Electromagnetism
Electricity and magnetism were long thought distinct. Then, in 1831, Michael Faraday discovered a magnetic field about a wire conducting DC current. Faraday also established that light is affected by magnetism.
In 1865, James Clerk Maxwell published equations that equated electricity, magnetism, and light as manifestations of the same phenomenon; that electric and magnetic fields were waves that traveled at the speed of light, and that light was also wavy.
Maxwell’s unified model of electromagnetism was a milestone in physics. The theoretical implications of electromagnetism inspired Einstein to formulate special relativity.
Electromagnetism acts between electrically charged particles. Via attraction of negatively charged electrons to positively charged protons, electromagnetism creates atoms.
The vacuum fluctuations of the electromagnetic field have clearly visible consequences, and, among other things, are responsible for the fact that an atom can spontaneously emit light. ~ Swiss physicist Ileana-Cristina Benea-Chelmus
Electricity and magnetism are dual manifestations of a single interactive force. A changing electric field generates a magnetic field and vice versa. This electromagnetic induction is the basis for electric generators, transformers, and induction motors.
Anyone who uses electricity is experiencing the effects of relativity. ~ American physicist Thomas Moore
Electromagnetism involves relativistic effects. Moving a loop of wire through a magnetic field generates an electric current. The charged particles in the wire – electrons and protons – are affected by the changing magnetic field: forcing some of them to harmonically sway, thereby creating an electrical current.
Imagine the wire at rest with the magnet moving. In this instance, the wire’s charged particles aren’t moving, so the magnetic field should not affect them. But it does. Current still flows. This shows that there is no privileged frame of reference; exactly the point that Einstein was making with special relativity: that all frames of reference are relative, and that their relations exhibit phenomenal effect.
Without relativity, neither magnetism nor light would exist, because relativity requires that changes in an electromagnetic field move at a finite speed instead of instantaneously. If relativity did not enforce this requirement, changes in electric fields would be communicated instantaneously instead of through electromagnetic waves, and both magnetism and light would be unnecessary. ~ Thomas Moore
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Besides being the source of light by dint of energetic glow, photons are the force carrier of electromagnetism. This is unobvious, as photons do not nominally interact with matter.
Magnets attract each other because they exchange virtual photons. Each virtual photon has its own frame of reference. In their supposed interaction, photons exchange momentum, thereby producing attraction or repulsion, depending upon relative energetic orientation of the object which they encounter. This is a relativistic effect.
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At an energy level of 246 GeV, the electromagnetic and weak forces unite into electroweak interaction. 246 GeV is estimated upon the calculated value of the Higgs field in a vacuum. Room temperature has a thermal energy of 0.025 eV.
