Why does the earth rotate on its own axis? Why does it revolve around the sun? Why does it not collide with the sun?
Answer .When the earth was formed, it rotated and revolved around the sun. According to Newton’s first law, an object sitting idle in the absence of any other force would remain idle, moving .This applies to linear motion and rotary motion.
So why did the earth rotate when other planets and stars formed? First, let’s look at how they all came into being. The stars, planets, moons, and other galaxies we see today are the result of the accretion of these vast clouds of dust and gases. It has kinetic energy at the time of the first particle. The same thing happens with size .There will be some cancellation due to thunderstorms here and there, but all of this will show a net rotational momentum for the combined object (planet, star..etc) .So all the stars and planets are spinning.
Now why does the earth revolve around the sun. The correct answer is coincidence .imagine that a girl is running close to you .you grabs her by the arm and tries to bring her closer to you because you likes her .Three things can happen. The girl is fat and she is running so fat, your hand strength will not be enough .She will go her way .It will only change the direction of the run a little. The minimum speed required to release the grip is called the escape velocity
The second thing that is likely to happen is that if her run is not so fast and not so heavy (momentum is low) she will come closer to you and collide with you.
In the most majority of cases any one of these will occur.
Thirdly, there is a possibility that the force you hold in her hand is not enough to bring you closer, but her momentum is not enough to free her hand and run away. Then she will continue to surround you. This speed is called the orbital velocity
So why did the earth rotate when other planets and stars formed? First, let’s look at how they all came into being. The combination of these vast expanses is the result of the stars, planets, moons, and other craters we see today. It has kinetic energy at the time of the first particle. The same thing happens with size .It’s a bit of a cancellation due to the collision here and there, but it’s a net rotational momentum for all these things together (planet, star ..etc) .So all the stars and planets are spinning.
Very, very few objects move at the exact orbital velocity .They are still orbiting the Sun .That is, the planets, moons, etc. 99.8% of the Solar System is the Sun.Thirty times larger than Earth, Jupiter and other planets, moons, tiny-comets and other craters add up to only 0.2 percent. That ‘s it.