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Author Topic: Speed of Light ?  (Read 9981 times)

Offline syhprum

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Re: Speed of Light ?
« Reply #25 on: 24/08/2006 12:36:27 »
When we speak of light (photons) travelling in a vacuum what we are in fact observing is photons travelling through the dark matter with which our galaxy in enveloped.
Has any attempt been made to measure the speed between galaxies away from the dark matter.
Not to mention the sea of quantum particles/anti-particles neutrinos, Gravitons, and the 2.7K CBR that fills space

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Offline Soul Surfer

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Re: Speed of Light ?
« Reply #26 on: 29/08/2006 09:26:00 »
An interesting and highly relevant thought syhprum, dark matter (the major constituent of the universe)does cause light to be deflected by its gravitational attraction.  hence the effects of "gravitational lensing"  that are well known and observed but it is only a very tiny amount  (seconds of arc) unless you are very close to an extremely dense object like a neutron star or a black hole.

However because of the relatavistic equations this deflection is not seen as being a speed change (like the refraction of likght though a glass lens) but a slight distortion in the fabric of the universe.

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Offline lightarrow

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Re: Speed of Light ?
« Reply #27 on: 29/08/2006 10:31:35 »
quote:
Originally posted by Soul Surfer


However because of the relatavistic equations this deflection is not seen as being a speed change (like the refraction of likght though a glass lens) but a slight distortion in the fabric of the universe.
Yes, because matter --> gravitational field, doesn't change the speed of light, it simply bends it.
« Last Edit: 29/08/2006 10:33:09 by lightarrow »
 

Offline syhprum

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Re: Speed of Light ?
« Reply #28 on: 29/08/2006 17:50:51 »
Our mesurements of the speed of light are those made in our galaxy enveloped in dark matter,
is there any evidence as to its speed outside this clump of dark matter as I understand that dark matter is not spread uniformly throughout space

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Offline Soul Surfer

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Re: Speed of Light ?
« Reply #29 on: 30/08/2006 08:07:26 »
There is plenty of evidence that the observed variations in the density of dark matter do not distort light any more than that caused by the observed variations due to gravitational deviation.  A singnificant variation in the velocity of light would cause severe distortion of our image of the universe



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Offline Soul Surfer

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Re: Speed of Light ?
« Reply #30 on: 30/08/2006 08:07:26 »
There is plenty of evidence that the observed variations in the density of dark matter do not distort light any more than that caused by the observed variations due to gravitational deviation.  A singnificant variation in the velocity of light would cause severe distortion of our image of the universe



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Offline lightarrow

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Re: Speed of Light ?
« Reply #31 on: 03/09/2006 10:51:07 »
About the speed of light, if I have understood correctly, (please let me know if I'm saying something wrong), we perceive a change in it, only if we look at the space as if it were euclidean, but, actually, it's not, near massive objects.

So, considering the real geometry of space-time, light always move along a geodesic, which is the analogue of the straight line in an euclidean space, and in that geometry we don't see any change of light's speed.
« Last Edit: 03/09/2006 10:52:08 by lightarrow »
 

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Re: Speed of Light ?
« Reply #31 on: 03/09/2006 10:51:07 »

 

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