When we look up at the starry sky and marvel at the vastness of the universe and the abundance of stars, we rarely realize that the earth under our feet is spinning in space at an astonishing speed.

The Earth's rotational speed, taking the equator as an example, has a linear velocity of up to 15 meters per second and an angular velocity of 0 degrees per hour. At that speed, if you put it on a racing car, it would be an incredible gallop. However, for a planet as large as Earth, such a speed seems insignificant.

Observed in space, the Earth appears perfectly spherical, and the linear velocity due to its rotation varies from latitude to latitude, with the fastest at the equator and gradually slowing down as latitude increases, until the north and south poles reach zero. Despite this, the rotation of the earth still brings with it the phenomenon of day and night, as well as various natural laws related to rotation on the earth.

In addition to its rotation, the Earth revolves around the Sun, with a linear velocity of about 1 kilometers per second and an angular velocity of about 0 degrees per day. The Earth's orbit is elliptical, which means that the Earth's distance from the Sun varies throughout the year, bringing about a change of seasons. Such a rapid revolution speed is the fundamental reason why we perceive the changes of the four seasons.

However, despite the speed at which the Earth rotates and revolutions so fast, we hardly feel any movement associated with it in our daily lives. Why is that? How do we perceive the rotation and revolution of the Earth?

Although the speed of the Earth's rotation is amazing, the reason why we can't feel it is because of the enormity of the Earth. The size and surface area of the Earth are so large that even though the Earth rotates at a very fast speed, this change in angular velocity is negligible to us standing on its surface. If we stand at the North Pole and observe a point on the equator, although it moves 004 meters per second, the angular velocity changes by only 0.0 degrees, a small change that we cannot perceive.

In addition to this, we lack a suitable reference on Earth to perceive the rotation of the Earth. References are essential for determining whether an object is in motion or not.

For example, when we sit in a moving car, we can feel the car moving forward by looking at the trees on the side of the road. However, on Earth, there is no fixed and unchanging reference around us that allows us to intuitively feel the rotation of the Earth. In the vastness of the universe, other celestial bodies move in space at similar speeds, which also makes the rotation and revolution of the earth not outstanding on the scale of the universe.

The rotation and revolution of the earth is very smooth, which is an important reason why it is difficult for us to detect its movement. Since the birth of the earth, the speed of its rotation and revolution has maintained a high degree of uniformity, with little change. Scientists have found that although the Earth's rotation has slowed down over the past billions of years, it has changed so slowly that humans have been imperceptible to the change over the course of their lives. Therefore, although the Earth moves rapidly in space all the time, we have long been accustomed to its smooth rotation and are no longer surprised by this constant and steady movement.

The reference object plays a decisive role in our perception of the motion of the object. In daily life, we often use the objects around us as a reference to judge whether we are moving. For example, when we see a tree on the side of the road receding rapidly, we know that the car we are in is advancing. This relativity of reference is also applicable in aerospace. When the aircraft is in the air, the pilot judges the speed and direction of the aircraft by observing the scenery on the ground.

However, in space, due to the lack of obvious references, it is difficult for people to intuitively perceive the rotation and revolution of the Earth. Spacecraft and astronauts in space often judge their position and speed by using the Earth or other celestial bodies in space as a reference, but this is very different from how we feel it on Earth. In space, where there is no obvious reference, the rotation and revolution of the Earth are more subtle and difficult to perceive.

Still, we can indirectly perceive the Earth's rotation and revolution by observing certain phenomena in space. For example, the orbital motion of spacecraft in space, the day-night cycle of the Earth, and the relative position of celestial bodies can all be used as evidence of the Earth's rotation and revolution. Therefore, while it is very difficult to directly feel the rotation and revolution of the Earth in space, we can still experience these two basic motions of the Earth by other means.

The rotation of day and night on the earth is the phenomenon of the earth's rotation that we most intuitively feel. Whenever the sun rises and sets in the sky, it is actually the result of the Earth's rotation. The Sun itself is a relatively stationary star, but due to the Earth's rotation, what we see is the apparent motion of the Sun in the sky. This visual movement causes variations in day and night on Earth, as well as sunrise and sunset times in different regions.

Similarly, by observing the movement of celestial bodies, we are able to perceive the revolution of the Earth. For example, standing on Earth and observing it reveals that the Sun and other stars change positions regularly throughout the year, which is direct evidence of the Earth's orbit around the Sun. More specialized astronomical observations can reveal more precise laws of celestial motion, thus proving the rotation of the earth.

Therefore, although we cannot directly perceive the rotation and revolution of the earth, we can indirectly perceive both movements by observing phenomena in nature.

For example, rivers in the Northern Hemisphere tend to have their right bank more washed out than their left bank, and the whirlpools formed by the rivers are always counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.

These phenomena have become the basis for our understanding of the movement of the Earth, and have made us more aware that we live on a planet that is constantly moving and changing.

Although the Earth's rotation speed is insignificant on a cosmic scale, its uniformity and stability are crucial for the daily life of humans. The uniformity of the Earth's rotation means that the length of our day and night remains constant, bringing regularity and order to our lives. It is this steady rotation that allows us to arrange farming and rest according to the sunrise and sunset, and construct the time frame of human society.

However, although the Earth's rotation speed brings a steady rhythm to human life, it is not actually static. Scientists have studied ancient geological records and astronomical observations and found that the Earth's rotation speed has changed slowly over the past history. For example, the Earth's rotation period was shorter in ancient times than it is now, with only a few hours in a day. This change is subtle in the short term, but it is significant in the long term.

The variability of the Earth's rotation speed is of great significance for our understanding of the Earth's evolutionary history. It not only affects the Earth's climate and biodiversity, but also the interaction between the Earth and other celestial bodies. By studying these changes, scientists can better understand the Earth's place in the universe and how it has evolved over time.