The Existence of Plate Tectonics on Mars - Essay Example

The Existence of Plate Tectonics on Mars Contemporary researchers continue to debate whether or not Mars has a plate tectonic system similar to Earth. This paper reviews considerations regarding plate tectonics on Mars. Utilizing a review of literature, this paper also considers rocks one might find on Mars, as well as geophysical methods used to test the theory of Mars will ADD AT END Introduction Scientific observation of the surface of Mars has been greatly limited mostly to visual observations and the findings of remote controlled rovers sent by NASA to retrieve information. It is suspected that Mars may have had an atmosphere, water system, and crust similar to that of Earth. However, observations of the planet's current state shows Mars at much higher level of deterioration that that of Earth. NASA's latest Mars project, Phoenix, made a successful landing on Mars and spent five months collecting data that has yet to be fully analyzed on the planet's climate, soil, and atmosphere. This mission yielded further proof that there was a type of water on or near the surface of Mars. Soil samples collected prove that there could have once been sustainable life on the planet (Cowing). There have also been findings in recent years suggesting that Mars once had a molten inner core, much like our own. The presence of stripes along the crust layer of Mars, believed to be formed from the crust renewing itself through use of the molten core, lends further proof to the idea that there were once tectonic plates resembling those of Earth (Cain). "The theory of plate tectonics is based on the movement of rigid plates on the planet's surface. Plates are bounded a ridge where new crust is created, a trench or subduction zone, where the crust is consumed, and transform faults, along which plates slip" (Connerney, et al. 2005, p. 4). The question as to the existence of tectonic plates on Mars remains a very highly debated issues among scientists. Background on Plate Tectonics In its current state, Mars is essentially a dead planet, meaning there is no life present and little to no activity on behalf of the planet itself. The lakes and riverbeds have dried up and what is left of the atmosphere is being blown away in chunks by massive wind shears (Cain). Though it is believed that Mars could have once supported life, that seems virtually impossible now. New theories are supported by scientific evidence which suggest that the layers of Mars once greatly resembled the layers of Earth, including a molten core, tectonic plates, and a changing crust layer. It is believed that the molten core of the planet slowly cooled, leaving the stripes currently observable in the hardened crust. Proof of the tectonic plates was recorded by NASA's Mars Global Surveyor in a 1999 (NASA Press Release). While the initial findings only showed the striping of Mar's magnetic field in the southern hemisphere, new data shows that the magnetic field covers the entire surface of the planet in a pattern similar to that of Earth (NASA Status Report). (NASA/JPL) Along the striped lines of the magnetic field there are also fault formations and other geographic signs that point toward the existence of a tectonic plate system similar to that of our own planet. As an example of this, the Tharsis volcanoes on Mars are actually aligned in a straight line and it is now believed that, like the Hawaiian Islands, these volcanoes formed over a hot spot in the mantle (Cain). Fault formations, similar to the Martian ones, can only be formed by tectonic plates shifting, pushing new molten crust up from the planet's mantle and changing magnetic polarity of the area as it hardens (Cain). Unfortunately an exhaustive analysis of the geology of Mars has yet to be conducted. Therefore many of the currently accepted theories of the inner workings of the planet are based on what has been observed and studied on Mars combined with what is known about its sister planet, Earth. Whatever plate tectonics previously existed on Mars are assumed to be long extinct. There has been very little or no observable change in the Martian crust for many years. Where Earth is constantly changing due to its mantle and tectonic plates, Mars appears to now be solid throughout (Cain). Clearly there appears to be changes on the face of the planet however, this is more likely due the additional shearing off of its carbon dioxide atmosphere making it more vulnerable to being hit by meteors and asteroids (NASA Press Release). There are some researchers however, who question if Mars stripes formed through some other means, such as slow chemical alteration, rather than through creation of new crust, as evidenced on Earth by plate tectonics. Sean Solomon of the Carnegie Institution of Washington challenges the concept of plate tectonics on Mars; arguing that the theory proves challenging to comprehend. Solomon purports that Earth's upper ocean crust "is intensely magnetized because seawater cooled it rapidly forming tiny, easily magnetized crystals. But cooling a 30 kilometer slab would take tens of millions of years, leading to larger crystals that would be less easily magnetized" (Solomon, as cited in Kerr, p. 719). Solomon admits: "There's so much we don't know" (Ibid.). The amount of guesses and questions surrounding Mars mobile plates have some researchers wondering if perhaps the stripes were not formed through creation of new crust, but through some other means, such as slow chemical alteration. However, while the evidence suggests no active plate tectonics today, it also suggests that there existed such plate tectonics at some point in the history of Mars. New Evidence Gained in Study of Martian Rocks Several remote studies of the sedimentary properties of Mars have been conducted by NASA. The findings show a layer of carbon dioxide ice just below the surface of the planet, the only remnants of its early water system (NASA Status Report). Since the vast majority of the current surface of Mars was shaped by asteroid hits, dust from those strikes permeates the soil of the planet (Cain). Thanks largely to the less dense atmosphere of Mars scientists have been able to study rocks from the Red Planet as they fell to Earth as meteorites. A dozen or so small meteorites fell to Earth as the result of a large impact to Mars believed to have occurred several million years ago. The rocks that have been recovered on Earth were compared to the soil findings recorded on Mars to prove that they were in fact at one time a part of the Martian surface (Cowing). Of the rocks found and studied, one located in the Antarctic lends further proof to the idea that there could have once been some type of life on Mars. The rock contains magnetite crystals, formed by bacteria, which has been observed here on Earth. The crystals found in the Martian rock are very similar to the ones formed by the same bacteria on Earth. As there is no known way to produce the crystals non-biologically, the crystals could very well point to an ancient organism that once existed on Mars (Cowing). The geological structure of the meteorites is nearly identical to that of other rocks found and studied on Mars. There are known sedimentary and igneous rocks on the surface of the planet. It is believed that there were once metamorphic rocks present on Mars, but that they have long since disappeared due to the rapid cooling of the planet. The sedimentary rocks are purported to have been formed underwater on the ancient Martian surface (Cowing). Layered rock formations inside craters and depressions on the surface indicate that the rocks were formed by water in much the same way that they are formed on Earth. Another possible explanation is that a thick, dense early Mars atmosphere could have blown the soil into craters and other areas where the sediment would not have been disturbed which would have allowed the moisture in the air to assist in the formation of the rocks (NASA). Metamorphic rocks are rocks that have been changed by temperature and pressure. Since there is very little atmospheric pressure evident on Mars, there is only a very small chance of locating metamorphic rocks on the surface of the planet. Metamorphic rocks require intense heat and a constant changing of the planet, neither of which Mars has, leading to the conclusion that though the rocks may have at one time been in existence, they are not currently believed to be so (Cowing). While metamorphic rocks have been absent from scientific findings thus far, igneous rocks have played a large part in scientific discoveries concerning Mars over the last few years. In 2006, NASA's Spirit Mars rover discovered a new segment of igneous rocks near the center of the Gusev crater (NASA Status Report). These rocks were formed by an active volcano on Mars, a fact verified by their unaltered state. The volcanic rocks, formed by crystallized magma, contain amounts of potassium and sodium relative to the amount of silica present to be comparable to igneous rocks found on Earth (NASA Status Report). A rock with a larger amount of silica is hypothesized to explode violently from the surface while rocks containing more sodium and potassium are purported to have formed deeper in the Martian mantle from the partial melting of magma at a higher temperature. Due to the abundance of sodium and potassium evident, the Gusev rocks are referred to as alkaline rocks (NASA Status Report). The chart below illustrates the chemical makeup of these igneous rocks. (NASA) The new rocks, christened "Peace" by NASA, are possibly the most important rocks studied by the Spirit rover during its mission (Staff). The rocks lend more credence to the possibility of water having once existed on Mars. The high sulfate salt content, higher than any other rock previously analyzed by Spirit, goes deep into the rock, where previous specimens only maintained their sulfur salt deposits on the surface (Staff). Also unusual is that the amount of sulfur correlates directly to the amount of magnesium present, indicating the presence of magnesium sulfate, a mineral closely related to the presence of water, especially considering how the salt goes all the way through the rock. Scientists currently hypothesize that the salt deposits in the rock could have occurred from the rock being underwater where the liquid moved through the rock before dissolving, leaving behind the magnesium sulfate (Staff). This theory would work much like an Earth rock in a riverbed, where the water is constantly flowing over and around the rock. If the riverbed dried up, like the rivers and lakes on Mars, the rock would still contain some of the properties of the water. The black and white picture below shows the Peace rocks as observed by Spirit. The rock in the center of the frame is the one documented by the rover. (NASA/Spirit) In addition to the alkaline Peace rocks discovered and studied by Spirit, the new rocks found containing traces of bacteria are also considered to be igneous rocks (Staff). Further testing, including the analysis of data retrieved from NASA's last landed mission to Mars, the Phoenix, will lead to a better understanding of the geological makeup of Mars. Mission to Mars Mars has been studied via telescope and space exploration for the last several decades. It has always been a point of interest to humans due to the similarities to Earth that it exhibits. Even though these similarities are numerous and proven through scientific evidence to exist, Mars appears to be a dormant planet, even though its age is estimated at around the same as that of the Earth, around 4.6 billion years old (Cain). The differences in the planets are explained through the large difference in the sizes of the planets. It is widely believed that since Mars is only a fraction of the size of the Earth, it cooled much faster, quickly halting its tectonic processes, and leading to its current state (Cain). In an effort to unlock the secrets contained within the Red Planet, NASA along with other government agencies have sent many different unmanned missions to Mars, hoping to gain evidence to support their theories concerning the evolution of the planet. These missions range from explorers sent into orbit around Mars designed to take pictures and atmospheric readings to more sophisticated robotic missions that have been able to take surface readings and soil samples. The next big step in the exploration of Mars is to send a manned mission to the planet in order to explore and study findings first-hand. While much progress has been made without sending humans into the far reaches of space, exploration of Earth's sister planet is greatly hampered by only having a machine there with limited capabilities that will not be able to return its samples to Earth for further study in laboratories. In depth study of the planet would be much more complete with an actual team of astronauts there who are trained in many different capacities, who could travel over a much further distance than the Mars rovers, exploring previously unseen territory. These scientists could also not only study what is physically found on Mars, but they could also bring the samples back to Earth for further dissection in laboratories. In the search for evidence of ancient life on Mars, it will eventually be necessary to gain first-hand documentation from someone who has been there. Another means for collection of data on mars would be the use of the LOCI or Laser - Based Optical and Chemical Imager. Utilizing a "point and shoot" laser technique as noted in ("Shooting Life in Mars" 2008), the scientists can identify organic molecules lodged in Martian samples. This method will reportedly preserve more of a rock sample while at the same time reducing the risk of contamination. While too large to carry to Mars, the LOCI would be used for more intensive analysis of the specimens brought to earth. Therefore, I propose a manned mission to Mars and the use of Nuclear Based Technology to further study the theory of plate tectonics on Mars. Conclusion Mars is a great keeper of secrets for the scientific community. With each mission new and exciting things are discovered about the planet that once so closely resembled our own. Proof of the existence of tectonic plates is growing with each new finding. As we have more modern and sophisticated technology to send into space for the recovery of information, the higher the yield of that information in regards to the history of Mars. With the current growth of space exploration, it is not unfeasible that a manned mission to Mars will occur within the next generation. As knowledge about this planet is continually gained, we find indicators for the distant evolutionary future of our own planet. Works Cited Cain, Fraser. "Mars Once Had Plate Tectonics." 21 October 2005. Universe Today. 1 December 2008 . Coleman., N.M. (2001). Detecting ground ice from recent fluid flows on Mars. 7 Dec. 2008 . Connerney, J.E.P., Acuna, M.H., Ness, N.G, Kletetschka, G., Mitchell, D.L., Lin, R.P., and Reme, H. (2005). Tectonic implications of Mars crystal magnetism. PNAS. 7 Dec. 2008 . Continents in Collision: Pangea Ultima. (2000, October 6). 5 Dec. 2008 < http://science.nasa.gov/headlines/y2000/ast06oct_1.htm>. Cowing, Keith. "NASA Announces New Evidence Regarding Past Life on Mars." 26 February 2001. Glencoe. 3 December 2008 . How can you tell rocks on another planet apart (N.d.). Earth and Apace Sciences. University of Washington. . Kerr, Richard A. "Signs of plate tectonics on an infant Mars" Science. Washington. Apr 30. 1999. Vol. 264. lss. 5416; pp. 719-721. "Mars." The Columbia Encyclopedia, Sixth Edition. 2008. HighBeam Research. 5 Dec. 2008 . Mcrae, Kim A. "Martian stripes imply ancient plate tectonics." The Chronicle of Higher Education. Washington: May 7, 1999. Vol 4.5. Is.. 35; pg. A24. NASA. Martian Meteorites. Caltech. Mars Today. New York, 2006. NASA Press Release. "Science at NASA." 29 April 1999. Plate Tectonics on Mars 3 December 2008 . NASA. "Sedimentary Mars." 4 December 2000. Science at Nasa. 3 December 2008 . NASA spacecraft shows diverse, wet environments on ancient Mars. US Fed News Service, Including US State News. HT Media Ltd. 2008. HighBeam Research. 5 Dec. 2008 . NASA Status Report. "NASA Mars Rover Spirit Discovers New Class of Igneous Rocks." 26 August 2006. Mars Today. 2 December 2008 . NASA/JPL. Crustal Magentism Readings Across Mars. NASA. Universe Today. New York, 2005. NASA/Spirit. Peace. NASA. Space.com. Los Angeles, 2005. "plate tectonics." A Dictionary of Astronomy. 1997. HighBeam Research. 5 Dec. 2008 . Plate Tectonics on Mars (1999, April 29). Space Science News Home. 5 Dec. 2008 . Shooting Life on Mars (2008, Oct. 17,) 7 Dec. 2008 . Staff. "New Rock Type Found at Mars." 15 February 2005. Space.com. 3 December 2008 . "Tharsis Montes." A Dictionary of Astronomy. 1997. HighBeam Research. 5 Dec. 2008 . Read More