For us to understand the formation of the desert mirage, we would have to understand how light travels through the air. In any case, when the air is uniform in terms of temperature whether it is cold or hot then light passes through it in linearly..Desert mirage is a phenomenon that is caused by what is dubbed as ‘total internal reflection’ meaning during an extremely hot day, the air just in contact with sand becomes hotter than the air above it due to the high temperature of the sand. The resultant effect causes the refractive index of the air in contact with the sand to be lower than that of the air above it. Thereafter, sunlight goes through a medium ofa higher refractive index to that of a lower refractive index. During the formation of a desert mirage, from a given angle, the angle of incidence appears greater than the critical angle and the entire conditions of total internal reflections are achieved. Therefore, it causes the sunlight to reflect from the interface of both the air columns itself without getting in contact with the sand. That is the reason the desert mirage always appears as a watery surface from far off distances. Incidentally, when approaching the desert mirage, the angle of incidence of sunlight minimizes and becomes less than the critical angle. At that particular point, the total internal reflection does not happen and hence the desert mirage fades away. Desert mirages are commonly visible if the distance from a point is greater than a critical distance determined by the refractive index of the air columns to satisfy the condition of the critical angle for total internal reflection to happen.
Since time in memorial, oasis remains an amazing sight to desert wanderers. What is means is that it provides shade from the scotching desert sun and more crucial is water. Desert wanderers value the importance of water and they would stop at nothing to search for it. Apparently, wanderers’ greatest fears while travelling in the desert would be that the oasis in the near distance would turn out to be a desert mirage. The strenuous look in the windblown sands and refracted desert light longed to see an oasis. In the event the oasis results to be a desert mirage, the disappointment would be devastating. As the wanderers’ are always in a mission, desert mirage would definitely derail their mission. Among the Arabs desert wanderers, a desert mirage was regarded as an evil spirit of the desert that seem to led travellers astray, luring them further away into the heart of the waste as they pursed it before finally disappearing. The wanderers would now irrecoverably lose themselves in the pathless sands.This would mean that there would begin tracing back there route the which in itself would consume much of their time, in order to continue with their journey. Needless to say, desert mirages have resulted to wanderers encountering hostility from territorial tribes in the desert who might be out there to protect they area. In other circumstances, this might be fatal or in fair condition sustain minor injuries. Additionally, as the wanderers purse their quest in the desert, the occurrence of desert mirage may cause them encounter environmental hostility such as animal attacks, snake bites or desert storms which possibly could have been avoided otherwise.