Vida extraterrestre

Cuando estaba chiquita una vez ví la "autopsia de un extraterrestre". De esos típicos monitos con ojos gigantes, y desde entonces les había tenido pavor. Después, durante la mayor parte de mi adolesencia no me gustaba ver películas de invasión de extraterrestres porque no podría dormir de miedo. Ahora ya no me daría miedo un contacto así, de hecho me gustaría mucho vivir un contaco intraestelar. Y como ultimamente me he puesto a leer tareas viejitas de mi clase de astronomía para refrescar la memoria ahora que trabaje en el planetario (yey!) me topé con este ensayo que escribí sobre vida extraterrestre. No tiene mucho sobre mi opinión, pero está (o creo que está) informativo. No lo tradujé porque está bien pinche largo, pero si lo leen díganme que opinan sobre vida extraterrestre y lo que escribí. *Los paréntesis son pies de nota*

Searching for Answers

On Earth, humans are gifted with the condition of life. Carl Sagan one said “ We find that we live on an insignificant planet of a humdrum star lost in a galaxy tucked away in some forgotten corner of a universe in which there are far more galaxies than people” (Sagan screen 1). For centuries, many people have wondered about our existence: is Earth the only planet in the entire universe with life? This is an extremely tough question to answer, since, up to date, there is no scientific evidence that there are other civilizations, or even any kind of life in the rest of the universe as we know it. There are countless stories about humans beings having experiences with extraterrestrial creatures; yet, as Sagan said “extraordinary claims must be supported by extraordinary evidence.” (qtd. in Cosmos 12) There are several considerations that should be made prior to assuming there is or isn’t life in the universe other than us, such as theories about the origin of life on Earth and the universe, planets along other stars, and the probability of intelligent civilizations outside Earth.

According to www.anwers.com life is the property or quality that distinguishes living organisms from dead organisms and inanimate matter, manifested in functions such as metabolism, growth, reproduction, and response to stimuli or adaptation to the environment originating from within the organism. There are several theories about the origin of life. The most common and taught is Charles Darwin’s evolution theory, that states we evolved from inorganic and dead objects to become alive. However there is another theory that does not agree that life could evolve form non living-items. Could it be possible that someone or something delivered the “seed of life” to Earth in order for us to evolve metabolisms, grow, reproduce, and respond to stimuli? Some people would say yes. Panspermia is a theory about the origin of life that assures life in the universe has “existed eternally and living organisms do not arise form nonliving matter, but are transmitted from planet to planet”(Sagan and Shklovskii. 7). If this was to be true it would mean that life is eternal in the universe and we are merely common. However, no assumptions can be made regarding the origins of life knowing that there are supportive and contrary evidences for both theories.

Our Sun is just one of thousands of millions stars in the universe. The Italian philosopher Giordano Bruno wrote “ innumerable suns exist; innumerable earths revolve about these suns in a manner similar to the way the seven planets revolve around our sun. Living beings inhabit these worlds” (Sagan and Shklovskii. 7). So far, two of the things that Bruno said have been proven right. There are innumerable stars in the universe, and planets do revolve around them. Thanks to technologies such as the astrometric technique, the Doppler technique and transit and eclipses techniques there have been more than one-hundred detections of extra solar planets. Unfortunately, given that all detections have been made with indirect techniques we do no know much about these planets.(Bennett et al. 405).Finding out if there really are inhabitants in these worlds is a hard quest. Knowing how life is on Earth, there are some requirements that have been recorded about what would be necessary for life elsewhere if it was to be anything like life on Earth. Some of these basic requirements would be: a source of nutrients from which to build living cells, energy to fuel the activities of life, and liquid water. Consequently the quest must start looking for planets, habitable worlds, that are likely to have these necessities (Bennett et al. 718). Unfortunately, as little as there is known of the planets found in other solar systems; extra solar planets are identified in their majority of jovian nature. Therefore, they have been called red jupiters. Life would no be suitable in red jupiters at all.

While there is no provable evidence of terrestrial planets revolving other stars, some astronomers firmly believe there is a large possibility that there are terrestrial, habitable planets in the universe. There are countless galaxies in the universe, countless stars in those galaxies, and countless planets revolving around those stars. Frank Drake took that into consideration and formulated an equation that calculates the number of extraterrestrial civilizations in the Milky Way that we might have a possibility of contacting. Drake took into consideration the following factors necessary for intelligent civilizations to evolve: the rate of star formation in our galaxy (R*), the fraction of those stars that have planets (ƒp), the average number of life that can support life per star that has planets (ηe), the fraction of the above that would develop life (ƒl), the fraction of the above that are able to communicate or have the desire to do so, and the expected lifetime of such civilization and came up with the following equation: number of civilizations (N) = R* × ƒp × ηe × ƒl × ƒi × ƒc ×L. (Drake equation par. 1)

Project SETI (Search for Extra-Terrestrial Intelligence) astronomers share some views with Drake. If planets like Earth are rather common in the universe along with stars, then we are not a privileged and rare species, like some people suggest, but rather typical. This concept is know as mediocrity assumption (SETI pars. 1-14). “If this basic assumption of mediocrity is correct, and other intelligent species are present in any number in the galaxy at our technological level or above, then communications between the two worlds should be inevitable” (SETI pars. 4). Which is why SETI astronomers have felt the urge to propose projects for interstellar communication such as the Arecibo message aimed to the globular cluster M 13 in 1974 from the Arecibo Observatory in Puerto Rico. This message was an illustration composed by 73 rows and 23 columns per row, numbers carefully chosen because they are prime and do not occur in most cases naturally. The message presents information about the location of Earth in our solar system, basic characteristics of humans, the population of Earth, our solar system, the composition of our DNA, and a sketch of telescope Arecibo itself(Figure 1 is the image and it shows how to decode the original message). Unluckily, “Given the limitations of the speed of light for message transmission, no reply would be possible before the year 52,174” (SETI Arecibo Message par. 3).

Chances of extraterrestrial life and civilizations are very relative. The truth depends on the personal approaches and theories each person decides to consider, knowing there is no known provable evidence, and all advances lead us to theories that often contradict each other. As time passes by, chances are that technology will advance and there will be a time when our civilization is capable of interstellar travel and other technologies that answer the ultimate question: are we alone? Understanding if we are the first civilization in the history of the universe to ever arise, or if we are one among thousands of other civilizations would help us understand who we are, where we come from, and where we are moving forward to. Our perspective of God and faith would be affected and changed into history. However, for now, we are still in the pursue of “extraordinary evidence.”