| 词条 | Observer (physics) |
| 释义 |
The term observer has a number of non-equivalent uses in science. Special relativity{{main|Observer (special relativity)}}The term observer in special relativity refers most commonly to an inertial reference frame. In such cases an inertial reference frame may be called an "inertial observer" to avoid ambiguity. Note that these uses differ significantly from the ordinary English meaning of "observer". Reference frames are inherently nonlocal constructs, covering all of space and time or a nontrivial part of it; thus it does not make sense to speak of an observer (in the special relativistic sense) having a location, except for denoting the origin of his reference frame. Also, an inertial observer cannot accelerate at a later time, nor can an accelerating observer stop accelerating. General relativityIn general relativity the term "observer" refers more commonly to a person (or a machine) making passive{{citation needed|date=April 2012}} local measurements, a usage much closer to the ordinary English meaning of the word. Commonly used are FIDO (fiducial observer, stationary), FFO (free falling observer), ZAMO (zero angular momentum observer, corotating). Quantum mechanics{{Main|Observer (quantum physics)}}{{See also|Schrödinger's cat}}In quantum mechanics, "observation" is synonymous with quantum measurement and "observer" with a measurement apparatus and observable with what can be measured. Thermodynamics and information theorySee for example Maxwell's demon. See also
1 : Concepts in physics |
| 随便看 |
|
开放百科全书收录14589846条英语、德语、日语等多语种百科知识，基本涵盖了大多数领域的百科知识，是一部内容自由、开放的电子版国际百科全书。