Planet Four Talk

Images keep flashing up and disappearing before I get a chance to do anything with them. Or disappear halfway through and I can't get them back!

  • Bob.Day41 by Bob.Day41

    I' m sure these are ridges, not valleys

    Posted

  • Portyankina by Portyankina scientist

    And I am sure, they are valleys, not ridges. Want a bet? 😉

    You have to know the direction of the sun illumination to be able to tell if topography is positive or negative. Your brain assumes, that the light comes from the top left corner (well, most brains do this by default) and that's why the wiggly lines look like they stand up from the surface - it fits with illuminated part being closer to sun and shadow being in the opposite side. In reality sun comes from bottom-slightly-right. So, bright part of those lines is going down side wall. And the shadow is casted by the other channel side.

    And if you still disbelieve me, we have got height measurements over such channels, they are really channels.

    Cheers!

    Anya

    Posted

  • JellyMonster by JellyMonster

    The scientists are right... see my post 'seeing is believing?'.

    Posted