1441: Turnabout

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Whizbang
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Re: 1441: Turnabout

Postby Whizbang » Mon Nov 03, 2014 8:54 pm UTC

The laser gun fires a signal containing the exact GPS coordinates of the gun. It then follows up with the actual laser a fraction of a second later. The mirror on the moon has a super-fast processor and motors to perfectly turn the mirror to direct the laser back at the gun, minus a foot, it appears.

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gmalivuk
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Re: 1441: Turnabout

Postby gmalivuk » Mon Nov 03, 2014 9:05 pm UTC

HES wrote:
gmalivuk wrote:[It doesn't reflect on the same path, but on a parallel one.

How much will the earth have moved during the travel time?
I was just pointing out that that's what a retroreflector does. In reality the laser spreads out enough by the time it gets to the moon and back that the relative movements involved don't actually make much difference. It doesn't come back as a narrow beam like that anyway.
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Whizbang
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Re: 1441: Turnabout

Postby Whizbang » Mon Nov 03, 2014 9:06 pm UTC

The mirror is a (magic) focusing mirror that refocuses the laser so that it will be the same size when it reaches the gun as when it left.

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mathmannix
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Re: 1441: Turnabout

Postby mathmannix » Mon Nov 03, 2014 9:41 pm UTC

only with a fine coating of moon dust!
I hear velociraptor tastes like chicken.

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Re: 1441: Turnabout

Postby AarexTiaokhiao » Mon Nov 03, 2014 9:42 pm UTC

Cool xkcd comic!


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