Only when we recognize that we are seeing an illusion can we make some mental corrections to the scene. For example, we know the pencil in the glass is not bent even if our eyes try to tell us so. But recall what happens initially when we are surprised by such a scene. We must process more information to make true sense of the scene before our eyes. The appearance of the inferior mirage always indicates that the surface air is much warmer than the air above it due to the strong heating of the surface by the sun or some other heat source.
Scale is greatly exaggerated.
The superior mirage occurs under reverse atmospheric conditions from the inferior mirage. For it to be seen, the air close to the surface must be much colder than the air above it. This condition is common over snow, ice and cold water surfaces. When very cold air lies below warm air, light rays are bent downward toward the surface, thus tricking our eyes into thinking an object is located higher or is taller in appearance than it actually is. The superior mirage can also cause objects appear to be taller than they actually are, called towering , or shorter, a condition termed stooping .