Theory of relativity
The theory of relativity, or simply relativity, refers specifically to two theories:
Albert Einstein's
special relativity and
general relativity.
The term "relativity" was coined by
Max Planck in 1908 to emphasize how special relativity uses the principle of relativity.
Encyclopedia
The
theory of relativity, or simply
relativity, refers specifically to two theories:
Albert Einstein's
special relativity and
general relativity.
The term "relativity" was coined by
Max Planck in 1908 to emphasize how special relativity uses the principle of relativity.
Special relativity
Albert Einstein's 1905 paper "
On the Electrodynamics of Moving Bodies" introduced the
special theory of relativity. Special relativity considers that observers in inertial reference frames, which are in uniform motion relative to one another, cannot perform any experiment to determine which one of them is "stationary". This is actually
Galileo's principle of relativity; Einstein's contribution was to explicitly include electromagnetism within this principle, which required that the Galilean transformations be replaced by the
Lorentz transformations. The resultant theory has many surprising consequences. In particular, it requires that the
speed of light in a
vacuum be the same for all these observers, regardless of their motion, or the motion of the source of the
light, since the invariance of the speed of light is a consequence of Maxwell's equations of electromagnetism.
General relativity
General relativity was developed by Einstein in the years 1907 - 1915. General relativity replaces the global Lorentz symmetry of special relativity with a local Lorentz symmetry in the presence of matter. The presence of matter "curves" spacetime, and this
curvature affects the path of free particles . General relativity uses the mathematics of differential geometry and tensors in order to describe
gravitation as an effect of the
geometry of spacetime. This theory is based on the general principle of relativity, which requires all observers to experience the same laws of physics, not just those moving with uniform speed, hence its name.
See also
References and links
See the
special relativity references and the
general relativity references.
External links
- — An open access, peer-referred, solely online physics journal publishing invited reviews covering all areas of relativity research.
- — A complete online course on Relativity.
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- — A terse dose of insight on the subject.
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- — A basic introduction to concepts of Special and General Relativity, as well as astrophysics.
- — A short course offered at MIT.
- from the University of New South Wales.
