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Re: Curved space and fields

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On 10/30/2018 8:29 AM, Edward Prochak wrote:
> On Monday, October 29, 2018 at 11:45:46 PM UTC-4, Wally W. wrote:
>> On Mon, 29 Oct 2018 12:26:30 -0700 (PDT), Edward Prochak wrote:
>>
>>> On Monday, October 29, 2018 at 8:50:20 AM UTC-4, john wrote:
>>>> Fodder for much interstellar humor
>>>
>>> Yes you are!
>>
>> Who said this isn't the place for ad homs?
> 
> You caught me. I am so ashamed.
> 
>>
>> And who chided another for personal attacks?
> 
> yes I did. I deserve this.
> 
>>
>> Let's talk physics: mirrors, and how it takes a special mirror to see
>> ourselves as other see us:
>> https://en.wikipedia.org/wiki/Non-reversing_mirror
>>
>> That's how to discuss physics without an agenda, right?
> 
> Nice touch! cool transition.
> 
> Such properties of mirror surfaces are used in highly
> reflective materials by extending the 90 degree reflection
> to 3 dimensions.  A little physics that makes life safer
> by making road signs more visible, and (to get back to
> John's topic) even making tests of gravity possible.
> 
> https://science.nasa.gov/science-news/science-at-nasa/2004/21jul_llr
> 
> "Here's how it works: A laser pulse shoots out of a telescope
>  on Earth, crosses the Earth-moon divide, and hits the array.
>  Because the mirrors are "corner-cube reflectors," they send
>  the pulse straight back where it came from. "It's like hitting
>  a ball into the corner of a squash court," explains Alley. Back
>  on Earth, telescopes intercept the returning pulse--"usually
>  just a single photon," he [University of Maryland physics professor
>  Carroll Alley] marvels.
> 
>  The round-trip travel time pinpoints the moon's distance with
>  staggering precision: better than a few centimeters out of
>  385,000 km, typically."
> 
> Thanks for bring us back on track Wally.
> 
> Enjoy,
> Ed
> 

corner cubes have a divergence metric too, how much the spread the beam
out. also there are two types, one is single piece of glass, the other 3
first surface mirrors (less lossy).  Also the laser uses long train of
pulses to average, improving SNR.


looks like it got axed in 2009;
https://www.theguardian.com/technology/2009/jun/21/mcdonald-observatory-space-laser-funding

another place (not sure if this is right, still have laser divergance)

"Scientists use laser range-finding to measure the distance to the moon
with great accuracy. A brief laser pulse is fired at the moon, then the
time interval is measured until the "echo" is seen by a telescope. A
laser beam spreads out as it travels because it diffracts through a
circular exit as it leaves the laser. In order for the reflected light
to be bright enough to detect, the laser spot on the moon must be no
more than 1.0 in diameter. Staying within this diameter is accomplished
by using a special large-diameter laser."


check this out, using your own camera;
https://phys.org/news/2014-05-distance-moon.html

basic Math here;
http://scienceblogs.com/builtonfacts/2010/12/16/all-right-im-gonna-delay/

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Curved space and fields john <johnsefton288@gmail.com> - 2018-10-29 05:50 -0700
  Re: Curved space and fields Odd Bodkin <bodkinodd@gmail.com> - 2018-10-29 14:34 +0000
    Re: Curved space and fields moroney@world.std.spaamtrap.com (Michael Moroney) - 2018-10-29 14:43 +0000
      Re: Curved space and fields yporat08@gmail.com - 2018-10-29 09:07 -0700
    Re: Curved space and fields pnalsing@gmail.com - 2018-10-29 09:59 -0700
      Re: Curved space and fields "reber G=emc^2" <herbertglazier0@gmail.com> - 2018-10-29 10:04 -0700
      Re: Curved space and fields Odd Bodkin <bodkinodd@gmail.com> - 2018-10-29 17:32 +0000
        Re: Curved space and fields pnalsing@gmail.com - 2018-10-29 23:32 -0700
      Re: Curved space and fields Sergio <invalid@invalid.com> - 2018-10-29 12:34 -0500
      Re: Curved space and fields yporat08@gmail.com - 2018-10-29 23:03 -0700
        Re: Curved space and fields Odd Bodkin <bodkinodd@gmail.com> - 2018-10-30 12:12 +0000
          Re: Curved space and fields yporat08@gmail.com - 2018-10-31 17:44 -0700
            Re: Curved space and fields Odd Bodkin <bodkinodd@gmail.com> - 2018-11-01 14:36 +0000
              Re: Curved space and fields yporat08@gmail.com - 2018-11-01 08:21 -0700
                Re: Curved space and fields Odd Bodkin <bodkinodd@gmail.com> - 2018-11-01 16:11 +0000
                Re: Curved space and fields yporat08@gmail.com - 2018-11-01 10:44 -0700
                Re: Curved space and fields yporat08@gmail.com - 2018-11-01 11:52 -0700
                Re: Curved space and fields Odd Bodkin <bodkinodd@gmail.com> - 2018-11-01 19:59 +0000
                Re: Curved space and fields Odd Bodkin <bodkinodd@gmail.com> - 2018-11-01 20:03 +0000
                Re: Curved space and fields yporat08@gmail.com - 2018-11-01 18:42 -0700
                Re: Curved space and fields Odd Bodkin <bodkinodd@gmail.com> - 2018-11-02 11:34 +0000
                Re: Curved space and fields yporat08@gmail.com - 2018-11-02 04:57 -0700
                Re: Curved space and fields Odd Bodkin <bodkinodd@gmail.com> - 2018-11-02 12:10 +0000
        Re: Curved space and fields Edward Prochak <edprochak@gmail.com> - 2018-10-30 06:35 -0700
  Re: Curved space and fields mitchrae3323@gmail.com - 2018-10-29 11:16 -0700
    Re: Curved space and fields Sergio <invalid@invalid.com> - 2018-10-29 14:12 -0500
      Re: Curved space and fields "reber G=emc^2" <herbertglazier0@gmail.com> - 2018-10-30 08:19 -0700
        Re: Curved space and fields Sergio <invalid@invalid.com> - 2018-10-30 11:00 -0500
      Re: Curved space and fields mitchrae3323@gmail.com - 2018-10-30 14:02 -0700
  Re: Curved space and fields Edward Prochak <edprochak@gmail.com> - 2018-10-29 12:26 -0700
    Re: Curved space and fields Wally W. <ww84wa@aim.com> - 2018-10-29 23:45 -0400
      Re: Curved space and fields Edward Prochak <edprochak@gmail.com> - 2018-10-30 06:29 -0700
        Re: Curved space and fields Sergio <invalid@invalid.com> - 2018-10-30 11:10 -0500
          Re: Curved space and fields "reber G=emc^2" <herbertglazier0@gmail.com> - 2018-10-30 11:35 -0700
          Re: Curved space and fields Edward Prochak <edprochak@gmail.com> - 2018-10-30 12:42 -0700

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