Stephen Hawking is considered one of the best popular Science writers across the Globe. Especially his book 'A Brief History of Time' is the best seller among the books on popular science, dealing with evolution of Universe from Big Bang to Black Holes.
Various aspects of evolution of Universe on the basis of Physics have been dealt with, in a powerful manner in the book and it deserves best laurels. But any theory of Physics needs empirical proof and the undersigned author tried to analyse the theories with the experimental findings of a magnificent experiment at the order of recent CERN experiment, otherwise known as Hadron experiment. The results of the analysis are given below.
The purpose of this article is to first, present the theories put forward by Stephen Hawking in his book and second, compare it with the findings of CERN experiment and other popular books written by Erwin Schrodinger, Fritjof Capra, J.B.S.Haldane, Ernst Opik and to bring forth the point that the three major findings of the book lack experimental support.
- The Questions Considered in the Book 'A Brief History of Time':
The primary questions put forward by Stephen Hawking in the book are:
Was there a beginning of Time?
Could Time run backwards?
Is the Universe infinite or does it have boundaries?
- Question no1, Concept of TIME According to Stephen Hawking:
Stephen Hawking in this book has taken the concept of increase in Entropy as a measure of time. In fact he defines three concepts to define the concept of arrow of Time as:
The increase in Entropy,
The Psychological Time. In the order of sequence by which we serialise the happenings and
The direction by which the Universe is expanding (Chapter 9, Arrow of Time)
Though he considers all the above three as true reflections of Time arrow (Time moving forward) he gives prominence to Entropy because he considers increase in Entropy as a measurable quantity and reversible exactly in reverse direction to enable Time travel in both directions. We already know that Entropy (disorder) increases with increase in time. Hence he concludes that increase in Entropy is increase in time.
Earlier we studied that entropy is a measure of Disorder. The disorder of the Universe tends to the maximum, thus marking the death of the Universe. Hence Mr Hawking starts from zero disorder and measures the age of the Universe from the amount of disorder presently existing, somewhat akin to Carbon dating.
The postulate that Entropy in the reverse direction reduces time cannot be empirically proved. The disorder, one day the disorder may be totally nullified by some Natural Force and order may be restored. Hence measuring Time using Entropy is basically not possible unlike measuring Age of Earth using Carbon dating. Also Mr Hawking brings the concept of Negative Entropy, a measure of order for reversal of Time. For this, he is taking the example of a Jigsaw game (page 154)
He asserts that the initial position of Jigsaw pieces which constitute a whole image is in order and marks time as zero. Then its position becomes disordered marking a progress in time. When they are re-assembled, the Time reverses in the negative direction and becomes zero when perfect order is regained. The same is the case with a broken cup. During the forward journey it enters into total disorder and in the reverse direction, it brings back order.
For the sake of simplicity let me give the following flow chart of Time Arrow in both directions as envisaged by Stephen Hawking:
I. Movement of Universe in the forward Direction:
1.Zero Time represents Perfect order,
- progress in Time means, disorder increases. (More Entropy)
- End of Time means Maximum disorder OR Maximum Entropy (Singularity)
II.On the reverse side:
1.End of Time means.Maximum disorder
2.Regression in Time: Disorder decreases (order or negative Entropy increases)
3.Beginning of Time means Perfect order (Zero Entropy)
This is the vivid description of Time in terms of Entropy given by Stephen Hawking in his book 'A brief History of Time".