Space Tibetan water droplets photography

There is also gravity in the air. The law of universal gravitation, there is gravitation between any two objects. People in space are weightless.

universal gravitation

Newton discovered a law of interaction between objects in 1687. There is mutual attraction between any objects, and the force is directly proportional to the mass of each object and inversely proportional to the square of the distance between them. The law of universal gravitation was first put forward by Newton in the book Mathematical Principles of Natural Philosophy published in 1687.

Newton not only explained the law of planetary motion with the law of universal gravitation, but also pointed out that the moons of Jupiter and Saturn also have the same law of planetary motion. He believes that the moon is not only attracted by the gravity of the earth, but also by the gravity of the sun, thus explaining the two-average difference and business travel that have long been discovered in the movement of the moon.

In addition, he also explained the orbit of comets and tidal phenomena on the earth. Neptune was successfully predicted and discovered according to the law of universal gravitation.

After the appearance of the law of universal gravitation, the study of celestial motion was formally based on the mechanical theory, thus creating celestial mechanics. Simply put, the greater the mass, the greater the gravity, and the gravity generated by the mass of the earth is enough to accommodate everything on the earth.

Any two particles are attracted to each other by the force in the direction of the line. Gravity is directly proportional to their mass product and inversely proportional to the square of their distance, and has nothing to do with the chemical properties or physical states of two objects and intermediate substances.

Different explanations

Gravity is considered as one of the basic forces in the universe in classical physics, which is directly proportional to mass and inversely proportional to the square of distance. But in Einstein's theory, gravity is no longer the basic force, but only a manifestation of the bending of space-time structure. The reason leading to the bending of space-time structure is huge mass.

For example, the planets in the solar system revolve around the sun. The explanation in classical physics is that planets revolve around the sun because they are attracted by the sun.

According to the general theory of relativity, the space-time around the sun is influenced by the great mass of the sun, forming a curvature of spacetime, and the planets move according to their geodesics.

Baidu encyclopedia-gravity