More on Illusions: Light

Light is one of the most fundamental energies of this universe, the reason we perceive this universe to be as we do, and what we take for granted most of the time.

But like everything else, light isn’t perfect, and its imperfections manifest at their highest when it suffers refraction. Now the question arises:

What exactly is refraction?

Refraction is the change in direction of wave propagation of light due to a change in its transmission medium.

When light undergoes refraction, it bends and changes its direction, contrary to the popular belief that light always travels in a straight path, irrespective of its mode or medium of propagation.

Case I:

Why does light bend?

While digesting all this information, yet another question arises:

The answer to this question is very simple or very complex, depending on the way you look at it.
Most physics teachers or professors would have you believe that this happens due to Fermat’s principle, which states that:

Fermat’s principle or the principle of least time, named after French mathematician Pierre de Fermat, is the principle that the path taken between two points by a ray of light is the path that can be traversed in the least time.

Assume the guard to be a single wave/particle of light

In this above picture, the particle/wave (the guard) of light should know its destination in order to calculate the path of least time.

But this principle leads to even more issues.The primary one being that in order for a particle to take the path which takes the least time, it has to be aware of its position in the future!

This would mean that the particle/wave of light should be able to predict where it should be in its near future. But as we know, this cannot be true. This leads me to conclude that this principle is wrong.

So what will give us the best understanding of how and why light bends?

Try to think a group of light waves as a car

The model which does not seem to cause any discrepancies is the above model(I don’t know the name).

If you consider a group of light waves, then the top- leftmost light wave will hit the material(denser medium) first. In direct analogy with a car, if power is provided only to the left set of wheels, then the car will automatically turn towards its right.

This analogy can also be applied to a tank. If we supply power to only the right set of tracks, then the whole tank will turn to its left.
The same thing happens with a light wave. When the 1st wave hits the medium, it slows down the entire wave function, and consequently the entire wave pivots around due to the outermost wave still being outside the medium for a fraction of a second. Think of it as a hinged door pivoting around.

Thus we have seen that even light can bend, and it is not immune to the effects of basic physics.

In this next case, I will cover an even deeper aspect of light:
How and why we see the world as we do?

Case II:

The electromagnetic spectrum consists of all the different wavelengths of electromagnetic radiation, including light, radio waves, and X-rays. We name regions of the spectrum rather arbitrarily, but the names give us a general sense of the energy of the radiation; for example, ultraviolet light has shorter wavelengths than radio light. The only region in the entire electromagnetic spectrum that our eyes are sensitive to is the visible region.

The entire electromagnetic spectrum

Only 1/7th of the entire electromagnetic spectrum is visible, and out of that the colors which the human eye (pigeons can also process the ultraviolet spectrum in addition to normal white light) can process are the VIBGYOR.

So how do we know a certain object to be of a certain color?

This is because the object absorbs the wavelengths of the light being thrown on it except the color it appears to be, which it reflects. So does this mean that that object is all colors except the one it appears to be? Or is our version of reality true?


Such questions may plague humanity for all of time, but alas, everyone has limited time on this globe, and so do I.

I sign off by saying that any comments are welcome, and that I experienced great enjoyment in putting my thoughts down, and I hope you too experience the same enjoyment and child-like wonder while reading them.


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