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B Can we know what exists in planets' subsurfaces?

  1. Aug 31, 2016 #1
    imagine this situation: there's a very similar planet to earth with almost the same atmosphere and surface. we want to know what lies beyond the surface to know if life exists there. so could we send or observe radio waves or microwaves with a similar telescope as arecibo that penetrates several cm of pure aluminium and image the subsurface beyond it? (supposing we'd had enough technology able to see at those distances)?
     
    Last edited: Aug 31, 2016
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  3. Aug 31, 2016 #2

    Borg

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    Telescopes don't send out emissions, they just receive. And, even if we wanted to send a signal that far, the distances are just too great to ever hope to receive anything back no matter how strong a signal was sent out.
     
  4. Aug 31, 2016 #3
    yes i know, but let's imagine we'd had enough technology or this planet was at the same distance as mars or jupiter, will this work?
     
  5. Aug 31, 2016 #4

    Borg

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    If we were that advanced, it would be a lot easier to just go there to perform the measurement.

    I really don't get the "pure aluminum" surface statement in your original post but we would notice something like that with today's technology and would be sending probes to examine a surface like that. Imaging several cm of the surface with or without a metal covering at those distances would be beyond any technology that I can imagine.
     
  6. Aug 31, 2016 #5

    davenn

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    The Aricebo radio telescope can be configured to be used for both transmit and receive
    The surface of Venus was successfully radar mapped using the Arecibo Dish to see what was under the cloud cover.
    Ham radio operators have even used the same dish to reflect radio signals off Venus and back to earth
    This is regularly done off the moon ... it's called moon bounce. As far as I'm aware, Venus is the only other
    planet from which this has been done.

    but seeing what is below the surface is another much higher level of difficulty


    Dave
     
  7. Aug 31, 2016 #6
    Let me see if i understood... can we know then what lies beyond the sueface of venus?
     
  8. Aug 31, 2016 #7

    davenn

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    no, I didn't say that
     
  9. Aug 31, 2016 #8
    So, the radio bouncing in venus cannot tell us that? How can we do it then?
     
  10. Aug 31, 2016 #9

    davenn

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    bouncing radio signals (radar) off the surface of Venus tells us the topography of the surface ...
    Highs, lows, large bumps ( hills - mountains) etc ... we don't know what is below the surface of Venus

    it's difficult enough to do ground penetrating radar of the earth from orbit, let alone other planets in our solar system or beyond

    MOST ground penetrating radar for below the Earth's surface is done at the surface using sound
    small portable units are good for a couple of metres or so ... used lots in archaeology

    NY_Dutchess_GroundPenetratingRadar.JPG


    much larger systems use thumper trucks, strong sound boomers or explosives
    these are used in seismic mapping and are good up to a couple of km's

    Marine-Seismic-Survey-Cartoon.jpg

    illustration%20of%20seismic%20surveying.jpg

    p-9759-gns.jpg


    Dave
     
  11. Aug 31, 2016 #10

    1oldman2

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  12. Aug 31, 2016 #11

    davenn

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    it's not detecting subsurface directly as in ground penetrating radar
    It is detecting surface emissions caused by cosmic rays that penetrate the surface and interact of with minerals etc up to 1m depth


    Dave
     
  13. Aug 31, 2016 #12

    1oldman2

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    This is true, I was just fishing for possible ways the op's question might be answered. tricky business with today's tech but one never knows whats around the corner.
     
  14. Sep 1, 2016 #13
    Thanks! And it would be possible (or is it possible already) to increase the strength and sensibility of ground based telescopes and astronomy radars to know what lies beyond the surface of planets? Would be possible that these increased radio waves penetrate metal too?
     
  15. Sep 1, 2016 #14
    I'm certain that NASA is probably working on this problem. Could you imagine the scientific possibilities if we could map the caves of Mars? If there is any life left on Mars, it's underground. Europa is another place where seeing underground is of great interest.

    Rock is simply very hard to penetrate. We can't even explore our own cave systems with radar, people still literally have to climb down them and explore.

    It takes a lot of power to produce waves powerful enough to get through all that material. Do you know how the measure the depth of the ice shelves in Antarctica (which is nothing by comparison?) Dynamite.
     
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