Why is the earth able to spin forever? Where does its energy come from?

Every day, the earth rotates once, and due to the rotation of the earth, we can see the sunrise and sunset every day. Since the birth of the earth 4.6 billion years ago, the earth has never stopped rotating, and the earth will continue to rotate in the future until the day when the earth is destroyed. But why does the earth rotate? Where does the power of the Earth's rotation come from?

The energy of the earth's rotation comes from the beginning of the earth's birth. Energy is generated by the impact of rocks. With the accumulation of material and dust, the conservation of angular momentum makes the rotation speed faster, and finally a rotating earth is formed.

Why does the earth rotate?

The earth is made up of dust and matter that revolves around the sun. When the disk of matter moves around the sun, it will inevitably have an impact, and the kinetic energy generated by the impact will make the disk start to rotate. Due to the action of gravity, huge rocks begin to attract the surrounding matter to gather, and gradually form a protoplanet. Since the matter itself has kinetic energy, according to the conservation of angular momentum, with the accumulation of matter, the protoplanet begins to rotate. Like a figure skating athlete, pulling the legs and arms back makes their spin speed up.

As the size of the planet increases, the probability of being hit by other celestial bodies increases. With the impact of rocks, the rotation of the planet begins to be affected, and various rotation modes also appear.

The Earth is not a planet that rotates vertically. The Earth's axis of rotation is slightly inclined. Looking at other planets in the solar system, Venus' rotation direction is opposite to that of Earth and other planets. , Scientists believe that these special rotation patterns are caused by celestial collisions.

At the beginning of the formation of the solar system, a violent impact may have directly reversed the rotation direction of Venus, and Uranus and the Earth also tilted their rotation axis due to an impact.

Why does the earth spin forever?

The rotation of the earth seems to never stop, but on earth, the spinning top will eventually stop. The secret that the earth can rotate forever is that the earth's rotation has almost no resistance. Space is a near-vacuum environment. The earth's rotation will not be subject to various frictional resistances like a top. The only force that can significantly slow down the earth's rotation, It's gravity.

Among the gravitational effects on the earth, the most obvious ones are the moon and the sun. Since the earth is not a smooth sphere, and the surface is uneven, the gravitational effect on each surface of the earth is different, and the surface with greater gravitational force faces the moon or the sun. , the rotation will decelerate due to the increase in gravity. According to the calculations of astronomers, the rotation period of the earth will be extended by 1.78 milliseconds every 100 years due to the effect of gravity, which is not a big problem.

There is basically no resistance to the rotation of the earth, and the kinetic energy of the earth's rotation is also a huge treasure trove. Contemporary space launch missions will use the speed of the earth's rotation to help the launch vehicle speed up, thereby saving fuel. However, according to the conservation of kinetic energy, the launch vehicle uses the kinetic energy of the earth, and the kinetic energy of the earth's rotation will be reduced, resulting in a deceleration of rotation.

For the earth, the mass of the launch vehicle is very light and will not have a significant impact on the earth's rotation, but many scientists worry that the increasing number of rocket launches may have an irreversible impact on the earth's rotation in the future. In the near future, humans really don't need to worry about whether the earth's rotation will stop~