rest mass
In special relativity, the (inertial) mass of an object depends on how fast that object moves relative to the observer. The rest mass is the inertial mass of an object, measured by an observer relative to whom the object is at rest. With ...
relativity principle
Basic principle of special relativity: for two observers moving relative to each other with constant relative velocity (more specifically: for two inertial observers) the laws of physics are the same. There is no key experiment by which one could argue that ...
relativistic
Models, effects or phenomena in which special relativity or general relativity play a crucial role are called relativistic. Examples are relativistic quantum field theories as theories based on special relativity, or the relativistic perihelion shift as a ...
relativistic mass
One prediction of special relativity is that, the faster an object already is, the more difficult it is to accelerate it even further. One consequence of this is that it is impossible to accelerate a material object to the speed of light: ...
Relativistic Heavy Ion Collider
A particle accelerator operated by Brookhaven National Laboratory on Long Island, New York. It brings heavy ions - the nuclei of atoms that have been stripped of all their electrons - into collision at high energies; the resulting states of matter give ...
resonant detector
Detector for gravitational waves in which it is attempted to measure the influence of these waves on an oscillating test mass. More information about how such detectors work can be found in the spotlight topic Small vibrations. ...
relativity theory
The modern theories of space and time that go back to Albert Einstein: His special theory of relativity, which ignores the effects of gravitation, and his general theory of relativity, in which gravitation is included as a distortion of space and time. For ...
reference frame
Already in special relativity, motion is relative, and whenever there is talk about a moving clock, one must give the additional information: Moving relative to whom or what? Such a "whom or what", in other words: An object together with a ...
