5th Class Science Earth, Moon and Sun Our Universe

       Introduction

There are eight planets, which revolve around the Sun. Sun is at the centre of the solar system. Some planets in our solar system are called inner and some are outer planets. Inner and outer planets are categorized according to the distance from the Sun. In this chapter, we will study about the solar system and its components.

            Our Universe

Universe is everything that exists in totality. For example stars, planets. Sun, steroids, all other celestial bodies etc. All stars and clouds are made up of hydrogen and helium.

             Astronomy

The branch of science that deals with the study of space Is called astronomy.

            Planets

Planet is a celestial body made up of rocks, metals and gases, which revolve around a star, for example Earth, Mars, Jupiter etc. There are 8 planets in our solar system.

            Star

Star is a ball of hot and bright gases.

There are billions of stars in the universe. Stars appear to twinkle from the surface of the earth.

           Solar System

Solar system means the family of the Sun that is the family of 8 planets orbiting around the Sun. It also includes the moons of the planets, asteroids, meteors and comets etc.

Outer planets: The inner and outer planets are differentiated according to their distance from the Sun. There are four outer planets in our solar system, these are, Jupiter, Saturn, Uranus and Neptune.

Inner planets: There are four inner planets, which are closest to the sun and revolve around the sun. These are Mercury, Venus, Earth and Mars.

Sun

Sun is a medium sized, middle aged star and a ball of bright and hot gases. It has been burning and shining since billions of years and would continue to do so for about 10000000000 years.

The temperature of the Sun's surface is about 6'000^oc and the hotness increases from the surface to the core of the Sun. The Sun has spots, which are little bit cooler than the rest part. The Sun is in the second stage of its career. It is the nearest star to the Earth, about 15 crore kilometer from us. The diameter of Sun is 110 time the earth's diameter. The Sun's light looks white but actually it's a mixture o seven colors.

Violet

Indigo

Blue

Green

Yellow

Orange

Red

        Solar Eclipse

This phenomena occurs when moon (Which circles around the earth) passes directly between the earth and the sun and hides the sun partially or full, from Earth's view.

Solar eclipse can only happen during a new moon. Two to five solar eclipses occur in a year..