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#1
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Jerry Stuckle wrote in news:m18uud$pa8$1@dont-
email.me: But I'm not familiar with what a Bose-Einstein condensate is doing in this area . Could you please elucidate? I wish I could! All I know is that someone 'slowed light to a crawl' by passing it through one. I knos so little about it that I can't make useful thoughts about the comment. I'm also unsure or relativistic effects. When I read about it, I got as far as reading of some transformative 'foreshortening' described in one book, only to get completely foozled, and read later than that whole notion was badly described to the point of beign wrong anyway. Whatever the theory says, I never found a translation into English that I could grasp. The one thing I did get was that the approach to this 'speed', a quantity defined as if on a linear continuum, is unapproachable and that all attempts to do so seem to result in exponential chages tending to infinity. For that reason, and that alone, I assume it is not a speed, no matter how it may look. But that is just how it feels to me when I try to think about it. |
#2
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On 10/10/2014 3:45 PM, Lostgallifreyan wrote:
Jerry Stuckle wrote in news:m18uud$pa8$1@dont- email.me: But I'm not familiar with what a Bose-Einstein condensate is doing in this area . Could you please elucidate? I wish I could! All I know is that someone 'slowed light to a crawl' by passing it through one. I knos so little about it that I can't make useful thoughts about the comment. I remember an article recently in one of the magazines which indicated scientists had actually stopped a pulse of light for a indefinite time. I also remember where they slowed light down to a very slow speed. I don't remember that Bose-Einstein condensates were involved, but I'm not sure. I'm also unsure or relativistic effects. When I read about it, I got as far as reading of some transformative 'foreshortening' described in one book, only to get completely foozled, and read later than that whole notion was badly described to the point of beign wrong anyway. Whatever the theory says, I never found a translation into English that I could grasp. The one thing I did get was that the approach to this 'speed', a quantity defined as if on a linear continuum, is unapproachable and that all attempts to do so seem to result in exponential chages tending to infinity. For that reason, and that alone, I assume it is not a speed, no matter how it may look. But that is just how it feels to me when I try to think about it. Well, one thing - the speed of light is not actually a constant. It is a constant in vacuum, but in other materials it is slower. So if the friction/viscosity effects of glass were ignored, for instance, you'd still have a maximum velocity. It would just be rather significantly less than in a vacuum. -- ================== Remove the "x" from my email address Jerry, AI0K ================== |
#3
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Jerry Stuckle wrote in news:m19tmu$snl$1@dont-
email.me: Well, one thing - the speed of light is not actually a constant. It is a constant in vacuum, but in other materials it is slower. So if the friction/viscosity effects of glass were ignored, for instance, you'd still have a maximum velocity. It would just be rather significantly less than in a vacuum. That's true.. refractive index and such. I read recently that a negative refractive index can exist, but I don't remember how that works. The thing is, once the light leaves the glass and returns to air or vacuum, normal 'speed' is instantly resumed. ![]() definitely such, though the same name occurs in other things even less understood by me) had basically just a humungous refractive index, but I don't think I read of any obvious relation to refraction either in that slowed-light report, so I tend to have a 'watch-this-space' view in its general direction. I suspect it will take several reports of new things before some pattern emerges than I will understand. I'm wary of thinking of refractive index's effects as friction or viscosity. I suspect that those notions relate to things with rest mass and electrical charges and don't model closely to what light is up to. At the risk of sounding silly, I think Terry Pratchett had a point when he said that wherever light gets to, the dark is already there, waiting for it. Personally I think that neither exists without the other, and the only reason we can posit 'nothing' is because we can posit 'a thing'. Whether such talk obstructs or helps science I am never entirely sure. |
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