2006-06-17 18:21:20 · 12 answers · asked by Anonymous in Science & Mathematics ➔ Astronomy & Space
No. Based on stellar observations, researchers at UNSW have discovered that the fundamental constants of the universe have been changing. Whether it is the speed of light or the fine structure constant that is changing is still up to debate.
Edit: ok it seems quite obvious now that no-one here knows what you are talking about and are just repeating what they have heard in high school physics classes. Someone even think light slows down due to absorbtion!!! I have found a link that may interest you. It explains things quite well and accurately but still won't give you a conclusive answer. It contains a few links to Journal articles if you want to delve deeper.
http://www.phys.unsw.edu.au/einsteinlight/jw/module6_constant.htm
2006-06-17 18:27:34 · answer #1 · answered by Paul C 4 · 8⤊ 2⤋
The speed of light is constant. It also does not slow down based upon what material it is entering contrary to popular belief. The time we measure for light to travel through materials is longer then through a vacuum because the light is absorbed and re-emitted. The longer a material takes to absorb and re-emit the light, the slower light appears to be going. In fact, the photons are traveling at the speed of light in between each atom.
There is no way to tell whether or not light has changed its speed in the past. Current theories make the assumption that light has never changed since we have yet to see the speed of light change speed naturally.
2006-06-18 01:33:14 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Ummm Possibly the speed of light was different by tiny fractions earlier in history. Some data from the world's oldest known plutonium at the "natural" nuclear reactor in Uganda in Africa shows that certain decay constanats have changed slightly over the millions of years involved, so the possibility exists that light velocity may have been less.
But light is a constant across the universe in vacuum.
2006-06-18 01:49:34 · answer #3 · answered by covertwalrus 3 · 0⤊ 0⤋
The speed of light is different depending on what medium it is passing through. We typically refer to the speed of light in vacuum when we are reporting a number.
Scientists have yet to come up with a way to investigate the question of whether light has had the same speed in vacuum since the beginning of time, or the beginning of our universe, or forever, or whatever.
2006-06-18 01:28:13 · answer #4 · answered by enginerd 6 · 0⤊ 0⤋
So far as we know, the spoeed of light in a given material has always been the same. As light is constantly being generated and disersed/abosrbed, a force that would slow it would seem improbable.
However, light passing through different mediums does have different speeds.
2006-06-18 01:29:20 · answer #5 · answered by sciguy 5 · 0⤊ 0⤋
What LeBo said. If light is travelling through anything other than a perfect vacuum it is slowed: the amount of this slowing depends on what material it's passing through according to it's refractive index.
As to the second part of your question, I don't know. I would think it has always been it's current speed.
2006-06-18 01:34:25 · answer #6 · answered by Xraydelta1 3 · 0⤊ 0⤋
1 the speed of light is constant until it sees a cop.
2 it was much more valueable in the past before we invented the light bulb.
2006-06-18 06:38:32 · answer #7 · answered by hmmmmm 1 · 0⤊ 0⤋
The speed of light depends on what material it is traveling through. If it is traveling through a vacuum, then the speed is the maximum. If it is traveling through an opaque glass, it meets a lot of resistance and travels more slowly.
2006-06-18 01:25:13 · answer #8 · answered by Anonymous · 0⤊ 0⤋
It is the same as the speed of dark.
2006-06-18 01:27:15 · answer #9 · answered by vande-man 3 · 0⤊ 0⤋
it attains speed depending on the nature of the material it travels through...and it also depends upon the refractive index of the material....
2006-06-18 01:26:26 · answer #10 · answered by sniper 3 · 0⤊ 0⤋