# Nature of this pristine force

• ion
In summary, the nature of rotational force on celestial bodies is a combination of inertia and gravity, with some extreme cases being locked rotations and revolutions. The rotation and revolution periods of each planet can be found on various websites and the initial impetus for a planet's rotation is believed to be the rate of impacts during its formation. The rotational period of a planet can also reflect its development history and can be affected by collisions with other large masses. The original axis of a planet can be determined through conservation of angular momentum and any deviations from the norm can be attributed to collisions.

#### ion

What is the nature of this rotational force that affects all celestial bodies? What was the initial impetus? How does physics explain it?

Thank you,
ion

I think you should try to clarify the term "rotational force". However rotations and revolutions of celestial bodies are in general a combination of inertia and gravity. In some extreme cases (e.g. our moon), the rotation and revolution periods are locked, so we always see the same face.

I know what you mean, I've been trying to figure this out as well.

I've come across this site which details the rotation time of each planet on it's axis plus the revolution time around the sun. The revolution time of each planet is as expects ie it increases the closer a planet is to the sun. Check this site out for exact figures
http://www.marsdenshs.qld.edu.au/subjects/science/junior_science/astro/solar.html [Broken]

Also another thread that might interest you is
[URL]https://www.physicsforums.com/archive/topic/1689-1.html

Hopefully someone might be able to give us a full explanation. At best I would guess a planets rotation was initiated/set by the rate of impacts on the planets surface during the creation of our solar system.

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I know what you mean, I've been trying to figure this out as well.

... At best I would guess a planets rotation was initiated/set by the rate of impacts on the planets surface during the creation of our solar system.

The above is very true. Many people's idea of the formation of the solar system is of 9 planets forming simply from a cloud of swirling gas orbiting the Sun. However, the system was much more dynamic than this, with proto planets colliding, enormous collisions with other large masses etc. The rotational period of a planet reflects their development history, as well as, in the case of the Earth, the effect the moon has slowing us down.
Venus was tipped almost upside down in its early history and spins very slowly the opposite way to all the other planets! Uranus is on its side too, due to collisions.

Venus was tipped almost upside down in its early history and spins very slowly the opposite way to all the other planets! Uranus is on its side too, due to collisions

Just out of interest how do astronomers know what the original axis of the planet was?