This is a story of humanity's search for an understanding of the universe we inhabit, a search that has its roots in pre-history. Early communities had a very good understanding of those cyclical changes of Nature that had an immediate effect on their lives, such as the seasons of the year, the phases of the moon and the consequent ebb and flow of ocean tides. However this was very far from what we would now consider a scientific understanding, since the behaviours of Nature were usually considered to be of supernatural or divine origin, inscrutable to humankind.
In the astonishing burst of civilization which emerged in Asia Minor
several centuries before the birth of Christ, a few individuals emerged
in Ancient Greece who began to inquire into the
workings of the natural world. Their views held sway for sixteen centuries.
This ancient learning was preserved through the Dark Ages by Arab and European
mediaeval scholars who, for the most part, restricted
their work to annotating and commenting on it. The Renaissance
For convenience we can consider two main streams of enquiry; both were motivated by practical considerations. The first was the study of the motion of the stars and planets which aided the increasingly popular navigation of the globe; the second was the motion of earthbound objects which was important for many aspects of daily life and in military applications.
The revolutionary work of Galileo and Newton demonstrated that an astonishingly few hypotheses solved all the problems in both of these two streams of research. Newton's Principia, one of the great books of all time, laid out fundamental principles of mechanics, gravitation and optics that remained unquestioned till the early part of the 20th century.
The systematic study of electricity and its connection to magnetism culminated in the synthesis of all electromagnetic phenomena in Maxwell's four equations at the end of the 19th century. At that time, many believed that science was on the verge of uncovering all of Nature's secrets. Ironically, the very experiment that triumphantly confirmed the prediction by these equations of electromagnetic waves contained the seeds of a complete re-evaluation of all of the "classical" physics up to that point.
In his annus mirabilis of 1905, Einstein published three papers of immense significance. The first established beyond a doubt that molecules had a real existence. The second showed that Newton's ideas on kinematics were only approximations, and introduced the revolutionary theory of Special Relativity. The third demonstrated that light, conclusively proven by Young to be wavelike in nature, had also particle-like properties, thus ushering in the whole new field of Quantum Mechanics.
The succeeding three decades saw an explosion of creativity which ushered in modern physics. The secrets of the atom were uncovered, the field of nuclear physics was born, and the understanding of these fields had reached suffient clarity that the new science was available to the makers of the Second World war which broke out in 1939.
Since then, the pace of advance of science has been extraordinarily rapid. The advances of Solid State Physics and Modern Optics have transformed our world, and the discoveries in Particle Physics, Cosmology and Astronomy are changing for ever our view of ourselves and our place in the Universe.