Although they are two of the most influential theories in physics, quantum mechanics and the theory of relativity are incompatible. Quantum mechanics explains matter and energy as discrete energy packets known as quanta, whereas general relativity depicts gravity as a curvature of spacetime.
There are numerous ways to combine relativity and quantum physics, but none of them has received widespread acceptance. The creation of a quantum gravity theory, which would interpret gravity in terms of quantum mechanics, is one strategy. Another strategy is to change one or both ideas to make them work together.
String theory is one of the most promising methods for combining relativity with quantum mechanics. The attempt to unify all the fundamental forces of existence, including gravity, is made by the theory of everything known as string theory. According to the theory of strings, all matter and energy are composed of microscopic vibrating strings.
Loop quantum gravity is a further promising strategy. A quantum gravity theory called loop quantum gravity views spacetime as a web of loops. Although loop quantum gravity is still in its infancy, it has made some strides towards unifying relativity and quantum mechanics.
One of the biggest problems in modern physics is the integration of quantum mechanics with relativity. The development of a successful quantum gravity theory would fundamentally alter our view of the cosmos.