Thursday, 23 April 2009

This is a Story...

This is a story from the 17th Century.
It was a fine morning in the city of Greece. The town square was packed with people. Three people were about to be executed on the guillotine; a priest, a lawyer and a Theoretical Physicist. The priest was to go first. He was made to place his head in position and then asked if he had any last words. He said “Yes, yes, I do! I want everyone here to know that I am innocent. I believe in God and am sure that he will not let me die.” And so the blade of the guillotine was lifted up and the rope was let go. To everyone’s amazement the blade stopped just inches above the priest’s neck. The priest was set free.
It was now the Lawyer’s turn. He too was asked to position his head correctly and if he had any last words. He said “I do not believe in God, but Justice shall save me.” And so the blade was lifted again and again, the rope was let go. And again the blade stopped just inches above the lawyer’s neck. The lawyer too was set free.
And now it was the Physicist’s turn. Like before he too was asked if he had any last words. And he said “I don’t believe in God and I am not familiar with the workings of Justice but I do believe in Science. And if you look up” he continued “you will see that the rope has a knot which gets stuck in the pulley as it comes down. If you remove the knot, the guillotine will work properly again.”
And that, my dear friends was the end of the Physicist.

I heard this told by Michio Kaku, one of my favourite physicists. 

Sunday, 12 April 2009

Free Will Does NOT Exist.

Mr Raj, this is in reply to your comment on my previous blogpost. The reply was so long that I thought it would be better to put it in a separate blogpost instead


But no matter what decisions we make it is a result of electrical impulses in our brains. And these electrical impulses are a result of the movement of Sodium+ ions in our brain. Irrespective of how we make our decision we still can't make the Sodium+ ion move in a way that defies the laws of physics. When you choose to marry someone the "love" you feel corresponds to specific areas of the brain firing electrical impulses. By using Newtonian Mechanics slightly modified with General Relativity and the Principles of Quantum Mechanics we can calculate the fate of all the Sodium ions that created the electrical impulses. That is the theory put in its simplest form. If we ant to count the external factors, we take into consideration the events that happen around us. For example, choosing a career. It is a few specific events in a person's life that leads a person to choose a career. Other factors include mental ability, opportunities and finances. Mental abilities are completely determined by the size and health of specific sections in the brain which consists of atoms whose fate can be determined. Opportunities are determined by the state of the economy and other factors which are affected by the import/export of goods and specific economic events. All these events include matter which is made up of atoms whose fate can be predicted. Finances mean money and other assets which can be liquidated into cash thus helping you to get some education thus helping you to choose the desired career. Since money and assets are made up of matter they contain atoms whose fate can be predicted. As for events in a person's life those events are a direct result of interaction between matter particles (if the event involves you father telling you something his mouth is affecting the air molecules to move which carries the sound to your ears which make your eardrums move causing electrical impulses in your brain causing a decision/opinion to be formed.) I could also explain with appropriate detail how any other factors affect the decision making process. Give me any event ant I'll explain it. As difficult as it may seem to believe, all events ARE predetermined by the laws of physics. The notion that we are free to act as we wish is an Illusion. In fact we are forced to act as though free will existed by the Laws of Physics. Because, In theory we can map every single movement of each and every particle in the universe right from it's creation about 380000 years after the Big Bang up to it's destruction(Whenever that is). If we can do that in the atomic level it follows that we can do that in the macroscopic level. The only reason that we haven't done this yet is because as the size of the system we are dealing gets larger, the number of equations which we deal with gets larger and larger. So to predict the fate of a system as large as the human body we would nee computers with at least a hundred (or more) times the computing speed of today's computers. According to Moore's law (Which states that power of computers doubles approximately every 18 months. And it has stood wonderfully till now) that will take another 50-100 years. But stepping stones to the creation of such 'quantum computers' of immense power have already been laid. Scientists have used the power of 7 atoms vibrating exactly in phase with each other to calculate that 5 x 7 = 35. Although this is simple, we may see exceedingly complex quantum computers as the years advance.

Friday, 10 April 2009

Free Will - Does it Really Exist?

 "To Newton and Einstein, the notion of free will, the notion that we are masters of our own destiny was an illusion. The commonsense notion of reality, that concrete objects that we touch are real and exist in definite states, Einstein called "objective reality." He most clearly presented his position as follows:

I am a determinist, compelled to act as though free will existed, because if I wish to live in a civilized society, I must act responsibly. I know philosophically a murderer is not responsible for his crimes, but I prefer not to take tea with him. My career has been determined by various forces over which I have no control, primarily those mysterious glands in which nature prepares the very essence of life. Henry Ford may call it his Inner Voice, Socrates referred to it as his daemon: each man explains in his own way the fact that the human will is not free . . . Everything is determined . . . by forces over which we have no control . . . for the insect as well as for the star. Human beings, vegetables or cosmic dust, we all dance to a mysterious time, intoned in the distance by an invisible player." - From: "Parallel Worlds", by Michio Kaku

The above statement may seem more related to the concept of God than Science, but scientifically speaking, this statement holds good. Because, theoretically, if we calculate the fate of every particle in a human body taking into account all the forces acting on it we are effectively predicting the fate of that person! The problem is, that the number of forces acting on one particle alone are so numerous that we would need a computer with computing ability millennium ahead of the current level to calculate the fate of a system as large as a human body.

This theory however leads to a most startling conclusion. It implies that the fate of every single particle in the world is predetermined and can be predicted right up to it's destruction. Effectively this means that all events that happen in this world, from the motion of stars and galaxies right down to the beat of a butterfly's wing and your neighbour picking his nose was predetermined by the Laws of Physics at the time of the Big Bang! 

     

Thursday, 9 April 2009

The Strange World of Quantum Physics - Heisenberg's uncertainty Priciple.

A few days ago, I came across a very interesting effect of Heisenberg's Uncertianty Principle.
The theory states that it is impossible to know simultaneously with an infinte degree of accuracy both the position and velocity of a particle. In a very beautiful and exquisite way the diffraction pattern one observes in light is one of the proofs of this theory. 
Imagine that we are shining a light through a large slit so that there is a beam of light falling on a screen.
Now imagine that we are slowly making the slit smaller and smaller. The iwdth of the beam will get smaller ans smaller. But afte a certain point Heisenberg's Uncertainty Principle comes into action. since we know the position of the light  beam with greater and greater accuracy, we will know the velocity and therefore the momentum with lesser and lesser accuracy(Since P=mv). This results in the beam of light widening out and displaying a diffraction pattern as follows:

A Limerick

There was once a young man from Trinity,
Who took the square root of infinity,
The number of digits,
Gave him the fidgits,
So he dropped math and took up Divinity.