Quantum mechanics, science dealing with the behavior of matter and light on the atomic and subatomic scale. It attempts to describe and account for the properties of molecules and atoms and their constituents—electrons, protons, neutrons, and other more esoteric particles such as quarks and gluons. These properties include the interactions of the particles with one another and with electromagnetic radiation (i.e., light, X-rays, and gamma rays).
The geometric theory of gravitation developed by Albert Einstein, incorporating and extending the theory of special relativity to accelerated frames of reference and introducing the principle that gravity is a consequence of matter causing a curvature in space-time.
String theory, often called the “theory of everything,” is a relatively young science that includes such unusual concepts as superstrings, branes, and extra dimensions. Scientists are hopeful that string theory will unlock one of the biggest mysteries of the universe, namely how gravity and quantum physics fit together.
- Gravity: the force that attracts a body toward the center of the earth, or toward any other physical body having mass.
- Electromagnetism: the interaction of electric currents or fields and magnetic fields
- Strong nuclear: the short-range attractive force between baryons that holds together the nucleus of the atom.
- Weak nuclear: he interaction between elementary particles and the intermediate vector bosons that carry the weak force from one particle to another
All the forces of nature should be capable of being described by a single theory. But only at high energies should the the behavior of the forces combine, this is called unification