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The Thinker
Join Date: Mar 2005 Posts: 3,278
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10-18-2005, 05:17 PM
| Quote: |
Originally Posted by AntonioLao pages 9 and 10. | Thanks. Quote: |
Originally Posted by AntonioLao Only if the speed of the graviton is the same as the speed of the photon. | I've read many experiments whcih have been done that sort-of proof that the speeds are equal. There ws one that treduced the speed of a gravitons to a barier from 275,000km/s to 325,000km/s. | | | | Raider of the lost time
Join Date: Nov 2003 Posts: 5,934
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10-18-2005, 05:47 PM
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Originally Posted by GUILLE There ws one that treduced the speed of a gravitons to a barier from 275,000km/s to 325,000km/s. | Speeds lower than light speed would strongly indicate that graviton has a mass greater than zero.
__________________
Time independence: [∂E(g)]²=[∂F(a)×∂r(a)]·[∂F(b)×∂r(b)] and Mass independence: ¶a(t)·¶r(t)=c²
| | | | The Observer
Join Date: Jan 2005 Posts: 1,951
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10-18-2005, 08:54 PM
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Originally Posted by AntonioLao Experiments showing group velocities greater than c include that of Wang et al. (2000), who produced a laser pulse in atomic cesium gas with a group velocity of 311c. In each case, the observed superluminal propagation is not at odds with causality, and is instead a consequence of classical interference between its constituent frequency components in a region of anomalous dispersion (Wang et al. 2000). | Antonio;
I was unable to find any reference to a laser experiment by Wang et al;
Can you point me to a book or web-site? I'm not quite sure what you are referring to with your response. Is that truly 311c or should it be 3.11c?
Thanks;
Dave
__________________ David  | | | | Moderator
Join Date: Aug 2005 Posts: 7,647
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10-19-2005, 12:37 AM
|  What would happen to a photon in a black-hole!
What in theory would happen to a poor little photon who got caught up in a
black-hole and was pressed into a singularity,would it be erased,canceled out,
or stretched into oblivion,light it seems gets sucked into a black-hole never to escape! but is that the case?in theory could not the light-photons be transported to another dimension via this black-hole which could be a conduit
for this very purpose.can you stretch light-or just thought?Maybe the very reason light vanishes at a black hole is because it is channeled away and has nothing to do with gravity at all.Just a thought.
kind regards michael. | | | | Raider of the lost time
Join Date: Nov 2003 Posts: 5,934
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10-19-2005, 12:31 PM
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Originally Posted by dleviwing Can you point me to a book or web-site? | The website is http://scienceworld.wolfram.com/physics/Superluminal.html The article is published in Nature 2000: Wang, L. J.; Kuzmich, A.; and Dogariu, A. "Gain-Assisted Superluminal Light Propagation." Nature 406, 277-279, 2000. Quote: |
Originally Posted by mkirkpatrick What in theory would happen to a poor little photon who got caught up in a black-hole and was pressed into a singularity | The existence of black holes remains circumstantial. There is no direct evidence that they exist. So, in theory when a photon is gravitationally trapped within a black hole, it will gain tremendous amount of energy by decreasing its wavelength and increasing its frequency.
__________________
Time independence: [∂E(g)]²=[∂F(a)×∂r(a)]·[∂F(b)×∂r(b)] and Mass independence: ¶a(t)·¶r(t)=c²
| | | | The Observer
Join Date: Jan 2005 Posts: 1,951
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10-19-2005, 01:06 PM
| Antonio;
Interesting phenomena, it's almost as if the light is being conducted rather than transmitted through the medium. I see the group velocity index you stated for cesium should have been (-311) to preserve pulse slue rate and shape.
group-velocity index of ng = -310( 5)
Thanks;
Dave
__________________ David | | | | Raider of the lost time
Join Date: Nov 2003 Posts: 5,934
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10-19-2005, 01:30 PM
| Quote: |
Originally Posted by dleviwing I see the group velocity index you stated for cesium should have been (-311) to preserve pulse slue rate and shape.
group-velocity index of ng = -310( 5) | Thanks, although didnt quite understand your technical information. Since I'm not an experimentalist I'll just have to let it go at that without further inquisition on my part.
__________________
Time independence: [∂E(g)]²=[∂F(a)×∂r(a)]·[∂F(b)×∂r(b)] and Mass independence: ¶a(t)·¶r(t)=c²
| | | | Raider of the lost time
Join Date: Nov 2003 Posts: 5,934
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10-19-2005, 04:20 PM
| | the question that I have waited to ask within the context of this post is whether photons from the same source can ever overtake each other? We know that photons from different source cause interference patterns. The logical answer is that a photon can overtake another if and only if it accelerates, which is the same as saying that its speed increases.
__________________
Time independence: [∂E(g)]²=[∂F(a)×∂r(a)]·[∂F(b)×∂r(b)] and Mass independence: ¶a(t)·¶r(t)=c²
| | | | Banned
Join Date: Apr 2005 Posts: 562
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10-19-2005, 06:02 PM
| | Antonio, it seems to me that light can accelerate, by changing direction but never speed. So maybe, if one photon was gravitationally bent, then another photon from the same source could overtake it? I'm not entirely sure though, maybe when light bends around an object it actually speeds up such that it gets around the object in the same amount of time it would have taken to move straight through it. Does gravitational bending of light technically count as a type of acceleration? Probably not if you say it's just due to the curvature of space time. The effect is one of acceleration it would seem nevertheless.
Dave, if you don't mind, could you explain to me why you say QM posits a universal speed limit greater than c? If I understand correctly it's because that was the velocity of the initial expansion or something?
thanks, sub
| | | | Moderator
Join Date: Aug 2005 Posts: 7,647
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10-19-2005, 09:09 PM
| Can a photon torpedo outrun illuminocity?
You posed an interesting question Antonio,regarding photons and can they ever
outrun one another if all are from the same source!I do not know the answer to that question.But the idea struck me while thinking of this,In theory if you had
a space craft like say the Enterprise in Star-trek, and you were travelling at
warp one,which I think is just the speed of light.what would in therory would
happen if you fired a Photon-torpedo straight ahead of the ship?would the photon-beam move ahead of the ship,and if it did would it in theory be moving
at faster than light speed! I am aware that this will more than likely never happen,but do you know of a law that would permit this to happen?
Look forward to your reply.
kind regards michael. | | | | | |
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