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Author Topic: Can we control the speed of light?  (Read 3354 times)

Offline The Scientist

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Can we control the speed of light?
« on: 19/07/2010 12:43:40 »
We know that the speed of light is 299,792,458 metres per second. But are there any  ways of controlling the speed of light? Please share your views with us. Thanks!


 

Offline imatfaal

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Can we control the speed of light?
« Reply #1 on: 19/07/2010 15:05:37 »
that's the speed in a vacuum.  you can 'control' it by sending it through another medium; the ratio of speed in a vacuum to the speed in a medium is called the refractive index.  the refractive index of glass is about 1.5 - so every time you shine a light through glass you are making it drop to around 200,000,000 m/s.  some materials lower the speed of light to practically pedestrian speeds - upon checking wikipedia it seems that a bose-enstein condensate of rubidium can halt light in the correct circumstances!
Matthew
 

Offline syhprum

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Can we control the speed of light?
« Reply #2 on: 19/07/2010 17:33:38 »
I say this with tongue in cheek but is it not slowed down by strong gravitational fields such as exist close to Neutron stars and black holes
 

Offline LeeE

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Can we control the speed of light?
« Reply #3 on: 19/07/2010 18:49:59 »
As far as I understand, light is not slowed by strong gravitational fields, but because of the gravitational curvature of space there may be 'more' space for it to travel through in the vicinity of a gravity well.

When viewed by a distant observer, in flatter space and who is measuring the speed by the rate of angular displacement, it might appear to slow down as it approaches the gravity well.
 

Offline syhprum

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Can we control the speed of light?
« Reply #4 on: 19/07/2010 19:49:42 »
Yes I realise what is the reason when I stop to think before typing.
The light moves at its normal speed but takes a longer path dipping into the gravitational well.
 

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Can we control the speed of light?
« Reply #4 on: 19/07/2010 19:49:42 »

 

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