Groups > sci.physics.relativity > #451431

Light Slowing Down

Newsgroups	sci.physics.relativity
From	Keith Stein <keithstein111@gmail.com>
Subject	Light Slowing Down
Message-ID	<dbVmC.56047$LD5.18435@fx07.am4> (permalink)
Organization	virginmedia.com
Date	2018-03-04 16:31 +0000

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Let us, for the sake of argument, assume that i am on a galaxy which is 
10,000,000,000 light years from the earth. By a bit of good
planning i have my laser with me and i shine this laser at you for a 
whole year. The front of this laser beam will take exactly 
10,000,000,000 to reach you here on Earth (hopefully you will still be 
alive eh!). The rear end of my laser signal will take slightly longer to 
reach you because the speed of light has decreased in the year i've been 
holding this laser. If light decreases by my suggestion of one part in 
10 billion per year, the rear end of the signal will take exactly 
10,000,000,001 years to reach you here on Earth.

Thus the light beam from my laser is stretch by a factor of 2 ( because 
the end of the beam left 1 year after the start, and took 1 year longer 
on the journey.). However the number of waves sent will be exactly the 
same as the number received, (assuming you are careful and don't miss 
any,) so the wavelength must also have been stretched by a factor of 2. 
This is equivalent to a red-shift of 1, and corresponds reasonably well 
with what is found in practice.

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Light Slowing Down Keith Stein <keithstein111@gmail.com> - 2018-03-04 16:31 +0000
  Re: Light Slowing Down Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-04 18:08 +0100
    Re: Light Slowing Down SolomonW <SoloomonW@citi.com.au> - 2018-03-05 19:08 +1100
      Re: Light Slowing Down Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-05 11:58 +0100
        Re: Light Slowing Down SolomonW <SolomonW@citi.com> - 2018-03-06 08:22 +1100
          Re: Light Slowing Down Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-05 22:51 +0100
            Re: Light Slowing Down SolomonW <SolomonW@citi.com> - 2018-03-06 19:08 +1100
              Re: Light Slowing Down Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-06 11:57 +0100
                Re: Light Slowing Down SolomonW <SolomonW@citi.com> - 2018-03-06 23:01 +1100
                Re: Light Slowing Down Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-06 13:56 +0100
                Re: Light Slowing Down SolomonW <SoloomonW@citi.com.au> - 2018-03-07 13:54 +1100
                Re: Light Slowing Down Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-07 06:57 +0100
                Re: Light Slowing Down SolomonW <SolomonW@citi.com> - 2018-03-07 17:19 +1100
      Re: Light Slowing Down Lofty Goat <rlwatkins@gmail.com> - 2018-03-11 12:52 -0500
        Re: Light Slowing Down Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-12 02:24 +0100
  Re: Light Slowing Down SolomonW <SoloomonW@citi.com.au> - 2018-03-05 19:06 +1100
    Re: Light Slowing Down Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-03-05 12:39 +0100
      Re: Light Slowing Down mlwozniak@wp.pl - 2018-03-05 05:38 -0800
        Re: Light Slowing Down mitchrae3323@gmail.com - 2018-03-05 12:12 -0800
      Re: Light Slowing Down mitchrae3323@gmail.com - 2018-03-05 17:33 -0800
    Re: Light Slowing Down Keith Stein <keithstein111@gmail.com> - 2018-03-05 17:18 +0000
      Re: Light Slowing Down SolomonW <SolomonW@citi.com> - 2018-03-06 08:34 +1100
        Re: Light Slowing Down Keith Stein <keithstein111@gmail.com> - 2018-03-10 21:53 +0000
  Re: Light Slowing Down mitchrae3323@gmail.com - 2018-03-05 12:39 -0800
  Re: Light Slowing Down Keith Stein <keithstein111@gmail.com> - 2018-03-19 08:59 +0000

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