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Thread: Convex craters?

  1. #1
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    Convex craters?

    In moon photos like this



    at first I interpreted the image as displaying "convex craters", or flat hills :-? (light supposedly is coming from the left).

    But flattened hills like that look strange (and they have no geologic rationale).

    Hence I must suppose the opposite: the image displays the usual CONCAVE craters, and the light is coming from the RIGHT

    which explanation is the right one for you?

  2. #2
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    Turn the image upside down. Itís an optical illusion. Inverting the image changes the illusion.

  3. #3
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    The feature is Maskelyne, thought to be volcanic. The irregular areas around the center cone are ejecta splatters or ancient lava, I assume.

    The central feature inside the "crater" (cone) seems to be a mesa, possibly from upwelling magma.

    https://scitechdaily.com/lunar-recon...nar-volcanism/

    https://earthsky.org/space/moon-saw-...y-recent-times

    Also, upside-down image making the scene clearer.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

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    Last edited by Roger E. Moore; 2019-Aug-01 at 03:31 PM. Reason: 2nd reference

  4. #4
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    i'm still undecided and i'm sitting on a fence



    those damn features that I call convex craters (for lack of a better term )

    A) look like mesas of SW USA (but HOW those strange mesas supposedly formed, in a world - the Moon - without wind or rain?!)

    or B) might be normal concave craters that appear convex to us (tsk tsk) for some nasty optical illusion...

    help me to decide

    Last edited by Barabino; 2019-Aug-11 at 07:57 AM.

  5. #5
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    up, up...

    Quote Originally Posted by Barabino
    or B) might be normal concave craters that appear convex to us (tsk tsk) for some nasty optical illusion...
    it's more an error in assessing the picture (guessing whether light comes from left or from right side), rather than a proper optical illusion...

    Last edited by Barabino; 2019-Aug-20 at 05:20 AM.

  6. #6
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    I still can't decide whether it is Convex Craters or Flat Hills. Can anyone help me regarding this?

  7. #7
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    Roger E. Moore's post above offers a genesis for the raised platform. A bit out of my realm, but there is the concept of high-latitude Martian pedestal craters to consider.

    I often joke that the biggest hindrance for communications between Geologists and Astronomers is their divergence on the expected "sun location" in an image of an impact structure. As suggested above, simply inverting the image can address the problem, and once the proper illusion is obtained, the image can be slowly rotated back while keeping the illusion of depth vs height correct. Never before have I seen an image that offers both!

  8. #8
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    no, the ones in the photo are normal concave craters, that appear convex for an "optical illusion" thaI I can't explain 100% - but rotating the image reveals the truth!

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