The three planets are approximate equidistance from the sun. This means that, their characteristics are relatively similar. However, there are remarkable differences between the three planets. In order to explain why the atmosphere of Mars, Venus, and Earth are different, the paper shall discuss the atmospheric characteristics of atmosphere of each of the three planets. This paper has clearly brought up the differences in the atmosphere of the three planets being studied.
Difference in Atmosphere of Mars, Venus and Earth
Venus and Mars do not support life. This is because Venus has extremely high temperatures while Mars is too cold to support any life. In terms of size and mass, Venus is approximately 95% bigger than the Earth with an extra mass of about 82% to that of the Earth (Koupelis, p. 79). The only similarity between the Earth and Venus is that, both planets have iron nickel core and a rocky crust. Another significant difference is that, Venus is made up of 96% carbon dioxide, 3.5% nitrogen, and 0.5% account for other gases unlike the case of Earth and Mars. Venus is also made up of sulphuric acid droplets that form a cloud. These clouds prevent astronomists from seeing the planet clearly. In addition, Venus presents another significant difference from the Earth in terms of air pressure. It has an air pressure of about 92% times more than that of the Earth (Koupelis, p. 77-79).
The lower clouds in Venus move at a speed of about 210 kilometres per hour while the upper clouds move at a speed of about 370 kilometres per hour. This is not the case in planet Earth. Also, in Venus, the clouds in the polar regions are weak and remain unchanged even with changes in height. This is because of the presence of a huge hurricane-like vortex. At the centre of this vortex, there are no winds, which can be found. Venus has presented itself as the hottest of all the three planets under investigation. This is because the planet has a temperature of 477 degrees Celsius. There are claims that the planet could have been twice hotter than it is today (Thompson and Turk, p. 292). The greenhouse effect is responsible for the increased temperature. This means that the super-abundance of carbon dioxide within the atmosphere results into a huge greenhouse effect. In addition, the presence of large content of carbon dioxide in Venus presents another significant difference between the three planets. Unlike Venus, carbon dioxide in the Earth is locked up in sediment contents (Thompson and Turk, p.297).
According to Gorlitz, Venus was cooler than it is today (p.78). This is because of the abundance of water. In addition, a lot of carbon dioxide got held up within the rocks many years ago. However, the situation has changed through the process called runaway green house. In this process, Venus has turned up to be the hottest planet. This can be attributed to its closeness to the sun compared to the other two planets. Another difference is that, rocks in Venus are harder than those rocks found in the planet Earth due to water loss from the rocks through a process called dissociation (Gorlitz, p. 108). This means that, water in Venus was always in gaseous form. In this case, the water could rise high up in the atmosphere whereby it was heated by Ultraviolet light from the sun. This process led to dissociation of water molecules into oxygen and hydrogen atoms. In addition, the Earth and Venus differ in terms of the ratio of ordinary hydrogen to deuterium. The ratio of ordinary hydrogen to deuterium is 1000 to 1 on the planet Earth. On the other hand, in Venus, the ratio is approximately 10 times greater than that of planet Earth (Gorlitz, p. 111). Unlike the Earth where volcanic eruptions still occur, in Venus, such eruptions are no longer occurring (Lang, p. 66).
Unlike Venus and Mars, the Earth, has an atmosphere that is composed of 78% nitrogen and 21% oxygen and less than 0.0001% Earth mass, with 0.023% amount of water (Koupelis, p. 82). The planet has free oxygen, and it is the only planet that supports life compared to Venus and Mars. However, this oxygen is at a risk of disappearing because of massive destruction of plants. Destruction of plants will prevent the process of photosynthesis from taking place. This leads to lack of adequate oxygen being released by plants into the atmosphere (Lang, p. 68). Unlike Venus, most of the planet Earth is covered with water. This water helps to prevent the atmospheric carbon dioxide from exceeding the normal levels. This is because the water acts as a solvent where carbon dioxide dissolves. Additionally, the Earth has a protective layer called the Ozone, which prevents most of the ultraviolet rays from reaching the earth’s surface. The ozone layer helps to promote life on the earth surface (Lang, p. 69).
Mars differ with the Earth in many ways that may be explained in terms of mass, size, percentage of the gas content, and temperatures among others. According to Koupelis, planet Mars has a mass of about 0.1 of the Earth’s mass, and a thin atmosphere of 0.01as compared to that of the Earth (p. 78). This planet also does not have much heat as compared to the Earth and Venus. In addition, it has a carbon dioxide content of 95% and Nitrogen of 3%. Mars has a rapid cooling system and a layer of atmosphere that makes a greenhouse effect insignificant. At night, the temperature at Mars is approximate 180 degrees Fahrenheit. This temperature is too low to support life. The large disparity in temperature on Mars, leads to the emergence of a very strong wind, which whip all over creating a dust. The dust covers the entire planet making the planet invisible for about six months (Thompson and Turk, p. 78).
This scenario presents another significant difference between the three planets. In addition, Mars differs with the other two planets in terms of air pressure. In this planet, air pressure is extremely low to support the existence of pure liquid water. In this case, at a very low pressure, water exists either in the form of frozen liquid or as gas. Another significant discrepancy is that, unlike the Earth, Mars has no protective Ozone layer. Therefore, all the ultra-violet light can reach Mars (Gorlitz, p. 106). Also, Mars is a cold desert. This is because Mars is at a very low gravity, and that, a lot of asteroid blaster part of the atmosphere. More importantly, Mars has a run-away refrigerator greenhouse effect that started occurring many years ago. This is not the case with the other two planets- Venus and Earth (Lang, p. 85).
Therefore, based on the above discussion, it can be observed that the atmosphere of the Mars, Earth and Venus differ from each other greatly. This is in terms of temperatures air pressure, gases content, size, and mass among other aspects.
Gorlitz, Vivien. Encyclopaedia of Paleoclimatology and Ancient Environments. Berlin: Springer Netherland, 2007. Print.
Koupelis, Theo. In Quest of the Universe. Sudbury, Mass: Jones and Bartlett Publishers, 2011. Print.
Lang, Kenneth R. The Cambridge Guide to the Solar System. Cambridge: Cambridge Univ. Press, 2011. Print.
Thompson, Graham R. and J. Turk.Earth Science and the Environment. Australia: Thomson Brooks/Cole, 2007. Print.