ENGL 108
2013.4.22
(原创 未经允许 不得转发或引用）
1826 days of Mars
Within our solar system exists a truly fascinating celestial body. It is Earth’s orbital neighbor and its creation, history, color, and features are extraordinary and unique. However, it shares some similarities with Earth which is why it has fallen under close observation from the human race in recent decades but has been visible to our earliest ancestors due to its most apparent characteristic, its color. It is known informally as the red planet, formally as the planet Mars. What makes the red planet red? How was Mars formed? Why does Mars possess special significance to the human race? What discoveries have made Mars a scientific, as well as a social, icon? These questions and many others can be answered by the research that has been collected since the study of the planet began hundreds of years ago. Mars is one of the most incredible celestial bodies to have ever been found due to its physical properties, features, and possible supreme significance in the future of the human race.
The creation of Mars followed much the same template as the other three terrestrial planets in our solar system, Earth, Venus, and Mercury. It all began over six billion years ago with a gaseous solar nebula that contained every element found in the universe and the specific material that would form the planet Mars (Bennett 318-320). Around five and half billion years ago, the elements of Mars began finding their gravitational orbit spinning around the extremely dense center of the solar nebula known as a proto-star, which would eventual become the sun (but that is information for another essay). Approximately five billion years ago, this material began to accrete, meaning it collected due to gravity as it orbited the proto-star, much like a snowball rolling down a hill and growing in size. Eventually, enough material accreted that a celestial body with its own gravitational field was formed and began attracting material at an even faster pace. This process in the planet building stage is referred to as “clearing the orbital neighborhood” and is a required process for a celestial body to earn the title “planet” (321). Upon acquiring enough material, young Mars underwent a massive re-shaping process into its current spherical structure due to the immense gravitational forces radiating from Mars itself and the gravitational forces acting upon Mars from the proto-star (321). Between four and a half and five billion years ago, roughly ninety five percent of the material Mars would ultimately possess had been accreted and its shape was nearly a perfect sphere (322). The other five percent of material would come from intense meteorite bombardment of the young planet, a phase that all the inner terrestrial planets underwent, due to the lack of protective atmospheres around the planets and the vast amount of meteorites present in the early solar system. The surface of Mars resembled to surface of the present day Earthen moon, with a heavily cratered landscape ( 218). Also, the surface of Mars was extremely hot, nearly molten. The newly formed planet had not had time to cool and temperatures reached well over 200 degrees Fahrenheit. The interior of Mars raged, expelling the necessary energy to heat the planet so immensely and volcanic activity was violently abundant. It would take over another billion years for the planet to fully cool and complete its formation process (219). This cooling would allow Mars to develop a solid crust on which permanent feature could form over time. The surface of Mars would become a diverse landscape of mountains, volcanoes, valleys cut by flowing water, and polar ice caps. All of these features would give modern day scientists the information they needed to hypothesis the almost incredible processes involved in creating the red planet and the current processes that exist there today.
Imagine standing on the peak of Mount Everest, the highest point on Earth; a mountain that soars over twenty nine thousand feet above sea level. Now imagine you were standing at the top of the highest point on any planet in our solar system. You would be on Mars, and your altitude above the surface of the red planet would be nearly three times that of Earth’s Mount Everest, eighty eight thousand feet (Olympus Mons). The name of this geologic feature that dwarfs Earth’s highest mountain is Olympus Mons, Latin for “Mount Olympus”, fitting for a place high enough to be home to the gods. Olympus Mons was an incredibly valuable discovery to astronomers and geologists alike, giving valuable insight into Mars’ past and details about the interior of the planet.
Olympus Mons is a massive extinct shield volcano, a geologic feature formed in much the same way as the Hawaiian Islands by having a land mass resting on top of a bulging body of magma, known as a “hot spot”, below the surface (Olympus Mons). Shield volcanoes are the largest types of volcanic formation in terms of land mass displaced and in the case of Olympus Mons, height as well. However, an important difference exists between the shield volcanoes on Earth and those on Mars. On Earth, shield volcano creation usually results in a long string of volcanoes due the large tectonic plates that move over the “hot spot” causing fresh crust to be forced upwards as the plate moves in a given direction. On Mars however, Olympus Mons is the lone shield volcano dominating the landscape. This in turn revealed to geologists that Mars possessed no tectonic plate activity and that the crust of Mars remains in a fixed position (Olympus Mons). Another key concept is that, in order to grow to such a massive size, Olympus Mons must have been an active volcano for quite a long period of time. This idea combined with the fact that Mars as a whole was extremely volcanically charged led scientists to hypothesize that early in Mars’ history, vast amounts of volcanic gas was being emitted into Mars’ atmosphere (Olympus Mons). In turn, this meant that Mars may have once possessed a much thicker and warmer atmosphere; an atmosphere in which liquid water could manifest in the form of rain and flow freely. This hypothesis was groundbreaking. Scientists had previously hypothesized that Mars had had liquid water based on the deep canals and washouts present on the planet, but now they had a means for which that water originally manifested on the planet, thus completing the theory. The fact that Olympus Mons and the other volcanoes on Mars have gone extinct suggests that activity in Mars’ interior is dwindling and that the core itself may be near death if it is not dead already (Olympus Mons). Olympus Mons, aside from being just an incredible discovery for its sheer proportions, has also proved to be a priceless discovery in unraveling the turbulent past of Mars.
Olympus Mons, the mountain of the gods, is arguably one of the most significant astronomical and geological discoveries of the twentieth century or any century for that matter. It is a truly massive feature that dominates the Martian landscape and dwarfs even the largest of mountains and volcanoes on Earth. The insight into Mars’ history provided by this colossal formation cannot be measured and has answered some of the important questions that humans have pondered about our red solar neighbor. Thanks to Olympus Mons, those questions and possibly more in the future can be laid to rest once and for all.
Another feature that has proved vital to researchers of Mars is known as the Valles Marineris. The Grand Canyon is one of the seven natural wonders of the world and is the deepest, longest canyon on Earth. If there were a seven natural wonders of the solar system, count the Valles Marineris would be voted in unanimously. Reason being that it would take approximately twelve Grand Canyons placed end to end to equal the length of the Valles Marineris and four Grand Canyons stacked on one on top of the other to equal the depth of the Valles Marineris. It would stretch from southern California to New York and circles a fifth of Mars’ diameter (Nine Planets). Besides its staggering statistics, the Valles Marineris has provided priceless information about the presence of water on Mars and how Mars may once have been covered with liquid oceans, lakes, and rivers.
Scientist believe that the Valles Marineris and other “flow” canals found on the surface of Mars were carved by liquid water in the same manner as they are on Earth (Bennett 318). For decades scientists knew that water existed in the polar ice caps on Mars, but it wasn’t until the Mariner orbital missions that detailed satellite imaging of the Martian surface revealed what appeared to be dry river beds and clearly cut canals (NASA). This discovery of possible liquid water in Mars’ past sparked questions of previous life existing on Mars, a debate that continues to this day in the scientific community; though, the existence of liquid water on the planet would certainly bring the arguments one big step closer to their end.
When the term “life” is used in this case, it is not referring to highly advanced multi-celled plants and animals. However, the potential for simple microorganisms to manifest on Mars in much the same way life began on planet Earth is promising given that the proper conditions once existed. Strong evidence of liquid water has surfaced through the satellite imaging of Mars, meaning that the temperature of the planet would have been suitably warm enough for single-celled life forms to appear (NASA). The only way to prove this situation would be to discover fossil evidence of a microorganism in Martian rock; which may have recently occurred. The meteorites Nakhla and Shergotty were once pieces of the crust of Mars. They were ejected into space by a meteorite collision on the surface of Mars. Nakhla and Shergotty traveled through space for millions of years until they were caught by Earth’s gravitational field and fell to our home planet and then fell under intense study by astronomers and biologists alike (Timesonline). As the meteorites revealed information about the surface of Mars a startling discovery was made; there appeared to be extremely small fossils of microorganisms within the meteorites (Timesonline). This would prove that life had, in fact, existed on Mars. However, skepticism came in the form of arguing that the microorganisms had formed on the meteorites after they landed on Earth. This skepticism was quickly squelched, however, when isotopic dating of the rocks revealed that the micro organic fossils were over four billion years old (Timesonline). From these discoveries, the theory of thee existence of life on Mars has taken a giant step forward in the process of being proven.
The next question scientists asked was “What happened in Mars’ history that led to the loss of liquid water on the planet?” It was hypothesized that approximately four billion years ago Mars underwent a massive climate change (Mars Society). With volcanic activity fading on the planet during this Amazonian period, fewer gases were being pumped into the atmosphere making it thinner and thinner. On top of this, scientists hypothesize that the magnetic field that contained and preserved the Martian atmosphere also weakened around this time as the interior of the planet that drives the magnetic polarity became less active (Mars Society). These two factors combined lead to less heat being able to be captured on Mars from the Sun’s energy. In a sense it was the opposite of the greenhouse gas effect on Earth which is the process of extra heat being trapped in Earth’s atmosphere by gases that contained the Sun’s energy. Upon the loss of this ability for Mars to store heat, the surface temperature dropped immensely. Temperatures fell to under negative 200 degrees Fahrenheit at the poles and under negative 150 degrees Fahrenheit on the night side of the planet (Bennett 320). This dramatic drop in temperature would have froze all liquid water on the planet in a matter of centuries with the greatest amount of water freezing at the poles and creating the polar ice caps seen on Mars. The remaining water would have penetrated the surface of Mars and eventually froze. It is believed that large quantities of water exist under the surface to this day. The polar ice caps give scientists a glimpse into how the cycle took place billions of years ago. Mars has a slightly tilted axis of rotation like Earth, which causes Mars to have seasons. During Martian winter, the polar ice caps grow in surface area as ground water freezes and permeates the surface in the extreme cold. During Martian summer, slightly warmer temperatures cause the ice caps to shrink as water returns below ground (324). This is believed to be how the process occurred on ancient Mars causing there to be the absence of liquid water on the surface. Clearly, scientific observations of Mars have led to incredible discoveries about the planet, our solar system, and the universe, but infinite questions remain unanswered about the Red Planet.
Mars may be the fourth planet in our solar system but the information and knowledge it has provided humanity with, even possibly answering the eternal question of life elsewhere than Earth, has made it first on the list of many scientists. With dozens of missions performed by NASA to study the Red Planet, new light has been shed on the creation, history, features, chemistry, and life bearing potential of Mars. Future missions will undoubtedly reveal new discoveries and add depth to, or possibly change, existing theories about Mars. Someday it may be proven that what humans know of Martian history, and its life giving qualities, produced life forms, though on the most simple biological scale, life forms nonetheless. If life did in fact exist on Mars, it can be stated with almost complete certainty that other life forms exist somewhere in the universe in a solar system like our own. That is a truly inspiring theory for scientists to continue their exploration of the universe with the utmost vigor and passion.
Works Cited
Bennett, Jeffrey. Cosmic perspective. 5th ed. San Francisico, CA: Pearson Addison-Wesley, 2008. Print.
"Evidence of life on Mars lurks beneath surface of meteorite, Nasa experts claim - Times Online." Times Online | News and Views from The Times and Sunday Times. Ed. Time. 27 Nov. 2009. Web. 11 Dec. 2009. .
The Mars Society. 2001. Web. 11 Dec. 2009. .
"Mars." The Nine Planets Solar System Tour. Ed. Bill Arnett. 21 Aug. 2008. Web. 11 Dec. 2009. .
"NASA - Mars." NASA - Home. Ed. National Areonautical and Space Association. 13 Sept. 2007. Web. 08 Dec. 2009. .
"Olympus Mons ................................................." Worsley School OnLine... the website for Worsley School ................... Oct. 2005. Web. 11 Dec. 2009. .
