*Michael Munowitz*

- Published in print:
- 2006
- Published Online:
- September 2007
- ISBN:
- 9780195167375
- eISBN:
- 9780199787104
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780195167375.003.0002
- Subject:
- Physics, History of Physics

From a distance, bits of matter tend to attract. Up close, violating a certain threshold, they repel. In equilibrium, somewhere in between, they strike a balance. The pushes are counteracted exactly ...
More

From a distance, bits of matter tend to attract. Up close, violating a certain threshold, they repel. In equilibrium, somewhere in between, they strike a balance. The pushes are counteracted exactly by the pulls, and groups of interacting particles settle into a provisional stability. They cluster hierarchically into composite structures that run the gamut from protons and neutrons, to atoms and molecules, to stars and planets. Each assembly is governed by one or more of the four fundamental forces: the gravitational force, the electromagnetic force, the strong nuclear force, and the weak nuclear force. The never-ending tug-of-war between attraction and repulsion shapes the material universe and gives it the potential to evolve from state to state.Less

From a distance, bits of matter tend to attract. Up close, violating a certain threshold, they repel. In equilibrium, somewhere in between, they strike a balance. The pushes are counteracted exactly by the pulls, and groups of interacting particles settle into a provisional stability. They cluster hierarchically into composite structures that run the gamut from protons and neutrons, to atoms and molecules, to stars and planets. Each assembly is governed by one or more of the four fundamental forces: the gravitational force, the electromagnetic force, the strong nuclear force, and the weak nuclear force. The never-ending tug-of-war between attraction and repulsion shapes the material universe and gives it the potential to evolve from state to state.

*Hanoch Gutfreund and Jürgen Renn*

- Published in print:
- 2017
- Published Online:
- May 2018
- ISBN:
- 9780691174631
- eISBN:
- 9781400888689
- Item type:
- chapter

- Publisher:
- Princeton University Press
- DOI:
- 10.23943/princeton/9780691174631.003.0015
- Subject:
- Physics, History of Physics

This chapter shows how the principle of special relativity and the principle of the constancy of the velocity of light uniquely determine the Lorentz transformation. Unlike in pre-relativity physics, ...
More

This chapter shows how the principle of special relativity and the principle of the constancy of the velocity of light uniquely determine the Lorentz transformation. Unlike in pre-relativity physics, space and time are not separate entities. They are combined into a four-dimensional spacetime continuum, which is most clearly demonstrated in the formulation of the theory of special relativity due to Hermann Minkowski. The chapter then defines vectors and tensors with respect to the Lorentz transformation, leading to a tensor formulation of Maxwell's equations, of the electromagnetic force acting on charges and currents, and of the energy-momentum of the electromagnetic field and its conservation law. It also introduces the energy-momentum tensor of matter and discusses the basic equations of the hydrodynamics of perfect fluids (the Euler equations).Less

This chapter shows how the principle of special relativity and the principle of the constancy of the velocity of light uniquely determine the Lorentz transformation. Unlike in pre-relativity physics, space and time are not separate entities. They are combined into a four-dimensional spacetime continuum, which is most clearly demonstrated in the formulation of the theory of special relativity due to Hermann Minkowski. The chapter then defines vectors and tensors with respect to the Lorentz transformation, leading to a tensor formulation of Maxwell's equations, of the electromagnetic force acting on charges and currents, and of the energy-momentum of the electromagnetic field and its conservation law. It also introduces the energy-momentum tensor of matter and discusses the basic equations of the hydrodynamics of perfect fluids (the Euler equations).

*William J. Mullin*

- Published in print:
- 2017
- Published Online:
- March 2017
- ISBN:
- 9780198795131
- eISBN:
- 9780191836480
- Item type:
- chapter

- Publisher:
- Oxford University Press
- DOI:
- 10.1093/acprof:oso/9780198795131.003.0013
- Subject:
- Physics, Particle Physics / Astrophysics / Cosmology

The four forces in nature—electromagnetic force, strong nuclear force, weak nuclear force, and gravitational force—arise from the exchange of virtual bosons: photons, gluons, W bosons, Z bosons, and ...
More

The four forces in nature—electromagnetic force, strong nuclear force, weak nuclear force, and gravitational force—arise from the exchange of virtual bosons: photons, gluons, W bosons, Z bosons, and gravitons. Coulomb’s law and Newton’s law represent the long-range electric and gravitational forces, respectively, while the two nuclear forces are short range and are involved in α, β, and γ radioactivity. In virtual particle exchange, the interacting particles make temporary transitions to an excited state in which a boson is exchanged between the interacting particles. Feynman diagrams give a graphical description of these processes. The graviton is the quantum of gravity waves, the latter recently observed at LIGO. The proton and neutron are each made up of three quarks, which exchange gluons to provide the nuclear interaction. The weak interaction arises from the exchange of W and Z bosons. The Standard Model is the current theoretical understanding of elementary-particle interactions.Less

The four forces in nature—electromagnetic force, strong nuclear force, weak nuclear force, and gravitational force—arise from the exchange of virtual bosons: photons, gluons, *W* bosons, *Z* bosons, and gravitons. Coulomb’s law and Newton’s law represent the long-range electric and gravitational forces, respectively, while the two nuclear forces are short range and are involved in α, β, and γ radioactivity. In virtual particle exchange, the interacting particles make temporary transitions to an excited state in which a boson is exchanged between the interacting particles. Feynman diagrams give a graphical description of these processes. The graviton is the quantum of gravity waves, the latter recently observed at LIGO. The proton and neutron are each made up of three quarks, which exchange gluons to provide the nuclear interaction. The weak interaction arises from the exchange of *W* and *Z* bosons. The Standard Model is the current theoretical understanding of elementary-particle interactions.