A Brief History of Time

I finished all my exams a little early this term (and thank god for that), so I could dive right into the huge pile of books that had emerged on my desk through the semester. The first one was A Brief History of Time from Stephen Hawking which is a very interesting book.

Mr. Hawking talks about some interesting topics ranging from the very foundation of physics, it’s history and how our understanding of the universe evolved over time. There was Aristotle, who thought, that everything consists of the five  elements (earth, water, fire, air and aether - a divine substance that makes up the stars and planets). Then came Sir Isaac Newton with his laws and gravitation, Albert Einstein with theory of general relativity. Now we have quantum mechanics and string theory, that are based on the wave-particle duality.

The physicists went through all this in search of a grand unified theory, a theory of everything, one concept that will define the whole universe. The thing is, we’re not there yet and it might take some time. There are still things, that cannot be accurately described by the current principles of quantum mechanics or string theory.

The book also explores black holes and their role the big bang (as the beginning of the universe). I must admit, that I couldn’t understand it all when I read the book for the first time. Shame on me, I’ll have to give it a shot another time.

(In)finite Space-time

Another interesting thing, that was introduced in the book is a concept of a finite space with no beginning or end and how to imagine such a situation. You see, in life, everything has a beginning and everything, at some point eventually comes to an end. So it comes very hard to us to think in terms of a space that is not infinitely large, but has no beginning nor ending. Well, the example is right there! We live on it! Take for instance the surface of planet Earth. It’s definitely not infinitely large, but have you seen an end of the world somewhere? 2D surface of a 3D sphere is an example of space of finite size, but with no distinguished points of beginning or end. But how to extend it by one coodrinate to 3D/4D? Can we apply this principle to the space-time continuum or the time itself? Does it mean that our universe doesn’t neccessarily have a begining or end, that it just is?

Entropy

Another interesting principle concerns closed systems’ entropy. According to the second law of thermodynamics, entropy of an isolated system increases over time, it never decreases. Sounds familiar? Well, in case you’re a software engineer, I’m sure it does :-). By this law, code degrades and we cannot do anything about it - it’s physics! Unfortunatelly, for all spagheti-code producers, enthropy can also be reduced by increasing entropy somewhere else e.g. (surprisingly) putting some work to the system ;-).

Final Thoughts

There’s a lot more interesting theorems, thoughts and principles from physics, philosophy and many others areas of human knowledge. I think it’s definitely worth reading. Give it a shot!