Human behavior explained through Physics principle

You never know what the next moment is going to bring in front of you. At times, you may come across something which is totally unexpected. Something like this happened to me recently.

I was attending one session on Physics. We were discussing about unit of measuring distances, to be precise, very large units of them viz. light years, AU etc. The professor went on to explain, why light years. The lecture continued like – distance between Sun and Earth is measured in light years because the distance is too large and it is not feasible to measure it in conventional units, so we need larger units. So one light years is – distance traveled by light in one year.

Discussion continued, about AU (Astronomical Unit) and went further about how do we measure distances of stars which are far away from Sun, what are the techniques for it?

One of the method was, we know Earth is moving at certain speed in certain orbit. One of the method used this knowledge of Earth's speed and orbit to find distance of stationary object. I will try to explain it here,

(Sorry for the bad diagram, but it is really difficult for me use paint. And anyway that's not the point that we are trying to see here.)

The arc represents orbit through which Earth moves. So when Earth is at position 1, the star appears to right side of the observer, while when Earth is at position 2, star appears on left. Now using the knowledge of orbit, arc, speed of Earth, if we put up some geometrical expressions, we can find the distance between Earth and Star.

To explain this principle, rather to experiment it, professor suggested us one exercise.

He wrote one sentence on Blackboard, "This is reference sentence"

Then, he asked to hold our pen in hand, stretch the hand, and keep the pen exactly in front of our face. Now the he asked to close one eye, and then asked us what is the position of pen with respect to sentence written on blackboard.

With my left eye closed, I could see the pen somewhere on the word "reference"

Then, with my right eye closed, I could see the pen somewhere on the word "sentence"

So this was it, pen was stationary, but as I looked through different eyes, 'Position' of pen 'appeared' to be changed.

The reason being, distance between my left eye and right eye!!!

And this was the Eureka moment for me, suddenly it struck to me that, position of stationary pen appear different to me when I observe it through my own eyes, then how can two different people observing something have same views about anything. If a distance of couple of centimeters in my two eyes result in 'difference'; then it is bound for two different people to have different views on same thing.

Physics principle explains Human behavior with this experiment!!!