ISEN-ASTC-L is a service of the Association of Science-Technology Centers
Incorporated, a worldwide network of science museums and related institutions.
*****************************************************************************

It seems to be very well settled that the speed of light (c) is a fixed 
constant that is not influenced by the relative speed of the observer.  It 
is about 186,282.397 miles per second in a vacuum.  c remains a constant 
irrespective of the relative speed of the observer with respect to the light 
source.  In other words, an observer moving towards the light source 
measures the same c as well as that measured by an observer moving away from 
the light source.

It is also true that ancient galaxies exhibit a red shift in the observed 
light as viewed from earth.  This is due to the doppler shift which 
indicates that the galaxy is moving away from us.

The question that I have is that a doppler shift (or red shift) is not 
possible unless the light being observed is moving slower (causing a longer 
wavelength) at the point of observation than the light that is emitted from 
the point source.  However it is not possible for the speed of light to be 
slower than c at the point of observation irrespective of the relative 
velocities between the source and observer.

Can anyone explain how a doppler shift can the observed from an ancient 
galaxy if the speed of light does not change?

Jack Cannon
[log in to unmask]

***********************************************************************
For information about the Association of Science-Technology Centers and the Informal Science Education Network please visit www.astc.org.

Check out the latest case studies and reviews on ExhibitFiles at www.exhibitfiles.org.

The ISEN-ASTC-L email list is powered by LISTSERVR software from L-Soft. To learn more, visit
http://www.lsoft.com/LISTSERV-powered.html.

To remove your e-mail address from the ISEN-ASTC-L list, send the
message  SIGNOFF ISEN-ASTC-L in the BODY of a message to
[log in to unmask]