# What is the essence of gravity? Neither Newton nor Einstein found the final answer

In ancient times, people did not have a scientific understanding of the phenomena of nature. In the eyes of the ancients, all the operations of the world were dominated by gods, so many myths and legends appeared. With the continuous progress and development of human beings, science began to sprout, and some wise people began to look at the world with a scientific perspective.

Speaking of the origin of human science, many people will think of the western world. Yes, science entered the human world just from the West. Especially since the 17th century, Western science has made a qualitative leap, that is, the great scientist Newton proposed the law of universal gravitation.

Speaking of Newton, I believe my friends know that an apple landing is such a common phenomenon, but it attracted Newton’s attention. He thought: Why did the apple land instead of fly to the sky? Through continuous thinking, we found the existence of gravity, and opened a new exploration direction of human physics.

Newton deduced the mathematical expression of universal gravitation by observing the motion of celestial bodies and the motion of earth’s matter and combining with the three laws of Kepler’s planetary motion. Gravity was discovered by Newton, and this discovery is of great significance to human beings, let us open the chapter of studying the law of the essence of matter.

According to the law of universal gravitation, as long as there is mass, there is gravitational action between all things. The magnitude of gravity is inversely proportional to the square of the distance and directly proportional to the mass. With the law of universal gravitation, we have initially revealed the laws of motion of galaxies and celestial bodies in the universe. Many people wonder why so many galaxies and celestial bodies in the universe can float and move very regularly? All this mystery has to do with gravity.

Gravity dominates all the movements of the universe. Newton discovered the existence of gravity, which makes us understand that the bridge between all things is gravity. But what is the essence of gravity? Newton discovered gravity, but did not explain to us: what is gravity? How did it come about? Where does it come from?

From Newton’s discovery of gravity in the 17th century to the end of the 19th century, scientists have been exploring the nature of gravity for more than 200 years, trying to figure out how this mysterious gravity came from? If there’s no progress all the time.

At the beginning of the 20th century, a great new star in the scientific community rose, and he was Einstein. Einstein was also very curious about the nature of gravity. He didn’t approve of all kinds of conjectures about the nature of gravity at that time. After exerting his imagination, he put forward the general theory of relativity.

The proposal of general relativity has made a major breakthrough in the problem of gravity and led scientists to find a new direction of exploration. In fact, general relativity is also a theory of gravity, which only analyzes and studies the problem of gravity from completely different angles.

Einstein believed that gravity is not a force in the traditional sense, but a geometric effect. Relativity tells us that the universe is not flat, but there is a bending phenomenon. We can imagine the universe as a film that can be infinitely compressed. Objects with mass exist on the film. These objects with mass will exert pressure on the film and form a depression. In this way, the surrounding of the object will be bent. After the space structure is bent, the matter will move along the curved space, thus showing the universal gravitation.

According to this principle, Einstein created the gravitational field equation, which can better describe all kinds of gravitational phenomena in the universe and surpass Newton’s gravitational theory. If any theory wants to be true, it needs to be proved by scientific experiments. Has Einstein’s gravitational field equation been proved by scientific experiments? Certainly.

Through Einstein’s new theory of gravity, scientists found that when a distant star passes near the sun, it will appear obvious deflection. According to the principle of relativity, this is because the star has a larger mass and the space around it is more distorted. Therefore, when photons pass here, they will appear obvious deflection. This is completely in line with the general theory of relativity The calculation results are given.

Through the theory of relativity, Einstein also predicted other gravitational phenomena, such as the existence of black holes, gravitational waves, gravitational time expansion effect and so on. With the continuous progress of human science and technology, these gravitational phenomena have been confirmed one by one. Real photos of black holes were first released in 2019, and gravitational waves were actually detected by scientists in 2016.

These gravitational phenomena predicted by the theory of relativity have become reality one by one, which proves the correctness of the theory of relativity and the greatness of Einstein. Therefore, in the ranking of great scientists in the scientific community, Einstein won the first place, while Newton can only rank second.

So did Einstein find the essence of gravity? Can relativity fully explain the mystery of gravity? The answer is No. although the theory of relativity is so great that we can recognize the phenomenon of gravity from another level, it still has its limitations, and is not the final theory of gravity. There are some gravitational phenomena that cannot be explained by the theory of relativity, such as the singularity problem, the quantum theory of the micro world and so on.

Singularity is related to the origin of the universe, but what is the singularity? There is no definite answer yet. Only when we really understand the nature of gravity can we really understand the singularity. In addition, many phenomena in quantum mechanics completely subvert our cognition. The gravitational phenomenon in quantum mechanics is completely different from that in macro mechanics, so it is impossible to explain quantum mechanics with macro gravitational theory.

Therefore, Einstein’s description of gravity is only an approximation of the essence of gravity. Although it is close to the essence of gravity, there is still a distance from the real essence of gravity. It is not the ultimate theory of gravity. If it is the ultimate theory of gravity, then both the singularity problem and the quantum gravity problem in the micro world can be solved.

Einstein naturally understood that his theory of relativity had not yet completely solved the essence of gravity, so in his later years, he devoted himself to the research and exploration of the grand unification theory, but he did not make a breakthrough until his death. The grand unification theory has always been the most mysterious and complex problem in the scientific community. If anyone can really understand it, he may be able to surpass Einstein and take the lead in the scientific community.

On the way to explore the grand unified theory, scientists put forward a variety of conjectures, such as quantum gravity theory, string theory and so on. In the theory of quantum gravitation, the graviton is very important. It is a basic particle with no static mass and the speed of light. However, until now, scientists have not found any evidence of the existence of gravitons.

String theory, on the other hand, is even bigger. Its basic idea is that the basic unit of nature is not dot like particles such as electrons, photons, neutrinos and quarks, but very small linear “strings”. String theory also puts forward the theory of multi-dimensional space, that our universe is divided into 11 dimensions, the space of human survival is only three-dimensional universe.

String theory can perfectly crack the essence of gravity. If its correctness can be proved, then the problem of the essence of gravity can be solved. At that time, human civilization will enter a new stage and become a higher civilization in the universe. Unfortunately, string theory is totally different from our current physical theory, and there is no evidence to prove its correctness.

If string theory is correct, many things in modern physics will be completely overturned and rewritten. So, for scientists, we hope that string theory is correct and that it is just a conjecture. Of course, the pace of science is constantly moving forward. As long as we are given enough time, we believe there will be an answer in the future.