- System introduced by a Russian mineralogist, Vladimir Vernadsky, in the year 1920s
- The Earth has two motions. It rotates on its axis, inclined at an angle of 23 ½0
- Earth is considered a unique subsystem in the planetary system.
- The lithosphere, hydrosphere and atmosphere are the abiotic components of the Earth
- The planetary system consists of Eight planets : Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and about 90 satellites.
- Mercury, Venus, Earth, and Mars are smaller in size - these planets are called rocky planets.
- Jupiter, Saturn, Uranus and Neptune are bigger in size. They have small amounts of rocks and large amounts of gases, and are called Gaseous Planets.
- The Sun is the main source of energy for the planetary system.
- The Sun consists of 92% hydrogen, 7.8% helium and 0.2% other gases.
- The temperature on the surface of the Sun is 6,000 degrees Celsius and the temperature at the center of the Sun is more than 15,000,000 degree Celsius
- The Sun shines as a consequence of the fusion of hydrogen into helium, which is constantly taking place in its core. Hence, astronomers call the Sun a “Big Fire Ball”
- Scientists believe that the Sun will cease its function when the hydrogen is exhausted. It can burn for another 5,000 million years.
- It is estimated that the Sun had enough hydrogen to burn for 10,000 million years.
- Our Solar System is part of one such galaxy known as the Milky Way.
TNPSC - Geography - 11th Standard Text Books
5/15/2016
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