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Regarding BC's question:
A teacher member of the PTSOS** list posted:
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We're discussing Special Relativity in my conceptual physics class,
and a student asked WHY light goes at 300,000 km/s, and what limits
it.
Have you any recommendations for a response?
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The reason light travels at 299792458 m/s is that the meter is defined as 1/299792458 of a light-second. If other definitions were used for the meter and/or the second we would expect to have different numerical values for c.
Does one answer such questions by: physics deals w/ how and what,
not why (that's meta-physics), or delve into Maxwell -- which leads
to why is mu 4Pi E-7 and e 8.85 etc.
[mu]_0 = 4*[pi]*10^-7 N/A^2 because it is defined that way. It is chosen to have that value so the definition of the ampere comes out the way it does (i.e. the equal current in two parallel infinitely long and narrow wires separated by a meter such that the magnetic force one exerts on the other is exactly 2*10^-7 N/m.
[epsilon]_0 has the value it does because of the previous definitions fixing the values of c and [mu]_0 ([epsilon]_0 = 1/([mu]_0*c^2) ).
bc stumped, after cursorily searching JD's site.
p.s. is the answer a just-so story?
More or less. In short these values are what they are by the arbitrary definitions of the system of units used.
David Bowman
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