Siberian Illusion - Elevation or Depression

Posted by Gazers Team on

Siberian Illusions

Notice the main vein in the satellite image above. Do you think it's an elevation like a mountain range or a depression? Look closely. Focus.

The Answer

While it may appear to be an elevation, it's actually a depression. Its a valley with frozen lakes and white portions are plateaus. Your brain tricked you into perceiving it like an elevation and there is a very good reason for that. Our brain is used to light from the sky, hence when we look at a photograph, we subconsciously assume that the light source would be around the top of the photograph. Since this is Siberia, the light source, the Sun, here is in the south.

Now look at the picture again carefully. Focus on the shadows. Imagine the Sun is on the south and its casting a shadow towards the North. If we flip the image, it become super-apparent. Here you go.

flip siberian illusion

This form of brain trickery is also called the crater illusion. When astronomers look at features on a celestial body, one has to be careful to see where is the light source and hence how the shadow is being cast. Otherwise, its easy to see a hill as a crater and a crater as the hill.