jueves, 8 de septiembre de 2011

Spinning Earth

Though it seems perfectly still, the Earth is actually spinning around at an average speed of more than 1.600 km/h. We are unaware of this rapid movement because we are locked firmly to the ground by gravity.

  As the Earth spins and whirls through space, the view of the Sun from different places on the Earth is constantly changging, bringing not only day and night but all the seasons, too.

 At any one time, half the Earth is facing towards the Sun and is brightly lit, while the other half is facing away from the Sun and is in darkness.

 As the Earth turns, the dark and sunlit halves move around the world, bringing day and night to different parts of the world.

 Because the Earth turns eastwards, we seen the Sun rising in the east as the Earth turns our part of the world towards it, and setting in the west as it turns us away from the Sun.

 The Earth turns completely around once every 24 hours, which is why there are 24 hours in every day.

 The Earth does not spin upright, but is tilted at an angle, which always remains the same.

 When the Earth is on one side of the Sun, and the Northern Hemisphere ( the world north of Equator) is tilted towards it, it receives more sun, bringing summer.

 At the same time, the Southern Hemisphere is tilted away from the Sun, bringing winter.

 Six months later when the Earth is on the other side of the Sun, the Northern Hemisphere tilts away from the Sun and so there is less sunlight and it is winter here.

 The Southern Hemisphere now gets more heat and light from the Sun and has its summer time.

 The part of the Earth close to the Equator is never tilted far away from direct sunlight so it is always hot and there is little change in the seasons.

 In between, as the Earth moves around the Sun and neither hemisphere is tilted more towards it, we have spring and autumn.




What Causes Earth's Seasons? Translation movement

What Causes day and night? Rotation movement


 

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