On a hot summer day when I drive on the highway, I see what appears to be water in the distance. This mirage phenomenon I can more or less understand (even though it would be nice to get a clear explanation). But what puzzles me is that objects (cars, bridges, trees)located at the place of those reflections are reflected in those illusionary bodies of water. How does that work? You even see it in movies, for example, when a plane lands on a hot runway…
The buildings are part of the mirage too.
When you see a water mirage on hot pavement, you’re really seeing a mirage of the sky. The light from the sky is bent upward. When it is seen by you, your brain figures the image is coming from something on the ground. Since the image is shimmering (distortion because of the hot air), you also deduce that it’s a liquid, most probably water. Adding to the effect is that the light is bluish. The final effect is that you interpret the image as a puddle of water in the road reflecting the sky.
If there’s a tall building lined up with the pavement you see the mirage on, the light from that building is also bent and seen by you. Being a more distinctive pattern, your brain interprets it as a building. But seeing it in a puddle, you figure that it’s a reflection of the building you see ahead.
That’s a good answer byut it doesn’t quite explain the scientific principle behind the whole thing.
What’s happenning here is that the sun is heating the ground to very hot (btw this also works in cold temperatures, it’s simply opposite)and the ground heats the air above it. But it doesn’t, all of a sudden, heat all the air aboe it to exactly it’s tyemperature. There are stages.
Now, since the speed of light is different in air at different temperatures, when the light reflecting of that pavement (or other objects, oases, armies, what-have-you) it goes through the first part of the air and then when it hits the second layer of airand the part that got there first is now going faster and therefore the image appears at a different place.
Now, the common phenomena known as a mirage is that the light reflectinug off of a far away oasis or lake is refracted up into the air and when it reaches a high enough heigt and the air begins to cool down it is refracted back down and appears to be shortly off in the distance when in actual fact it is miles away.
This somewhat “supernatural” phenomen is something to which i personally attribute much religious significance. If you were a) walking through the desert or b)walking through a frozen desert (i.e. siberia) and suddenly saw a) a shimmering figure of light or b) the armies of heaven in the sky, given a certain level of suggestibility brought on by famine and thirst some wild conclusions are to be had. For instance, that you are witnessing a miracle or some such nonsense.
Alternately, what you may be witnessing on te road is what is known as black ice ( in the winter anyway), and is another facet of refraction. The light is now no longer refracting but totally reflecting. The air is at such an angle and at such a temperature where the light from the sun has reached the critical angle for refraction and is no longer passing through it. This makes it look like, yes, the sky is on the road, along with any buildings that may happen to be in that region of sky.
Forgive nme if that’s unclear, it was written in haste. e-mail me for clarifications.
Sincerely, SDStaff hopeful
Well, since nhaerens said he understood the mirage phenomenon, I just worked on explaining the reflected buildings.
My mom said she’s seen the distant-object mirage. There was some big building in Pasedena, CA that she saw in some other LA suburb. What tipped her off is that it appeared in the sky. Definately a weird experience.
I used to see the heat mirage that I described all the time. (I grew up in a desert.) It prevalence was due to the cloudless days, hot & dry summers, and straight, flat roads.
Supposedly the Vikings at sea occasionally saw mirages of land hundreds of milesaway. Something to do with the seawater being warmer than the surrounding air.