Sci-Fi Science

Time travel has occurred in numerous science fiction films ranging from the classic HG Wells "The Time Machine", to the excellent television show Doctor Who. Usually when time travel appears in Sci-Fi there is very little description of how it's actually being done. In reality, time travel is not impossible - you're doing it right now, moving through time at a constant rate of 1 day every day. The science of time travel is complex.

So, where do we start? How about time? What is time? The Oxford English Dictionary defines time as "a limited stretch or space of continued existence”, or “as the interval between two successive events". We glance at our wristwatches and notice the second hand slowly counting the passing seconds. We are in our own time machines: Our hearts are pumping blood, we're breathing; we are existing through time (at least until our own personal time machines seriously malfunction).

What are the possibilities of moving through time at a rate different to one day per day? Common sense tells us that it's all nonsense - time travel is impossible. However, common sense is not always such a good guide. Some hundred years ago common sense said man could never fly; now we travel all over the world.

The commonest objections to time travel are the so-called paradoxes. For example, if we could travel through time, imagine what would happen to a time traveller if he (or she) travelled back in time and killed their own grandmother at birth. In theory the time traveller will therefore never be born, so the journey could never have been made in the first place; but if the journey never occurred then the grandmother would be born which means the time traveller would have been born and could make the journey ... and so on and so on. This is a paradox.

There are two possibilities to resolve this paradox. The first is that the past is totally defined, i.e. everything that has happened or must happen, including the time traveller’s attempt to kill his grandmother, cannot be altered and so nothing will change the course of history. In other words, the time traveller will experience endless "mishaps" in trying to kill their grandmother and will never achieve the murder, thus keeping time (or at least events) intact.

The second possibility is more complex and involves the quantum rules which govern the subatomic level of the universe. Put simply, when the time traveller kills their grandmother they immediately create a new quantum universe, in essence a parallel universe where the young grandmother never existed and where the time traveller is never born. The original universe still remains. Stephen Hawking believes he can explain the origin of our universe as a variation of this parallel worlds theme.

Having explained these paradoxes how does one travel through time? The secret is to travel at speeds close to the speed of light. The main text of the web site explains this in greater detail. The obvious problem with travelling very near the speed of light is that as you approach C (the speed of light) time slows down until at C time stops. How can you go faster if time has stopped? The answer involves a complex process called quantum tunnelling and is discussed at length in the main text of this web site. Then once the velocity becomes greater than C time moves backwards and the traveller has entered the realms of negative time.

We now know that the theoretical evidence for time travel is considerable. There is, however, one question we have avoided until now. If time travel is possible, where are the time travellers? There are a number of possibilities. The most obvious and pessimistic of these is that life on Earth may simply not survive long enough for the technology to evolve. Nuclear wars, giant asteroids smashing into our planet, quantum instabilities developing within the Sun etc. could all stop mankind (or any other race) in its tracks.

Yet the absence of time travellers need not indicate anything nearly so sinister. It is possible that they have been here, and are here right now, but have been discreet about their presence in order to ensure that they return to something closely approximating the future universe of their departure. A further possibility is simply that none has arrived in this particular universe! Many conspiracy theories are based on the possibilities of time travelling aliens having the ability to control all world events on Earth while managing to remain completely hidden from our view. The CIA may be stranger than you think.

So to summarise, we have seen some simple ways of travelling vast distances and have noted some of their drawbacks. We have also looked at some of the more exciting possibilities, but some more real break-throughs are required. New mathematical methods need to be developed and new physical models of the universe must be conceived. Not a job for the faint hearted! Fortune it is said favours the brave. Nowhere will that be more true than in the race to understand the ultimate laws of physics. The race that achieves that first will go straight to the top of the premiership of civilisations. Lets make sure it's going to be us!

		THE TIME TRAVELLER: ONE MAN'S MISSION TO MAKE TIME TRAVEL A REALITY (BOOK) Prof. Mallett is a real, world known, scientist and this book comes highly recommended.
		PHYSICS OF THE IMPOSSIBLE: A SCIENTIFIC EXPLORATION OF THE WORLD OF PHASERS, FORCE FIELDS, TELEPORTATION AND TIME TRAVEL (BOOK) Michio Kaku takes us through an excellent description of Sci-Fi science. This comes highly recommended.
		TIME TRAVEL IN EINSTEIN'S UNIVERSE (BOOK) This amazing book makes difficult scientific concepts accessible to the layman through analogy. This is not just a book for sci-fi film fans, however; anyone with a general interest in science will find it rewarding. The theories and ideas presented here are often extremely complex but this is nevertheless an exceptionally readable and enjoyable book
		TIME TRAVEL FOR BEGINNERS (BOOK) John Gribbin is an internationally successful science writer and broadcaster whose many books for adults include In Search of Schrodinger's Cat, Almost Everyone's Guide to Science, Q is for Quantum and Science: A History. His wife Mary is a teacher with a special gift for communicating difficult concepts.
		SCIENCE FICTION AND PHILOSOPHY: FROM TIME TRAVEL TO SUPERINTELLIGENCE (BOOK) A timely volume that uses science fiction as a springboard to meaningful philosophical discussions, especially at points of contact between science fiction and new scientific developments.
		A BRIEF HISTORY OF TIME: FROM THE BIG BANG TO BLACK HOLES (BOOK) Stephen Hawking wrote the modern classic A Brief History of Time to help non-scientists understand fundamental questions of physics and our existence. Among the topics covered are gravity, black holes, the Big Bang, the nature of time and physicists' search for a grand unifying theory.
		THE ILLUSTRATED BRIEF HISTORY OF TIME (BOOK) In this revised, expanded and illustrated edition of "A Brief History of Time", Stephen Hawking includes the most recent developments in the field of cosmology, many of which were forecast by himself. The "big bang", "wormholes", black holes, particle physics, the vastness of intergalactic space, and matter and anti-matter are introduced.
		EXPLORING BLACK HOLES: AN INTRODUCTION TO GENERAL RELATIVITY (BOOK) The goal of this unique book is to provide the tools for readers to become active participants in carrying out their own investigations about curved spacetime near Earth and black holes. Five chapters introduce basic theory and seven projects guide readers in the analysis of major applications.
		THE EDGE OF INFINITY (BOOK) In the past, they were recognized as the most destructive force in nature. Now, following a cascade of astonishing discoveries, supermassive black holes have undergone a dramatic shift in paradigm. Astronomers are finding out that these objects may have been critical to the formation of structure in the early universe, spawning bursts of star formation, planets, and even life itself.
		BLACK HOLES AND TIME WARPS (BOOK) Ever since Albert Einstein's General Theory of Relativity burst upon the world in 1915, some of the world's most brilliant minds have sought to decipher the mysteries bequeathed by that legacy. This volume is a history of Einstein's ideas as they made their way through the increasingly political world of science.
		OUT OF THIS WORLD: UNIVERSES, BRANES, STRINGS AND OTHER IDEAS OF MODERN PHYSICS (BOOK) After introducing general relativity and quantum mechanics - the twin foundations of 20th-century physics - he explains how these two theories simply cannot both be true. Then, in a series of chapters, he introduces us to the seemingly outlandish and bizarre ideas that astronomers and physicists have come up with to account for this apparent theoretical inconsistency.
		PARALLEL UNIVERSES: THE SEARCH FOR OTHER WORLDS (BOOK) Explores the degree to which a belief in parallel universes shapes the thinking of contemporary physicists in areas as diverse as relativity, psychology, quantum mechanics, and cosmology.
		COSMIC TIME TRAVEL: A SCIENTIFIC ODYSSEY (BOOK) A fascinating examination of the possibility of time travel and the scientific breakthrough that may make it happen.
		FASTER THAN LIGHT: SUPERLUMINAL LOOPHOLES IN PHYSICS (BOOK) A highly recommended short read that discusses a range of theories for travelling at superluminal velocity and proposes a few good ideas.
		THE END OF CERTAINTY: TIME, CHAOS AND THE NEW LAWS OF NATURE (BOOK) The Nobel laureate and founder of chaos theory challenges the accepted laws of nature, explaining why Einstein's belief that time is merely an illusion is incorrect.
		BLACK HOLES, WORMHOLES AND TIME MACHINES (BOOK) It begins with simple ideas in geometry and describes what Einstein's theories of relativity are about and how they have been used to understand the universe and some of the exotic structures it may contain. This book is aimed at readers who do not have a background in science but who are interested in the answers to questions such as: what was there before the Big Bang; what does the inside of a black hole look like; does the universe have an edge; do parallel universes exist?
		LORENTZIAN WORMHOLES: FROM EINSTEIN TO HAWKING (BOOK) Wormholes, spacewarps, timewarps and time machines have permeated popular culture. This technical monograph looks at the science behind the science fiction, covering the history and theories of wormholes, spacewarps, and time travel.
		UNVEILING THE EDGE OF TIME: BLACK HOLES, WHITE HOLES AND WORMHOLES (BOOK) An updated look at black holes chronicles their discovery and formation and offers two known ways for humans to build a time machine using the laws of physics.