- Education and Science»
Is what we see real?
Every kid gets excited when he/she sees a rainbow. You go for a ride across the countryside and your eyes are met by a beautiful scenery. The sea, the sunset, the trees and all those visual treats put the mind at peace. If I were to ask you what the sun looks like, your answer would be that it's a glowing yellow disc in the sky. Some of might say that the sun is red or white depending on the time of the day. Well, you are quite correct. What we see is a portion of reality and not the complete truth.
Double Alaskan Rainbow
The world as you see it is an image, a two-dimensional illusion. To understand this we must know the following two things
1. Everything we see is because of light.
2. Our eyes can only detect light of a particular range of 'wavelength' or 'frequency'.
So how do we see? When light enters our eyes and strikes the retina (which is a kind of screen on the back of the eyeball), electrical impulses are generated. These impulses travel to the brain where they are decoded or 'understood'. Interestingly, the image formed on the retina is inverted but our brain re-inverts it and so we see the world as it is. Or do we?
Before I talk about light, let me just add that there are two types of cells in the retina. Rods which are many many times more abundant than Cones, are responsible for your night vision. You know, when after some time of darkness your eyes get adjusted to the dark and you can see. Cones on the other hand, detect color. There are three different types of cones responsible for the detection of three different colors (red, green, blue).
Now that we know 'how' we see, we shall talk about 'what' we see. But just after a brief introduction of what light is. To put it simply, light is an electromagnetic wave. Now, what is an electromagnetic wave? It's a wave that consists of changing electric and magnetic field. To quote numerous textbooks, "a changing electric field produces a changing magnetic field, which in turn produces a changing electric field." So the oscillations are self-sustained.
Now I'm sure you know this. But the speed of light in vacuum is the upper limit of speed in the universe. (Faster than light instances can occur, but no information is ever found to be mediated faster than light)* every wave has a wavelength (λ) and a frequency (ν). The time taken for one complete oscillation is the frequency whereas the distance between two successive wave crests is the wavelength. the speed of light is denoted by 'c' and
Light of less frequency and large wavelength is less energetic whereas light with high frequency and small wavelength is more energetic.
Our eyes can only detect light within frequency range 430-790 Tera hertz (10 followed by 12 zeroes). You see where I'm going with this. Since our eyes can see in a limited range of wavelength of light, there is a whole lot of information which goes unprocessed. In other words, what we see is not how the world truly is. Light is just a source of information.
If we were to access and picture all the information, that comes as light, sound, and other forms of energy, our perception of the world would have been overwhelming and yes, a little messy.
But if our eyes suddenly become less capable, we will be living in a dull world with less shades and colors. No one can tell you exactly how the picture would have been. But we can't complain. I think whatever we can see now is quite elegant.
What is your opinion regarding the ability to see literally everything?
© 2015 Aakash Dixit