"Len Gaasenbeek" wrote in message
news:9emdnbOUJrKTMDTenZ2dnUVZ_sednZ2d@wtccommunica tions.ca...

SIMPLE EXPLANATION OF THE SAGNAC EFFECT.

Suppose I am sitting in the centre of a stationary spaceship. When I look
at the front of the spaceship, its image will travel towards me at c.

Similarly, when I look at the back of the spaceship, its image will travel
towards me at c, but in the opposite direction.

When a stationary observer outside the spaceship looks at me, he will also
see both the internal front image of the spaceship, as well as the
internal
rear image of the spaceship travel towards me at c. In other words light
travels at c in all directions inside the spaceship, as observed by me and
the outside observer.

Next let us suppose that the spaceship passes the stationary earth-bound
observer by at a velocity of v miles per hour.

For me inside the spaceship, the image of the front of the spaceship and
the
rear of the spaceship will still travel towards me at c. That is to say,
light continues to travel at c in all directions inside the spaceship in
relation to the spaceship, whether it is in motion or not.

But what does the stationary observer on earth see?
As far as he is concerned, the image of the (interior) front of the
spaceship will now travel towards me at (c-v), whereas the image of the of
the rear of the spaceship will travel towards me at (c+v).

It should be noted however that the relative speed between the observed
images remains 2c. That is to say, the relative speed at which the
interior
rear and front image of the spaceship travel towards each other remains:
(c-v) + (c+v) = 2c.

In summary:
Due to the internal EFOR (Electromagnetic Field Of Reference) of the
spaceship, light continues to travel at c in relation to the spaceship,
whether it is in motion or not.

However to the stationary observer on earth, the speed at which light
travels inside the moving spaceship is (c+v) while traveling towards the
front, and (c-v) while traveling towards the back of the spacecraft.

For a more detailed explanation, see the second of my 'Selected Papers'
titled: 'Frames of Reference', which you will find at my website at:
http://www2.rideau.net/gaasbeek

Enjoy, Len.
.................................................. .....

Re "For a more detailed explanation, see the second of my 'Selected Papers'
titled: 'Frames of Reference', []":

In your first scenario there are two parties. So, either can be the FoR, and
regardless the same speed will be observed - in so far as an observer of
just one moving body can have a concept of speed.

In your second scenario there are three parties. If you are going to make
.... if relationships between the two scenarios are going to effect then it
will be on some common ground. The choice of common ground - the choice of
FoR - is either the light or the spaceship - if one is coherent.

The alternative is something such as this:
http://groups.google.ie/group/sci.ph...9e1b8f83006f3a

If you agree, perhaps you should link to it from your front page - that
might help undo the mess the SRians are.

Peter Kinane
http://www.effectuationism.com