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Thread: The Planets Report

  1. #1 The Planets Report 
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    Apr 2009
    Christina Cortman

    The Planets Report
    Earth and Space Science

    The solar system is defined as the region of the universe near the sun, that includes the sun, the nine known major planets and their moons or satellites. The planets, in order from their distance to the sun, include, Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. The three moons that are talked about in this report are the moons from Jupiter, Saturn and Neptune. Their names are Io, Titan and Triton.
    In the following report you will learn important and interesting facts about the planets and their moons, some of which may surprise you.

    Mercury is 57,910,000 km. from the sun and has a diameter of 4,880 km. It moves quickly across the sky and has a mass of 3.30e23kg. Mercury has been visited by two spacecrafts, the Mariner10, which flew by in 1974 and 1975, and The Messenger, which was launched by NASA in 2004 and will orbit starting in 2011 after several flybys. At itís closest point to the sun, the perihelion, Mercury is 46,000,000 km away. And at itís aphelion, it is 70,000,000 km away. The atmosphere is very thin and it consists of atoms blasted off by the solar wind. Itís interior is dominated by a large iron core, with a radius of 18-19 thousand km, and a silicate outer shell which is only 500-600 km thick. At least some of the core is probably molten. Mercuryís surface is heavily cratered and very old, and has no plate tectonics. The temperature variations are the most extreme in the solar system ranging from 90K to 700K.

    Venus is 108,200,200 km from the sun with a diameter of 12,103.6 km and a mass of 4.869e24kg. It is the brightest of all the planets and hotter than Mercury even though it is twice as far away from the sun. Itís dense atmosphere produces a greenhouse effect that raises the temperature to 400 degrees to over 740K. Venusí atmosphere is composed mostly of carbon dioxide and the pressure at the surface is 90 atmospheres. More than twenty spacecrafts in all have visited Venus, including The Mariner 2 in 1962, Pioneer Venus, Venera 7, Venera 9, Magellan, and Venus Express which is currently in orbit. It has no magnetic field, therefore producing a slow rotation.
    On June 8, 2004, Venus passed directly between the Earth and the Sun, appearing as a large black dot across the sunís disk. This is known as the ďTransit of VenusĒ and it is very rare. The last time this happened was in 1882, and it will happen again in 2012. But if you miss it in 2012, the next time it will be happening is not until 2117. Venus probably once has large amounts of water, but because of the high temperatures, it probably all boiled away, leaving the planet quite dry at the moment.

    Earth is probably the most interesting planet for a lot of people to learn about because itís the one we live on. It is the only planet with known life and it is located 149,600,000 km from the sun. It has a mass of 5.972e24 kg and a diameter of 12,756.3 km. All of the other 8 planets got their names from Greek or Roman mythology, whereas Earth originated from Old English and Germanic.
    Earth is divided into several layers which have distinct chemical and seismic properties. They are as follows: the crust, upper mantle, transition region, lower mantle, D layer, outer core, and an inner core. The crust is thinner under the oceans and thicker under the continents. The temperature of the Earthís core is said to be hotter than the surface of the sun. The atmosphere of the Earth is composed of 77% nitrogen and 21% oxygen. 71% of the Earth is covered with water and it is the only planet where water can exist in liquid form on the surface. Earthís chemical composition consists of: 34.6% iron, 29.5% oxygen, 15.2% silicon, 12.7% magnesium, 2.4% nickel, 1.9% sulfur and 0.05% titanium. All of the planets have different ways that the measure a day, Earth has a 24 hour day according to itís rotation. The Earthís crust is divided into several separate solid plates, called tectonic plates, which flow around independently on top of the hot mantle below. Plate tectonics are important, especially when dealing with earthquakes and volcanic eruptions. They can help us locate the starting point of an earthquake and it can help us stay prepared.

    Mars is the fourth planet from the sun and the seventh largest in the solar system. It is located 227,940,000 km from the sun. It has a diameter of 6,794km and a mass of 6.4219e23 kg. Mars has a very thin atmosphere composed mostly of 95.3% carbon dioxide, 2.7% nitrogen, 1.6% argon, and traces of about .15% oxygen and 0.03% water. Like Venus, Mars produces a greenhouse effect, but it is only enough to raise the surface temperature by 5K.
    Several spacecrafts have visited Mars and left us with some very interesting facts. These spacecrafts include: the Mariner 4 which visited in 1976, Mars Pathfinder successfully landed July 4, 1997, Mars Expedition Rovers in 2004, and the Phoenix in 2008. Currently, the Mars Reconnaissance Orbiter, the Mars Odyssey, and the Mars Express are orbiting Mars. There have been many scientists who believed that if there was life on another planet, that it would exist on Mars. Experiments were done and have come to the conclusion that there may have at one time been life on Mars but at the moment, there is no proof of any now living. Many of the scientists believe that the tests done were inaccurate because there were only two small samples taken and they were from unfavorable locations.
    Mars is easily visible to the eye, but only for three or four months while it is closest to the Earth. The size of this planet depends on the position of the Earth at the time of measurement.

    Jupiter is the largest planet in the solar system. It is more than twice as big as all the other planets combined with a diameter of 142,984 km and a mass of 1.900e27 k. The location of Jupiter is 778,330,000 km from the sun. Jupiter is a gas planet which means it does not have a solid surface. The outermost layer is composed primarily of ordinary molecular hydrogen and helium which is liquid in the interior and gaseous further out. The gaseous material gets denser with depth. Tiny amounts of water, carbon dioxide, methane, and other simple molecules are also present. The interior of this planet is about 20,000 K which is very hot. It is the fourth brightest object in the sky and has four large moons which are, Io, Europa, Ganymede and Callisto.
    Spacecrafts that have visited Jupiter include, Pioneer 10 in 1973, Pioneer 11, Voyager 1 and Voyager 2, and the Ulysses. Galileo orbited Jupiter for 8 years and the Hubble Space Telescope still regularly observes this planet.
    Jupiter has rings like Saturn but they are much fainter and smaller. They are dark in color and contain no ice. It is said they are probably composed of very small grains of rocky material.

    Saturn is the second largest planet in the solar system located 1,429,400,000 km from the sun. It has a diameter of 120,536 km and a mass of 5.68e26 kg. The first to observe Saturn with a telescope was Galileo in 1610. Since than it has been visited by Pioneer 11 in 1979, Voyager 1 and 2 and Cassini. When viewed through a telescope, Saturn appears flattened. It is the least dense of all the planets and itís specific gravity is less than that of water. It is the only planet which is less dense than water.
    The atmosphere is made up of hydrogen with small amounts of helium and methane. The interior is 12,000 k at the rocky core and has a liquid metallic hydrogen layer and a molecular hydrogen layer. There are traces of various ices also present.
    As Saturn moves into orbit, Earth passes through the rings every few years.
    The ring system is divided into seven major divisions with alphabetic designators in the center of the discovery. They are, D, C, B, A, F, G and E. F and G are very thin and difficult to see whereas A, B and C are broad and visible. The origin of the rings are unknown and may only be a few hundred million years old.

    Uranus was the first planet discovered in modern times. It had been seen many times in previous years but was always ignored as just another star. It is located 2,870,990,000 km from the sun and has a diameter of 51,118km and a mass of 8.683e25 kg.
    It has only been visited by one spacecraft, Voyager 2 on January 24, 1986. Uranus is composed primarily rock and various ices with only about 15 percent hydrogen and a little helium. Itís atmosphere is 83% hydrogen, 15% helium and 2% methane. The magnetic field is unlike that of the other planets. It is not centered on the planet, it is tilted about 60 degrees. Uranus has 21 moons and 6 that are unnamed.

    Neptune is located 4,504,000,000 km from the sun with a diameter of 49,532 km and a mass of 1.0247e26 kg. Like Uranus, it has only been visited by one spacecraft. The Voyager 2 visited Neptune on August 25, 1989. It is a gas planet and has rapid winds confined to bands of latitude and large storms of vortices. The winds are known to be the fastest in the solar system reaching up to 2000 km/hour. The atmosphere is made up of mostly helium and hydrogen with small amounts of methane and it has a small core made up of rocky material.
    It has rings like some of the other planets and one seems to have a twisted unusual structure. They are dark but the composition of the rings is unknown.

    Pluto is located 5,913,520,000 km from the sun and the diameter is only 2274 km with a mass of 1.27e22 kg. There is little known about this planet because it is so small and far from the sun that it is hard to observe through modern technology. It is probably composed of 70 percent rock and 20 percent water ice.
    Pluto was accidentally discovered in 1930 and is referred to as the ďdwarf planet.Ē It is smaller than seven of the solar system moons and has not yet been visited by spacecrafts. They hope to be able to by the year 2015. It has one known satellite, Charon. There are two tiny moons orbiting the planet, Nix and Hydra. Little is known about the atmosphere but scientists believe that it probably consists of nitrogen with some carbon monoxide and methane. The atmosphere may only exist as a gas near its perihelion. Although the composition is unknown, the density of the planet is about 2gm/cm^3.

    Moons In the Solar System

    Discovered by Galileo and Marius in 1610, Io is the fifth of Jupiterís known satellites and the third largest. It is slightly larger than Earthís moon with a diameter of 3,630 km and a mass of 8.93e22 kg. It orbits 422,000 km from Jupiter making itís distance from the sun 778,752,000 km. Io has a thin atmosphere composed of sulfur dioxide and possibly some other gases. The surface is very young and has very few craters. On the other hand, it has hundreds of volcanic calderas, some of which are active. Io is primarily composed of molten silicate rock and a core made of iron. Although the average temperature of hot spots located on Io is a low 130 K, some of itís hottest spots may reach up to 2000 K. It has been visited and observed by Pioneer 10 and 11, Voyager 1 and 2, and Ulysses.

    Discovered by Christiaan Huygens in 1655, Titan is the fifteenth and largest of Saturnís known satellites. It orbits 1,221,830 km from Saturn making it 1,430,621,830 km from the sun. Because of itís thick hazy atmosphere, it is hard to really study Titan. The atmosphere is composed of primarily molecular nitrogen with more than 6 percent argon. There are trace amounts of at least a dozen other organic compounds which make up methane.
    Titan is composed of half water ice and half rocky material. Itís temperature reaches 94 K, which is -290 F. It has been visited by several spacecrafts such as Pioneer 11, Voyager 1 and 2 and Cassini, none of which have been able to give us a very thorough description of the moon.

    Triton was discovered by Lassell in 1846. It orbits 354,760 km from Neptune making itís distance from the sun, 4,504,354,760 km. The diameter of Triton is 2700 km and it has a mass of 2.14e22 kg. It is composed of 25 percent water ice and the remainder is rocky material.
    The interesting thing about Tritonís orbit is that it is retrograde, meaning it orbits backwards. It has an atmosphere but it is very small, only about 0.01 millibars. The atmosphere is mostly composed of nitrogen with a small amount of methane, giving it a thin haze that extends 5 to 10 km. Triton has only been visited by one spacecraft, Voyager 2 in 1989, and all of the information we have on this moon was obtained from this visit.
    There are few craters visible on the surface which means that it still has a very young surface. Itís temperature is 34.5K making it as cold as Pluto. Because it is so far from the sun, little sunlight is absorbed. With temperatures like this, methane, nitrogen and carbon dioxide all freeze to a solid.
    One of the most interesting things about this moon is that even with itís cold temperatures, it still has volcanoes. They are called ice volcanoes and when they erupt, they erupt liquid nitrogen, dust or methane compounds from beneath the surface.

    Why Pluto is no longer considered a planet.

    Growing up in school, we were all taught that there were nine planets and that some of these planets had moons or satellites that orbit around them. Recent studies have said otherwise and have not included Pluto in the list of planets. One of the main reasons is that Pluto is too small. It is smaller than Earthís moon and itís own moon, Charon, is about half the size of Pluto itself. Astronomers suggested that instead of being referred to as a planet and a satellite, they be referred to as a binary system.
    Some scientists believe that Pluto may have even originated somewhere else in space and got caught in the sunís gravity. It may have been one of Neptuneís moons at one point. Another reason that they decided to remove itís planetary status is because of they way it orbits. All of the planets orbit the sun in a flat plane, whereas Pluto orbits at a seventeen-degree angle to this plane and crosses Neptuneís orbit.
    The final decision was made August 24, 2006, when the International Astronomical Union passes two resolutions officially revoking Plutoís planetary status. The Resolutions are 5A and 6A. These Resolutions made a list of criteria that all the planets must meet in order to keep there status and Pluto did not meet these because it crosses Neptuneís orbit. Because of this, they have named Pluto a ďdwarf planet.Ē There are now 44 known dwarf planets and astronomers believe that they will continue to find more reaching in the hundreds.

    The Sun

    The sun is about 4.5 billion years old and the largest object in the solar system. It has a diameter of 1,390,000 km and a mass of 1.989e30 kg. The temperature of the sun on the surface is 5800 Kelvin and 15,600,000 Kelvin at itís core. There are sunspots that are considered ďcoolĒ regions on the sun which only reach up to about 3800 Kelvin. Conditions at the core are definitely the most extreme. At present, it is composed of 70 percent hydrogen, 28 percent helium and some metals that amount to less than 2 percent.
    The surface is also known as the photosphere and above that is the chromosphere.
    Sunís power is produced by nuclear fusion reactions. Each second, about 700,000,000 tons of hydrogen are converted to about 695,000,000 tons of helium and 5,000,000 tons of energy in the form of gamma rays.

    Doing research on the planets can really help you have a better understanding of the universe we live in. It is important to know about the planet we live on as well as the air we breath and the sun and moons that we see everyday. All of these planets and moons have so many interesting facts about them that it was hard to just sum it all up and choose the ďimportantĒ ones. The nine planets and moons discussed in this report is only a fraction of all of the things in the universe that are being studied and observed all the time. There are many more satellites, moons and other things that are very interesting to read and learn about.

    Bibliography Page



    Lafferty, Peter. ďSpaceĒ. Crescent Books. 1992.

    Price, Fred William. The Planet Observerís Handbook. Cambridge University Press. 2000.

    Parker, Steve. ďPlanet EarthĒ. Pioneer House. 2000.

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  3. #2  
    WYSIWYG Moderator marnixR's Avatar
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    hope you don't mind, but since your second post was an exact copy of your first, i've taken the liberty of deleting it - marnixR

    "Reality is that which, when you stop believing in it, doesn't go away." (Philip K. Dick)
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