"Spoonfed" wrote in message ups.com...

Sue... wrote:
Daniel Weston wrote:
"Why is the speed of light the same for all observers?" Ans: No body
knows.

Students of electromagnetism know...or think they know:
http://www.conformity.com/0102reflectionsfig3.gif from:
http://www.conformity.com/0102reflections.html

http://physics.nist.gov/cuu/Images/alphaeq.gif from:
http://physics.nist.gov/cuu/Constants/alpha.html

But the study of electromagnetism is
uh...harrrrd.... ya hafta be workin' harrrd ;-)

Seems like the right direction... But all that hard stuff is pretty
confusing. Do you suppose we could find some explanation that may not
be so hard? Maybe not a timeline but at least a list of goals, and
maybe a roadmap to understanding?

Okay, start with a stationary charged particle. It has a central
electric field. If that particle is moving, if I am not mistaken, it
creates a magnetic field. However, somebody moving along with the
particle doesn't see the magnetic field.

Now, I don't quite see how this particular idea leads to a constant
speed of light, but it is a bit strange, anyway. I'm just bringing it
up because that's a question I've never fully explored.

I do remember sometime in college when I THOUGHT I understood how
electric and magnetic fields explained the speed of light. Multiplying
the permittivity times the permeability of free space yielded the speed
of light. However, I can't remember what would make a person multiply
these two values together, except that they happen to produce the speed
of light.

So, I guess the question I want to ask is, why do you multiply
permittivity and permeability together?

When you juggle with Maxwell's equations, they turn out
to produce standard wave equations that all have
epsilon_0 * mu_0 as a coefficient of the second order
partial time derivative term.
The standard wave equation has 1 / wave speed^2
as its coefficient at that place
http://mathworld.wolfram.com/WaveEquation.html

Dirk Vdm