4th Class Science Our Universe ­­­Our Universe

­­­Our Universe

Category : 4th Class

 

Our Universe

 

Synopsis

 

Tit Bits

From the earth, stars seem to twinkle because the light from the stars is affected by the different layers of wind in the blanket of air covering the earth.

 

  • There are millions of stars in the sky.

 

  • Some stars seem to form interesting shapes and patterns. They are called constellations. Constellations are usually given names based on the their shapes.

e.g., Orion constellation, Saptarshi or big bear constellation.

 

  • The sun is also a star and it looks bigger because it is closer to us. All the other stars are very far away from the earth.

 

  • Huge spheres which move around the sun in fixed paths are called planets. The path of a planet is called its orbit.

 

  • Our sun and its planets together form solar system. The planets are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

 

  • The following are some facts about the solar system:

 

 Biggest planet               

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 Jupiter

 Nearest planet to the sun     

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Mercury

 Brightest planet             

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Venus

 Planets with rings            

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Saturn

 Planets without satellite      

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Mercury, Venus          

 Beautiful planet             

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Saturn

 Red planet                 

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Mars

 Farthest planet to the Sun     

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Neptune

 

  • Our earth spins around itself. This is called rotation and it takes about 24 hours to complete one rotation. Rotation causes days and nights.

 

  • Earth moves around Sun. This movement is called revolution. Revolution takes days or one year. Revolution causes seasons like summer, winter, autumn and spring.

 

  • Venus rotates the slowest, Jupiter the biggest planet rotates the fastest.

 

  • When the earth rotates, the half which faces the earth receives light and will have day. The other half which does not get any light will be dark and have night.

 

  • The earth rotates from west to east. So, the sun seems to rise in the east and set in the west.

 

 

  • The earth is divided into two equal halves by an imaginary line called equator. The part above the equator is called northern hemisphere and the part below the line is called southern hemisphere.

 

  • During revolution, the axis of the earth is tilted at an angle. Revolution causes changes in seasons.

 

  • The moon is the natural satellite of the earth.

 

  • A satellite is any free-flying object orbiting the earth or any other planet.

 

Other Topics

Notes - Our Universe
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