| The Solar System Essay, Research Paper
Our understanding and our modern perception of our solar system, the Milky Way, has been drastically reshaped from the corresponding perception of only a few hundred years ago. Our Solar System, the Milky Way is probably about 4-5 billion years old. Only in the last 400 years or so have we realized that the earth is not the “center”, and that in the Universe alone there is an immense 200 billion “Suns” in a galaxy like our own. Although the origin of the solar system is uncertain, most scientists believe that it began to develop about 4 1/2 billion years ago from a large cloud of gas and dust.
The Sun is the largest celestial body in the Milky Way Solar System, with more than 1.000 times the mass of everything else added together. It’s the Sun’s huge gravity that keeps all of the nine planets, their moons, the asteroids, the comets, and the dust between the planets all orbiting the Sun. It would take more than 100 Earths placed side-by-side to go from one edge of the Sun to the other and can hold 1,3 million Earths The Sun is a star, and shines because it generates light and heat by nuclear reactions in its core.
Mercury even though 36 million miles away from the sun, is still closest to the sun out of all the other planets and is difficult to observe from the Earth because it rises and sets within two hours of the sun. Mercury’s surface has several different types of terrain. Some regions on Mercury are heavily creatored, suggesting that they are very old surfaces that were probably formed about 4 billion years ago. Between these regions are areas of gently rolling plains that may have been smoothed by volcanic lava flows or by accumulated deposits of fine accumulated a large number of impact craters. Elsewhere on the planet are smooth, flat plains with few craters. These plains are probably younger and volcanic in origin. The largest impact basin on Mercury, Caloris, is about 800 miles across and is surrounded by mountains that rise to heights of about 1.2 miles. Mercury the eighth largest planet is very dense and has a magnetic field that is about 1 percent as strong as Earth’s, which suggest the existence of a core composed of iron and nickel and constituting about 40 percent of the planet’s volume. The surface gravity is about one third as strong as Earth’s. A thin atmosphere of hydrogen, helium, potassium, and sulfur surrounds the planet. Radar images taken of Mercury in 1991 show what are considered to be large ice patches at the planet’s North Pole. Mercury has no satellites, but rotates on its axis three times for every two revolutions around the sun and has a more elliptical orbit that do most other planets. Temperatures in terms of the Kelvin scale, an absolute temperature scale in which 0 K is the lowest possible temperature, corresponding to -459.67 degrees F. Surface temperatures on Mercury range from about 675 K at “noon” to 100 K just before “dawn.”(temperatures of about 295 are comfortable for humans) It takes almost 59 Earth days for Mercury to complete one rotation about its axis, but the time between one sunrise and the next is 176 Earth days.
The next from the sun is Venus. Venus is the most brilliant natural object in the nighttime sky, after the moon. Venus is the closest planet to the Earth and is also the most similar to Earth in size, mass, and density. These similarities suggests that the two planets may have had similar histories. Venus rotates once every 243 days in retrograde motion, or apparent backwards motion. Venus is very difficult to observe because its surface is completely obscured by thick layers of dense clouds. The atmosphere of Venus is mainly composed of carbon dioxide, with droplets of sulfuric acid in the upper clouds. The upper atmosphere moves rapidly, completely circling the planes in four days, while the winds at the surface are gentle. The surface temperature is approximately 750 K, even hotter than Mercury’s noon temperatures. The large amount of carbon dioxide in Venus’ atmosphere accounts for the extremely high temperatures near the planet’s surface and the greenhouse effect that traps and absorbs the sun’s heat. Because of the clouds, only 15% of the sun’s light reach the planet’s surface. Days on Venus are dim and overcast. Some places on Venus the surface has been severely fractured and folded by stress caused by the convection of the Venusian mantle, the part of the planet just above the core. The highest mountain on Venus, Maxwell Montes, is about 7 1/2 miles high and might possibly be a volcano.
After Venus is our planet, Earth. Earth is the 5th largest planet and 149,600,000 km from the sun. Earth is divided into several layers that have distinct chemical and seismic properties. The crust varies considerably in thickness, it is thinner under the oceans, thicker under the continents. The inner core and crust are solid; the outer core and mantle layers are plastic or semi-fluid. The various layers are separated by, which are evident in seismic data; the best known of these is the discontinuity between the crust and upper mantle. Most of the mass of the Earth is in the mantle, most of the rest is in the core. The core is probably composed mostly of iron though it is possible that some lighter elements may be present, too. Temperatures at the center of the core may be as high as 7500 K. The lower mantle is probably mostly silicon, magnesium and oxygen with some iron, calcium and aluminum. Unlike the other planets, Earth’s crust is divided into several separate solid plates, which float around independently on top of the hot mantle below. There are (at present) eight major plates and twenty more small plates. The Earth’s surface is covered with 71% water, which is also responsible for most of the erosion and weathering of the Earth’s continents. Earth’s temperature is relatively stable. The atmosphere of the Earth is 77% nitrogen , 21% oxygen, with traces of argon, carbon dioxide and water. The greenhouse effect raises the average surface temperature about 35 degrees C above what it would be without the oceans would freeze and live we know it would be impossible. Earth only has one natural satellite, but thousands of small artificial satellites have also been place in orbit around the Earth.
Mars, the fourth planet from the Sun, is also the seventh largest. Mares are 277,940,000 km from the Sun. Named after the Greek god of War, Mars has been known since prehistoric times as an object of great interest to astronomers. Unlike Venus, Mars generally has no obscuring layer of clouds. In addition, it passes relatively close the Earth in its orbit. Mars is about half the size of the Earth and its atmosphere is composed mostly of carbon dioxide. The temperature at the planet’s surface varies widely during the course of a Martian day, form about 190 K just before dawn to about 240 K in the afternoon. At the center of the planet is probably a small iron or iron sulfide core. If Mars has a magnetic field, it is so week that no instrument has been able to detect it. Mars like the Earth is tilted on its rotational axis. Liquid water cannot exist on Mars’s surface because of the low temperature and pressure’ water exists only as ice deposited at the poles and perhaps trapped below the surface and as vapor in the atmosphere. Mars is very desolate and barren and is covered in craters and are prone to violent sandstorms. The UV radiation of Mars would kill any known life. Mars has the largest volcano in the solar system, Olympus Mons, at a height of 17 miles, the volcano is three times higher than Earth’s Mount Everest. Valk Marineris, a 2,000-mile canyon that is three times deeper than the Grand Canyon. Mars has a very thin atmosphere composed mostly of the tiny amount of remaining carbon dioxide plus nitrogen, argon, and traces of oxygen and water. Mars has two moons Phobos and Demos.
Between Mars and Jupiter there is the Asteroid Belt. An Asteroid is a small rocky chunk of mater that range in size from579 miles and in diameter to less than .6 miles in diameter. Most of them are small and are believed to be planetesimals ancient chunks of matter that originated with the solar system. There are 5,000 tracked and documented asteroids, 13,000 are identified, and there are an estimated 1,000,000 of them. Objects that cross the Earths orbit and could possible hit earth are called Apollo Objects
Jupiter the largest of the planets and is the fifth planet from the Sun. Jupiter is 1300 times larger than the Earth and more than twice as all the other planets combined. Jupiter is 778,330,000 km from the Sun. Jupiter probably has a core of rocky material amounting to something like 10 to 15 Earth-masses. Above the core lies the main bulk of the planet in the form of liquid metallic hydrogen. The vivid colors seen in Jupiter’s clouds are probably the result of subtle chemical reactions of the trace elements in Jupiter’s atmosphere, perhaps involving sulfur whose compounds take on a wide variety of colors, but details are unknown. Earthly observers for mote than 300 years have seen the Great Red Spot. The Great Red spot is an oval about 12,000 by 25,000 km, big enough to hold two Earths. Jupiter radiates more energy into space that it receives from the Sun. The interior of Jupiter is hot: the core is probably about 20,000 K. The heat is generated by the Kelvin-Helmholtz mechanism, the slow gravitational compression of the planet. Jupiter is just about as large in diameter as a gas planet can be. If more material were to be added, it would be compressed by gravity such that the overall radius would increased. A star can be larger only because of its internal heat source. Jupiter would have to be at least 80 times more massive to become a star. Jupiter has a huge magnetic field, much stronger than Earth’s. It extends more than 650 million km in the direction toward the Sun. Jupiter has rings like Saturn, but much fainter and smaller. Unlike Saturn’s, Jupiter’s rings are dark. They’re probably composed of very small grains of rocky material. Unlike Saturn’s rings, they see to contain no ice. Jupiter has 16 known satellites, he four moons and 12 small ones.
Saturn is the sixth planet from the Sun and the 2nd largest at 1,429,400,000 km from the Sun. Saturn is the least dense of the plants; its specific gravity (0.7) is less than water, methane, ammonia and “rock” , similar to the composition of the primordial from which the solar system was formed. Saturn’s interior is similar to Jupiter’s composition of a rocky core, a layer of a molecular hydrogen layer. Traces of various are also present. Saturn’s interior is hot (12000 K at the core) and Saturn radiates more energy into space than it receives from the Sun. Saturn is the last of the naked eye planets. Saturn has 18 satellites, more than any other planet in the solar system. Cameras of Voyagers 1 and2 revealed that there are really ten of thousands of rings extending from about 4,300 miles to 46,000 miles. The Rings are composed of dust and frozen water and possibly premoon mater. Rings are also divided into three main parts, A, B, C.
Uranus is another large gaseous planet. It is denser than Jupiter and Saturn and is composed of hydrogen, helium, substantial amounts of water, and probably some methane, ammonia, rock, and metal. Trace amounts of methane in its upper atmosphere hive it a blue-green color. The temperature increases with atmospheric depth. The core of the planet is most likely rock and metal. Uranus’ rotational axis is tilted an unusually great 98 degrees from a hypothetical line perpendicular to the ecliptic plane. Uranus rotates in retrograde, or clockwise, motion about once every 17 hours. The planet has a strong magnetic field in which the magnetic north is tilted and exceptionally great 60 degrees from the rotational North Pole. Uranus has 15 known satellites, which are composed mostly of ice and are heavily created.
Little was known about the planet Neptune, which was discovered in 1846. Its mass is comparable to that of Uranus, and it has a similar composition. Its thick atmosphere of hydrogen, helium, and some methane gives it a bluish color. Like the other gaseous planets, Neptune rotates rapidly, once every 16.1 hours, and has a slightly larger diameter at the equator that at the poles. The atmospheric temperature has been found to be at about 60 K, higher than expected for a body so far from the sun. (4,504,000.000 km from Sun) Its high temperature suggests that Neptune has another, possibly internal, heat source. The planet probably has a rocky core surrounded by water ice and liquid methane, which in turn are surrounded by hydrogen and helium gasses. Neptune has rapid winds confined to bands of latitude and large storms or vortices. Neptune’s winds are the fastest in the solar system, reaching 2000 km/ hour. Neptune has eight known satellites. The largest satellite, triton revolves around Neptune in a direction opposite to that of the other satellites in the solar system. Nereid, the second largest revolves in the normal direction but in a very eccentric orbit.
Pluto was discovered in 1930, when looking for planet X. Pluto is a tiny, low-density planet made up of 97 percent nitrogen and small amounts of frozen carbon monoxide and methane. Pluto has one moon named Charon and is about 750 miles across. Pluto’s orbit is much more elliptic than those of the other planets and is titled 17 degrees from the ecliptic plane. When it is at perihelion, Pluto is nearer the sun than Neptune.
Planets and moons are not the only part of the solar system. Today there is still many parts of the solar system we are unaware of or even unsure of. Some astronomers theorize about a planet X, or even a sister star to the Sun. There are many disturbances in space and a planet X or a sister stars could possible answer the questions astronomers have about the solar system and the planets around us.
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