David H. Burns wrote:
> moved with the earth,

Fairly easy to disprove by observing things outside the solar system, IIRC.

> (3) it exists but is theoretically undetectable, and perhaps more. 
> Didn't the "Lorentz-Fitxgerald"
> contraction also come out of this as an attempt to preserve the aether? 

It was to explain why it was undetectable, IIRC.

> So the idea that the speed of light is a constant comes from Maxwell. Does
> simply "fall out" of his equations or is it an assumption or what?

It's based on the charge to mass ratio of the electron, IIRC.  I used to be 
able to calculate what the speed of light would be for different charge to 
mass ratios, but that was back in high school.

The fact that it was based only on charge and mass and not the relative 
speed of the observer is what made it a "constant".

> Come to think of it, isn't the speed of any wave in an unchanging 
> unmoving medium
> constant and dependent on the properties of the medium?

Nope. Your wake never catches up with you when you're in a boat.

> The idea that the velocity of light is a fundamental constant is 
> something dictated by
> theory or maybe better a fundamental assumption of Einstein's theory.

My understanding is that "the speed of light" showed up in a number of 
physics equations unrelated to light as such. Thus, it had to be a constant, 
or there would be an adjustment in those equations to account for the 
observer's motion. Again, this is just my vague memory.

> I think two of his basic assumptions were (in my words):
> 
> 1) The speed of light is constant in all frames of reference.
> 
> 2) Other than that, the observations made from within any frame of 
> reference are valid
> only within it.

The third being "the same thing happens regardless of the frame of reference 
from which you look at it."  I.e., what *actually* happened doesn't change 
depending on how you look at it.

> Of course the "light bearing aether" survives in a way as the 
> "electrical and magnet fields of space".

A field isn't aether. A field is a technical term that basically means "a 
collection of vectors with certain properties."  It's not a physical thing, 
but a mathematical thing.

-- 
   Darren New, San Diego CA, USA (PST)
   Understanding the structure of the universe
    via religion is like understanding the
     structure of computers via Tron.

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