The Solar System and Satellites
The Solar System consists of the eight planets that orbit our Sun and other celestial bodies such as moons, comets, asteroids, minor planets, and dust and gas. Sun is considered as the centre of the solar system and all the planets revolve around the sun. The Sun is the ultimate source of heat and light energy for whole of the solar system.
The Solar System
The Solar System consists of the eight planets that orbit our Sun and other celestial bodies such as moons, comets, asteroids, minor planets, and dust and gas. Sun is considered as the centre of the solar system and all the planets revolve around the sun. The Sun is the ultimate source of heat and light energy for whole of the solar system. The whole of the solar system is bound together by the gravitational pull of the sun. The Solar System formed 4.6 billion years ago from the gravitational collapse of a giant interstellar molecular cloud.
The eight planets in the solar system in the increasing order of their distance from the Sun are Mercury, Venus, Earth and Mars, Jupiter, Saturn, Uranus and Neptune. Out of these eight planets the first four are known as inner or terrestrial plants while the later four being the outer or giant planets. The last two planets i.e. the Uranus and Neptune are composed mostly of substances with relatively high melting points compared with hydrogen and helium, called ices, such as water, ammonia and methane. However, out of all the planets of solar system, only earth has been found to have conditions suitable for life. Earlier there were nine planets in the solar system including Pluto, However, international Astronomy Union removed Pluto from the list of planets and labeled it as the Dwarf planet due to the small size of Pluto in comparison to the other existing planets of our solar system. These planets and other celestial bodies revolve around the sun. However, there are other objects which revolve around these planets which are known as Satellites.
Satellites are basically the celestial bodies which orbit other celestial bodies of greater mass such as moon which is the only natural satellite of earth. The inner planets i.e. Mercury and Venus do not have any satellite while Mars has two natural satellites namely Phoebos and Deimos. The giant planets such as Saturn and Uranus have extensive system of natural satellites. Lo. Europa, Ganymede and Calisto are the four major natural satellites of Jupiter. Jupiter has maximum number of moons/Satellites i.e. 51 moons which is followed by Saturn having 36 moons. On the other hand, the artificial satellites also exist which are man-made and launched from the earth. These satellite may perform certain specific functions. The first artificial satellite was Sputanik-1 launched by Soviet Union in 1957. These artificial satellites perform variety of functions such as Weather monitoring, Space surveillance, Global positioning system etc. These artificial satellites based on their orbits of rotation are known as geosynchronous satellites, Geostationary satellites etc. India’s first satellite was Aryabhatta which was launched in 1975. These days, many satellites are being launched to perform the specific purposes such as defense, remote sensing, weather forecasting, spying, space research, television broadcast etc.
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