Why does earth rotate?


earth rotationIt is believed that the earth is made up of cloud of gas and dust particles called nebula that collapses under its own gravity and started spinning. When this cloud and dust particle condensed they remained in rotation and the rotation is speeded up when condenses at the center. So it is said that earth had been rotating since it was formed but now the question arises that why doesn’t it stops? It is because in our everyday life we see if we push an object it moves for sometimes and then stops and force is required to keep it moving but this assumption is wrong. Objects will keep on moving till another force is applied to stop it. When an object comes to rest after moving for a while, friction acts on it and it stops. Same is the case with earth. It is moving and remains spinning till the force is applied on it to stop.

Luhman says” the earth keeps spinning because it was born spinning”. He further says that the speed of rotation of earth is slowing down because of tidal pull by themoon. It is slowing at the rate of nearly one millisecond per year. He says that the length of days at the times of dinosaurs was 22 hours. Tidal pull of moon is also receding the moon at the rate of nearly one millimeter per year. Luhman says “it would have appeared much larger in our sky than it does now”.
All planets rotate in same direction and in almost same plane.

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3 COMMENTS

    Earth has magnetic field with North & South poles. Earth rotates on its axis and the axis of rotation is tilted compared to the magnetic poles. I feel this tilt creates force for earth to rotate on its axis. Moon doesn’t have magnetic field and therefore does not rotate on its axis. The principle applies to all planets in the solar system.

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