The Solar System

The Solar System

   
Our Solar System consists of the Sun, the Stars, and everything bound to it by gravity – the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune and dwarf planets such as Pluto, dozens of moons and millions of asteroids, comets, and meteoroids. Beyond our own solar system, we have discovered thousands of planetary systems orbiting other stars in the Milky Way.

Sun is at the Centre of the solar system with eight planets (i.e. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune), satellites, asteroids, meteors and comets that move around the Sun.

The Sun   

It is be of the opinion that the Sun was born about 5 billion years ago. Since that time, it is continuously emitting huge amount of heat and light, and it is expected to glow in a similar manner for the next 5 billion years or so. The Sun is essentially a sphere of hot gases. The disc is also called the Photosphere.  The radius of the Sun is almost 100 times the radius of the earth and its mass is about a million times the mass of the earth. The Sun is the nearest star from us. The light of the Sun takes about 8.3 light minutes to reach us. The light of the nearest star (Proxima or Alpha Centuari) to the Sun reach earth in about 4.3 light years.

The Planets

 The word ‘planet’ comes from the Greek word “Planetai” which means ‘wanderers’. Planets keep changing their positions with respect to the star A planet is a large astronomical body and are actually spinning around the Sun.   Apart from the Moon, five planets are visible to the naked eye in the night sky. 

1. Mercury -   It is nearest to the Sun. It is the smallest planet of the solar system, nearly of the same size and mass as the moon. It takes 88 days for one orbit around the Sun and 59 days for one spin on its axis. It has no satellite. There is no atmosphere on mercury. The surface of mercury is rocky and mountainous. One side of the surface facing the Sun receives maximum heat and light. The surface of this planet does not receive Sunlight or heat on its other side. One part of mercury, therefore, is very hot while the other part is very cold