# Mirage refelctions

## Recommended Posts

You know those mirages you see on a hot road or highway when driving? Well, do they reflect or distort light? What Im really wondering is...If you were to shine a light (or laser) into one of the mirages, would the light show on an object behind it? And from that object's point of view, where would the light be coming from?

Just Curious (like always)

##### Share on other sites

I believe the light is "bent" from above to down to the road, then goes to your eyes. Shine a laser at the mirage... it might go up, or it might hit the mirage, I don't know.

##### Share on other sites

I think it would be a cool test.

I know it reflects light to some extent b/c I could see the reflections of the cars headed in my direction in the mirage.

##### Share on other sites

Perhaps it is more refracting light?

##### Share on other sites

A mirage is formed due to refraction of light.

Refractive index depends on material density, which in case of air depends on temperature. On a hot day, a gradient of temperture is formed vertically in the air. In essence you can think it as layers of air with different density, as the coldest layer will be at the bottom (coldest => most density => most refractive index) , if u draw a geometrical ray diagram you will realise that light rays tend to become more horizontal. As a result, it apperas as if there is some water and you seem to see the reflection of objects in it (a mirage).

By the prnciple of reversibility of light, if you did shine a laser into it, you would see the laser at the back of the mirage, but you would need to have a screen or something. A powerful laser, should be able to show you the path of light rays thru the mirage as well.

##### Share on other sites

hmm...I would really love to set up an experiment like this. Is there any way of controlling or creating a mirage?

##### Share on other sites

I think the situation will not occur when the image seem to be on the horizontal.

##### Share on other sites

I think the situation will not occur when the image seem to be on the horizontal.

umm...could you rephrase that? why wont it occur when on the horizon?

##### Share on other sites

hmm...I would really love to set up an experiment like this. Is there any way of controlling or creating a mirage?

If you need to experiment, you might need a material that has a gradual gradient in refractive index vertically or horizontally. Then, by shining light on it (in a proper direction of course), you would in essence create a mirage of your own.

##### Share on other sites

what about heating the surface and the air around it? would that be necessary?

##### Share on other sites

All you need is a refractive index gradient, thats essentially what causes a mirage.

##### Share on other sites

what would work for a refractive index gradient?? What could I use to carry out an experiment for making a mirage?

##### Share on other sites

• 2 weeks later...

...well!? anything? Anyone?

##### Share on other sites

I SAY AGAIN---what would work for a refractive index gradient?? What could I use to carry out an experiment for making a mirage??

##### Share on other sites

alright, what if I were to create a mirage by superheating the air around an object...then i were to focus a high powered laser, such as the ones attached to 747s that are used to take down missiles, what would the affect be? Would the beam refract off of the mirage? would the object underneath be untouched? Or would the laser only be refracted for several degrees, then continue on through the mirage?

##### Share on other sites

alright, what if I were to create a mirage by superheating the air around an object...then i were to focus a high powered laser, such as the ones attached to 747s that are used to take down missiles, what would the affect be? Would the beam refract off of the mirage? would the object underneath be untouched? Or would the laser only be refracted for several degrees, then continue on through the mirage?
I believe the light from your source would just be bent the same as the light from the ambient source.
##### Share on other sites

what do u mean by that? The source being what?

##### Share on other sites

alright, what if I were to create a mirage by superheating the air around an object...then i were to focus a high powered laser, such as the ones attached to 747s that are used to take down missiles, what would the affect be? Would the beam refract off of the mirage? would the object underneath be untouched? Or would the laser only be refracted for several degrees, then continue on through the mirage?

First off, mirages (I believe) are a cumulative effect. By that I mean that you are looking down a stretch of highway or sand or whatever and you see what appears to be water or whatever (I like that word). This happens because of the air just above the road. But you are looking at the air above a stretch of road that is a hundred meters or more long. The accumulation of that air into a space about an inch or two wide from the perspective of your eye allows you to see the total refracting (or reflecting) power of all that air. What I mean is that if you were only looking over a meter of road, you wouldn't see that mirage (or at least not nearly as powerful). so I don't think you could apply the mirage effect to any anti missile defense plans you may have, as you would not have enough surface area to make a 'mirage' of any strength. I just looked over what I just wrote and it's confusing even to me and I don't even know if it is right.

As for your experiment to see how laser light would react to a mirage... why don't you find a lonely stretch of flat highway on a hot day and set up a laser-pointer (or whatever) at whatever angle you like and follow the beam down the highway with a white sheet of cardboard to see what happens to it.

##### Share on other sites

well, i wasnt too confused by it.

First off, i realize that it would never work for protecting a missile or something that small, plus at the kenetic state of a missile, there would be a high wind, and in order for a mirage to stay, there cannot be a fast air exchange, b/c there must be a constant air temp. What I was really wondering, is if you were to take an object, such as an airport, or some building, or large object of priority, and cover it with a mirage (if that's at all possible) would it be protected from a super high powered laser.

##### Share on other sites

I may seem stupid, but why don't you go somewhere where theres a mirage, have somebody stand far away and shine a laser pointer at them. *Is sorry for sounding stupid*

##### Share on other sites

lol, not at all. If I could just find an empty stretch of highway somewhere, but you never know who will come along and ruin the experiment. The conditions should be just right. I really dont know how they work, and if they're just caused by superheating still air, so I wouldnt know how to re-create one in a lab.

But if I find the time and place, I'll definitely try to find a long stretch of highway.

##### Share on other sites

its to do with refraction caused by the localy heated air (just above the hot road surface) being less Dense.

the way to test this would be get a laser and aim just above a candle flame and then look at the resultant "dot" on the wall, does it move?

I know the answer to this, but Ill let you find out for youself, I don`t want to spoil it

##### Share on other sites

• 1 month later...
unfortunately, I dont have any candles here. I'll try to find one. I assume that the dot would move about constant to the flame. Am I correct in this assumption?
##### Share on other sites

yeah the air closest to the ground is hottest not coldest.

this is possible as the upper atmosphere is alot colder than the lower atmosphere.

## Create an account

Register a new account