Books Review: A Brief History of Time #1

by - February 10, 2015

I will not argue on what is in this book and sorry if there are many mistakes in writing review in english, simply I want to argue or writing a review about how A Brief History of Time impacts me. At first, it is not that easy to understand this kind of book. Although it was made for lets call it society, still im as an engineering student who study at nuclear engineering (that used to play with relativity or whatelse) found that it is hard to understand.

Chapter 1: Our Picture of The Universe

Well, this chapter told us about what in the past or even present people think, see, and argue about the whole universe system. In this book, Stephen Hawking wrote that Aristotle in his book On The Heavens was able to put forward two good arguments (about the shadow of the moon that is round and the northern stars view) that earth was a round sphere rather than a Hat plate (that Greek people used to trust). And now we already knew that the earth most likely looks like a sphere rather than a round or even a Hat plate.

Well, about the universe model, Ptolemy ever made a great model of our galaxy. Ptolemy’s model is provided a reasonably accurate system for predicting the positions of heavenly bodies in the sky but using an assumption that sometimes moon orbit is 2 times closer to the earth which means, one time moon will appeared 2 times larger than usual (which is we know that it is absolutely incorrect).

Augustine said that the concept of time has no meaning before the beginning of the universe (which means easily there is no time before the universe was made). When someone asked him what god do before He created the universe, then he replied that Time was a property of the universe that god created, and that time did not exist before the beginning of the universe.

Interesting point so far, by Hubble’s observations, he said distant galaxies are moving rapidly away from us (or in short one can said that the universe by itself is expanding). So we could say that it might be the universe itself in the earlier time have been close together where all of those are exactly in a point which its density was infinite. For those who are forgot about the density concept, we could say that density is mass/volume which it means in the earlier time, universe was ever come close each other in a point which had a very very big mass (it is really very big) and had a really really small volume (nearly zero). At this situation, it was very dense and that’s why we could say at the earlier time universe had an infinite density.

Hubble suggested there was a time that a big bang happened (for those who really didn’t know this, you must be kidding me) In which under such conditions all the laws of science and all ability to predict future would break down (simply we could say that all of those are not working).

Stephen Hawking wrote that, in order to talk about the nature of the universe and to discuss questions we have to make sure understand what a scientific theory is. A theory is just a model of the universe or a restricted part of it and a set of rules that relate quantities in the model to observations that we make. A theory can be called good if it satisfies two requirements. First of all, it must be accurately describe a large class of the observations on the basis of a model that contains only a few arbitrary elements. Second. It must make definite predictions about the results of future observations.

To make sure all of us understand this, Stephen hawking states that Aristotle believed on Empedocles’s theory that everything was made out of four elements earth air fire and water. Okay let say this is a simple theory, but can it make a definite prediction later? Ofc NO. Then ofc this is not a theory. It is different with one Newton theory which is consists of three parts but it could make a definite prediction, then it is called a good theory. It is also said that any physical theory is always provisional which means only a hypothesis, because we can never prove it no matter how many times the results of experiments agree with some theory, we can never be sure that the next time the result will not contradict the theory. To disapprove the theory itself, we could just make another method of observations. If its result differ from a theory then we have to abandon that theory or at least modify it.

Well, what Stephen Hawking wants to do is simply provide a single theory that describes the whole universe. Scientist in its approach divide it into 2 parts. First, there are the laws that tell us how the universe changes with time (in short something that could predict what will happen next, and what was happen in the past. Or if you are an engineering students we could say this is a function with time f(t)). Second, there is the question of the initial state of the universe. Ofc many of us debate on this, one said scientist must only focus on first part, because God could have started the universe off any way He wanted, He could made it in a completely arbitrary way but yet it appears that He chose to make it evolve in a very very regular way according to certain laws. In this case, Stephen Hawking trusted that therefore it seems there is an equally reasonable to suppose that there are also laws governing the initial state.

So it is ofc really difficult to make or devise a theory to describe the universe all in one go (we could say by using only this theory, we could describe everything in the universe), thus scientist divide it into several partial theories by neglecting the effects of other quantities or representing them by simple sets of number (once again, in solving some problems, usually we are as an engineer neglect something to make it easier to solve it. Lets say we are calculating the actual time of free fall body from Y metes of high, sometimes or even most of us neglect air resistance)

Today scientists describe the universe by using 2 partial theories. There are the general theory of relativity (trust me, I didn’t learn this in class) and quantum mechanics. In short, general theory of relativity describes the force of gravity and the large-scale structure of the universe that size from a few miles into a big big big one, about 1 miles being followed by 24 zeros after it while quantum mechanics deal with something that is very small. But both of them is contradicting each other, so they cannot both be correct. What Stephen Hawking wants to find is a theory that will works on general theory of relativity and quantum mechanics.

In such a condition ofc we knew that it is logic to say Stephen might made a progress toward that laws. The discovery of a complete unified theory may not aid the survival of our species or even affect our lifestyle. But as we know, as a people we are very curious about something that they don’t know, a desire to know much, a desire to get more knowledge.

In this part, I cannot say that Stephen wrong. He might be right about the people curiosity. But as we know, so far what Stephen thought now is the most accurate things (but read again, there is never any physical theory that always works to something with assuming and neglecting few things), so it might be one day what Stephen said is not true. It is depend on ourself again, knowledge itself is not an objective matters. Knowledge that we got itself is being processed by our brain or simply being digested. Things that are not important or not match with our basic belief will be thrown away. By this way, things that we have found so far is never ever be an objective one. It must be contain at least a little subjective things. By learning, it must made us continue to remember Allah as our God. If it is not, we have to ask ourself whether it is we learn in a wrong way or what we have learnt is something that must not be learnt and being forbidden by Islam.

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