It's a mysterie to me!
2007-01-21 03:58:03 · 9 answers · asked by J F 1 in Science & Mathematics ➔ Physics
3.0x10^8 m/s.
2007-01-21 04:03:59 · answer #1 · answered by San Jose 3 · 0⤊ 0⤋
The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning "swiftness". It is the speed of all electromagnetic radiation in a vacuum, not just visible light.
In metric units, c is exactly 299,792,458 metres per second (1,079,252,848.8 km/h). Note that this speed is a definition, not a measurement, since the fundamental SI unit of length, the metre, has been defined since October 21, 1983 in terms of the speed of light: one metre is the distance light travels in a vacuum in 1/299,792,458 of a second. Converted to imperial units, the speed of light is approximately 186,282.397 miles per second, or 670,616,629.384 miles per hour, or almost one foot per nanosecond.
Through any transparent or translucent material medium, like glass or air, it has a lower speed than in a vacuum; the ratio of c to this slower speed is called the refractive index of the medium. Changes of gravity, however, warp the space the light has to travel through, making it appear to curve around massive objects. This gives rise to the phenomenon of gravitational lensing, in which large assemblies of matter can refract light from far away sources, so as to produce multiple images and similar optical distortions.
2007-01-21 12:25:54 · answer #2 · answered by Mikhil M 2 · 0⤊ 0⤋
299 792 458 m / s
2007-01-21 12:03:01 · answer #3 · answered by soccercam14 2 · 0⤊ 0⤋
670,616,629.384 miles per hour. Amazingly, you will always measure the same speed, regardless of your relative velocity to the light source. Einstein used this single fact to derive all of special relativity.
2007-01-21 12:04:14 · answer #4 · answered by bobqwatson 2 · 0⤊ 0⤋
Near 300,000 kilometers per second.
More precisely, 299,792,458 metres per second, in the vacuum (just a tiny bit slower in air, a bit slower within glass of other refractive materials). Please see the source below for more information.
2007-01-21 12:21:10 · answer #5 · answered by jcastro 6 · 0⤊ 0⤋
3 X 10^8 meters/sec...really, really, really fast!!
2007-01-21 12:03:45 · answer #6 · answered by hcbiochem 7 · 0⤊ 0⤋
186,000 Miles per second.
2007-01-21 12:02:50 · answer #7 · answered by Dogness 5 · 0⤊ 0⤋
BY THE TIME U READ THIS. IT HAS PASS
2007-01-21 12:01:49 · answer #8 · answered by RRRRRRRR 3 · 0⤊ 0⤋
Try this: http://en.wikipedia.org/wiki/Speed_of_light
2007-01-21 12:08:07 · answer #9 · answered by Anonymous · 0⤊ 0⤋