Subject:
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Re: Evolution of Earth and moon (was: Couldn't resist)
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Newsgroups:
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lugnet.space, lugnet.off-topic.geek
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Date:
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Wed, 11 Jul 2001 01:57:09 GMT
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Viewed:
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9125 times
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In lugnet.space, Ross Crawford writes:
> In lugnet.space, Larry Pieniazek writes:
> > In lugnet.space, Lindsay Frederick Braun writes:
> > > Weren't there other methods used recently as well? I'm not
> > > sure that any would be as accurate as a laser, given that
> > > the international meter standard is based on the speed of
> > > light (as of the 1980s, I think). Somehow using radar sticks
> > > in my mind, but that might just be a holdover from earlier
> > > measurement in the 1940s and 1950s.
> >
> > Would there be any difference in the accuracy of laser vs. radar? I'm not
> > enough of an EE geek to know, but thought "no" because they're just
> > different wavelengths of the same thing, right?
>
> Not quite. There's a good comparison here
> http://www.howstuffworks.com/question396.htm talking about speed radar
> versus laser. Basically the laser is more accurate, but requires more
> accurate aiming by the operator.
More accurate at measuring *speed*. We were talking about distance. Careful
reading of both articles reveals no claimed difference in accuracy for
distance measurement, since it's the same technique being used. (the speed
difference is because one is measuring doppler shift and the other is
measuring difference in distance from one pulse to the next, but distance in
both cases is measured by the time for signal return)
Great site, thanks for the ref., my kids will love it! However my question
still stands.
++Lar
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