Welcome to Citizendium: Difference between revisions
imported>Joe Quick mNo edit summary |
imported>Todd Coles (updated article/draft of the week) |
||
| Line 104: | Line 104: | ||
=== Article of the Week <font size=1>[ [[CZ:Article of the Week|about]] ]</font> === | === Article of the Week <font size=1>[ [[CZ:Article of the Week|about]] ]</font> === | ||
The '''[[Ether (physics)|ether]]''' (also spelled<ref>Generally speaking the spelling "ether" is more modern than "aether". Note, however, that two Americans, A. A. Michelson and E.W. Morley, spelled it as "ether" as early as 1887.</ref> '''aether''') was a concept in [[physics]] made obsolete in 1905 by [[Albert Einstein|Einstein]]'s theory of [[special relativity]]. | |||
'''[[ | |||
The | The idea of an ether was introduced into science by [[René Descartes|Descartes]] in [[Principles of Philosophy|Principia philosophiae]] (1644). Until that time, forces between two bodies that are not in direct contact were assumed to act through space—by [[action at a distance]]. Descartes replaced this explanation by one based on an intermediate medium (ether) consisting of vortices that transmit forces between bodies at a distance. | ||
<font size=1>[[ | The ether concept became especially predominant in the 19th century by the work of [[Thomas Young|Young]] and [[Augustin-Jean Fresnel|Fresnel]] who revived [[Christiaan Huygens|Huygens]]' wave theory of light. They replaced [[Newton]]'s light corpuscles by waves propagating through the ether. In order to explain [[stellar aberration]], first observed in the 1720s and then shown to be caused by the velocity of the earth relative to the velocity of Newton's light corpuscles, Young (1804) assumed ether to be in a state of absolute rest. [[James Clerk Maxwell|Maxwell]] showed in the 1860s that light waves are [[electromagnetic wave]]s transverse (perpendicular) to the direction of the propagation of the waves. Following Young and Fresnel, Maxwell assumed that electromagnetic waves are vibrations of the ether. | ||
<font size=1>[[Ether (physics)|['''more...''']]]</font> | |||
=== New Draft of the Week <font size=1>[ [[CZ:New Draft of the Week|about]] ]</font> === | === New Draft of the Week <font size=1>[ [[CZ:New Draft of the Week|about]] ]</font> === | ||
'''[[ | In computer and network security, a '''[[Worm (computers)|worm]]''' is a form of [[malware]] that, once it activates inside a victim's computer, can replicate and propagate itself without further user activity. Worms often take up valuable memory and network bandwidth, which can cause a computer to stop responding, and can also allow attackers to gain unauthorized remote control of one or more computers. | ||
While the idea of a parasitic worm goes far back in biology, the term appears to have first been used as, as a concept in computing, in [[John Brunner]]'s 1975 science fiction novel, ''[[Shockwave Rider]]''. Actual software, under tightly controlled conditions, was developed in 1981-1982. <font size=1>[[Worm (computers)|['''more...''']]]</font> | |||
|} | |} | ||
Revision as of 21:17, 24 February 2009
 |
| |||||||||||||
A new wiki encyclopedia project—and more!
Write for the Citizendium—knowledge is fun!
Learn about us
Important new community pages
Support us
|
Article of the Week [ about ]The ether (also spelled[1] aether) was a concept in physics made obsolete in 1905 by Einstein's theory of special relativity. The idea of an ether was introduced into science by Descartes in Principia philosophiae (1644). Until that time, forces between two bodies that are not in direct contact were assumed to act through space—by action at a distance. Descartes replaced this explanation by one based on an intermediate medium (ether) consisting of vortices that transmit forces between bodies at a distance. The ether concept became especially predominant in the 19th century by the work of Young and Fresnel who revived Huygens' wave theory of light. They replaced Newton's light corpuscles by waves propagating through the ether. In order to explain stellar aberration, first observed in the 1720s and then shown to be caused by the velocity of the earth relative to the velocity of Newton's light corpuscles, Young (1804) assumed ether to be in a state of absolute rest. Maxwell showed in the 1860s that light waves are electromagnetic waves transverse (perpendicular) to the direction of the propagation of the waves. Following Young and Fresnel, Maxwell assumed that electromagnetic waves are vibrations of the ether. [more...] New Draft of the Week [ about ]In computer and network security, a worm is a form of malware that, once it activates inside a victim's computer, can replicate and propagate itself without further user activity. Worms often take up valuable memory and network bandwidth, which can cause a computer to stop responding, and can also allow attackers to gain unauthorized remote control of one or more computers. While the idea of a parasitic worm goes far back in biology, the term appears to have first been used as, as a concept in computing, in John Brunner's 1975 science fiction novel, Shockwave Rider. Actual software, under tightly controlled conditions, was developed in 1981-1982. [more...] | ||||
- ↑ Generally speaking the spelling "ether" is more modern than "aether". Note, however, that two Americans, A. A. Michelson and E.W. Morley, spelled it as "ether" as early as 1887.