fundamental forces

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fundamental forces

The four basic forces of nature: the gravitational force, the electromagnetic force (both long established), and the two nuclear forces, the strong force and the weak force. These forces act between elementary particles, i.e. the basic building blocks of matter. All the visible matter in the Universe and its behavior may be described in terms of these particles and the forces acting between them. The standard model of elementary particles uses gauge theories (based on the idea of symmetry) to describe the electromagnetic, strong, and weak forces: each is generated by the interaction between particles, which involves the exchange of an intermediate particle known as a gauge boson. These intermediates effectively ‘carry’ the force from one particle to another. Different gauge bosons are exchanged in the three types of interaction: the electromagnetic force is carried by photons, the strong force by gluons (see quark), and the weak force by neutral Z and charge W particles.

The gravitational force occurs between all particles, the electromagnetic force between charged particles, e.g. electrons and protons. The strong force arises between hadrons, e.g. protons and neutrons, and between the constituents of hadrons, i.e. quarks, and is the force binding together particles in the nuclei of atoms. The weak force occurs between both leptons and hadrons and is responsible for radioactivity. The four forces vary greatly in range: the gravitational and electromagnetic forces have an infinite range whereas the other two have an extremely short range. They also vary greatly in strength: the gravitational force is the weakest over very short distances (˜10–39 times the strength of the strong force) but on a cosmic scale it dominates the others.

Attempts to construct a single theory unifying the four forces have been progressing. Steven Weinberg and Abdus Salam in the late 1960s found a mathematical description – the electroweak theory – that successfully unified the electromagnetic and weak forces so that they could be regarded as two aspects of the same phenomenon. There are various grand unified theories (GUTs) that aim to provide a mathematical framework in which the strong, electromagnetic, and weak forces emerge as parts of a single unified force. A symmetry is said to relate one force to another. Since the forces are very different in strength and character this symmetry is broken in the present-day Universe. GUTs predict that the symmetry holds only when the temperature is greater than about 1027 K, when particles would have extremely high energies, above 1024 electronvolts. Such extremes of temperature and energy occurred in the very young Universe immediately after the Big Bang. GUTs are thus of great importance to cosmology.

The ultimate goal is to incorporate the gravitational force into the unification by formulating a satisfactory theory of quantum gravitation. This would produce a theory of everything, (TOE); one candidate is string theory.

Collins Dictionary of Astronomy © Market House Books Ltd, 2006
References in periodicals archive ?
Four fundamental forces (Electromagnetic, Weak, Strong and Gravity) acting through corresponding quantum particles known as gauge bosons (photon for electromagnetic, W and Z particles for weak force, gluon for strong force and yet to be discovered illusive graviton for the force of gravity) together are the cause of actions that shape and govern the universe.
TEHRAN (FNA)- Recent findings indicating the possible discovery of a previously unknown subatomic particle may be evidence of a fifth fundamental force of nature, according to new research by theoretical physicists.
"Mapping the Future of Work in Menat", co-authored by Rania Rostom, GE's chief innovation officer, GE Menat; and Marco Annunziata, GE's chief economist, highlights the enormous opportunities of the region to leverage the power of innovation through three fundamental forces - the industrial internet, advanced manufacturing and the global brain.
In Chapter Two, he highlights the connections between Kant's doctrine of opposed fundamental forces of attraction and repulsion and some contemporary notions--prominent in Stahl's chemistry--of fluidity and elasticity, showing how these notions enabled Kant to reject both mechanistic atomism and his own earlier quasi-Leibnizian views.
Without it, the Standard Model theory that combines all the fundamental forces and particles of the Universe would have fallen down.
Peter Moller of Los Alamos National Laboratory's Theoretical Division, said that understanding this would yield important insights about the fundamental forces in nature, especially on the astronomical/cosmological scale.
Everything in it is made of a few fundamental particles, which are governed by four fundamental forces. Scientists at Cern use immense scientific instruments to study those particles and how they interact.
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Explanation for the recurrences of large-number 1040 in astrophysics, and some insight into the nature of fundamental forces. Proceedings of Indian National Science Academy, 1997, v.
He's the co-founder of string field theory and continues Einstein's search to unite the four fundamental forces of nature into one unified theory.
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The relative strengths of the fundamental forces of nature are fine-tuned, and Stenger points out that they "are not even constant in our universe, but depend on the energies of the particles interacting with one another," thereby discounting their importance.

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