unified field theory
Collective designation for Einstein's unsuccessful attempts to formulate a theory in which gravity and other interactions, notably electromagnetism, are described in a unified manner - a theory in which gravity and electromagnetism would be ...
ultraviolet
Variety of electromagnetic radiation with frequencies between a few and a few hundred quadrillion oscillations per second, corresponding to wave-lengths between a few hundred and a few billionths of metres. Known in everyday life as that part of the radiation ...
twin effect
Effect of special relativity, variant of the time dilation effect: A twin that uses a high-powered rocket to travel in space with a speed near that of light before returning ages less than his twin sibling that has remained on Earth. The question why this ...
tunnel effect
A quantum mechanical phenomenon that can be pictured as follows. Imagine a ball rolling towards a hill: Leaving quantum effects aside (in other words, in classical physics), we expect that what happens depends on the ball's energy: If the ball moves ...
tritium
Variety of hydrogen in which the atomic nucleus contains two neutrons and a proton. In ordinary hydrogen, the nucleus consists of a single proton; in heavy hydrogen (deuterium) there is one additional neutron. In the context of general relativity, tritium ...
triangle
In a plane and other flat space: Geometrical object consisting of three points ("vertices") with three connecting straight lines. The definition can be made more general, in a way that applies to curved spaces, as well: A geometric object consisting of ...
transversal
A wave is called transversal if the effects associated with it (the electric forces associated with an electromagnetic wave, or the space distortions caused by a gravitational wave) act only in directions perpendicular to the wave's direction of propagation. ...
