Time and Space

As the famous excerpt goes "Time goes faster the more hollow it is. Lives with no meaning go straight past you, like trains that don't halt at stations."- Carlos Zuin Zafon

The article is a compendium of alternatives- formulating predictions, stimulation and affirmations. It gives a review to the first two chapters of a book "A Brief History of Time" which is articulated very precisely as a bird's eye view on Universe (cosmology) and spacetime by the British physicist Stephens Hawking. The structure, origin, development and eventual fate of the universe, basic building blocks that make up the universe (such as quarks), Big-Bang and Black Holes and the fundamental forces that govern it (such as gravity) were also elements to voice on and emerged as the paradigm of invention in cosmology. The book appealed to the readers in such a fashion that it was organized in a linear mode with most chapters logically depending on the preceding chapters. With sheer luck and marked as one of the most posthumous books on science, it was on London's Sunday Times bestseller list for over four years, sold more than 10 million copies in 20 years and was translated into 35 languages from the year 1988 till 2001 which is both astounding and sensational for any book on science.

Wonders dazzle the earth, one of the pre ponderous wonders being Time. Time is not an expression of an unending saga, but a paradox in search of the unknown. To draw logical conclusion from our random thoughts, it is to bring us closer to the laws governing our Universe. By this I don't mean being loquacious at first, but to bring incessant perspectives on the laws governing our Universe which is again scaled by other writers. As Bertrand Russell quoted in this book "A Brief History of Time"- "The world is really a flat plate supported on the back of a giant tortoise."

Most of the people would consider the portrayal of our Universe as an infinite pillar of tortoises rather dismaying. They proceed from stories to stories woven around their primal tales, first as a restless youngster to the verges of a pauper searching for sheer knowledge amids this gruelling poverty. The facts behind the Earth being the centre of the Universe or the moon appearing twice bigger at times got great scientists of our times in a contemplative mood to come up with better hypotheses. Copernicus substantiated the idea of the Universe beyond the natural boundary of fixed stars and celestial spheres and Newton on providence of the fall of an apple went on to pronounce the role of gravity which causes the moon to orbit in an elliptical orbit around the Earth. The golden rule behind the principle of gravity led to the hypotheses that stars attract each other so that they do not appear stock still, but this, also led to an argumentation that stars are strewed over a finite region of space. The universe is not static, but might be rather expanding would lead to a complete unified theory drawing us closer to the laws governing our Universe.

Time is a peerless and invincible facet of the scientific realm that it enters the fray of space and gravity without any special modesty. The origin of the universe forecasted as a great topic of study and debate over the centuries over time. Early philosophers like Aristotle thought that the universe has existed through time immemorial, while theologians such as St. Augustine believed it was created at a specific time. St. Augustine also believed that time was a concept that was born with the creation of the universe. More than 1000 years later, German philosopher Immanuel Kant criticised stating that time goes back forever. In 1929, astronomer Edwin Hubble discovered that galaxies are moving away from each other.

Consequently, he stumbled upon a conclusion that there was a time, between ten and twenty billion years ago, when they were all together in one singular extremely dense place. This discovery brought the concept of the beginning of the universe within the province of science. To affirm to such critics and to augment the voices of doom to the laws governing our Universe, scientists use two partial theories, Einstein's general theory of relativity and quantum mechanics.

Einstein's postulate that the laws of nature should appear the same to all freely moving observers was the foundation of the theory of relativity. Its beauty and simplicity convinced many thinkers, but was open to a heap of criticism. Questions such as - Was everything relative or was fixed to absolute standards emerged! On a meeting when Maxwell and Newton were both discussing about the predicaments of light waves, Newton raises a profoundly motivational question, that if light was supposed to travel at fixed speed, one would have to say that fixed speed was to be measured relative to a specific standard.

Newton's rhetorical question has been repeatedly cited in scientific texts to illustrate both the nature of light and limitations of its various predicaments. The notion of ether as an iconic strand to the strings of thoughts of Newton led to the aspect that speed of light travelling through it should be relative to the speed of different observers moving through the ether. The fundamental postulate behind the theory of relativity governing space and time was that the laws of science should be the same for all freely moving observers, no matter what their speed. To accelerate a particle to the speed of light would be impossible because it would take an infinite amount of energy. To give an upshot to Maxwell's theory and the speed of light from a more precocious frame of mind: all observers should measure the same speed of light no matter how fast they are moving. To illustrate this, the best known theory is of Einstein's magnum opus: on the equivalence of mass and energy from the illustrious equation

(where E is the energy, m is the mass and c is the speed of light). Among its realization as an exemplar was that if the nucleus of a uranium atom fissions into two nuclei with slightly less total mass, this will release a tremendous amount of energy.

Eintstein's general theory of relativity transformed space and time from a passive background in which events took place to active participants in the dynamics of the Universe. The Universe is expanding with the distance between any two galaxies steadily increasing with time. The concept of general relativity completely transformed the subtle nuances of the origin and fate of the universe. A static universe could have been created forever or could have been created in its present form in the past. However, if galaxies are moving apart now, it seems that they must have moved closer together in the past. About fifteen billion years ago, they would all have been on top of each other and the density would have been very large. This state was called the "primeval atom" by Georges Lemaitre, who was the first to investigate on the origin of universe that we now call "Big Bang". Einstein was even more reluctant to admit that general relativity predicted that time would come to an end for massive stars when they reached the end of their life and no longer generated enough heat to balance the forces of their own gravity. Einstein premonitioned that such stars would settle down to a final state until they become black holes, regions of space-time that are so warbled together that light cannot pass through them.

The special theory of relativity received high veneration and acclamation on explaining that the speed of light appears the same to all observers and in describing the consequences when objects move at speeds close to the speed of light. However, there were accusations from the Newtonian theory of gravity which said that objects attracted each other with a force that depend on the distance between them. The contrary arguments were not really vanquished. In a book Charles Lamb wrote — "Nothing puzzles me like Time and Space, yet nothing troubles me less than time and space, because I never think of them."Sir Isaac Newton in his book.

Principia Mathematica, published in the year 1687 gave us the first mathematical model on Time and Space. In Newton's model, time and space were a background in which events took place. Time was demarcated from space in the sense as if it were a railroad track that stretched to infinity in both the directions. However, time, itself was considered eternal. Most of the thinkers presume that only a few thousand years or so the physical universe has come into existence. Intellectual titillation comes from in-thetrenches of curiosity. Certain questions props up in the reader's mind ---"If the universe had been created, why had there been an infinite wait before the creation? On the other hand, if the universe had existed forever, why hadn't everything that was about to happen already happened, meaning that history was over. In particular, why hadn't the universe reached thermal equilibrium, with everything at the same temperature?"

General relativity combines the time dimension with the three dimensions of space to form what is called spacetime. The theory incorporates the effect of gravity by saying that the distribution of matter and energy in the universe warps and distorts spacetime. Objects in the spacetime move in straight lines, but because spacetime is curved, their paths appear bent.

They move as if affected by a gravitational field. To bring forward the nuances of scientific finesse into the picture, time should have a maximum o r minimum value --- in other words, a beginning or an end. Such a point of beginning or end stems from an infinite density called singularity. Besides light cones, Stephen Hawking also talks about how light can bend. When light goes past a highly massive object, such as a star, the light changes direction slightly towards the object. To comprehend beyond the origin and fate of the universe, physicists find justification in the quantum theory of gravity. Quantum theories of systems such as atoms, with a finite number of particles, were formulated in the 1920's by Heisenberg, Schrodinger and Dirac. Heisenberg's uncertainty principle showed that the uncertainty in the position of a particle times the uncertainty in its momentum must always be bigger than Planck's constant, which is a quantity that is closely related to the energy content of one quantum of light.

The summary to the article provides a yardstick as to how Einstein's general theory of relativity connected both space and time as a singular quantity and how it catalyzed the oblivious scientific realm into a more active domain of thought and inspiration of cosmological recipe. Even the glitches were warbled in an argumentative tone full of predictions and affirmations, they were justified very explicitly in a linear fashion. From the welter of information provided around them and to think strategically far into the future from a spectrum of data, Stephen Hawking's flagship book " A Brief History of Time" spurs interest into the minds of the readers enough to augment their scientific competencies in clusters beyond Time and Space as their thoughts and curiosities are inextricably woven together.

Munmi Bhattacharya Research Scholar Centre of Energy