From Here to Eternity

***^1/2/*****                                                                                                   Science

From Eternity to here: The Quest for the Ultimate Theory of Time

Sean Carroll

Time has baffled philosophers, scientists, and the masses since the dawn of thought. It is impossible to imagine a world without time and it is equally difficult to accept time just as another dimension of our universe. Our existence and even the infinite universe with its billions of stars seems a play in the hands of this omniscient, omnipresent and ever moving entity ‘Time’.

           

Sean Carroll, a theoretical physicist, attempts to understand this phenomenon in light of latest scientific theories. In this process, he leads us through the alleys of Newton’s classical physics, Einstein’s relativity and the uncannily weird deductions of quantum mechanics.

           

Through all his effort, his attempt to unravel the mystery of unidirectional nature of time, is plainly apparent. Every law of physics is invariant in time reversal, i.e., they are as true for forward movement in time as in its movement backwards. But our experience tells us that events in our world evolve only in one direction. Galaxies are moving apart, they never seem to coalesce; living-beings are evolving from single cellular bacteria to the multicellular wonders as human beings but we never find humans, tigers, and birds devolving in to the now extinct intermediate forms like archaeopteryx; and as Sean Carroll repeatedly says, milk and coffee mix together but do not separate spontaneously, eggs break but never does a broken egg reassemble into a complete egg; we remember our past but never our future. What is it that has woven this element of asymmetry in the fabric of time? What has bestowed on time this immutable direction? In nutshell the whole book is an effort to understand this ‘Arrow of Time’. This quest leads us to some of the most fundamental discoveries in physics, as well, to some of physics’ most intriguing theories. It encompasses in its truest meaning the whole cosmos from its beginning to its ultimate end.

           

Sean Carroll explains these esoteric topics with extreme simplicity and clarity. He rarely uses an equation or scientific terminology without explaining it with marked lucidity. Initially he introduces us to the meaning of time and explains how second law of thermodynamics- which comprises the important concept of Entropy- gives direction to time. He then tackles evolution of universe and its ultimate fate. For time cannot be separated from universe, it being as integral to universe as space. In second part of the book he discusses relativity in some detail and also writes about time-machines, which deal with a fascinating feature of the theory of General Relativity. In the next section he delves deeper into entropy, disorder, and quantum mechanics. In the last part he talks about black holes which are essential for complete understanding of entropy, inflationary theory of universe, and the largely speculative theory of Multiverse. He sums up all his assertions and quest of previous chapters, in the last chapter and elucidates why he feels that ‘Multiverse’ theory of evolution of universe comes nearest to explaining the Arrow of Time.

           

Sean Carroll, in this book, takes us on a thrilling journey of exploration and discovery. He fearlessly confronts some of the most mystifying and intricate theories of physics, as he endeavours to explain these to lay people like us. He fearlessly questions the capability of certain well-entrenched theories to explain the riddle of the Arrow of Time. He is bold to offer newer interpretation of old theories. His language is beguilingly simple. Simplicity often masks the profundity and depth of the topic being discussed. This is a must-read for a lover of popular science. It provides newer understanding of time, the beginning and end of universe and how theories of physics are inextricably linked to these facts.