In physics, invariants are usually quantities conserved (unchanged) by the symmetries of the physical system. (See Noether's theorem.) Since antiquity, people have tried to understand the behavior of matter: why unsupported objects drop to the ground, why different materials have different properties, and so forth. ... Square with symmetry group D4 Symmetry is a characteristic of geometrical shapes, equations, and other objects; we say that such an object is symmetric with respect to a given operation if this operation, when applied to the object, does not appear to change it. ... Noethers theorem is a central result in theoretical physics that expresses the one-to-one correspondence between the symmetries and the conservation laws. ...

The correspondence between symmetries and conserved quantities is apparent through conservation laws. Much work has been done, especially in quantum physics, to relate every conserved quantity to some symmetry. One such quantity that still defies all such attempts is mass. Some examples of invariance include: In physics, a conservation law states that a particular measurable property of an isolated physical system does not change as the system evolves. ... Fig. ... Jump to: navigation, search Mass is a property of physical objects that, roughly speaking, measures the amount of matter they contain. ...

• Acceleration is invariant under the Galilean transformations.
• The speed of light invariant under the Lorentz transformations of special relativity.
• Time invariance makes energy a conserved quantity, hence an invariant.
• Translational invariance implies that momentum is conserved.
• Rotational invariance implies that angular momentum is conserved.

Jump to: navigation, search Acceleration is the time rate of change of velocity, and at any point on a v-t graph, it is given by the gradient of the tangent to that point In physics, acceleration (symbol: a) is defined as the rate of change (or time derivative) of... The Galilean transformation is used to transform between the coordinates of two coordinate systems in a constant relative motion in Newtonian physics. ... Cherenkov effect in a swimming pool nuclear reactor. ... Jump to: navigation, search The Lorentz transformation (LT), named after its discoverer, the Dutch physicist and mathematician Hendrik Antoon Lorentz (1853-1928), forms the basis for the special theory of relativity, which has been introduced to remove contradictions between the theories of electromagnetism and classical mechanics. ... Jump to: navigation, search A simple introduction to this subject is provided in Special relativity for beginners Special relativity (SR) or the special theory of relativity is the physical theory published in 1905 by Albert Einstein. ... In physics, momentum is a physical quantity related to the velocity and mass of an object. ... In mathematics, a function defined on an inner product space is said to have rotational invariance if its value does not change when arbitrary rotations are applied to its argument. ... Jump to: navigation, search In physics the angular momentum of an object with respect to a reference point is a measure for the extent to which, and the direction in which, the object rotates about the reference point. ...

See also

• Contravariant
• Covariant
• Principle of relativity
• Conservation of energy