The sun is set against the dawn, the orange color against the gray and the vibrant force of the sun against its motionless surroundings. To many spectators, the sun undulates or pulsates slightly. Why is this so? The sun is nearly the same luminance as the grayish clouds. Notice how the sun nearly disappears if you remove the color. (Click painting to reset.) This lack of contrast explains the painting’s eerie quality.
The sun is perceived differently is different parts of our mind. To the more primitive subdivisions of our brain, the sun is nearly invisible. But to the primate subdivision, the sun appears normal. Thus, there is an inconsistency between our perception of the sun in the primitive and primate portions of our brain. The sun is poorly defined and ambiguous to the portion of our brain that carries information about position and movement.