Atmosphere Evolution on Rocky Planets - Essay Example

Atmosphere Evolution on Rocky Planets Customer’s Name: Lecturer’s Name: Course Code: Date Introduction Atmosphere has been evolving through the years with the improvement or deterioration attributed to factors that are both natural and anthropogenic. In the first atmosphere there was many gases basically the nitrogen gas found in the solar nebula. Alongside the hydrogen there were also other compounds of hydrogen including the hydrides which today are found in the form on Saturn and Jupiter planets. In the solar nebula there were also other compounds such as the ammonia, methane as well as water vapour. With time there was dissipation of the solar nebula releasing the gases which were moved by the solar wind. With the dissipation of the first atmosphere another atmosphere formed consisting mostly of the nitrogen gas although there was also presence of carbon dioxide as well as other inert gases. The other gases came from the activities of volcanism such as the eruptions of the volcanic mountains as well as asteroids bombardments on earth. Presence of the carbon dioxide alongside the water vapor led to reactions to form compounds of carbonates. These carbonate elements have been existence for very long back dating to more than there billion years ago. It is also postulated that it was around this second atmosphere that there were signs of different life forms attributed to the presence of the nitrogen gas (Donahue et. al, 1997). In the third atmosphere there was regular transfer and movement of carbon dioxide between the atmosphere and the formed carbonate compounds that acted as stores for these elements. Presence of free existing oxygen in the atmosphere was only reported about slightly more than 2 billion years ago at a Great Oxygenation Event. It was attributed that the source of the oxygen was the photosynthetic activity of the plants although it’s reduction was also attributed to the activities of oxidation that occurred in reducing of different materials for instance iron. Hence the existence of oxygen freely in the atmosphere started at a point where the rate of production of oxygen by the plants surpassed the rate of the consumption of the gas especially by the reduction of materials. With the increasing amount of oxygen in the atmosphere, this signified a shift from a reducing atmosphere to an oxidizing atmosphere with varying amounts of oxygen in the atmosphere that was not stable until later in the Precambrian period where it stabilized to above 15%. With that Phanerozoic period came the metazoan life form which was characterized with the breathing of oxygen. Oxygen levels in the atmosphere fluctuated for over 600 million years before it stabilized at the current 21%. The fluctuation was perhaps attributed to use of carbon dioxide by plants that in return gave oxygen in return, volcanic eruptions also gave rise to increased amounts of sulfur in the atmosphere which reduced significantly the amounts of oxygen in the atmosphere (Dorren & Guinan, 1994). Perhaps an interesting development to this is that the while the volcanic eruptions gave rise to the sulfur that reduced significantly the amount of oxygen in the atmosphere, the eruptions also released carbon dioxide that was being used up by the plants to avail more oxygen in the atmosphere. All these dynamics are perhaps a good explanation for the variation of the amounts of oxygen in the atmosphere. The stability of oxygen in the atmosphere was only witnessed with the development of the different animals in the atmosphere that were also using up the oxygen to meet their needs. The factors explain that the variation in oxygen not only alludes to the existing life forms but also the atmospheric evolution and variation that have taken place over the years. Atmospheric variations take place not only due to the natural factors but also the anthropogenic factors such as the pollution and the introduction of the greenhouse gases into the atmosphere. Most of these introductions are due to the human activities in the atmosphere (Dorren & Guinan, 1994). Compare evolution of atmosphere on Earth, Venus and Mars. Armed with a detailed understanding of our planet earth’s atmosphere it becomes easier, necessary and critical to study its composition, characteristics and pattern in comparison to other bodies that make part of the solar system. Bearing in mind of the content of the earth and its properties, we can use this knowledge to comprehend the formation and evolution of atmosphere of not only earth but also the other planets that are part of the solar system. In our case we would use the planets Mars and Venus perhaps because of the near proximity to the planet earth (Guinan & Ribas, 2002). However some scholars allude the use of Mars and Venus in the study to compare the atmospheres of the different planets to the fact that the two planets are the sizes of laboratories. Both the Mars and Venus are very rocky planets and form part of the inner core of the solar system. However one of the differences of these three planets is their proximity to the sun with Venus being the closest compared to earth and Mars that is furthest aware of the three planets. Exploring the evolution of the three planets especially for our case on earth, the study of Mars and Venus with regards to the atmosphere helps us in the comprehension of our own atmosphere, the earth’s atmosphere. Many theories have been put forward about the formation of the different planets, perhaps relating this can give us an idea of how our planet earth’s atmosphere formed. The whole solar system according to postulations was formed from majorly the cloud of gases and dust. Planets and the moon were formed through ignition by the sun that resulted to the formation of nuclear fusion. This led to the formation of larger clumps of matter made up of the dust and gas with this clump formation accelerated by the gravitational attractions that were mutual across the solar system. Protoplanetary that was formed subsequently was subjected to a lot of forces. These forces were acting on the clumps that were being formed (Kallenbach et. al, 2003). Explain differences in current atmospheric conditions on these planets Despite the similarity in their rocky characteristics as well as similarities in their histories of formation, Earth, Mars and Venus have atmospheres that are very different from each other. The atmosphere of Mars is thin while that of the Venus is described as the crushing atmosphere and finally the atmosphere of earth is a blue atmosphere that gives and supports life. Differences can also be classifies or studied in terms of the historical composition and formation of the atmospheric gases of the three different planets as this gives an idea of the atmospheric formations. For instance the differences in the densities of the gases in the three planets could perhaps be the reason for the difference in the three atmospheres (McGrath et. al, 2004). The atmosphere of the earth is majorly made up of nitrogen and oxygen. Yet it is a known fact from the study of evolution and formation of earth that earth’s oxygen is unique made more unique by the fact that it is only found on planet earth hence life. Oxygen in the earth is also known to be highly reactive with the different elements of the environment and hence there is need to constantly be availed in the atmosphere by the plants to prevent the shortage. Some of the elements that react with oxygen include metals and also the crust of different rocks that sequester the gases. However most of the earth is made up of nitrogen gas with this constituting 78% of the atmospheric gases. However there is a challenge in explaining how such a large amount of gas found itself on earth with regards to its formation and larger composition. However common to the three planets in perhaps the similarity in the nitrogen gas formation mechanisms as all the three planets have atmospheres that are nitrogen rich. Nitrogen has a similar atomic mass to oxygen but however unlike oxygen it is a relatively non reactive gas which support the fact that its made of eons through means of outgassing of planet earth’s surface especially on planets with gravity equal to or almost equal to that of the earth’s with a similar heaviness (McGrath et. al, 2004). Describe how earth’s atmosphere helped life to originate, survive and develop. For the planet Venus, its atmosphere is majorly composed of carbon dioxide with nitrogen forming a small part of its atmosphere. The amount of nitrogen in Venus is very small and is four times more than that of earth’s atmosphere. Although almost the same size as earth Venus undergoes a lot of volcanism which provides a great source of outgases products and materials. This is perhaps the reason behind the reason behind the larger amount of the nitrogen gas in the planet Venus four time that of planet Earth. Due to this amount of gases and larger source of the gas, the atmosphere of Venus is much denser than that of the Earth. On the other hand the atmosphere of Mars is the thinnest with only 3% of nitrogen (Johnson et. al, 2004). The surface air pressure on Mars is less than 1% Earth’s surface air pressure. This leads to questions of where did the Nitrogen on planet Mars go to or why is it diminishing? However in an effort to answer these questions and study of nitrogen it has been discovered that there is high quantity of heavy isotopes compared to the nitrogen on Earth. The presence of these heavy isotopes could perhaps be explained by the fact that the lighter isotopes escaped the planet leaving only the heavier isotopes in the planet. Maybe at some point the planet Mars had an almost equal amount of nitrogen as the earth but lost most of its nitrogen especially the lighter isotopes because of the fact that the planet could not hold onto the lighter isotopes because of its lower gravity compared to earth. Water is abundant on planet earth since the time of its formation with plenty of surface water existing on planet earth in its different forms. However for the planet mars there is little presence of surface water although there is presence of water stored in the permafrost as well as the polar ice caps. The little amount of water in the planet mars exists in 0.003% of the atmosphere compared to 0.4% of the earth’s atmosphere. Due to the low pressure in the planet Mars, water cannot exist in liquid form as this will quickly evaporate or sublime explaining why there is no presence of surface water in the planet. However there is plenty of evidence to show that there was water in the planet Mars. These include topographical evidence of lakes, rivers as well as other water bodies suggesting rains and snowing at some point of the planet’s life (Johnson et. al, 2004). Occurrence of volcanic activity in the planet Mars is also evidence that a lot of water vapour was released into the atmosphere at about 120 metres underwater hence availing more carbon dioxide on planet Mars more than that on Earth. This carbon dioxide should have been sufficient enough to support the existence of liquid water but however a number of factors did not favour this: such as the less gravitational pull on the planet compared to other planets especially earth. Then unlike planet earth, the planet mars does not have magnetosphere to protect its atmosphere from activities such as erosion from the solar wind. In the planet mars, the atmospheric gases are replenished by the volcanic eruptions although they are less frequent and smaller compared to those occurring on Earth. With this compounded by the lack of magnetosphere to protect the atmosphere the only option is that the volcanic activity is not sufficient enough to counter the loss occurring due to losses by the solar wind. All these therefore make it difficult for the planet Mars to maintain its surface water especially in liquid form (McGrath et. al, 2004). Venus is believed to have started out just like planet Earth and planet Mars with a lot of water in the planet although it is just a theory that does not have much evidence in the planet to support it. However recent scientists found evidence that could support this theory, the evidence in form of granite rock. As known, granite is a rock that can only be formed when tectonic activity occurs in the presence of water on basalt rocks. The presence of granite rock is sufficient to support that at one point there existed surface water in planet Venus. However today there is no water with only 20 ppm of water vapor as the only existing water form (Johnson et. al, 2004). How has life affected the atmosphere over time? Compared to earth, Venus is by far much denser and hotter maybe due to its atmospheric constitution which is majorly nitrogen and carbon dioxide with almost on water vapour in its atmosphere. Although it may have been like earth some point, its constant and frequent volcanic activity introduced a lot of carbon dioxide into its atmosphere which outgases the atmosphere resulting to its present conditions of high density and temperature. Researchers believe that the planet underwent a runaway green house effect which did not happen on earth as well. Differences in the two planets is explained by the carbon cycle difference in the tow planets with earth having the plant effect on the carbon sequestration a factor that is lacking in the planet Venus (McGrath et. al, 2004). References McGrath, M.A., E. Lellouch, D.F. Strobel, P.D. Feldman, R.E. Johnson, in Jupiter—The Planet, Satellites and Magnetosphere, ed. by F. Bagenal, T. Dowling, W.B. McKinnon (Cambridge University Press,Cambridge, 2004), p. 457 Johnson R.E., R.W. Carlson, J.F. Cooper et al., in Jupiter-The Planet, Satellites and Magnetosphere , ed. By F. Bagenal, T. Dowling, W.B. McKinnon (Cambridge University, Cambridge, 2004), p. 485 Kallenbach R., T. Encrenaz, J. Geiss, K. Mauersberger, T. Owen, F. Roberts, Solar System History from Isotope Signatures of Volatile Elements (Kluwer, Dordrecht, 2003) Guinan E.F., & I. Ribas, in The Evolving Sun and its Influence on Planetary Environments, vol. 269, ed. by B. Montesinos, A. Giménez, E.F. Guinan (ASP, San Francisco, 2002), p. 85 Donahue T.M., D.H. Grinspoon, R.E. Hartle et al., in Venus II, ed. by S.W. Bougher, D.M. Hunten, R.J. Phillips (The University of Arizona Press, Tucson, 1997), pp. 385–414 Dorren J.D., E.F. Guinan, in The Sun as a Variable Star , ed. by J.M. Pap, C. Frölich, H.S. Hudson, S.K. Solanki (Cambridge University Press, Cambridge, 1994), p. 206 Read More

The fluctuation was perhaps attributed to use of carbon dioxide by plants that in return gave oxygen in return, volcanic eruptions also gave rise to increased amounts of sulfur in the atmosphere which reduced significantly the amounts of oxygen in the atmosphere (Dorren & Guinan, 1994). Perhaps an interesting development to this is that the while the volcanic eruptions gave rise to the sulfur that reduced significantly the amount of oxygen in the atmosphere, the eruptions also released carbon dioxide that was being used up by the plants to avail more oxygen in the atmosphere.

All these dynamics are perhaps a good explanation for the variation of the amounts of oxygen in the atmosphere. The stability of oxygen in the atmosphere was only witnessed with the development of the different animals in the atmosphere that were also using up the oxygen to meet their needs. The factors explain that the variation in oxygen not only alludes to the existing life forms but also the atmospheric evolution and variation that have taken place over the years. Atmospheric variations take place not only due to the natural factors but also the anthropogenic factors such as the pollution and the introduction of the greenhouse gases into the atmosphere.

Most of these introductions are due to the human activities in the atmosphere (Dorren & Guinan, 1994). Compare evolution of atmosphere on Earth, Venus and Mars. Armed with a detailed understanding of our planet earth’s atmosphere it becomes easier, necessary and critical to study its composition, characteristics and pattern in comparison to other bodies that make part of the solar system. Bearing in mind of the content of the earth and its properties, we can use this knowledge to comprehend the formation and evolution of atmosphere of not only earth but also the other planets that are part of the solar system.

In our case we would use the planets Mars and Venus perhaps because of the near proximity to the planet earth (Guinan & Ribas, 2002). However some scholars allude the use of Mars and Venus in the study to compare the atmospheres of the different planets to the fact that the two planets are the sizes of laboratories. Both the Mars and Venus are very rocky planets and form part of the inner core of the solar system. However one of the differences of these three planets is their proximity to the sun with Venus being the closest compared to earth and Mars that is furthest aware of the three planets.

Exploring the evolution of the three planets especially for our case on earth, the study of Mars and Venus with regards to the atmosphere helps us in the comprehension of our own atmosphere, the earth’s atmosphere. Many theories have been put forward about the formation of the different planets, perhaps relating this can give us an idea of how our planet earth’s atmosphere formed. The whole solar system according to postulations was formed from majorly the cloud of gases and dust. Planets and the moon were formed through ignition by the sun that resulted to the formation of nuclear fusion.

This led to the formation of larger clumps of matter made up of the dust and gas with this clump formation accelerated by the gravitational attractions that were mutual across the solar system. Protoplanetary that was formed subsequently was subjected to a lot of forces. These forces were acting on the clumps that were being formed (Kallenbach et. al, 2003). Explain differences in current atmospheric conditions on these planets Despite the similarity in their rocky characteristics as well as similarities in their histories of formation, Earth, Mars and Venus have atmospheres that are very different from each other.

The atmosphere of Mars is thin while that of the Venus is described as the crushing atmosphere and finally the atmosphere of earth is a blue atmosphere that gives and supports life. Differences can also be classifies or studied in terms of the historical composition and formation of the atmospheric gases of the three different planets as this gives an idea of the atmospheric formations.

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