[zeroca]

Hello Mr. AntonioLao!

Presently it’s not important for us exactly when was the moment of beginning, so let’s omit it.

I almost fully agree with your reply except for the assertion that planets were formed out of planetesimal collisions, and the principal reason for rotating was (or is) exactly it. But let’s put off its consideration for a later time, if you don’t mind.

We agree that generally rotation means the existence of angular momentum. It’s the same as existence of a centrifugal force, which is applied to the center of rotating body vertically to the axis of rotation.

Earth’s rotation can be modeled by a gyroscope, but it can be analyzed by choosing any rotating system, for instance
1. Electrical centrifuge;
2. Rotating bicycle wheel (which’s fixed on the wall with its pivot);
3. Whirligig
And compare it with the Earth’s rotation to show principal discrepancies (marked with cardinal) and resemblances (marked with ordinal numbers).

I. ---- The case of el. centrifuge rotation is stationary (if it’s switched on for long) as it is in case of the Earth, but
1. The former is located on Earth’s surface (“within gravitational field of the Earth"), the latter is located in an “empty space”, and also
2. We can’t detect any outer influence (force), which could be considered as a locomotive force of Earth’s rotation (like an electricity in case of el. centrifuge), and also
3. The rotational axis of the Earth isn’t fixed, as in the cases of el. centrifuge and fixed bicycle wheel.

1. The case of rotation of bicycle wheel is an example of fading, attenuating rotating system, as well as the case of whirligig, but
2. Both of them are located within “gravitational field of the Earth” in contrast to the Earth, which’s located in an “empty space”, and also
II. ----The rotational axis of the whirligig isn’t fixed, as that of the Earth’s,

So, let’s firstly choose the whirligig and let’s made it rotate:
1. The rubbing between the top of whirligig and the ground’s surface serves as a frictional force, which slows rotation down, and also
2. The adjacent air to the whirligig serves as a frictional force against rotation, and we can prove it with a simplest experiment.

But for some reason the air, adjacent to the Earth doesn’t serve as a frictional force to slow down its rotation (despite the heterogeneity of its surface) and it didn’t happen for the period of 4.5 billions years. What’s the reason?
O. K.
Let’s take a helicopter and try to fly up into the air vertically from the surface of the Earth at the distance of 1-2 km in a good weather, and hang in this position. The force of attraction to the Earth equals to the raising one and this is the reason the helicopter remains hung immovably, but notice that it rotates along with the Earth at a speed of Earth’s rotation, so the helicopter has the same angular momentum as the Earth and it means that the air, or rather 1. The space adjacent to the Earth rotates as well together with the Earth and it means that planet isn’t only the globe alone, which rotates in an empty homogenous space, but planet is the unity of the globe and the adjacent space which’s organically bind to it (the adjacent space spreads up to some distance radially from the center of the Earth) and just this space contains the locomotive force of permanent angular momentum of planet’s revolving on its axis.

But how it happens, let’s speak another time.