The concept of gravity has been a topic of debate and research for centuries, and there are still many unanswered questions surrounding it. In Einstein's theory of general relativity (GR), gravity is viewed as an effect of the curvature of spacetime caused by the presence of massive objects. This means that gravity is not seen as a force like the other fundamental forces (strong, weak, and electromagnetic) in the standard model of particle physics.
On the other hand, quantum mechanics (QM) describes the behavior of particles at the subatomic level and has been extremely successful in explaining the other fundamental forces. In QM, particles interact through the exchange of virtual particles, such as gluons for the strong force and photons for the electromagnetic force. This led to the idea of a "graviton," a hypothetical particle that would mediate the gravitational force in a similar way.
So, why does QM see gravity as a force when GR describes it as a curvature of spacetime? The answer lies in the fact that these two theories are not yet fully reconciled. While GR is a classical theory, QM is a quantum theory, and there is currently no unified theory that can fully explain the behavior of matter and energy at all scales. Therefore, QM still treats gravity as a force, even though GR provides a more complete and elegant explanation of its nature.
As for the concept of the graviton, it is still a theoretical construct and has not been directly observed. Some physicists believe that it could exist, while others argue that it may not be necessary to explain the gravitational force. Ultimately, the existence of the graviton remains an open question, and further research and experimentation are needed to fully understand the nature of gravity.
In conclusion, the discrepancy between the way GR and QM view gravity highlights the need for a unified theory that can explain all fundamental forces. While GR provides a more complete understanding of gravity, QM still treats it as a force due to the lack of a unified framework. As for the graviton, it remains a theoretical concept that may or may not be necessary to explain the gravitational force.
