Shadows of the Mind

In these days I have been reading two books. The first one is, “The Shadows of the Mind” by Roger Penrose. Second is “Classical Dynamics of Particles and Systems” by Jerry B. Marion.

First I want to share about the Shadows of the Mind.

Though that book is little vague and complicated for me to understand, I enjoyed it reading. I learned some new concepts in physics and some new way of thinking.

First of all I am very much impressed with the beginning of the book where it was told about a little story of a daughter asking ingenious questions to his father. No matter about the names of the people. But it reminded me about my old time where my teacher used to tell me about our minds.

One day I went straight to my teacher and asked some questions, which later I came to know that they are the basic philosophical questions.  But they are simple questions like,

“Where are we? What is the end of the world? Where is the Universe? If Universe is there somewhere then where that place is situated? What is time? What really we are doing here in this Universe?”

These are the questions often comes to my mind and make me to think I am in the middle of a great mystery.

Really we are all in the middle of the very great mysterious and magical world ‼!

After asking these questions, my teacher said,

“Think that, there are fishes living very deep down in Atlantic or Pacific or any other ocean. It is very deep that is its depth is comparable to height of Mount Everest. The fish spends its whole time in the sea below that depth.

Now, if you and go one day and ask the fish “What is Air? What is Sun, moon and What is Space?”

Do you think it will know the answers?

To that fish the ocean is the only world. In other words, it will think the whole world is completely just filled with water. It will only know about the things that behave in the ocean.

But it never knows about air, sun, moon or space. It even can’t simply imagine the things outside the ocean.”

And he finally said that we are also just like those fishes and where else Scientists are like special kind of fishes, which tries to get out from that ocean.     

It is same as the story told in the preface of the book “Shadows of the Mind”. It is true that we can’t even imagine the world outside the Universe.

When you read these kinds of books, and when you understood a little, stop reading and try to think something more about us. Think about the place of humans in this Universe and Just wonder the universe.

From that book I learned some new basic outline of Quantum Mechanics. Though I couldn’t fully understand Elitzur Vaidman bomb testing problem and Magical Dodecahedra problem, I just had some outline of those concepts.

I learned about Turing machine, Church’s thesis, Gödel’s theorem.

Especially I learned a little about the concept of Spin in sub atomic particles which is not the spin we really imagine in real life.

Spin:

The subatomic spin is somewhat different from classical spin where the axis is fixed in one direction. Unlike classical quantum spin is directed in all directions and “h bar” is the unit by which spin is measured.

In quantum mechanical spin, 

first we will chose a direction in space and using Stern-Gerlach instrument we will just find the magnitude of spin in that direction in space. “h bar” is the unit to denote the magnitude of the spin in that direction.

I learned new things about PULSARs and about PSR 1913-16 that is Hulse Taylor Binary Pulsar. I learned how it was proved General Theory of Relativity by the predictions made in Binary Star System and how it was predicted gravitational waves. I learned what is meant by Gravitational lensing.

Though already I know some of the things, the books gave me a lot of information.