Electromagnetism, and also the strong and weak nuclear forces, are confined to their membranes, and thus to this universe.

ECONOMIST: A matter of gravity

These interact through electromagnetism, and also through the strong and weak nuclear forces.

ECONOMIST: Particle physics makes sense, but it assumes too much

Nor can the more exotic particles responsible for the weak and strong nuclear forces.

ECONOMIST: A matter of gravity

They do so via electromagnetism and the weak and strong nuclear forces.

ECONOMIST: The Higgs boson

The reason they have not been noticed by chipmakers, virologists and others who pay attention to things on the micron scale, he contends, is that, like dark matter, they are sensitive only to gravity, and relatively oblivious to the other three of nature's fundamental interactions: electromagnetism and the weak and strong nuclear forces.

ECONOMIST: Cosmology

The linchpin of the model is the underlying unity of two of the three forces: electromagnetism and the weak nuclear force.

ECONOMIST: Particle physics makes sense, but it assumes too much

The electroweak force is a synthesis of two previously identified forces of nature, electromagnetism (itself a synthesis, carried out in the 19th century, of the electric and magnetic forces), and the weak nuclear force, which governs radioactive decay.

ECONOMIST: The 1999 Nobel prizes

Equally importantly, the Higgs allows two of the four forces in nature -- the electromagnetic force and the weak force, which is responsible for most nuclear reactions -- to be unified and described by mathematics of the same type that describe the other two known forces, the so-called strong force and gravity.

CNN: Higgs and the holy grail of physics