Triangular Shadow of a Volcano


Perhaps you already encountered this photo before, as it became viral across the interwebs in the past few weeks. Can you explain why does the shadow of this volcano look like a triangle? The Mount Teide volcano itself does not have the strictly pyramidal shape like its geometric shadow might suggest. NASA explained it like this: “The triangle shadow phenomena is not unique to the Mt. Teide, though, and is commonly seen from the tops of other large mountains and volcanoes. A key reason for the strange dark shape is that the observer is looking down the long corridor of a sunset (or sunrise) shadow that extends to the horizon. Even if the huge volcano were a perfect cube and the resulting shadow were a long rectangular box, that box would appear to taper off at its top as its shadow extended far into the distance, just as parallel train tracks do.” Shot by Juan Carlos Casado and discovered by Jakub Kierzkowski who shared his discovery with us, the below spectacular photo shows Pico Viejo crater in the foreground which is located on Tenerife in the Canary Islands of Spain.

  • Stan

    The shadow appears triangular because what you are seeing is the irregular shape of the volcano “projected” deep into the atmosphere, where the irregularities are stretched out over hundreds of miles.

  • brad

    Great stuff =D Love the tapering shadow

  • Kimon

    I intitially thought the shadow was cast on some sort of mist and thus was vertical, then I realized the mountain didn’t match the shape. The NASA explanation is good enough for me.

  • Brendan

    Very cool not quite sure how that would work

  • Anadi


  • Sergio

    Yes, but doesn’t explain how a shadow can be projected onto the sky and be so clearly visible. I would have understood if it was a prairie or even a bank of clouds, but the open sky?

    • anna

      Agree…. something’s not right…

  • Grace loves owl city

    … I don’t get it…

  • Beholder

    Great! The explanation makes perfect sense, nevertheless it is still amazing. I’m spanish and didn’t know this one. Thanks for posting it and thanks to Juan Carlos Casado for such a breathtaking photo.

  • Anonymous

    I still don’t get how the triangle is made D: but this is a really sutnning feat. to observe!

  • Care Bear

    Volcanoes are not usually cool. This one, however, is.

  • yaro

    The answer is simple. The shot was made from the top of a volcano that’s higher and of a more cony shape than the one in the shot so the shadow we’re seeing here is not of the volcano in the photo and yes, the sun is low above the horizon behind the photographers back

  • ZL123

    Maybe it’s not the shadow of the volcano we’re seeing…

    • ZL123

      Just perhaps. But perhaps NASA’s right.

  • ElectricBuddha

    It is projected across the ocean, it comes to a point because it is so far in the distance despite being flat topped. Don’t forget that the shadow is cast much further because of the curvature of the earth.

  • anita

    i think the false horizon 1/3 of the way up and the moon that looks bright enough to be a dull sun makes the actual horizon (2/3 of the way up) difficult to see – excellent illusion!!

  • Lorraine

    This is a great photo strange to me but none the less beautiful, Like the moon its neat.

  • BladeOfDevil

    1. The sun is about 30° to the right of the photographer. (this is seen form the little hills in the left side of the picture)
    2. The shadow is not form Pico Viejo, it’s form Tiede. And the shadow of Pico Viejo is lost inside.

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