PAST AND PRETENSE

Chapter 3: Using and Understanding Science Fiction Nomenclature; time travel problems in Science Fiction by: G.F.WILLMETTS

'What will be, will be.'

Time travel fascinates both Science Fiction writers and readers alike. It comes from a desire to do something outside the known rules of the universe and our current technology.

The popularity of such TV series as Doctor Who, The Time Tunnel and Quantum Leap and films like The Time Machine, Millennium and the Back To The Future trilogy indicate a fascination with seeing the past or the future.

Interestingly, all of these, not to mention SF stories, have their own take on achieving time travel. Man is capable of entertaining the notion and often prefers travelling into the future than into the past.

In films, there is a tendency to have people from the future to enter our present because it is more economical on the budget; not to mention giving a different perspective on our current problems. Time travel stories into the past have to balance what people have learnt from history books to how life was probably enacted.

As observed from our own current history books, life is remembered with a certain amount of prejudice and censorship that is taken for truth. The future can be regarded as a cleaner block to extrapolate on.

Current SF writers tend to be more pragmatic to futuristic conditions than presenting simplistic, noble or purely decrepit places. 'Realistic' journeys into the past requires extensive research for realism plus reaction of the time traveller to the conditions.

Journeys back and forth have to account for time paradoxes. The mechanism of time travel and adjusting to the time period are rarely examined. I'm not claiming I have all the answers in this chapter, but will exploring and address some of the possibilities and problems.

Time travel, as Chapter 2 indicated, is possible under what we currently know about the universe. As a spacecraft approaches the speed of light, relativity indicates that local spaceship time will be slower than external universal time.

What could be a matter of a year in a spacecraft could be a couple centuries of external time. A round-trip would thus have you returning to a future time on Earth without aging drastically. Unfortunately, it's a one way trip as you could not do the reverse to return to the past.

Further accelerations only push you further into the future. There is no such thing as negative acceleration to push yourself back into the past. Acceleration and deceleration are all parts of the same effect and definitely relative to where you are.

You go forward or stop. Deceleration just slows you down to a stop. Even if it was possible to remain immobile in a stasis time field, the rest of the universe would continue forward.

Even the possibility of using a black hole's event horizon will only propel forward. Time is a forward one-way lane as far as all current observations have shown.

Don't confuse negatively-charged particles, like electrons, with an idea that everything has an opposite or reverse effect. Velocity is simply a linear, or one-way, effect.

Having said that and practically debunked most time travel stories that relied on negative acceleration or other methods to move into the past, what is there really there that can be used that can look practical in Science Fiction? A story set in the future is really no different to any other SF story. The only difference is it centres on the time traveller adjusting to the new time period. Time travel stories per sec depend more on the ability to move around in time than just stay in one era.

Time travel is a complex issue with many questions and answers that can't really be answered in an orderly fashion without referring to some other point made earlier or further into this chapter. I make no excuses for this other than saying that if you can't keep track, then you're not likely to make a good time traveller, or writer of same, without a sick bag.

First, we must examine just exactly what the passing of time actually means. It's not the measurements of a calendar or a clock. All they provide is a convenient measuring stick for relative forward time movement. Telling someone you'll see them next Tuesday is usually easy to understand for most people providing they use the same calendar.

Without corrections to match the changing revolution of the Earth and other errors over the years, calendars are useless beyond a few past centuries. If, in the future, someone decides they've had enough of AD and want to start a new age based on some revelation or encounter, you would be equally confused as to your exact date.

For the present, time travel will be restricted to our own planet. True time can be based on the period it takes for the Moon to revolve around the Earth as the Lunar Month of about 29 days. It can be based on the period that the Earth takes to orbit our Sun, some 365º days or the Solar Year.

Neither figures are totally reliable as over the millennia, the Earth has been gradually slowing down. If you want to complicate things further, you can base your calculations on the Lunisolar period, taking into account both time scale periods with each other. Not much help if you want to explain this to the reader within the story. This is probably why many authors prefer to give it in current day terms they think the reader will understand.

Keeping track of time hasn't been easy since Man started to measure it. The Greek year was 354 days and to sort out discrepancies every 8 years, they had a year with an extra 90 days! In 8 BC, the Romans decided upon 304 day year spread over 10 months. The Julian calendar in 46 BC was decided upon by Julius Caesar under advisement to be based on the solar year and making it a 12 month year.

Every 4th year, an extra day was added to compensate for the extra solar º day. Under Augustus, the days of the month were adjusted to what we have today. Years looked like they were going to plan until a discrepancy of 11 days too much was discovered.

Pope Gregory decreed that leap years shouldn't be applied to any leap year that couldn't be divided by 400. Until the Middle Ages, April and not January was the start of the year. You'd be a fool to go back to celebrate the New Year on the wrong date!

If you were to appear in other parts of the globe, you might have to compensate for the Jewish, Egyptian or Chinese years that are based on the Lunar month.

The Mayan calendar was probably the most accurate, as they were using the solar year earlier than we did, and appears to correct from the beginning. Imagine having to set a computer to work on these rules to give a practical indication as to what time you appeared in.

It's not impossible but would certainly complicate matters if the program didn't match the physical evidence discovered. There would be a need for immense testing to compare local dating with temporal shift for any sort of pin-point date accuracy. Is it any wonder that the Project Tick Tock scientists in Irwin Allen's The Time Tunnel took so long getting the 'fix' for where their time travellers were?

On a geological scale, time is roughly measured by the decay of radioactive elements. The universe is structurally falling apart all the time. The isotope Uranium-328 breaks into Thorium and other radioactive elements over a set time period or half-life of 4.5 billion years.

The measure of this half-life can be determined from the amount of Helium atoms, suspended from the decaying Uranium, in the surrounding rock. That might be considered a good option until you have to look for a supply of Uranium-carrying pitchblende. Primitive societies wouldn't have a need for or know where to find you a supply to analyse.

The isotope Carbon-14 has a shorter half-life of 5730 years give or take 40 years. Used as a time scale, it would be quite possible to miss both this century's world wars.

The main advantage is Carbon-14's availability. It can be found in all living beings but tends to deteriorate or breakdown in anything that has died. Like Uranium, the time traveller would still need a small portable lab to analyse the material to determine a length of time and calculate the current local time based off this information. Such activities would have to be hidden from local inhabitants to avoid awkward questions that potentially would make you a warlock or witch.

If it were possible for time to become reversible, then it would be seen somewhere as an observable natural phenomenon. A reality with areas behaving like this would be like a spring with various elements reconstituting themselves and prime elements, like Uranium, becoming really abundant.

There would also be some other effect limiting the range, preventing it spreading throughout the universe otherwise matter would be continually sucked in. Unchecked, time would reverse to 'the Big Bang' and then presumably, with nowhere else to go, yo-yo back in the opposite direction.

We could be living in such a reality ourselves but this would not allow time travel independently of this effect. Considering the current estimates for the life of the universe, such a process would be very slow indeed. Being part of the effect would also mean we would be unable recognise let alone do anything about it.

All telescopic and spectral analysis of astronomical observations to date hasn't spotted any local effect like this. If such a phenomenon happened naturally, it would not be an isolated incident. Any such area would be instantly fatal to any living being as they would be reconfigured to their constituent elements and die. Whether such a field could be used but protect the person using it from aging is hard to say. It wouldn't stop the rest of time moving forward. To move temporally independently of our reality would require isolation from the universe at large.

Paradoxically, decay or entropy is the forward motion of our universe. It is the principle of cause and effect. You can pour water from a jug into a cup. If the reverse were possible, you would forget your own actions as well. A civilisation that is continually never going nowhere in this fashion would cease to exist. To go back in time by natural methods means reversing all the actions of the universe and there's no power source available capable of harnessing such energies.

All of this is important to remember if your time machine is based off of any observable natural phenomena. In recent times, Science Fiction authors have cited Quantum Mechanics and sub-atomic particles, like tachyons, for the ability to move in time. Tachyons have been noted as probably capable of moving faster than the speed of light, gaining mass only when they slow down.

This has led to an interesting hypothesis that if they are moving faster than our time's forward momentum then they must be moving into the past. This being the case, the tachyons we observe are already going backwards, we will never see any current tachyons. As they aren't affecting anything, tachyons continue their journey unhindered. Quantum Mechanics has noted some unusual properties of sub-atomic material but it will need something more substantial to make it useful for time travel.

Even if they could be used, there is no way an organic being could be reconstructed as tachyons to move with them. The mass is negligible and has few properties that compare them to atoms. Even if it was possible, you would still need some device to reconstitute your body. Whether a tachyon field could be used to project regular matter in time is questionable as any energy properties are slight.

Gregory Benford's book Timescape saw the movement of tachyons into the past as a means to send Morse code messages back to alert them of an ecological disaster and prevent it happening. Benford saw the now-lost alternative future as a pocket universe rather than being the real one that takes over. There are a number of interesting dilemmas that arise from such actions, assuming that Nature would allow it to work.

An action that would be seen preventing a disaster could also be used to cause untold harm as well, as it gives the ability to radically change history. It's like going back and killing the young Hitler might well seem a good idea, but would his replacement be any better in the long term? Would the replacement do just the same or far worse? Whether Nature would permit itself to be so radically altered is debatable.

Although Benford's book cites actions after rather than the message being received will change the future, the fact that the message is received will be the real starting point of deviation. If you wanted to be really cynical, such time manipulation would only be fulfilling destiny and the alternative future would still be valid as nothing would have changed to stop it happening. That relates more to the alternate reality theorem, discussed elsewhere in this chapter.

In All The Myriad Ways anthology, Larry Niven stated that a society that develops time travel would one day produce someone who would go back in time and prevent its invention. In other words, you would have a reality that would be continually un-inventing its own time travel devices. Would such societies fall apart from continually interfering with development? As indicated in Chapter 2, all inventions affect everything else in life. If such a device existed once, then it's likely it would exist again.

There is a hypothesis that space near 'black holes' is distorted. The hypothesis is that if space-time is distorted, then this would allow movement into the past or future. Should such 'wormholes' exist, then it is likely the gravitational forces would destroy the spacecraft. 'This is SF, I make the spacecraft strong enough to take the forces, what then?' Like all causality areas, you'd jump into the future not the past. Moving into the past would put your original trip in doubt if left in your hands to influence it. Acceleration will always take you forward not back.

I'm sure, if you think about it, there must be other oddities like this that could fit this pattern that could be considered. Lest one suggests the Bermuda Triangle and all the disappearances there, this so-called mystery is surprisingly easily resolved. Ships disappear all over the world, whether by storm or the odd whirlpool causes by crust rifts. This 'Bermuda Triangle' is one of the busiest converging shipping lanes and aeroplane routes. All things being equal, the proportion of loses must also be greater. Using such areas for time travel was really done to death in the 70s.

Like with hyperspace, it has been hypothesised that there are folds in time where people can temporary shift back. I don't really believe that since such warps would work with anyone who wandered over them. Those who have encountered such time fluctuations may be seeing the past but unable to interact with it.

They are more likely triggering past-event energies unreeling before them. It is from such things some people can encounter past ghosts or events. You can view but can't touch. As such, it shouldn't be regarded as time travel. It can also be rationalised scientifically without switching genres.

Many cautionary Science Fiction tales depict the future societies of Man as likely to be falling apart from its own excesses. Personalities fade and our responses predictable. A lack of stimulation to enrich our lives. Can you honestly see that happening while free thought is allowed and for radicals of any culture allowed to influence others? Oppressive governments tend not to last for more than a generation or two before being over-thrown. Time travel stories are reflections of the period they are written, either wanting a good or bad future.

Such themes in Science Fiction are rarely carried out with any basis in reality. They are played out with the renaissance man addressing society values for comparison of how good or bad societies differ from each other. True, this kind of examination has also been done from an alien point of view, but only as a society dissection not as a comparison. Rarely are the consequences of any changes viewed after the initial intervention.

It is for this reason that time travel is seen as a thinly disguised examination of current standards. To do so in terms of less than fiction, let alone Science Fiction, is likely to face possible condemnation or death threats in the case of author Salmon Rushdie when he wrote The Satanic Verses.

By disguising the issues, the Science Fiction author believes a significant portion of readers will realise what is being got at and do something, not necessarily what he believes, to adjust their perceptions of society. Whether this is considered egotistical or not depends entirely on how many people are strongly influenced by the fiction they read, let alone act upon it.

This isn't so impossible as it might seem. The 'Big Brother Is Watching You' slogan from George Orwell's 1984 is embedded in western society's conscience about how government is watching you, whether people have read the book or watched the film. Such cases are only triggered when there is a mutual understanding between author and population that transcends the original medium and strikes a recognised nerve. With the way police and security camera populate our streets, 'Big Brother' has slipped through the door. Whether anyone will exercise it for political control may no longer be an Orwellian fantasy.

Although 1984 is not a time travel story, its themes have been carried over to time travel stories reflecting oppressive or observant societies and many authors have used Orwell's vision for their futures. Placing a renaissance man in such a situation suggests that the present man can change his own future sub-textually.

Would this work for real? As our future is always going to be uncertain as to what it will look like, let's compare the effects of taking an early 20th century man to our present. New technology. New fashions. New cultural taboos. Re-arranged prejudices. A lot to learn and adapt to. I'm barely scratching the surface. This is all within the space of 90 years! Would he adapt to the changes or create enough interest to change culture to his way of thinking? More likely, at most, he would cause a fad for a few months before something else surfaced to take its place. I doubt if there would be an overall effect simply because there would be little that would be regarded as distinctively influential.

If the man was famous, like Thomas Edison or a young Ernest Rutherford for instance, then their science would definitely be an anachronism. Morality would be inflexible to regimes these days that tolerate homosexuality and sorting out racist, although likely to appeal to certain extreme left or right politically-based people. Cultural changes are so rapid these days that any old moral stance won't last very long. There is also a worse dilemma in that neither gentlemen would be allowed back to their own time with what they'd learnt!

Think now of transporting a present man into the future and compare the situation. Where will mankind be in 90 years time? Science Fiction invariably places time travellers much further into the future and authors spend more time showing us how close it is to today. The concern is with failing development rather than the time traveller fitting in with his new and possibly better environment. It either indicates how bad we were or how bad we will become.

Man has shown himself progressively more refined in many ways as the centuries pass. He's become a more effective efficient killer which is unlikely to change, no matter what depiction of Buck Rogers represented. With the ability to travel anywhere in the world, Man is now a global animal. In the future, budget permitting, this will no doubt eventually continue out into the Solar System. We are more adaptable than someone from the turn of the century but there is no anticipation for cultural shock. There is still the likelihood of being a 'fish out of water' for the most open-minded person.

A primitive century man would be a curio rather than a prime mover. Even if our future heirs lead, what is to us, decadent life-styles one displaced individual would make little difference. Even political radicals fail when the majority of the people won't back them. It would need more than a handful of people supporting it but a large proportion of a nation.

This is an important consideration bearing in mind how many stories have been written on this theme. How can an ancient man do anything significant in such a future? He would be seen as a political rabble-rouser and either isolated or killed should he lead any sort of revolution that the majority of people would not want.

Martyrs do change the world but the effect of a renaissance man or woman is less likely to change everything in a society. The time traveller would be sensible to keep his mouth shut about his origins. People would, assuming he was believed, be more interested in how he got there then what he had to say.

If it was possible for someone from the future to come to the present, there is just as much likelihood for cultural shock even if they are expert on our time period. It would be in reverse. No convenient technology. Quaint out-dated customs. The time traveller from the future would be equally out of place. Adapting to the new time would also take...er...time.

For the most part, time travel in Science Fiction is a convenient metaphor. A means to tell readers about an unusual society from a current Man's view point. This 'unusual society' tends also to be a heightened allegory of some aspect of our current society. As such, time travel stories are not expected to be viewed under quite 'realistic' terms as other SF stories. It's a pity, as there is a wealth of story possibilities that have yet to be explored in this sub-genre. This is all side-tracking from the main issue of how to achieve time travel in a plausible fashion. Social and political order will be explored at some depth in Chapter 10.

It doesn't take much thought to create a time machine in fiction. A few words with possibly a brief technical explanation and new sub-atomic particle or science rule designed to baffle everyone and it exists on paper. This allows anything from the creation of extra-dimensional space to using advanced available alien technology. Who's going to doubt you? Your guess can be as good as the most respected scientific minds of our century. Whether it is plausible or not depends on how you address the problems of not only the time machine but in how you act in the future and especially the past.

The lack of mechanical devices or natural phenomena for time travel, shouldn't prevent alternative methods being used. With Science Fiction being the idea genre, this is an ideal place to imagine how to go about doing something that can't be done. The Trancers film trilogy employs mind transfer replacement into the body of an ancestor rather than rely on any physical transfer. Such actions mess up time when the ancestor gets killed earlier than expected, wiping out an entire family line and ignores the effects on the rest of the reality.

Richard Matheson's novel Bid Time Return (filmed as Somewhere In Time) depends on the time traveller believing himself into the past. If such a plot device were possible then the past would be full of future people with the desire to live in a period they think will suit them.

Films and television exploit the element of time travel far more than any other sub-genre of Science Fiction. It's easier on the film's budget on the whole, especially if futuristic time travellers are visiting our time, and is something that can quickly be explained (?!) without loosing the interest of the viewer.

Modifications to the short story Vintage Season by C.L. Moore and Henry Knutter resulted in the film Timescape (UK title not to be confused with the Benford book. US titles: The Grand Tour (1991)/Disaster In Time (1992)). Here, future time travellers journey into the past to observe catastrophes first hand for the thrill. The film has a Hollywood happy ending, in contrast to the story, but manages to retain the message that nothing stays the same forever.

Apart from having to work out what time period you have arrived in, the time traveller has also to be aware of spacial co-ordinates. The universe is expanding while the Earth is revolving around the Sun. If your Time Machine does not move spacially as well, you will appear in vacuum, light years from anywhere. Anchoring yourself to the ground and move back in relation to where you are is likely to affect the surrounding area. Your time travel field needs to be isolated from current reality but capable of moving relative to it.

Do you turn back the time of the universe or step away from it in some way as the TARDIS does in Doctor Who? From an energy conservation point of view, the latter option uses the least energy and escapes our universe's rules. As suggested in Chapter 2, hyperspace would be a convenient place for isolation and with reverse rules taking effect.

If it takes the combined resources of a couple nations to create a spacecraft, it would take that of a world to work on such a time machine of such a magnitude. Politically, it would be the biggest debating point ever for committing someone to time travel. It would not be a solitary scientist's invention.

For your own safety, it would be convenient to have the time machine as part of a spaceship capable of travelling to your destination when you arrive. It would probably be wise not to appear directly on or in your destination. Such a journey should not be too long or time would be wasted. Your situation will probably be worse as there will be no indication as to what time period you have arrived in.

Assuming your time travel machine is mechanical in nature, you're going to be a long way from spare parts if anything goes wrong and the technology isn't advanced enough to make replacements. This theme has been applied mostly in SF films, like the Back To The Future trilogy, since viewers easily recognise the problems of devices breaking down. Time Machines capable of generating vast amounts of energy are hardly likely to be as inconspicuous or resemble a police call-box or a DeLorean.

Where one time machine was made, a second can also be constructed for rescue. A device or material not prone to decay could be left in a suitable place to be 'discovered' in the future.

If this option is chosen, then the location of such a device would have to be somewhere known but not previously explored, lest it violates cause and effect. If the recording device was discovered before you left, then the problems you are going to encounter could be sorted out before you go, so why would you leave the device anyway? Would you leave knowing things are likely to go wrong? Would this knowledge influence what you would do in the past? More likely the message won't appear until you go back to make it happen. People from your present won't know any different until the event happens. Reality will work to maintain the natural order of causality.

All of the above may appear to give insurmountable problems. You might even be looking to me to solve your problems for you. That being the case, my rates are quite reasonable and I'd like payment in advance. For this chapter, it should be enough to point out the loopholes and some possible alternatives without having to necessarily follow any particular idea that I might be favouring at the time of writing this chapter.

Before we go any further, we need to again address just exactly where we are, relative to where we originally came from. This has nothing to do with local time but as to how time can be described from the time traveller's point of view. Saying we are in the past or future is relative to where we came from.

What we normally define as 'past', 'present' and 'future' are only relative local-time terms. You move in time and what was your present is now your new time period's future. Their present is your past. The present you came from is their future. The only thing you might agree upon is that anything before your and their current present is now the past. Current terminology cannot take this into account in defining the time traveller temporally to where he or she is.

Many years ago, I came up with one possible solution. I'd be the first person to admit it's not perfect, but until a time grammar is established, this might well do for the present and our current language. Relative time is measured based on the 'When'. 'Where' doesn't really cut it because it's only an indication of where you've been and, in most cases, is still a common element to time traveller and those who live there.

The 'When' applies to the existing time. It suggests a future event but can at least be made applicable in most time instances. A 'When' is always on the point of happening. If you are in the past, the future-when hasn't happened relatively yet. Events are always in the state of 'when it happens'. It applies more to the time traveller than those in any particular local time period.

The 'Present-When' or 'Now-When' is where you are at the present. If you can travel into the past, then you are in a 'Before-When' or 'Past-When'. Move forward in time, and you are in a 'Future-When' or 'Later-When'. It should make it possible to say, rather straight-faced, 'I'm fifty years later-when than I started.' Other variations like 'Up-When' or 'Down-When' can also be used, although this sounds like you're in an elevator.

Should time travel become possible in our reality, then someone might come up with a better choice or you might have some better notion yourself. Whatever the choice of words, always ensure its usage rolls off the tongue comfortably - awkward words won't enter a regular vocabulary easily - nor take account of wherever or whenever you are.

Travelling into the past or the Past-When, even if possible, causes all sorts of problems. If you are discovered and publicly believed a time traveller, then it would create a state of panic or confusion in the population. No matter what anyone did, the belief that you were going through a pre-ordained life-cycle would always be in the back of your and their heads.

You would attempt to second-guess every decision you ever made as to whether it was a good judgement or to do the opposite in an attempt to shake up your own destiny. Alternatively, you might be more reckless and do whatever comes to mind first believing it to be the right decision. If it is, then life would be forever predictable. The chaos this would cause would risk destroying whatever future the time traveller came from, assuming that it could not be changed.

Suppose you were wrong. If your future did not exist, then how did you return to the past to cause the problem in the first place? This has had far more problems than just accidentally or deliberately killing your grandfather or any close relative and stopping yourself being born. Any event could stop you being born. This has led many to believe that time travel into the past is impossible. Whatever constitutes reality will prevent you affecting events whenever you arrive, unless of course, you are part of the unfolding events and have returned to fulfil this vital role.

This make pre-destiny viable but unlikely for you to do anything that will prevent your own creation or your Future-When. It also suggests that if a certain role is going to be carried out, then someone else or maybe another time traveller would be appropriated at the right time to fulfil these actions.

This is also an old idea that has been widely explored by many Science Fiction authors as well as several well-known films and TV series. The problem then lies with whether you are aware of what you are doing, who you are supposed to be and what you are supposed to achieve. Until pulled out of a particular time-period, there may not be any awareness of the contribution the time traveller is making. In books, the time traveller replaces a significant person who either dies accidentally or clearly does not have the knowledge, talent or insight to do what is expected of him or her.

A time traveller from the future tends to have certain skills likely to make him superior to anyone in any Past-When. Whether such abilities extend to the self-sacrifice such a replacement could be, remains to be seen if carried out in our existing reality.

Such actions would be regarded as fulfilling the needs of reality annd might well be the only reason time travel becomes possible, and then for a limited time. Whether the nature of the universe could be regarded as sentient enough to make such a decision is always open to debate.

In the TV series, Babylon 5, Ambassador Jeffrey Sinclair is delivered into the past to complete the prophecy and becomes the Minbari war-leader Valen. He knows that whatever decisions he will make will be the correct since he already knows that Valen's decisions brought victory in the Great War. Such knowledge can lead to complacency or worry about any decision being made because no matter how wrong the choice is, that is what would be required to happen. Nature will not allow any other option in multiple choice. Time travellers carry a heavy burden on their shoulders.

What this sort of experience should demonstrate is that time or nature will work to fulfil the required actions. Whether this is having a messiah or inventor at the right time, whatever governs the time stream will allow it to happen if it is going or should happen. If it didn't, you'd be hard-pressed to justify how a displacement of a mass from the future could exist in the past. I doubt if there is any regulatory body keeping a count of the total number of atoms in the universe, let alone removing the excess when discovered.

The longer a time traveller is in the past, eating, digesting and excreting his future atoms - that will no doubt find a way back to where they belong - the more his body will belong to that time period. Restored to his original Present-When is likely to have dire consequences if his old atoms cause his body to age the distance travelled in time. It might not, as the past atoms might also migrate as atoms of the present-when are digested. Premature aging by time travel would depend entirely on the means of temporal movement rather than what your body is composed of.

As the 'Killing Your Own Grandfather' hypothesis was raised, the past couple of paragraphs should have given some possible insight to the solutions available. As it's been a great talking point in SF circles for so long, this chestnut needs to be examined further. Let's assume we have the most ardent psychopathic time traveller willing to kill his own Grandfather. His actions would destroy his own life and certainly affect the future of anyone he was connected with. From what is said above and the time traveller is alive, he could not have killed his Grandfather. Reality would work to prevent such disruptive events happening. But, there is always, that 'But, what if...'

Let's kill the Grandfather. This opens the option that the man you thought sired your father wasn't the man you thought did the deed. Your Grandmother could have been embroiled in an adulterous affair and your father was the result. She could have already been pregnant. She might have been able to go to a sperm bank. Reality wins with nothing significant changed relating to your own existence, although one of your relatives would no longer be there. You might get some guilt over killing the wrong person, who would probably have died anyway since he wasn't your Grandfather.

A different slant on this and the time traveller takes his Grandfather's place - appearance-wise, they could look very much alike - resulting in you siring your father who sires you. A crazy bit of in-breeding but would explain your own psychopathic behaviour. Reality still wins by completing the loop. Nature adjusts to fulfil the gap. Whether this is regarded as pre-destiny or the universe is obliged to go through a series of events in a particular order will always be open to debate. I'm not going to make work for everyone by laying any opinion on this in cement. Most solutions have a way of looking logical and have been attempted in fiction.

You could still exist after killing your Grandfather since you were no longer part of the future where the later events happened. Some think you would simply vanish but as you are already there and done the deed, vanishing might restore the original time.

While we're in the process of sorting our hypotheses', let's not forget the Alternative Realities Theorem. This idea was devised to cover all eventualities. Essentially, for every decision made, there is an alternative reality formed covering the other choices you could have made. Killing your Grandfather channels time in two directions. You would create another divergent reality that will accept any changes made and create another divergence and preserve your own time.

You can return to your own future without destroying your own reality and your own Grandfather would have still sired your Father. Things would be exactly the same as when you left and nature would still be satisfied, except for this extra diverging reality. Here you would not exist and probably most of your bloodline. Ultimately, you would not have changed your own past. Reality wins again.

In theory, that sounds fine but leaves a big open question as to where does the energy and matter come from to create these co-existing alternative realities? Once something is changed, it stays changed and creates a paradox of why you're still alive. Active time travellers would be forever creating alternative realities. Such decision-making would not be confined to the people of one planet, but to any sentient being and every atom in the universe.

Decisions would not be just a simple yes/no choice but also for a variety of options. Heidenburg's Hypothesis applied to this reminds us that the observer, or time traveler, will also be affected by his actions. The divergent realities would also create yet further divergences based on the multitude of decisions made for each alternative. It would be a mess that no cosmic accountant would like or want to sort out. All this would be on top of divergences that would be going on all the time. In effect, the time traveller could also end up walking through a route of divergent realities that fits his actions.

Many have chosen to believe Quantum Physics would allow multiple realities to exist but I think that's more of a convenient available choice because so few people really know much about it. In a lesser-enlightened age, atomic energy was also viewed as the be-all and end-all for solutions. Saying something is so without the necessary information to back it up still leaves it nearer fantasy than Science Fiction. Time Travel, in an SF context, requires consistency in how things work.

If the Alternative Realities Theorem worked, it would follow a logical orderly fashion else all our reality would be would be just one from many many many. As the aforementioned Larry Niven raised in All The Myriad Ways, you wouldn't care what you did because some other version of you would do the right thing anyway. Reality, from all observations, tends to work in an orderly fashion.

It would attempt to keep the number of alternatives under control. Most choices made are likely to cancel each other out. A minor decision is hardly likely to affect the overall reality and thus the minor alternatives will merge back together again. It would take a very significant event change for a radically different alternative reality to sustain itself and break from the pattern. Personally, I don't think there would be too many as a shift in a grain of sand to the left instead of the right isn't likely to snowball into a significant event. Napoleon winning the Battle of Waterloo is likely to have a significant snowball effect which would create a separate reality that might eventually condense with other alternatives.

Even by this process, there would still be a multitude of alternatives and alternatives of alternatives. It's also possible that many might still be minor alterations that could still revert back to whatever might constitute what could be the correct overall reality destiny plan after these divergences. By being part of these alternative realities, we are hardly likely to notice what is going on. Such continual merging must yield a remarkable amount of free energy from nothing at all at some point. If it was detectable then it might be usable.

For the aspiring SF writer, this sounds like a grand scheme of things that will enable all things to be possible and attribute his story universe to an alternate reality. The problem is that most SF stories are set in alternative realities as most of them use alternative science rules or significant changes that have no bearing on our own reality without going through a song-and-dance of alternative realities.

The only real time this makes any difference is when you create a situation where characters can cross between the realities and can see the differences between their own and where they currently are. The main two examples of this are Alternities by Michael Kube-McDowell and the TV series Sliders.

Both give the liberty to allow changes to be made to these alternative realities without really damaging the one you originally came from. Neither actually explore the total ramifications of further divergences caused by their characters' actions.

Creating an alternative reality in this fashion is the nearest thing any writer has to playing God. When it comes to having people travelling across a multitude of realities, this 'God' has a nasty habit of being a devil in disguise, spreading mayhem and disaster.

All good story elements in themselves, but does little to explain why there should be so many alternative realities being created if at all. If such realities were continually being created and nature permitted passage, some natural phenomenon to bridges the alternatives would exist long before a mechanical device could be created.

Allowing bridges between realities is likely to compound the problem and Nature is likely to conspire to prevent this happening unless it was pre-destined, i.e. a set of alternative realities that have to be affected by people moving between them to restore order. If nature creates alternative realities then it will preserve itself throughout.

Using our reality as the example there are some things that need reminding. The universe prefers the least effort in doing anything. The first law of Thermodynamics and the Conservation of Energy, that has yet to be disproved, states that although its form can be changed, neither matter or energy can be destroyed. If the supply of energy and matter is so limited, where does the energy source for alternative realities come from?

A change in the past affects the future. End of story. The second law of Thermodynamics states that entropy works towards creating an equilibrium in an enclosed system. Take this as the universe as a whole, then the energy source for alternative realities would not be the home reality.

Are we to assume that there are higher dimensions (whatever that means. Is there anything beyond the finite width, height, length and time?) with their own supplies of matter/energy waiting to change into alternative versions of our reality? This has the same sort of vanity about it that has Man believing he was made in the image of God about his importance in the universe. Under such restrictions, Alternative Realities would never happen.

Leaving you to ponder on temporal mechanics for the moment, lets investigate further your situation should you appear in your immediate past. Providing you remain unobtrusive and don't stand out in a crowd, the opportunity to look around at old sights and stir memories of what it used to be like might sound appealing.

From a practical point of view, period dress and having the correct local currency would be essential in any deliberate time journey. Returning 30 years into the past of most countries will cause you great problems of explaining, in present slang, the funny money, and its dates, you're currently using. Worse, carrying easily recognised fake currency will also cause similar confusion if discovered. Not only will you have to explain counterfeit currency, you risk imprisonment or death.

A seasoned time traveller would therefore elect to carry something that can easily be traded than local currency. On Earth, this would probably mean precious jewels or gold, but not too much or people will suspect you of being a thief.

Precious metals, unless shaped into jewellery, are likely to raise questions as to how it was obtained, especially if it doesn't match your appearance. It would also be equally essential to know where such items can be traded without raising too many questions, being killed or robbed.

Having something to trade is useless unless there is some familiarity with the local dialect, language or people. The further back you travel, the more radically different the language becomes. In The Doomsday Book by Connie Willis, time traveller Kivrin is equipped with an internal language translator, rather than rely totally on what she had been taught, and wrist bone spur audio log.

This book is also of importance in noting the dangers of taking illnesses into the past as they can just as easily affect an earlier time-period as their illnesses moved to the present. Ensuring all the relevant inoculations for anything encountered. The people, lacking suitable inoculations, in the visited time period are in far greater danger than yourself.

An out-of-place stranger might well be killed for being different, a bad omen or sorcerer. As such, the use of any futurist device should be avoided at all cost. They can hardly be forbidden because such a means got you there in the first place. Such devices should be concealed or disguised so as not to draw attention to themselves.

Since the atoms that make up your body are not the same as the younger version of yourself, there shouldn't be problems co-existing with yourself. Would you want to meet an earlier version of yourself? Would your youthful version recognise you as the adult version? People's idea of their own appearance is from mirror images - in reverse.

It might not occur to the younger you, who you really are. You might be thought of as a distant relative but that may not dwell or be remembered by your younger counterpart as you only have vague recollections yourself. Nature is also likely to act to prevent the younger you making the connection until the older you does so and keeping time in order. After all, you don't remember meeting yourself but only someone with a passing resemblance. It only becomes really apparent when the adult you goes through the motions.

The chances of two closely-matched versions of the same time traveller meeting and aware of the situation would be remembered by both if it occurred. The temptation to give advice from either version is likely to either confirm or disrupt the existing meeting. As the events take place anyway, it won't make any difference, but it might.

Could multiple future selves of the same time traveller visit and meet in the same time period? They might not be sharing the same atoms if sufficient time is allowed to pass between travels.

The problem lies with remembering it has happened. The temptation to tell an earlier version of yourself to avoid certain actions could jeopardise your future, no matter how bad you feel it is. On the other hand, telling a younger version some advice fulfils your past, despite the fact you know the advice might not necessarily be carried out faithfully. Confused? A time traveller has to be flexible for all things.

None of the above problems are particularly new. Robert Heinlein addressed many of them in Time Enough For Love, particularly the last third of the book, and alternative realities in The Number Of The Beast. This does not mean you should follow Heinlein's route, but it should give you pause to thought regarding regular problems.

Still, why bother to go at all? It seems a lot of effort just to go sight-seeing from a historical perspective. It does allow a great opportunity to see and maybe record things as they were. Recording events from first-hand experience would be a historian's dream.

Bringing back evidence would be better, except the time machine might be too small to return anything significant or risk disrupting events. You could buy a long-term lease on some building, warehouse or disused cave that is unlikely to be torn down and store artefacts that can be preserved and collected when you return to your present-when. There is still a risk of them being destroyed but the odds would be more favourable.

In a toy nostalgia book I once read, I couldn't help noticing that there was an extreme lack of Mickey Mouse and Buck Rogers merchandise available considering how much was produced at the time....It just seems that most of it has vanished! Considering the minute amount of memorabilia that turns up in basements and attics today, this doesn't make much sense to say it was all destroyed.

People still find old comics but not so much memorabilia as was sold. Maybe, a future-when Mickey Mouse Club or more likely, a get-rich-quick dealer, decided they ought to go back-when and buy as many of these objects as they can or even buy them direct from the distributors' warehouses. I state 'buy' or the books wouldn't balance and it would be easy to discover that the items had been stolen. Reality hasn't been altered and their eventual destination has already been settled. Such insights might make it easier to locate the activities of a time traveller.

John Varley with his short story, Air Raid, that became the film/novel Millennium, addresses this problem in a clearer perspective. Time travellers from the future return to the past and kidnap people who are about to die in aeroplane crashes.

By doing this they don't violate the past events that would affect their own future. Considering how susceptible their future was to being changed, when their own gadgets are left in the past, these decaying-bodied time travellers might have considered changing their own future for the better.

On the other hand, this might have been considered playing the role of 'God', not to mention how precious they regard their own lives to be. It's a pity that the so-called 'time quakes' felt by earlier changes didn't show a change in their future period as the effect took place.

Although we've already looked at the future from being a one-way trip, a true time machine could visit the future and return if pre-destiny permitted it. The dilemma is now placed in the hands of the time traveller. Whatever knowledge he returns to his own Present-When, can be used to influence events that will take place from the moment of return. Arriving in the Present-When with vital information, the time traveller is 'accidentally' killed or robbed of his memory before he could tell anyone. Perhaps a time traveller from the future will come back to ensure his own future will not be disrupted by the earlier traveller's actions. The implications should always be considered on any action that could be taken.

Destiny is likely to weave its path in the route already discovered. It won't allow you to violate your own present with the knowledge of next week's football results or lottery numbers unless it's intended that you become a millionaire and decide luxury is better than time travelling. Whether using this knowledge is expected to be used to create the future unforeseen is something that can be speculated upon by any aspiring SF author.

I have always felt that the film, The Final Countdown's real story, behind the scenes, was that of Commander Richard Tideman Owen's rise as a technological engineering magnate that eventually would create the American aircraft carrier Nimitz that would take his younger self back to the past in the temporal distortion that completed his life-circle. His reluctance to change history was probably altered by the fact that events might not have been going the way he knew history until he started to intervene and then he started to shape reality the way it was. To correct that, to his knowledge, he would have been forced to act.

Time travel is invariably used as a means to get to an adventure far more than being the adventure itself. Science Fiction authors have long thought they have exhausted all the possibilities open with moving around in time. Rather than creating access to past or future times for a 20th century man to explore, it's now far easier to work with fresh cloth and create a new world that might or might not be populated by Man.

Throughout this chapter I have given constant reference to 'Nature' as a physical force. Many of you could interpret 'Nature' being a 'God' or some form of sentience life-form. Chapter 7 will clarify my own thoughts on religion. As you haven't got that far yet, I'll clarify this point here. 'Nature' or 'Reality' is the accumulated scientific laws - including those we know, can guess at and the rare odd ones we've yet to discover - that make our reality work as we see it. Although real science will be examined in more detail in Chapter 8, the only additional information needed here is that other than conditions, Nature is pretty much the same throughout the universe. If it could be disrupted too easily, time travel would be rife.

The SF writer needs to tread warily and with good reason in explaining the necessity for time travel. These days, it is not enough to simply want to do it on a whim. The consequences for disaster or improvement must be fully realised if your story wants to avoid looking hackneyed or like others in this sub-genre.

To create a new angle for purely time travel orientated stories is going to leave any author open to theme plagiarision should it become popular. For writing purposes, it would be essential to have the correct motivation to exploit such a device. Would it be people from the future visiting us or us to them? Why? Above all, consider all the implications of what happens upon arrival and prolonged stays. Time travel stories are always popular, despite few good ones existing. With sufficient thought an aspiring SF writer might well come across an idea that can set up a significant sub-branch of thought in Science Fiction. Time, for the moment, is an extended route into an unknown future.

This chapter will appear to be a downer as far as time travel stories go, if based on current knowledge and technology. Of all the chapters in this book, this has to be regarded as the least like Science Fiction, yet the second most commonly recognised theme connected to SF. This shouldn't necessarily mean a total rejection of the time travel story, just a recognition that care is needed if a tale utilising it is to be done well. It is important to recognise what has been written already and develop from it, rather than go over old ground. Time never stands still. Neither should Time Travel stories.

G.F.WILLMETTS

BIBLIOGRAPHY: If you're interested in reading or viewing (I'm an SF fan regardless of the medium) other time travel stories apart from those in the main text, try:-

• The Annubis Gates by Tim Powers
• Door Into Summer by Robert Heinlein
• The Forever War by Joe Haldeman
• The End Of Eternity by Issac Asimov
• Goodnight Sweetheart - BBC sit-com/drama
• Quest For The Future by A.E. Van Vogt
• Star Trek: City On The Edge Of Forever from a screenplay by Harlen Ellison
• Time And Again - Clifford Simek
• Time's Last Gift - Philip JosÈ Farmer
• Timescape - Gregory Benford
• The Uncanny X-Men # 141-142: Days Of Future Past - Chris Claremont/John Byrne

Science Fiction Nomenclature (c) G.F. Willmetts with the proviso of freedom to apply to stories you are planning or writing based on theories discussed that do not belong to other authors noted.

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