Why is the Earth rotating?

Why is everything in the solar system spinning? And why do almost every rotation have the same direction?

This cannot be accidental. Look down at the Earth from above and you will see it turning counterclockwise. The same goes for the Sun, Mars and other planets.

4.54 billion years ago, our Solar System formed inside a cloud of hydrogen , this cloud is different from the Orion Nebula or the Eagle Nebula with wonderful pipes of nature.

It then needs some impact, such as shock waves from a nearby supernova, and this creates a region of cold gas that accrues through its gravity. When it shrank, the cloud began to spin.

The artist's drawing depicts a protoplanetary disk around a newly formed star.(Credit: ESO / L. Calçada).

But why are they spinning?

It is due to conservation of rotational momentum.

Think of a molecular individual in the Hydro cloud. Each particle carries its own momentum and floats through space. When these molecules combine with other molecules by gravity, they need to balance the momentum of each particle. A perfect equilibrium of zero is possible, but it's really hard.

That is, some of them will slide past each other. Like hand-skating people pulling together to spin faster, the contraction of the pre-Solar Nebula with the momentum of its balanced particles becomes faster.

This is when preserving the spin momentum begins to take effect

As the Solar System rotates faster, it flattens into a disk with an area of ​​bulge in the middle. We see similar structures everywhere in the universe: Shapes of galaxies, around rotating black holes .

The Sun formed from the bulge in the center of this disk, and the planets formed outside. They inherit the rotation from the overall motion of the Solar System itself.

During a few hundred million years, all matter in the Solar System gathered together into planets, asteroids, moons and comets . Then intense radiation and stellar winds from young stars The sun blows away the rest.

There are no other unbalanced forces acting on them, so the inertia of the Sun and planets have kept them spinning for billions of years.

And they will continue to spin until they collide with other objects, billions or even trillions in the future.

Earth rotates to preserve its angular momentum.

Finally, why does the Earth spin?

The Earth rotates because it is born in a accretion disk of a hydrogen cloud that shrinks from each other's gravitational force and is needed to preserve its angular momentum. It continues to spin by inertia.

The reason they all turned in the same direction was because they were born together in the same nebula billions of years ago.

The earth can stop rotating, change the direction of rotation, the angle of rotation . only when an unbalanced force is acting on it.

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