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Everytime I extend my hand to type on the keyboard, it behaves quite predictably and the alphabet I hit appears magically on the screen of the computer. Its almost like clockwork. But is the world exactly the way we see it. I can see my cellphone lying on my study table, along with my ipod but are these things there in reality. What I see is just a representation of the world created by my brain based on the visual inputs from the optic nerve. The algorithm used to create the image from the visual sensory perception has evolved to help me survive and leave offsprings and not to accurately depict the true reality.
All this may sound like fiction quite like the popular hollywood blockbuster Matrix but the conjecture made here could just be true. Reality could be far different from what we perceive. These are just the conculsions arrived at by recent strides in physics and quantum physics is at the heart of it. The mathematical equations that predict the outcome agree with observed results but the process or behavior of sub atomic particles is anything close to what we have seen or can understand. Richard Feynman said that if you think you understand quantum physics then you dont understand quantum physics. Perhaps he was hinting at the fact that the models of quantum physics are beyond human comprehension. Could the same be true of physical reality as well….if at all there is any physical reality.
At the heart of the entire quantum debate is the double slit experiment. This experiment alone highlights some of the most interesting facts about reality as far as we understand them. The experiment is quite simple yet leaves so many questions that a whole army of scientist are working day and night to explain.
Imagine a source of electrons shooting towards a wall in which there are two slits. These slits are just narrow to allow an electron to pass if it comes in a straight line. So any electron approaching the slits at even a slight angle will not pass. Behind the wall with the two slits is a detector which turns color whenever an electron hits it. Now imagine the same set up with a gun spraying bullets in all directions and facing a wall with two holes to allow bullets to pass if they are not at an angle. Behind the wall with two holes is another wall. Now after many hours of firing of bullets you will find that some bullets actually pass through the hole and collect in two bunches directly in line with the two holes. Obviously you would say since the bullet went through one hole or the other and is expected to be found near the next wall in the same line.
Now run the same experiment with the electron. You would expect the detector to light up at two locations directly in front of the two slits. However that is not the case. What really happens is that you see a wave interference pattern on the detector. So electron which is actually a particle has behaved like a wave. Which means that it did not follow one path but many paths. Funny isnt it. Well it gets even funnier.
You could argue that the electron beams interfered with each other which is why there was a pattern. Next shoot one electron at a time from the gun and observe the pattern again. The wave pattern appears again. The question is what was the electron interfering with since we allowed only one electron to pass at a time. But this is not the end of the story
Now create a setup in which we somehow come to know which slit the electron passed through. You would expect that this observer should not have any impact on the output on the detector after all it is not participating in the experiment at all. You would be wrong again. This time the detector does not display any wave pattern. Instead the electrons have started to behave like bullets. Why and how we have little idea.
There are many theories to explain this fact. String theory being the front runner. However this does open many questions about the nature of reality. The most important is that all sub atomic particles (that form the constituents of our physical reality) are abstract till someone observes them. They decide to take physical shape only when being observed. Therefore could it mean that the universe is there because lifeform has emerged that can observe it and it never existed earlier. Could it be that each one of us creating a universe in his/her own mind from the big bang to the present and far into the future.
