so that's how you call it...craterchains wrote:god, kiss my "donkey".
A poser
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I was watching a NOVA program on "Absolute Zero" and they mentioned Bose-Einstein condensates that slow down light as it enters the condensate and allow it to speed back up as it leaves with any intelligence still attached. Obviously the speed of light can be manipulated by matter (and gravity). In a complete vacuum, the speed of light is constant. However, since a complete vacuum does not exist in a universe filled with matter, there is most probably some variance in the speed of light within it.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
bystander, what you are saying is like suggesting that Pi, for example, is not constant, because in real world ratio of hand-drawn circles' circumferences to their diameters varies.
And your answer to this, makc?
Physicists Slow Speed of Light
Physicists Slow Speed of Light
The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or for the Latin celeritas ("swiftness"). It is the speed of all electromagnetic radiation, including visible light, in a vacuum. More generally, it is the speed of anything having zero rest mass.
...
The speed of light when it passes through a transparent or translucent material medium, like glass or air, is slower than its speed in a vacuum. The ratio of c to the observed phase velocity is called the refractive index of the medium. General relativity explains how a gravitational potential can affect the apparent speed of distant light in a vacuum, but locally light in a vacuum always passes an observer at a rate of c.
...
http://en.wikipedia.org/wiki/Speed_of_light
Last edited by bystander on Tue Jan 22, 2008 8:17 pm, edited 2 times in total.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
Whoosh! Right over the top. Guess I aimed too high.FieryIce wrote:Thank you bystander, yes one does become sensitized with constant exposure and can spot bull$$** a mile away.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
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fireyIce, no need to attack me, I'm pretty much done talking to you in my last post addressed to you. Unless you have something "new" to say.
bystander, I don't see how it says anything different from what I said. Take a closer look:
The whole argument you quote relies on definition of c as constant, so "not being constant" cannot follow from it logically.
bystander, I don't see how it says anything different from what I said. Take a closer look:
I color-marked things by relevance. What you do is mix them all together and claim, on that basis, that c is not constant.The speed of light when it passes through a transparent or translucent material medium, like glass or air, is slower than its speed in a vacuum. The ratio of c to the observed phase velocity...
The whole argument you quote relies on definition of c as constant, so "not being constant" cannot follow from it logically.
No, you said the speed of light is constant. My point was that the speed of light is only constant in a vacuum. Since there is no complete vacuum in our material universe, the speed of light varies. Granted, that variance may be too small for us to measure, but it's there. c is the defined constant for the speed of light in a vacuum. In other mediums, the speed of light is not c.
In the article Physicists Slow Speed of Light, they slow light down to 38 miles per hour.
In the article Physicists Slow Speed of Light, they slow light down to 38 miles per hour.
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
and again, you mixed all up, or you are just being nitpicking.
the speed of light is, indeed, constant, just like Pi or e or i or 1 or 0. it is defined by International System of Units to be exactly 299,792,458 metres per second (actually, it is consequence of meter definition, as I posted a page ago).
if you really expect me to write "the speed of light immediately near observer in vaccuum aka c in relativity theory" instead of "speed of light" everywhere, then I will not, sorry, it is just too much writing.
the speed of light is, indeed, constant, just like Pi or e or i or 1 or 0. it is defined by International System of Units to be exactly 299,792,458 metres per second (actually, it is consequence of meter definition, as I posted a page ago).
if you really expect me to write "the speed of light immediately near observer in vaccuum aka c in relativity theory" instead of "speed of light" everywhere, then I will not, sorry, it is just too much writing.
I hope you arent going to claim now that jet planes violate relativistic speed limit daily?In the article Physicists Slow Speed of Light, they slow light down to 38 miles per hour.
No, but wouldn't that be fun. I could even do it in my car, even though it's not a DeLorean.
Maybe you think I'm nitpicking, but c is the speed of light in a vacuum not the speed of light. Light, and its speed, is affected by the medium through which it passes. If this wasn't so, we wouldn't have rainbows. The sky wouldn't be blue. Refraction telescopes would be useless. The ability to manipulate the speed of light (or electromagnetic radiation) is the key to quantum computing. If this is nitpicking, then I'm guilty.
Read the article. It's really quite interesting. http://www.hno.harvard.edu/gazette/1999 ... light.html
Maybe you think I'm nitpicking, but c is the speed of light in a vacuum not the speed of light. Light, and its speed, is affected by the medium through which it passes. If this wasn't so, we wouldn't have rainbows. The sky wouldn't be blue. Refraction telescopes would be useless. The ability to manipulate the speed of light (or electromagnetic radiation) is the key to quantum computing. If this is nitpicking, then I'm guilty.
Read the article. It's really quite interesting. http://www.hno.harvard.edu/gazette/1999 ... light.html
Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
alive to the gentle breeze of communication, and please stop being such a jerk. — Garrison Keillor
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bystander, I've got used to "speed of light" as an alias for "c". I would rather refer to what you mean by "phase velocity of light" (as they do in your quote) to avoid confusion, but discussion of names is rather pointless here. In the post that has diverted discussion from original subject to speed of light, capt.yesterday says:
from here, it is quite clear what is meant by "speed of light" in the thread afterwards.i want to know why nothing can travel faster than the speed of light?
Yeah, -1 * c.GOD wrote:BMA: Are you imagining that there's a minimum natural speed?BMAONE23 wrote:Would the solution be to state C as the maximum natural speed of light???