How does the earth get the angular momentem(the force which causes rotational motion, about its axis)?

Question

as we know,the gravitational force of sun provides the centripital force;which is needed to any object to perform the circular motion,so it is clear to me that how does the earth move around the sun in the circular path,but to perform the rotational motion about the axis,from where the earth gets angular moment,which is required if you want to make any object spinning about an axis passing through the object.

Answer 1

Gravity doesn't entirely explain why planets revolve around the sun. If gravity was all there was in the solar system, the planets would fall into the Sun. Instead, the Sun is traveling through space around the Milky Way Galaxy...thus causing the planets to miss 'hitting' the sun, and instead orbit around it. The planets cannot escape into space because of the sun's gravity.

The reason the planets revolve on their axis is from a number of reasons, the main one, our Earth is not a perfect sphere. Secondly, the mass and density of the sun is not absolutely perfect. Hence, the space distortion caused by the Sun is not symmetrical, therefore an imperfect gravitational force on the earth mass.

Getting back to the 1st reason, the oval shape of the Earth and the gravitational pull of the sun, and the sun's velocity within the Milky Way, all sum up to cause a spinning mass.

And thirdly, the initial inertial energy during the formation of the solar system was random and, like a curve ball pitcher, the thrust was off-center. The odds of a thrust that was dead-center is astonomical. The odds of missing other large asteroids is also astronomically large.

The only time an object would NOTspin if the initial thrust was dead center, there were no objects to interfere with its path, the object was absolutely circular and the sun gravitional force was even. Lacking the above, we'll always be spinning.

Then there's the "core is a molten mass locked in a vault" answer. As the gravity of the sun pulls on the earth, combined with the forward momentum of the earth, we establish a revolution of the planet. The fact that the earth has an active seismic body means that our liquid core has gravity act on it. Just like the revolution, the dynamic of forward momentum and solar gravity causes the planet to wobble, or rotate. The fact that is does so at the magnetic poles is due to electron discharge that makes the magnetosphere as well as defines the poles.

Answer 2

A force is required for orbital motion, as you correctly stated the force that keeps Earth in orbit around the Sun is the gravitational force between Earth and the Sun. However, a force is not needed to keep an object rotating about its own axis. Once it is rotating, it will continue to rotate unless some other force stops it (it's kinda like Newton's First Law for rotational systems).

The nebula that created our solar system was spinning, that is why all the planets orbit the Sun in the same direction, and why the Sun and most of the planets rotate in the same direction. Planets such as Venus rotate the opposite direction because of impacts that changed its rotation early on.

Answer 3

This may sound too simple, but the earth's motion about its central axis is said to have been the result of the original cataclysmic event that began our solar system. The spinning of the earth has only the tides to work against it and no other forces, therefore it will take a very long time to stop it from spinning. The tidal action, however, after a long enough time will eventually try to stop the motion of the earth spinning on its axis. It is just so weak in comparison with the mass of the earth, it is almost negligible.

Answer 4

To put it in laymans terms space is a weightless void. What you want to know is what force started its circular spinning. Instead of trying to think why hasnt it STOPPED. What you should wonder is this. Unless an outside force acts on it, an object in space is going to keep spinning, moving forever! As for starting or mantaining its spin the only explaination is gravity, from itself or the sun, and possibly our core and its reaction play a part.