What we call time in physics is not a real entity in the universe. The real entities in the universe are matter and energy. Energy gives motion to matter or allows the transformation of matter, giving us the illusion of passing time or more precisely a perception of an "arrow of time". The mistake about using time as a real entity in physics came first in the 18th century when L. Euler, in 1752, states that acceleration of a body is the time derivative of velocity. Instead, we will use d'Alembert definition of acceleration deduced by experimental results: (phi*dt)=dv, where dt is not time differential as in differential calculation but only a small constant of "duration", and phi the acceleration. Einstein theory was to think that time is a real entity in the universe and then space-time coordinates can describe the universe.

This is a provocative account of the astounding new answers to the most basic philosophical question: Where did the universe come from and how will it end?

'If you feel you are in a black hole, don't give up. There's a way out' What is inside a black hole? Is time travel possible? Throughout his extraordinary career, Stephen Hawking expanded our understanding of the universe and unravelled some of its greatest mysteries. In What Is Inside a Black Hole? Hawking takes us on a journey to the outer reaches of our imaginations, exploring the science of time travel and black holes. 'The best most mind-bending sort of physics' The Times Brief Answers, Big Questions: this stunning paperback series offers electrifying essays from one of the greatest minds of our age, taken from the original text of the No. 1 bestselling Brief Answers to the Big Questions.

From Nobel prize-winner Roger Penrose, this groundbreaking book is for anyone "who is interested in the world, how it works, and how it got here" (New York Journal of Books). Penrose presents a new perspective on three of cosmology’s essential questions: What came before the Big Bang? What is the source of order in our universe? And what cosmic future awaits us? He shows how the expected fate of our ever-accelerating and expanding universe—heat death or ultimate entropy—can actually be reinterpreted as the conditions that will begin a new “Big Bang.” He details the basic principles beneath our universe, explaining various standard and non-standard cosmological models, the fundamental role of the cosmic microwave background, the paramount significance of black holes, and other basic building blocks of contemporary physics. Intellectually thrilling and widely accessible, Cycles of Time is a welcome new contribution to our understanding of the universe from one of our greatest mathematicians and thinkers.

This book is for anyone who wants a fresh approach to modern physics. Are you tired of amusing anecdotes about scientists' personal lives and eureka moments? Bored of chronological narratives of scientific progress through the ages? No longer wowed by ideas like string theory? Interested in first principles thinking and what it can do for you? This book is for you. This book is designed to take you step by step through the fundamental principles that underlie the physics of space, time, and matter. It is a how-to guide for building up our universe from first principles. By posing questions and answering them with illustrations and examples, the book shows how we can demonstrate what we know about the universe with simple concepts and thought experiments. With this book, you too can apply first principles to build up your own model of the universe and how it works, one you can take with you, and apply it to other areas of your life such as your job, business, even your relationships. There are no complicated mathematics in this book and I have minimized the amount of jargon. Thus, it is suitable anyone of any educational background from high school on. The book aims to be straightforward about how we get from simple ideas to complex physical theories. So, if you are interested in a new way of looking at the universe and are not afraid to unlearn some of what you have learned, take a look inside.

What is superstring theory and why is it important? Can superstrings offer the fulfilment of Einstein's lifelong dream of a Theory of Everything? Co-authored by one of the leading pioneers in superstrings, this book approaches these scientific questions, looking at the scientific research.

In this masterfully written and brilliantly informed work, Dr. Rhorne, the Feynman Professor of Theoretical Physics at Caltech, leads readers through an elegant, always human, tapestry of interlocking themes, answering the great question: what principles control our universe and why do physicists think they know what they know? Features an introduction by Stephen Hawking.