefore, the microbial life survived by using Sulphur as a source of energy and growth. According to experts, the ability of microbial life to use Sulphur compounds was regarded as one of the earliest stages of transition by creatures from non-biological to biological life. We still have Sulphur based bacteria existing today, in areas like as hot springs and hydrothermal vents.

Second, scientists discovered tiny creatures such as Tardigrades or water bears that survived in the vacuum space. The European Space Agency experimented the creature, and it survived a harsh environment that was a combination of low pressure and extreme radiation (Daily News, 2008). Before the experiments on water bears, the only creatures to have survived in harsh conditions of vacuum and space were lichen and bacteria. Animals have never survived open space and finding those that can survive rehydration would be remarkable. According to marine biologists, several species of icefish have the ability to survive in frigid polar water. The environment is extremely cold with below-freezing temperatures. Such species have unique adaptations that make them survive in harsh conditions (Hanslmeier, 2013). They possess glycoprotein that helps them to lower the body fluid’s freezing points hence preventing the body tissues from freezing. In a situation when other animals find themselves in such conditions, they would not survive because frigid temperatures will destroy the enzymes hence preventing cellular chemical reactions.

In conclusion, it is still unproven whether we have a life beyond Earth. Scientists are working hard with their advanced technologies to come up with compelling pieces of evidence. Theories have been stated, but none has ever provided a concrete evidence. In the past years, a research about life on Earth has led to the discovery of life in harsh conditions that people believed to be uninhabitable. Such findings have left people questioning the existence of aliens. For instance, SETI is searching for electromagnetic signals from alien civilizations. On the other hand, NASA is on the mission to find extrasolar planets. They have explored planets with robots such as Mars rovers trying to find past surface water. Since we have not yet found any place in the universe to grow life, the Earth is the only convenient place. It has the atmosphere that can deflect intense cosmic and ultraviolet radiations (Gilster, 2011). Also, it has liquid water, stable stars and moderate temperatures. Therefore, the best places scientist should look for life includes planets in our solar system and neighbor planets such as Mars and Venus.

References

Caumette, P., Lebaron, P., Matheron, R., Normand, P., & Sime-Ngando, T. (2015). Environmental microbiology: Fundamentals and applications. J. C. Bertrand (Ed.). Springer.

Cranford, J. L. (2014). Astrobiological neurosystems: Rise and fall of intelligent life forms in the universe. Cham: Springer

Daily News. (2008, September 8). ‘Water bears’ are first animal to survive space vacuum. Retrieved March 25, 2016, from https://www.newscientist.com/article/dn14690-water-bears-are-first-animal-to-survive-space-vacuum/

Gary, S. (2014, March 3). ‘Life as we know it’ unlikely on super-Earths. Retrieved March 25, 2016, from http://www.abc.net.au/science/articles/2014/03/03/3954456.htm

Gilster, P. (2011, October 18). Habitable, Not Earth-like. Retrieved March 25, 2016, from http://www.centauri-dreams.org/?p=20210

Hanslmeier, A. (2013). Astrobiology the search for life in the universe. Sharjah, U.A.E: Bentham Science Publishers.

Jakosky, B. M. (2006). Science, society, and the search for life in the universe. Tucson: University of Arizona Press.

Linde, P. (2016). The Hunt for Alien Life: A Wider Perspective. Springer.

Redd, N. T. (2014, May 24). We’ll Find Alien Life in This Lifetime, Scientists Tell Congress. Retrieved March 25, 2016, from http://www.space.com/26000-alien-life-prediction-congress-hearing.html

Ulmschneider, P. (2003). Intelligent life in the universe: From common origins to the future of humanity. Berlin: Springer-Verlag.

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