The current theory of gravity is
general relativity, a theory developed by Albert Einstein at the beginning of the XX century, which has changed in depth our understanding of what are space and time. Similarly,
quantum mechanics has changed in depth our understanding of matter, energy and
causality. These two theories, today very well empirically supported, have opened a major conceptual revolution in physics. However, they appear to be incompatible, at least at a first reading, because each of the two is formulated on the basis of principles that are are explicitly contradicted by the other theory. Therefore in spite of the immense development of scientific knowledge it has delivered, the physics of the XX century has left us with a major confusion on what are the basic conceptual ingredients for understanding the physical world. In other words, the scientific revolution opened by general relativity and quantum mechanics at the beginning of the XX century is not concluded yet, and a new synthesis is required. Quantum gravity, merging general relativity and quantum mechanics should be this new synthesis.