The story of physicists' quest to answer a mind-boggling question: How can we travel through time? Since H. G. Wells' 1895 classic The Time Machine, readers of science fiction have puzzled over the paradoxes of time travel. What would happen if a time traveler tried to change history? Would some force or law of nature prevent him? Or would his action produce a "new" history, branching away from the original?In the last decade of the twentieth century a group of theoretical physicists at the California Institute of Technology undertook a serious investigation of the possibility of pastward time travel, inspiring a serious and sustained study that engaged more than thirty physicists working at universities and institutes around the world.Many of the figures involved are familiar: Einstein, Stephen Hawking and Kip Thorne; others are names known mostly to physicists. These are the new time travelers, and this is the story of their work--a profoundly human endeavor marked by advances, retreats, and no small share of surprises. It is a fantastic journey to the frontiers of physics. Some images in the ebook are not displayed owing to permissions issues.

Ryan Wasserman explores a range of fascinating puzzles raised by the possibility of time travel, with entertaining examples from physics, science fiction, and popular culture, and he draws out their implications for our understanding of time, tense, freedom, fatalism, causation, counterfactuals, laws of nature, persistence, change, and mereology.

About the possibility of time traveling based on several specialized works, including those of Nicholas J. J. Smith ("Time Travel"), William Grey (”Troubles with Time Travel”), Ulrich Meyer (”Explaining causal loops”), Simon Keller and Michael Nelson (”Presentists should believe in time-travel”), Frank Arntzenius and Tim Maudlin ("Time Travel and Modern Physics"), and David Lewis (“The Paradoxes of Time Travel”). The article begins with an Introduction in which I make a short presentation of the time travel, and continues with a History of the concept of time travel, main physical aspects of time travel, including backward time travel in the past in general relativity and quantum physics, and time travel in the future, then a presentation of the Grandfather paradox that is approached in almost all specialized works, followed by a section dedicated to the Philosophy of time travel, and a section in which I analyze Causal loops for time travel. I finish my work with Conclusions, in which I sustain my personal opinions on the time travel, and the Bibliography on which the work is based. Keywords: time travel, grandfather paradox, causal loops, temporal paradoxes, causality CONTENTS Abstract Introduction History of the concept of time travel Grandfather paradox The philosophy of time travel Causal loops Conclusions Bibliography Notes DOI: 10.13140/RG.2.2.17802.31680

There are various arguments for the metaphysical impossibility of time travel. Is it impossible because objects could then be in two places at once? Or is it impossible because some objects could bring about their own existence? In this book, Nikk Effingham contends that no such argument is sound and that time travel is metaphysically possible. His main focus is on the Grandfather Paradox: the position that time travel is impossible because someone could not go back in time and kill their own grandfather before he met their grandmother. In such a case, Effingham argues that the time traveller would have the ability to do the impossible (so they could kill their grandfather) even though those impossibilities will never come about (so they won't kill their grandfather). He then explores the ramifications of this view, discussing issues in probability and decision theory. The book ends by laying out the dangers of time travel and why, even though no time machines currently exist, we should pay extra special care ensuring that nothing, no matter how small or microscopic, ever travels in time.

The topic of time travel provides tantalizing conundrums to consider for STEM experts and sci-fi creators alike. Most scientists and mathematicians agree that time travel by humans is probably impossible, yet they have not been able to offer conclusive proof. This book describes how the very nature of time remains a fascinating and complex subject, whether viewed from the perspective of Einstein's relativity or the nanoscale realm of quantum physics. Readers will recognize notable fictional works in literature, film, and television in which time travel serves as a useful plot device as well as a means of examining human history and contemporary social issues.

Presents the current understanding of the nature of time and space, and an approachable explanation of Einstein's theory of special relativity; then goes on to connect these to possible time travel along with the accompanying paradoxes involved.