• deegeese@sopuli.xyz
    link
    fedilink
    English
    arrow-up
    29
    ·
    9 months ago

    The suns angular diameter is about 0.01 radian, so at a distance of 100km, the suns reflection will spread out to a disc about 1km across.

    392MW over a disc that size is 500w/m2, which is weaker than direct sunlight.

      • deegeese@sopuli.xyz
        link
        fedilink
        English
        arrow-up
        1
        ·
        9 months ago

        And each one makes a 1km2 spot.

        It’s not the aiming, it’s that the sun is not a point source.

    • mozz@mbin.grits.dev
      link
      fedilink
      arrow-up
      1
      ·
      9 months ago

      Yes; it is well known that if you look at yourself in a flat mirror, and then back up, your reflection will spread out bigger and bigger and get dimmer and dimmer, the further away you get.

      Wait

      • deegeese@sopuli.xyz
        link
        fedilink
        English
        arrow-up
        1
        ·
        9 months ago

        “You” are the sun in this scenario.

        As you back up, you fill a smaller and smaller fraction of the mirror. The reflection becomes less sun and more space.

        • mozz@mbin.grits.dev
          link
          fedilink
          arrow-up
          2
          ·
          9 months ago

          I have a little reflective disc. I will bet you $100 that a reflection of a sunbeam off of it will be exactly the same size (i.e. the same intensity, since it’s not getting any bigger) several meters away as it is a few inches away.

          • deegeese@sopuli.xyz
            link
            fedilink
            English
            arrow-up
            1
            ·
            9 months ago

            Try that in your backyard with a small mirror. You’ll find the sun’s reflection expands by about 1% of the distance.

            • mozz@mbin.grits.dev
              link
              fedilink
              arrow-up
              1
              ·
              9 months ago

              Ooooh

              Yes you’re 100% right - it’s not a point-source, so it will expand out slightly. I don’t know the math well enough, but I believe if you if you say you do + it works out to about 1% of distance.