Hello Friends,
Welcome to our channel - Education xPress!
My other channel you can refer to learn Astronomy.
@xTreamAstronomy
1. How Big Is Our Universe
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2. The Solar System
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Here you will learn Social Studies, Chapter 1 - Our Universe, for 3rd Standard, CBSE Board with Hindi Explanation.
Regards,
Charudatta Patil
Email: charumahim@gmail.com
WhatsApp: 9867799080
Introduction to Social Science
This particular subject deals with what we learn from the society and what good we do for the society. Social sciences include three subjects in them History- which tells us about our past, Geography- which tells us about physical features of earth and how human activities affect them and Civics – which tells us about what we do for the society and how do we follow rules and regulations to be a good citizen of our society.
Introduction
When we look at our sky in the night what do we see? We see moon and stars. When we look at our sky in the day what do we see then? We see the sun.
What is a Sun? Sun is also a star. It gives us heat and light. The sun looks bigger and brighter than other stars is because it is nearer to the earth.
Our Universe is an umbrella term for all the objects we see in the sky some are visible to use because they are nearer to earth and others are spread out in our universe. The universe consists of thousands of stars, planets and other heavenly bodies. All these objects are spread out vastly in our universe that is the reason why we are not able to see all the objects from earth. A large group or cluster of stars is called a galaxy. As this there are many galaxies in the universe.
The Universe
How was the universe formed? Many years ago, there was big explosion or as bang, and a huge fireball was created. The fireball spread out over a vast space. As it slowly cooled, tiny particles were formed. Over thousands of years, these particles came together to form the heavenly bodies. Scientists believe that this is how the universe was created. This idea is known as Big Bang Theory.
Our planet Earth is a tiny part of the galaxy called Milky Way or Akash Ganga. After many years of the Big bang on the edge of the Milky Way, the sun and the planets of our solar system were formed.
The Solar System
It includes the sun, the eight planets (as our ninth planet Pluto is not considered in our solar system anymore because it was so far from sun that it used to take years to complete its revolution), their moons or satellites, and pieces of rock and dust. The sun lies at the centre of the solar system. The most important part after the sun are our planets - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. The earth is the third planet from sun.
The word ‘Planet’ comes from a Greek word which means ‘wanderer’. All the planets move around the sun at different speeds and distances.
All planets have two movements. They spin round and round on an imaginary line called an axis. This movement is called rotation. Planets and satellites also revolve around the sun. This movement is known as revolution.
Many planets in the solar system have small companions called satellites moving around them. These satellites are of different shapes, sizes and numbers. Our earth has only one satellite, the moon, which shines in the night sky.
The sun is the only body in the whole solar system that has its own light. Planets and satellites have no light of their own. They shine because they reflect the light of the sun.
