Mirages
When it comes down to it a mirage is essentially just an invisible mirror. Which is still pretty damn cool. Mirages are simply the distortion of objects due to “layers” of air and come in three different types: inferior (where the mirage is under the real object), superior (where the mirage is above) and Fata Morgana (which is a complex, highly distorted mirage involving multiple images). The principle behind the mirage is rather a simple one. At different elevations air has different densities, typically due to heat, which in turn causes different refractive indexes. This difference in refractive indexes causes the light to bend as it crosses from hot to cold or cold to hot air due to refraction. As such the image you see is not where it really is but is simply light from the original object being bent towards you. In the example of the highway mirage above the “pool of water” is in fact simply the reflection of the sky being “bounced” towards the observer by a hot layer of air directly above the road.
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