Why is gravitational force considered a weak force?

Gravitational force is considered a weak force because it is significantly weaker than the other fundamental forces of nature.

In the realm of physics, there are four fundamental forces: gravity, electromagnetism, the strong nuclear force, and the weak nuclear force. Among these, gravity is the weakest. To put it into perspective, the gravitational force is about 10^36 times weaker than the electromagnetic force, 10^38 times weaker than the strong nuclear force, and 10^29 times weaker than the weak nuclear force.

The reason why gravity seems so powerful in our daily lives is because it acts over large distances and on large masses. For instance, the gravitational pull of the Earth, which is a massive object, is strong enough to keep us grounded and to keep the Moon in orbit. However, on a smaller scale, such as between individual particles, gravity's influence is negligible.

In contrast, the other three fundamental forces have a much stronger influence at the atomic and subatomic level. The electromagnetic force, for instance, is responsible for holding electrons in their orbits around the nucleus of an atom. The strong nuclear force holds the protons and neutrons together in the nucleus, overcoming the electromagnetic repulsion between the positively charged protons. The weak nuclear force, while weaker than the electromagnetic and strong nuclear forces, is still much stronger than gravity and is responsible for certain types of radioactive decay.

The weakness of gravity compared to the other fundamental forces is a major puzzle in physics. It is one of the reasons why it has been so difficult to develop a quantum theory of gravity that is compatible with the other three forces. This disparity is often referred to as the hierarchy problem and is a key issue in the search for a unified theory of everything in physics.

In conclusion, while gravity may seem powerful in our everyday experience due to its influence over large masses and distances, when compared to the other fundamental forces of nature, it is significantly weaker. This is why gravitational force is considered a weak force in the field of physics.