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russ_watters

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Anyway, look here: http://en.wikipedia.org/wiki/Solar_sail

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HallsofIvy

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"Light Sails" have long been a staple of science fiction. I don't know if NASA is doing any research but it would certainly been possible.

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Why is the speed of light limited to 3*10^8 m/s? What is blocking it from going faster than that?

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russ_watters

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The speed of light is a dictated by the permeability and permittivity of space, as a consequence of Maxwell's equations.

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prasannapakkiam

Well Watters has explained it clearly...

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it is the rate at which time flows.

Not sure where I heard that...

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Not sure where I heard that...

In a sense, c is the conversion rate between space and time. In many theoretical papers, "natural" units are adopted, where c = 1, \hbar = 1, etc. So that mass, length, time are all inter-convertible without changing the number.

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The speed of light is a dictated by the permeability and permittivity of space, as a consequence of Maxwell's equations.

From the speed of light, did we derive the permeability and permittivity of space, or is it the other way?

Can anyone explain permeability and permittivity of space in simpler terms? I googled those keywords, but gave me pages with lots of greek symbols, which I used to understand in the past, for a short period in my life.

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russ_watters

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If I understand the history correctly, I think they were measured about the same time the first accurate measurements of the speed of light were being taken (by Michelson). So the speed of light was separately measured and calculated and found to be the same value.From the speed of light, did we derive the permeability and permittivity of space, or is it the other way?

Basically, the resistance to passing magnetic and electric fields.Can anyone explain permeability and permittivity of space in simpler terms? I googled those keywords, but gave me pages with lots of greek symbols, which I used to understand in the past, for a short period in my life.

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