Question

What is the mirage effect?

Asked by: Ali Reza Shokati

Answer

A mirage is not only seen by thirsty desert wanderers. You can also see one driving comfortably along a black top highway on a sunny day. That 'wet' looking spot on the road up ahead could actually be a mirage that stays in the distance, as impossible to reach as a rainbow.

Normally, water in the distance is seen by its ability to reflect light off of its surface. In the case of a mirage, it is REFRACTION, not reflection, creating a similar effect. The hot surface warms the air immediately above it to a higher temperature than the air higher up. A light ray grazing the surface under those circumstances is bent, or refracted, upward. That's because light travels faster in warmer, less dense, air than in denser cold air. The faster motion of the lower part of a light ray speeds ahead of the upper part, causing it to bend (refract) upward.

When the refracted light ray meets your eye, it appears to be coming from the road surface instead of the distant sky. A reflected light ray follows a similar path, so the refracted ray is interpreted as a reflected one and a 'Mirage' is seen.

Reference:


Answered by: Paul Walorski, B.A., Part-time Physics Instructor

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'The strength and weakness of physicists is that we believe in what we can measure. And if we can't measure it, then we say it probably doesn't exist. And that closes us off to an enormous amount of phenomena that we may not be able to measure because they only happened once. For example, the Big Bang. ... That's one reason why they scoffed at higher dimensions for so many years. Now we realize that there's no alternative... '

Michio Kaku
(1947-)