What is the cause of the rotation of the planets

In summary, the cause of the planets and the Sun's rotation is due to the conservation of angular momentum, which allows particles falling into a gravity well to preserve momentum and impart spin to the accreting body. The natural state for rotating objects is to continue rotating until something stops them, and for smaller bodies, tidal forces work to synchronize their rotation with revolution. This can be seen with the Earth and the Moon, as well as with many other moons in the solar system.
  • #1
Bjarne
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What is the cause of the planets (and the Suns) rotation
 
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  • #3
vincentm is correct. Particles falling into a gravity well travel in a spiral path. It is not unlike flushing a toilet. Traveling in a spiral path allows them to preserve momentum until absorbed. This imparts spin to the accreting body [star, planet, etc.].
 
  • #4
Furthermore, the natural state of affairs is that rotating objects will continue to rotate until something comes along to stop it. For the larger bodies in the solar system, there aren't any significant effects on their rotation. But for the smaller bodies...

The main effect on rotation is tidal forces, which don't work to stop rotation, but to synchronize it with revolution. The Earth is big enough and near enough (and has had enough time) to coerce the moon into making one rotation once per revolution. Similarly, the Sun has locked Mercury into making 3 rotations per 2 revolutions. You also see this with many (most?) of the moons in the solar system.
 

1. What is the cause of the rotation of the planets?

The rotation of the planets is caused by their initial angular momentum. When the planets first formed, they were made up of materials that were already in motion. As these materials came together to form the planets, their collective motion caused the planets to rotate.

2. Does the Sun's gravitational pull affect the rotation of the planets?

Yes, the Sun's gravitational pull does play a role in the rotation of the planets. The Sun's gravity creates a tidal force on the planets, causing them to slightly bulge and creating a torque that can alter their rotation.

3. Why do some planets rotate in the opposite direction?

The direction of a planet's rotation is determined by the direction of its initial angular momentum. In some cases, collisions or gravitational interactions with other objects can alter a planet's rotation, causing it to rotate in the opposite direction.

4. Are all planets rotating at the same speed?

No, the speed of a planet's rotation varies depending on its size, composition, and distance from the Sun. For example, smaller planets tend to rotate faster than larger planets, and planets closer to the Sun rotate faster than those farther away.

5. Can the rotation of a planet change over time?

Yes, the rotation of a planet can change over time due to various factors such as gravitational interactions with other objects, tidal forces, and impacts from asteroids or comets. However, these changes are usually very gradual and can take millions of years to have a noticeable effect.

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