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Use 3D laser scanning to map Outer Space?

  1. Oct 29, 2015 #1
    Mobile, airborne, and terrestrial 3D laser scanning gives an unprecedented amount of data to companies, organizations, and governments.

    However, I am wondering whether or not 3D laser scanners have ever been used in astronomy, astrophysics, and in astrocartography... If they haven't, I believe it could be an interesting method to obtain precise topographical information for celestial bodies.

    Any thoughts?
     
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  3. Oct 29, 2015 #2

    Borg

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    Even a laser will disperse over extremely long distances.
     
  4. Oct 29, 2015 #3

    SteamKing

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    You do realize that a laser still travels at the speed of light, don't you? Even if it were possible to map a distant object with lasers, it would still take many years to get the data back here on earth. If an object is 10 light-years away, it would take 10 years for the laser to get there from earth and 10 years to get back.
     
  5. Oct 29, 2015 #4
    True. However, I don't believe that the margin of error would be great enough to neglect all the data that would be collected.

    I can imagine that 3D laser scanning would be optimal for automatic feature and object extraction for satellites that are orbiting various celestial bodies or even for rovers.
     
  6. Oct 29, 2015 #5
    I did take that into consideration. But I still don't see why it couldn't be used on satellites that are relatively nearby celestial bodies within our own solar system.

    Also, I am not sure of the margin of error you would get if you had to wait 20 years for the light to return to the 3D scanning apparatus -- but assuming that you could potentially look at features on distant celestial bodies in detail, 20 years may be well worth the wait!
     
  7. Oct 29, 2015 #6

    SteamKing

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    If you got anything back at all, it would probably be just noise. Even inside the solar system, the amount of power from returning radio signals sent by space probes is a decimal point followed by many zeroes, thus each signal requires a great deal of amplification in order to be detected.
     
  8. Oct 29, 2015 #7
    During the Cassini mission they used multiple radio telescopes on Earth to listen to and to track the 10-watt signal from Hugyens directly, despite it being 750 million miles away. http://www.nrao.edu/pr/2004/huygens/

    Perhaps you could use the same method (involving multiple 3D laser scanners scattered across the globe pointed at a particular celestial object) to acquire more accurate 3D laser scanning datasets for celestial objects, no?
     
  9. Oct 29, 2015 #8

    Borg

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    The signal from those objects isn't going to be anywhere near the 10 watts that Hugyens is putting out. What little bit of laser light reaches the objects will also be scattered.
     
  10. Oct 29, 2015 #9

    ogg

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    3-D laser...I suppose you mean using laser light to illuminate the rotating surface of some solar system body (without a significantly absorbing atmosphere). First thing that occurs has already been said, that even a laser beam (any beam) disperses. And of course the scattering from any surface will be a small fraction of the incident light (which will be a small fraction of the initial light). And of course the scattering back towards the source will be a miniscule fraction, and then it will continue to disperse... Too bad there's not some huge (thermonuclear) light source in the Solar System we could use instead...
     
  11. Oct 29, 2015 #10

    SteamKing

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    That's a good point. All of the light which reaches us from distant stars is but a minuscule fraction of what the individual star puts out at the source, and this small fraction is what we see twinkling in the sky at night. The brightness of any non-stellar light source, like a laser beam from a distant star system, will be orders of magnitude lower than that of the star or stars in the system.
     
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