speed of lightとは 意味・読み方・使い方

名詞

speed of light (plural speeds of light, abbreviation c)

1. (physics) The speed of electromagnetic radiation, which in a perfect vacuum is equivalent to 299,792,458 metres per second.

   Alternative form: c (symbol)

   Synonyms: lightspeed, light speed, Einstein's constant, Einstein barrier

   Early physicists developed insightful methods for measuring the speed of light.

   • 2008, BioWare, Mass Effect, Redwood City: Electronic Arts, →ISBN, →OCLC, PC, scene: FTL Drive: Appearance Codex entry:

     As the subjective speed of light is raised within the field, objects outside will appear to red-shift, eventually becoming visible only to radio telescope antennae.

   • 2011 September 22, Nick Collins, “Speed of light 'broken' by scientists”, in Daily Telegraph‎:

     The science world was left in shock when workers at the world's largest physics lab announced they had recorded subatomic particles travelling faster than the speed of light – a feat that Einstein said was impossible.

2. (colloquial, figurative) A very rapid speed.

   When her cat figured out that a trip to the vet was in the offing, he took off towards the closet at the speed of light.

3. (cellular automata) A rate of travel of a signal equal to one cell per generation, the fastest possible speed in the Moore and von Neumann neighborhoods.

   In a single generation, a cell can only influence its nearest neighbours, and so the speed of light (by analogy with the speed of light in physics) is the maximum rate at which information can propagate.

   • 1992 August 14, David I. Bell, “Spaceships in Conway's Life (Part 1)”, in comp.theory.cell-automata‎ (Usenet):

     The translated distance divided by the period is the speed of the spaceship. Since the maximum speed of propagation of a signal in Life is one cell per generation, this speed is known as c (the speed of light). This speed is also the fastest possible growth of any finite object for a finite number of generations (think of a long line of ON cells). However, growth (or even just movement) of a finite object for an infinite time cannot occur at this speed.

参考

Further reading

• speed of light on Wikipedia.Wikipedia
• speed of light (cellular automaton) on Wikipedia.Wikipedia