Search results
Results From The WOW.Com Content Network
Cherenkov radiation glowing in the core of the Advanced Test Reactor at Idaho National Laboratory. Cherenkov radiation (/ tʃ ə ˈ r ɛ ŋ k ɒ f / [1]) (also known as Čerenkov or Cerenkov radiation [2]) is electromagnetic radiation emitted when a charged particle (such as an electron) passes through a dielectric medium (such as distilled water) at a speed greater than the phase velocity ...
Theorized. 1967. A tachyon ( / ˈtækiɒn /) or tachyonic particle is a hypothetical particle that always travels faster than light. Physicists believe that faster-than-light particles cannot exist because they are inconsistent with the known laws of physics. [ 1][ 2] If such particles did exist they could be used to send signals faster than light.
In the context of this article, "faster-than-light" means the transmission of information or matter faster than c, a constant equal to the speed of light in vacuum, which is 299,792,458 m/s (by definition of the metre) [ 3] or about 186,282.397 miles per second. This is not quite the same as traveling faster than light, since:
A change in the distribution of energy and momentum of matter results in subsequent alteration, at a distance, of the gravitational field which it produces. In the relativistic sense, the "speed of gravity" refers to the speed of a gravitational wave, which, as predicted by general relativity and confirmed by observation of the GW170817 neutron ...
The speed of light in vacuum, commonly denoted c, is a universal physical constant that is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour). [Note 3] According to the special theory of relativity, c is the upper limit for the speed at which ...
The radiation from the supported charge viewed in the freefalling frame (or vice versa) is something of a curiosity: one might ask where it goes. David G. Boulware (1980) [9] finds that the radiation goes into a region of spacetime inaccessible to the co-accelerating, supported observer. In effect, a uniformly accelerated observer has an event ...
[2] [3] The most common definitions are: [4] The monitor chamber reads 100 MU when an absorbed dose of 1 gray (100 rads) is delivered to a point at the depth of maximum dose in a water-equivalent phantom whose surface is at the isocenter of the machine (i.e. usually at 100 cm from the source) with a field size at the surface of 10 cm × 10 cm.
In the physical sciences, the wavenumber(or wave number), also known as repetency,[1]is the spatial frequencyof a wave, measured in cyclesper unit distance (ordinary wavenumber) or radiansper unit distance (angular wavenumber). [2][3][4]It is analogous to temporal frequency, which is defined as the number of wave cycles per unit time (ordinary ...