solar system

At night you can see very many stars in the sky. But during the day, only one star is .visible, and that is  the Sun. This is not because there is anything extraordinary about it  but because it  is the star closest to us. The light of  the other, more distant stars is too feeble to be seen during the day time. The Sun's apparent magnificence had  led ancient civ~hsations  to think of  it as the 'head'  of  the univeise. Actually, it is only the 'head'  of its own family, known as the Solar System. This family consists of  :line planets, including the Earth, their satellites, asteroids and comets. Arranged according  to their increasing distance from the Sun, the nine planets which go around the Sun are: Mercury (Buddha), Venus (Shukra), Earth (Prith  VI), Mars (Mangal), Jupiter ('Brihaspati),  Saturn (Sham), Uranus (Arun), Neptune (  Varun), and Pluto ( Yama),. Except for Mercury and Venus, all the planets have big and small satellites going around them. There are also countless asteroids and comets in orbit around the Sun.  

All the planets and zsteroids, and some comets, revolve around the Sun in elliptical orbits. They all orbit the Sun in nearly the same plane. youcan inake a fairly accurdte model of  the Solar System from a single piece of  cardboard on which you can draw the planetary orbits.The only exception of  this model is the orbit of. - Pluto, which is inclined at an approrimate  angIe of-17⁰  to the general plane of  the Solar System. The North  Pole  of the  Earth determines the  'north side' of  the  Solar System. Seen from the "north side", all planets revolve around the Sun. Its gravitational attraction keeps them tevolving in  their orbits. If  tbe Sun were to suddenly vanish, the planets wouId all fly  off in straight  lines at  a tangent to their orbits,  

The Sun is the dominating member of  the Solar System. With a mass calculated  to be approximately 2X10²³g (grams), it contains almost 99.87% of  the mass of  the entire Solar System. Of the nine planets, Jupiter and Saturn are the most massive, accountingfor 92% of  the mass of  all planets. The planets do no generate their own light, like the'Sun does. They shine by  reflecting the Sun's light that falls on them. The percentage ofsunlight reflected by  any object is directly related to the amount and type of atmosphere that it possesses. Planets or satellites with no atmosphere, such as Mercuryand Moon  reflect less  light.  

All plaliets, except Venus and Uranus, rotate on their axes in the anticlockwise direction. So, on all these, like on the Earth, the Sun rises in the eastand sets  in the west. Venus and Uranus rotate in  a clockwise  direction and as a result, on these two planets the Sun rises in  the west and sets in the east! All planets except Uranus have their axes of rotations more or less perpendicular to the plane of  orbits (see Fig). The axis of  rotation of  Uranus is in its orbital plane, as though Uranus had toppled over.