2006-07-27 22:59:41 · 13 answers · asked by rvn 1 in Science & Mathematics ➔ Physics
the speed of light is virtually constant. However we measure it using an earth based scale ( how far light would travel in one earth year)
it is used to measure astronomical distances, not time .
2006-07-28 07:06:10 · answer #1 · answered by Anonymous · 1⤊ 0⤋
As many people have said the speed of light in a vacuum is constant. Just to clarify things a bit there is nothing special about light, the 'speed of light' is actually the 'speed of massless particles' and photons (the particle that carries light energy) happen to be massless.
Miss Prim is certainly wrong. If the speed of light varied substantially between interplanetaty/stellar/galactic space then the effects would be obvious and this has not been observed.
2006-07-28 08:20:24 · answer #2 · answered by m.paley 3 · 0⤊ 0⤋
The speed of light in a vacuum (c) is a universal constant.
Its value is 3 x 10^10 cm/sec, or 186,000 miles/sec.
Since the distance to the sun is 93 million miles,
and 2 x 93 == 186,
it takes 500 seconds for sunlight to reach the Earth.
This round number connection is interesting,
but would not occur for the other solar system planets.
2006-07-27 23:19:19 · answer #3 · answered by David Y 5 · 0⤊ 0⤋
It is currently thought by several institutions that the speed of light is in fact variable.......
(1) That there is the speed that we know of, labelled interplanetary
(2) That the next level many times faster, labelled interstallar
and
(3) The final level, many times faster still is labelled intergalactic.
These were based upon the different levels of gravity within the whole universe and may have some substance.....let's face it, why not since we know so little about it all anyway.
2006-07-28 03:55:03 · answer #4 · answered by Miss Prim 2 · 0⤊ 0⤋
The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin celeritas meaning "swiftness". Light travels slower than c through all other transparent mediums; the ratio of c to this slower speed is called the refractive index of the medium.
In metric units, c is exactly 299,792,458 metres per second. 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.
2006-07-27 23:15:14 · answer #5 · answered by The Wanderer 6 · 0⤊ 0⤋
Speed light varies with the medium. Thus speed of light in air will be different from glass which is different from the speed of light in vaccum. So the speed of light changes according to the medium in which it travels and not the location in the universe.
Having said that, one must note that speed of light changes when it is travelling into a black hole.
2006-07-27 23:54:01 · answer #6 · answered by Rabindra 3 · 0⤊ 0⤋
Its true the speed of light has been measured relative to the Earth (see Roemer speed of light measurements).
Measurements relative to the outskirt of the Universe was made by a scientist= I think he made a precise measurement but I am not sure.His name is.... I just dont recall.
2006-07-28 00:33:01 · answer #7 · answered by goring 6 · 0⤊ 0⤋
No, you are mistaken.
It's not a sun-earth calculation.
It applies to the universe.
It is is universal "speed-limit."
Light can travel slower in different mediums.
2006-07-27 23:03:05 · answer #8 · answered by NA A 5 · 0⤊ 0⤋
It is the same no matter where you calculate it from... The speed depends on which material the light is traveling through...
2006-07-27 23:07:19 · answer #9 · answered by Thomas NP 2 · 0⤊ 0⤋
The speed of light is a universal constant for our universe.
2006-07-27 23:03:10 · answer #10 · answered by Paul B 3 · 0⤊ 0⤋