The Fiction of Time Travel
A history of key works and ideas in fictional Time Travel, with consideration from modern science. A big subject dealing with the very foundation of reality.
The Early Period : Myth and Folklore
Transitions Between the Worlds
The earliest tales involve a journey to another world, initially the home of the gods and later faerie, on return from which after a few days years have passed on earth. Examples are found in the mythologies of most countries, but especially India and Japan, where the folk tale Urashima Tarō dates to the 8th century AD.
Comment : The universality of these tales is strange and may represent a relatively common experience. It would either seem that time runs much slower in these domains (perhaps an idea that influenced Einstein’s Special Relativity) or that the domains are outside of our normal Time and so points of exist and entry are arbitrary (an idea later used in some science fiction in the form of a higher dimension outside of our universe, typified by the film ‘The Mothman Prophecies’).
Carried by Spirits
Later folk tales describe people being carried through time by supernatural beings, the best known example being Walter Map’s 12th century tale of King Herla’s trip into the future under the influence of a supernatural Harlequin. Such tales become more common in the early modern period such as in Samuel Madden’s 1733 ‘Memoirs of the Twentieth Century’, in which a time travelling angel brings back documents from the far future (which is ironically now our past). This device is found as late as 1861 in Pierre Boiterd’s ‘Paris Before Men’, where a demon transports the protagonist into the distant past, and of course in Dicken’s ‘A Christmas Carol’ (1843) with its time travelling ghosts. This seems to support the idea of a supernatural realm that exists outside of Time, whose inhabitants can enter or leave our domain at any point.
An interesting variant of this device is found in the tales of supernatural carriages that appear to be perfectly normal stagecoaches, but turn out to be able to travel through Time as well as Space, examples being an anonymous tale ‘Missing One’s Coach’ from 1838. Even the Tardis can be seen as a modern variant of this, and arguably any tale involving transportation via Chrononaut’s from the future or another world can be seen as derivative of these tales.
A third category of supposed ‘time travel’ involves the Rip Van Winkle device of the sleeper who awakes in the future, an old idea put to good use in William Morris‘ ‘The News From Nowhere’ (1890). But this is not really Time Travel as such.
Middle Period : Early Speculative Fiction
An intermediate period between these folklore devices and modern science fiction exists in Victorian speculative fiction. Here the format of a science fiction story is adopted but with little attempt to derive its concepts from science.
Examples would be Edward Page Mitchell’s 1881 absurdist tale ‘The Clock That Went Backward’ in which an inherited clock has the power to reverse time when it goes backwards (due to a theory of temporal non-duality superficially derived from Hegel’s Absolute), as well as Eugène Mouton’s ‘l’Historioscope’ , in which a window to the past is used, or Mark Twain’s famous ‘A Connecticut Yankee in King Arthur’s Court’ (1889), where a strange electric storm transports the protagonist back to the Dark Ages. Of course this also seeds our later Speculative and Science Fantasy devices as opposed to pure those of pure Science Fiction.
Later Period : The First Modern Science Fiction of Time Travel
El Anacronopete (Enrique Gaspar 1881 published 1887)
The novel, in the format of a musical drama, is the first to feature a machine that travels through time: the ‘anacronópete’ (‘that which travels against time’). The anacronópete is an enormous cast iron box, propelled by electricity, which drives four large pneumatic devices ending in tubes in order to travel, as well as powering other machinery, including something that produces the García fluid, which causes the passengers not to grow younger as they travel backwards in time. In the first act, don Sindulfo explains his theory of time: it is the atmosphere that causes time as demonstrated by the conservation of food in hermetic cans. By flying fast against the rotation of Earth, the machine can “undo” the passing of days. The book also includes a strong religious aspect including a time journey back to the Creation where the protagonists meet God!
Comment : In some ways a naïve theory (with ageing caused by reversible chemical effects in the atmosphere and the arrow of time linked to the rotation of the Earth) but in other ways insightful as many reverse time theories neglect the reverse ageing problem, and there is a grain of truth in the rapid flight theory, given Einstein’s Special Relativity, though the speed of light would have to be exceeded, something unlikely by jet power! This can be seen as a transitional novel between the middle period speculative fantasy and the later more scientific stories. Though where speculation ends and fantasy begins is a more tricky philosophical issue.
(The reverse time problem was later deployed in Philip K Dick’s 1967 ‘Counter Clock World’ and Martin Amis’ ‘Times Arrow’ (1991) where the consequence are both humorously and tragically explored. It could be argued such zones could exist in the universe or a spontaneous local time reversal might occur).
Gaspar was a close friend of the French writer and spiritualist Camille Flammarion, whose 1881 story ‘Lumen’ features an alien spirit who travels across the universe faster than light and recounts the histories of the various civilisations it had incarnated in. No time travel is involved but the story seems to have influenced Gaspar’s work.
H G Wells and Scientific Time Travel
Well’s was the first writer to apply a serious scientific thought to time travel although he didn’t take it very far. His most famous novel The Time Machine (1895), and its 1888 precursor The Chronic Argonauts, describes Time Travel in terms of Time as the fourth dimension, which we might move through as easily as we can the other three dimensions.
Comment : Today we know Wells’ was correct in his metaphysics, and in modern terms his theory would involve converting the Time dimension into something more like a Spatial Dimension which could be travelled in, in the same way we could rotate an object so its length becomes its width. Unfortunately this doesn’t appear to be physically possible because Time is a very different kind of dimension, being not only a passive flow in one direction (designated by the Arrow of Time), but also based on units of not basic integers but the square root of -1 giving it its odd properties. What that means ontologically is open to question.
Well’s scenario also presumes the future already exists in a fairly predetermined way, as is believed by those Physicists who hold to Godel’s Einsteinian Block Universe theory. But is the future open (as Quantum Theory suggests) or closed (as Relativity suggests), and if its open can we really visit it or at best visit anything more than a potential future?
Temporal Paradox in Science Fiction
Tourmalin’s Time Cheques, Thomas Gutherie (1891)
This was the first book to introduce the concept of temporal paradoxes though in a more fanciful form. Where the protagonist engages the services of an apparently paranormal Time Bank, which banks or loans out portions of time as Time Cheques. A notion not unlike the later Heisenberg’s Uncertainty Principle which loans out energy for short time periods, but taken to absurd lengths. This naturally causes several problematic paradoxes.
Comment : Modern Philosophy has since identified more serious Temporal Paradoxes that may occur during Time Travel and many of these found their way into science fiction where they were further developed. The main temporal paradoxes are the Grandfather Paradox, the Reverse Grandfather Paradox, the Predestination Paradox and the Ontological Paradox.
Grandfather Paradox : The classic murder of one’s grandfather in the past, or the killing of self as a child, but covers any paradox that makes the the journey into the past impossible.
Reverse Grandfather Paradox : Any paradox that makes journey into the past possible, such as the saving of life of self in the past allowing one to travel back into the past in the first place. Note this implies the temporal loop is a fixed part of history and so has to happen.
Predestination (or Bootstrap) Paradox : A situation of pure temporal loop such as the case where a person travels back in time and becomes their own father. Such loops seem to become permanent histories and so imply predestination with no free will, or at least a limit on free will
The Ontological Paradox : A situation in which an idea or an object has no origin. For instance a Time Traveller could journey into the future and steal the best selling book of a famous author, on return he plagiarises the book and hopes it will become a best seller, but this does not happen instead the book remains obscure until the future author discovers it and plagiarises it himself creating a best seller. In this case no one actually wrote the book it appeared from nowhere!
Many Scientists feel these paradoxes make Time Travel in possible, some logicians even believe the contradictions make Time Travel logically impossible, though this is probably taking logic too seriously. And there are perfectly logical ways of overcoming many of these paradoxes.
Not surprising more science fiction writers than scientists or philosophers have attempted to solve these paradoxes or simply just present them.
Le Voyageur Imprudent by Rene Barjavel (1943) was the first to introduce the basic Grandfather Paradox to Science Fiction in a story in which the protagonist kills his own ancestor and ceases to exist as a consequence.
This idea spawned the destructive solution to temporal paradox, the notion they actually can occur but cause harm. An idea that also spawned the idea of the Time Police, as a preventative agency, and the Time War concept invented by Fritz Leiber in the late 50s. One softer version of this idea has it that only minor destructive changes are possible not major cosmic ones (hence characters may vanish but the cosmos will not collapse into irrational chaos). In minor changes memories are also thought to vanish too, so the missing elements are never actually missed.
‘By His Bootstraps’ by Robert Heinlein (1941) was the first book to bring complex non destructive paradoxes into the genre. Here the protagonist is confronted by two rival near future selves who return to the past and trigger events that lead him into a conspiracy in the far future created by a mysterious mastermind who invented the time machine and manipulated these events. The mastermind turns out to also be the protagonist himself as the time traveller from the original trigger event and a time loop is formed. The name of the novel was taken up as an alternative title of the Predestination paradox. In a later story ‘All You Zombies’ (1959), Heinlein added further complexity by giving his traveller a sex change and having him impregnate himself in the past as well as become his own son. As the story progresses all the characters turn out to be himself.
A similar idea is found in William Tenn’s 1955 story the ‘Discovery of Morniel Mathaway’, in which time travelling historian goes in search of a mysterious historical artist, whose work he ends up creating himself.
‘The Man Who Folded Himself’, a 1973 novel by David Gerrold, took Heinlein’s ideas to even more extreme lengths when the protagonist meets multiple versions of himself and interacts with them in bizarre paradoxes. Gerrold attempts to resolve the paradoxes with the alternate time line thesis derived from the ‘many worlds’ interpretation of Quantum Mechanics.
The Parallel Worlds device is now a commonplace one in contemporary science fiction, but it isn’t the only way to resolve paradox. In fact it’s rather a poor way, only a minority of scientists seem to take the concrete ‘many worlds’ theory seriously, due to its potential infinities and conflict with the principle of parsimony, as well as the conservation of energy law, certainly John A Wheeler, who helped form the idea of a plurality of virtual quantum possibilities, didnt take it that far. Philosophers too worry about the ethical consequences of the theory such as ‘infinite responsibility’. I think the interpretation is also quite badly motivated as well, in that its an attempt to preserve a purely random, physicalist ontology. An alternative Parallel Worlds device is sometimes used in which all the alternatives are virtual or potential, until a decisive final event fixes the real Time Line, and all the alternatives may or may not vanish like dreams, forgotten by their participants (the same thing that applies to any altered time-line in the soft destructive hypothesis).
A bizarre version of the multiple virtual time lines appears in the Phillip K Dick novel ‘Now Wait For Last Year’ (1966) in which not only are alternative time-lines experienced constantly experienced, but also one key character achieves immortality by constantly jumping sideways in time and swapping with his still living alternative selves concretising them as himself. In this novel all the alternatives are remembered.
The alternative solution involves Consistent Histories, sometimes formalised as the so called Novikov self-consistency principle, named after Dr. Igor Novikov, Professor of Astrophysics at Copenhagen University. Under this principle it is actually impossible to perform most Paradoxes, because the universe does not allow them. In the strong version of this consistency law new laws of nature may spring up that prevent certain actions from happening, or improbable occurrences may intervene and prevent the event. But in its most likely form normal, consistent events will form into coherent Time Loops. For instance the example given by the physicist Richard Feynmann, where a Time Traveller attempts to kill himself as a child in the past. He takes aim with a rifle only to miss and shot the boy in the shoulder, due to a sudden shoulder pain from an old injury when a stranger shot him in the shoulder as a boy. Thus changes can be made in the past but only logical consistent changes that do not involve paradoxes. Under such circumstances it would appear that even the assassin’s trip into the past was a necessary one and so unavoidable, raising problems of determinism and free will. Is everything thus determined or is our free will just limited by this?
There is nothing in the Consistent Histories idea that says we can or cannot change the past, as either we can’t and everything is predetermined, including these logical loops or interferences, or we can change the past but only in non contradictory ways.
But even changing the past without contradictions can have serious repercussions that may be very hard to avoid. We may travel into the past to change the present, as in the Terminator films, or even to change a tragic past event, but we cannot predict the consequences of this action. We may end up with something even worse. It may even be impossible to travel into the past without changing it. In the Ray Bradbury novel ‘The Sound of Thunder’ (1952) extraordinary measures are taken to prevent changes in the past, including hunts in which long extinct species, such as dinosaurs, are hunted shortly before they would naturally die. But when a butterfly is accidentally killed, the consequences of millions of years completely changes history for the worse, including the survival of at least some dinosaurs. This story introduced the idea of the butterfly effect.
Robert Silverberg’s ‘Up The Line’ (1969) also introduces the notion of the Time Patrol, who try to police the time traveller’s accidental and deliberate manipulations of the past and the dangerous paradoxes and consequences they create (only ultra cautious passive tourism is allowed in the story). This of course goes badly wrong.
Incidentally the use of the term UP here for going back in time is very unusual, For instance In the 1964 Outer Limits story, which became a graphic novel in 1986, ‘Demon with a Glass Hand’, by Harlan Ellison, forward Time Travel is referred to with the dimensional metaphor ‘going up’, which seems more intuitive, if the past is the foundation of the present.
But we still haven’t avoided bizarre and seemingly impossible paradoxes, Consistent Histories exclude many serious contradictions, and allow harmless paradoxes, but they do not prevent the Ontological Paradox, the production of something from nothing. A classic example of this is the 1967 story ‘The Technicolour Time Machine’ by Harry Harrison in which a post tragedy, time traveller travels back in time with a note advising his past self how to survive the tragedy. His past self keeps the note and eventually uses it to take back in time to his past self. The note therefore has no author and thus logically cannot exist, but nothing in the Consistent Histories approach or the Parallel Universe approach prevents or explains this paradox. Some regard this as evidence of the impossibility of Time Travel, others as evidence of the reality of Paradox.
An interesting treatment of time loop paradox is found in Phillip K Dick’s short story ‘A Little Something For Us Tempunauts’(1975), where not only is physical contradiction considered but also psychological, and for most of the story the actual temporal situation is a very ambiguous one.
The Technology of Time Travel
So much for temporal paradoxes, but is Time Travel actually possible? There are many methods in the literature, both plausible and fanciful, but which of these is realistic according to our current understanding? Arthur C Clarke’s Three Laws are very relevant here:
- When a distinguished but elderly scientist states that something is possible, he is almost certainly right; when he states that something is impossible, he is probably wrong.
- The only way of discovering the limits of the possible is to venture a little way past them into the impossible.
- Any sufficiently advanced technology is indistinguishable from magic.
This is certainly true in most science fiction , and that said we can now explore some thoughts on the possible and its limits.
The simplest form of Time Travel deploys Einstein’s Theory of Special Relativity which in this context simply states that due to the theoretical invariance of the speed of light in a vacuum and the actual geometrics of Space-Time the closer you approach the speed of light the slower time becomes. This is Time Travel in the sense that if your time slows and you move from and back to a faster time frame you will have moved into the future (note: this does not matter if the future is real or not because in Quantum Mechanical terms the faster time frame has already determined it). But is this travelling through time? In a sense it is because we cant do anything but travel through time, and in this case we just modify the relative rates, time just being a local phenomena not a universal one in Relativity Theory. To travel through time in any other sense may be meaningless, as it would mean travelling faster or slower than your local time flow which doesn’t make sense as you would no longer be in the same Space-Time (unless we invoke some kind of quantum parallel time flow).
This method is most famously featured in Pierre Boulle’s ‘Planet of the Apes’ (1963) where a near light speed space journey ends in a trip to Earth 700 years in the future. Phillip K Dick’s short story ‘A Little Something For Us Tempunauts’ (1975) also appears to be based on such a journey.
If it were possible to travel faster than light time would actually run backwards, whether it is or not is an open question. Special Relativity forbids it, but this is because of the infinities involved in the equations of a continuous mathematical model, if actual Space-Time has a quantum structure then these infinities dissappear and then the time flow shifts from a positive value through zero into a negative value (though this would require vast and perhaps impossible amounts of energy). It may be that only subatomic particles with very low mass could ever accelerated to this speed, giving rise to the theory of Tachyons (theoretically possible faster than light particles). If these could be sent back to the past and bounced back somehow, time mirrors or time communication may be possible. One alternative would perhaps be to slow light to a speed which was far easier to exceed and then in principle the same effect could be achieved. But even if we could achieve this the method would be very limited as the Chrononaut would age in reverse and so only be able to travel back within their own life span. This scenario was explored in more naïve, pre-Einsteinian form as far back as 1881 in the Anacronopete tale.
It is perfectly possible to slow light to the speed of an average bicycle or even stop it completely by passing it through a Bose-Einstein Condensate, or Quantum Gas, which would effectively slow light, and therefore time, to a snail’s crawl. In which case not only would we be able to in principle exceed light speed, for what it’s worth, but also experience time dilation effects at much slower speeds and great ones at high velocity. There are limits to this however.
Quantum Gas Effects
Such a gas has the odd potential to slow or even stop time within its space-time frame, as well as other useful effects, due to its production of Slow Light and the consequence of luminal invariance. Any collection of atoms, in volume of gas contained in a magnetic field, cooled to absolute zero will be void of all motion and therefore have a totally zero momentum. This means the momentum is a definite quantity and therefore their positions will be non-measurable or smudged in superposition, an Einstein-Bose Condensate or a macroscopic quantum gas. If a laser is beamed through this gas perpendicular to an arbitrary axis a selective transparency is electromagnetically induced (see technical appendix). A second laser beam fired along the arbitrary axis will be dispersed by the quantum smudge as it passes through the transparent gas, which has the effect of slowing the group velocity of the wave by over a millionth to 38mph. Thus time is effectively slowed in the gas. If the inductive beam is switched off the transparency is lost and any information in the beam is stored in the gas as excitation, until the beam and transparency is restored and the information is again transmitted. Amazingly if another Condensate has been entangled with this and the beam is restored to that instead the information carrying beam will emerge from here no matter how distant it has become.
In an extremely speculative sense we might say travelling through such a gas might lead into the future, it might even lead to the past if we moved fast enough or time slowed even further! The problem is of course is it would be at absolute zero or -273 C and its far from certain such gases can be manufactured on a large scale or exist naturally (though probably do in deep space). Even if they did exist passing through them would seem to be lethal without heavy insulation (although the near zero time rate may be of some help). Alternatively a frozen time quantum gas might also provide the ultimate suspended animation.
This may relate to the several time travel devices that involve mysterious fogs, clouds and gases that feature in many stories, themselves often drawn from folklore, most famously the origin of Buck Rogers in the novel ‘Armageddon 2419’ by Phillip Nowlan (1928) where the protagonist is frozen in a mysterious, radioactive cave gas for 500 years.
A better known way to time travel is via an Einstein-Rosen Bridge or Wormhole. In principle it is possible to curve space time so much that it loops round on itself, created a closed space-like curve, which would enable us to take a shortcut through space. By extension we can also do the same to time and create closed time-like curves. These are Einstein-Rosen Bridges.
These loops would be experienced as wormholes that leave one part of Space-Time and emerge at another (or even in another parallel universe if such things exist). It is was once thought such Wormholes might occur naturally, but it is now thought they are too unstable to exist long (though if some of the extra dimensional Superstring theories are correct, a modified Space-Time metric may allow them after all though its a long shot). One place they might form is within a enormous Black Hole, if such a rotating object was discovered it might be possible to navigate around its dangerous singularity (a hole in space in which absolutelty anything can exist or cease to exist) and enter a wormhole (a smaller or a non rotating Black Hole would destroy anything passing through it). But Roger Penrose believes singularities are so dangerous that some Cosmic Censorship Principle from getting anywhere near them. Alternatively the basic Time Dilation effect of a massive Black Hole predicted by General Relativity might be enough for Time Travel without actually entering the hole itself. The stories of Frederic Pohl explore a variety of forms of black hole exploitation. But in real life the nearest Black Hole is over 2000 LY away and creating a nearby one would seem both difficult and imprudent. Stephen Hawking also poured cold water on the idea by suggesting that Black Holes pull in so much radioactive material that they would be deadly to approach and he believes the radiation inside the Black Hole would also collapse any Wormholes that might form.
Wormhole construction on the other hand is a real possibility. Science Fiction has a long history of both space and time travel through wormholes, though they often skip the technical detail.
E. E. Smith’s Hyperspatial Tubes and the Ramsbotham Gates of Heinlein’s ‘Tunnel in the Sky’ (1955) are classic examples. While Madeleine L’Engle’s youth novel ‘A Wrinkle in Time’(1962) and Michael Creighton’s ‘Timeline’ (2003) go some way to describe how wormholes could be generated in order to travel through Time. The former suggesting Space-Time can be ‘pinched together until joined by a bridge’, but goes no further. Carl Sagan’s ‘Contact’ describes spatial Wormhole physics in great detail, but although temporal anormalies are described no temporal Wormhole physics is covered.
In real life physics howver several papars have been written about how to form such temporal Wormholes. In short transient micro-wormholes appear spontaneously all the time at the quantum level and only need enough energy to open them up wider. These can be achieved in theory by a vast cyclotron. Such wormholes would still be small and unstable but could be expanded and kept open by negative energy or matter, which ‘anti-gravitates’. Such stuff is also producible from sub atomic, quantum vaccuum states via the Casimir effect (see technical appendix). This process should create a spatial Wormhole. To turn it into a temporal Wormhole we simply rotate the ends of the tunnel at different velocities which creates a Time Dilation and turns the Wormhole into a Time Tunnel. Again though Hawkings suggests quantum virtual particles will build up in the wormhole and collapse it before it can be used, though others believe this radiation will just leak out.
Note that a Time Tunnel can never connect to a time before it has been constructed however and so is effectively limited to forward time travel or backward only with its own lifespan.
A similar Time Travel process is actually being developed now with more simple techniques than a Wormhole. The Mallet device, named after its developer Prof Ron Mallet, is predicted to work by using the Slow Light mentioned earlier. In this system a strange property of Slow Light is exploited, its tendency to gravitate more the slower it moves (energy gravitates just as matter does). This means by creating a double vortex of Slow Light, moving in opposing directions, a gravity well of such intensity could be created that it functions like a small Black Hole in producing Time Dilation. As with Wormholes, the energy required to transport a macroscopic object would be vast, but on a microscopic scale could be achievable even today, allowing sub atomic particles to time travel, and perhaps allow a temporal communication device of time telescope to be constructed. As before this will only work within the time span of the device, connecting its past self with its future self, and not outside those limits. But one weird possibility then would be a far future contact with a technology that was even more advanced in Temporal Engineering!
More Speculative Means
This is the limit of current physics but more speculation based on the frontiers of science is still possible. A popular means of Time Travel found in science fiction and typified by the Dr Who notion of the Tardis is a moving outside of our Space-Time continuum at one point and renentering it at another. While the fictional Tardis technology is closer to magic than science (and reflects the kind of folktales of otherworlds we started with) this idea remains in the bounds of possibility. But how it would be done is more difficult to imagine.
Science Fiction often refers to Hyperspace as a region outside of our universe, arrived at in a wide variety of ways, it was first described in Nelson Bond’s ‘The Scientific Pioneer Returns’ (1940) and further developed by Isaac Asimov in his Foundation stories (1942-1944). It soon became a staple of science fiction, and was slightly modified in various tellings, such as as the Subspace of the Star Trek series. The original notion was of a spatial shortcut outside of normal space to over come the problem of distance and the light speed limit. But authors soon realised it could be used for Time Travel as well, given the unified Space-Time continuum, and initiated a new form of Time Travel (also inspired by folktales). But although contextualised within the closed, curved universe of interpretations of Relativity Theory it is purely a fictional notion, or at least has no basis in modern physics, in which there is conventionally nothing outside of the Space-Time continuum.
The folklorish element of the idea was revealed early in ‘The Mystery of Element 117′ (1949) by Milton Smith, where a ‘hyperplane of hyperspace’ is discovered to be the realm of the dead!
But are there any indications of its possibility in cutting edge physics? One area is in M-Theory, a synthesis of all the String Theories, which postulates an extra extend dimension (which we can call the fifth dimension for convenience, the other multi-dimensions of String Theory being micro compact) which seperates an indefinite number of other universes (now concieved of as lower dimensional membranes). This seems very much like Hyperspace, but the main difference is none of the forces of our universe can travel in this dimension apart from gravity (whose assymetric strength in our universe is explained by it leaking into this dimension). Therefore we could never enter it it seems. The only concievable way being if we could some how code the structure of the matter of an object into a set of information states and transmit it as gravity waves through M-Space, perhaps bouncing it off another membrane and returnining it to our universe at another point and recreating the original material object. In otherwords a form of spatio-temporal transfer known in science fiction as Teleportation. An idea invented by Conan Doyle in his ‘Disintegration Machine’ (1927).
But if we are to use Teleportation (a highly problematic idea in itself given the uncertainty principle re the exact atomic configuration of any object) we might have to do it in our own local universe, especially as it seems to require a sender and reciever unit (contra Star Trek). We could use light speed particles to travel into the future or tachyons to travel into the past in this way. The quantum problem could be solved by using entanglement, non-locality and Quantum Teleportation which may have its own temperal features.
Much of the problems at this frontier are borne from the fact we do not yet know how to combine Relativity Theory and Quantum Theory. And of course we can’t exlude some unknown physical like domain beyond normal Space-Time yet to be discovered.
Time and Consciousness
A radical departure form this purely Physical Science is also possible. Many science fiction tales employ the idea that there is some psychic or consciousness based element to Time Travel.
The most famous of these is Slaughter House 5 by Kurt Vonnegut (1969). Here the protagonist becomes ‘unstuck in time’ during his various crisis moments, and then experiences his life events repeatedly in a random order, which are constantly identical. This seems to be due to his contact with perceptually time travelling aliens who experience life in four dimensions, and confirm it’s Predetermination. The protagonist adopts and preaches the alien fatalist creed. The idea is based on Einstein’s Block Universe but the aliens seem to have a temporal sense even if they cant physically travel in Time. There is also uncertainty as to whether the Time Travel involved with the protagonist is physical or perceptional.
More dramatically Time Travel is achieved by hypnosis in several stories, most notably in Jack Finney’s novels, such as ‘Time and Again’ (1970), but also in Richard Matheson’s ‘Bid Time Return’ (1975). A method developed in J. B. Priestley’s book ‘Man and Time’
In the ‘Time Traveller’s Wife’ (2003) by Audrey Niffenegger, the protagonist randomly travels through time due to some ‘genetic disorder’, perhaps implying a psychical element to the process.
In these tales the method is perceptual but the travel appears to be physical. This could be explained by some form of Idealist Philosophy in which reality is shaped by consciousness, which would be arguably completely at odds with Modern Science, or may just be based on a more mysterious notion that the Laws of Physics are manipulatable by mind. I’m sceptikal about both. If this were possible why don’t we see it more often.
One interesting version of a more plausible perceptual Time Travel is found in Daphne du Maurier’s ‘The House on the Strand‘ (1969) where a drug enables the protagonist to mentally travel in time, becoming a ghost like being in the 14th century percieving but unpercieved, and shadowing his doppelganger in that time, while his body moves around unpercieving in the 20th century! A whole genre of psychedelic time travel follows from this.
Certainly there is a very real tradition of apparently Paranormal Time Travel , the classic cases involving a mysterious turn in the road leading to a building in the past, such as the famous case of the British holiday makers in France who ended up in a 19th century hotel (1979) or reports of an experience of a bombing raid in Germany (Hutton and Brandt, Altona Ship Yards, 1932) eleven years before it actually happened. Of course we cant exclude hoaxes in these cases but they are comparitively common in Fortean Literature and in one case (a patient of Dr Raul Centeno, Peru) involved measured physical effects, namely a right side paralysis following an alleged encounter with a 17th century log cabin (with measurable left hemisphere electrical abnormalities). These stories are very odd but perhaps the most perplexing being the report from Air Marshal Victor Goddard to have flown over and disused Drean airfield in 1935, following a traumatic flight through some ‘strange brown clouds’ and an electrical storm, and seen it as it would be in service in 1939 (complete with changed uniforms and new style aircraft unknown in 1935). The ground crew oddly failing to see Goddard’s plane. Given Goddard’s other alleged experiences of prophetic dreams, ghosts caught by him in photographs, and UFOs investigated, perhaps we could dismiss him as a yarn teller with some of the others, but there is a definite common pattern to these experiences (even though some of Godard’s descriptions are reminiscent of the science fiction of his time).
More subtle perceptual changes involve odd shifts in time where the time experienced seems to expand or contract according to need, not in terms of simply duration but in real time, often in moments of intense concentration or involved group activity. I myself experienced something similar as a teenager when late for school and encountered a stranger who told me to forget about time and lateness and to concentrate on the conversation as we walked briskly. In the event a normally 20 minute journey was achieved in 10 minutes. This may relate to Henri Bergson’s idea that it was subjective Duration that was the real essence of Time, with objective Chronology a mere abstraction. But that leads off into more complex Existential notions of Time and Consciousness.
Perhaps Consciousness itself, or the potential for it in mental impressions or perceptions, is actual a maleable, psychic continuum much like Space and Time, and interlinked with them in a broader 6th dimensional Space-Time-Psyche (allowing for M-Theory), in which perceptual malleability is interlinked in the same way the malleability of Space and Time are. This would certainly explain another common Fortean experience of meaningful coincidence or Synchronicity, tying apparently random events up with states of mind, and may open up whole new psychic domains. But such things may be beyond our current understanding and takes us back to where we began in the magical folklore of our ancestors.
A final observation is if Time Travel is possible they must be here now, so where are they? A thought that opens up interesting experiments (including one undertaken this week …..)
Time Dilation under Special Relativity can be understood geometrically in terms of the Pythagoras Theorem, where the long leg represents the velocity of the vehicle as a vector, the short leg represents the velocity of a photonic oscillation within the vehicle (the timer pulse) and the long hypotenuse represents the real vector velocity of the photon in the on-board timer as the vehicle carries it through space. As the speed of light is invariant in a vacuum the hypotenuse must stay a constant length, but as the long leg approaches a similar length (the vector velocity near C) in order to preserve the geometry the short arm must shrink by increasing factors (the photon gets slower) and so time slows (relative to an external observer but not the travellers who are unaware of the motion). The whole effect depends on light speed, invariance and the laws of geometry. The infinities are produce by the Pythagorean Equation: A squared = C squared minus B squared when A squared reaches zero at light speed and is used in division (and so may be a mathematical artefact). A quantised Space-Time (a jigsaw of ‘space-time bits’) would need a different maths. There is a parallel with solutions to Zeno’s first Paradox of Motion here.
Time Dilation under General Relativity can be understood in terms of an extension of SR and the thesis of the Space-Time continuum. In SR mass increases at near light speed due to the principle of the conservation of momentum (p) between interacting frames of reference and the relatively differentiating momentums within those frames (p = m.v, where one relative velocity (v in m/s) has shrunk, due to the time dilation, it’s mass (m) must increase). When this is generalised in GR we can see that mass increases as time dilates, and given the relation of Space and Time as a single continuum we can say that increased mass or gravitation (space curvature) results in slower time (time curvature). Were as space curvature causes gravitational acceleration time curvature will cause temporal deceleration due to the negative value in its the Space-Time maths.
Energy as a gravitational factor can be similar understood as a correlation between the mass increase at high velocity and the increased kinetic energy with that velocity. When generalised we can say that energy increase produces increased gravitation, or curves Space-Time, just as much as matter does (the two being shown to be equivalent in the famous E = M.C squared formula). The Gravitation of the Earth can be shown to have a tiny factorial determined by its internal heat!
Superposition occurs when particles in quantum flux exist in more than one place at the same time spread out in all possible positions, or are travelling along all possible paths between source and destination. This is the normal state of matter and energy at the quantum level (and according to Decoherence Theory the normal state of matter and energy at all levels) until a measurement connects it’s domain with the rest of the universe, forcing it into a consistent, classical state for observers in that locality with a specific history. In Quantum Theory the future is indeterminate and probablistically random in this way until experienced (though a variety of virtual or potential futures may exist and be capable of interaction). This is at odds with Relativity Theory Cosmology which implies the Future is predetermined or fixed.
Casimir Effect Note
The typical example is of two uncharged metallic plates in a vacuum, placed a few micrometers apart, without any external electromagnetic field. In a classical description, the lack of an external field also means that there is no field between the plates, and no force would be measured between them. When this field is instead studied using quantum measurement, it is seen that the plates do affect the virtual photons which constitute the field, and generate a net force—either an attraction or a repulsion depending on the specific arrangement of the two plates. Although the Casimir effect can be expressed in terms of virtual particles interacting with the objects, it is best described and more easily calculated in terms of the zero-point energy of a quantized field in the intervening space between the objects. This means polarized energy is being produced from the void potential, in which all polar forces cancel to zero (the vacuum is thus not empty but rather is near infinitely full of opposing forces negating each other -1 and +1 = 0), which can be detected as virtual quantum particles. In addition to normal positive matter and energy, which gravitates, some negative matter and energy (not anti-matter) will also be produced, which ‘anti-gravitates’, and this is harvestable.
Quantum Gas Notes
Wave Velocity – This has two components, the phase speed and group speed. The group speed is the speed of propagation of the wave (the speed of the light beam or photon for instance), the phase speed is the speed of the phases within the wave (the line followed along the curves). All material that is transparent allows waves to pass through it but will modify the wavelength slowing the phase speed of the wave, thus causing Refraction and/or Reflection.
Transparency – Most Transparency effects are caused by the random distribution and spacing between atoms, thus solids are mostly opaque and gases are mostly transparent. One exception is glass which has a very random structure due to melting and rapid cooling (it can be made more opaque by cooling slowly and allowing ordered crystals to form). But atomic structure also plays an important role too. Different materials interact with light differently, depending on the nature of their atomic structure and the wavelength of the light (usually mixed). Some absorb light, others absorb and release it later, some scatter it or let it pass through unabsorbed and unscattered, while others reflect it, and all to varying degrees (plus various wavelengths interact differently producing colour). Any material that can coherently transmit all the light is transparent (if only on some wavelengths it’s a transparent colour filter), or if it only transmits defuse light it’s translucent.
Electromagnetically Induced Transparency – Atoms in superposition of the appropriate kind will make their substance transparent by creating a destructive interference pattern preventing photon absorption. This set up occurs when a coherent laser beam is streamed into the substance.
Refraction – The wavelength change that occurs with a wave’s transition across two media, with constant frequency, causes a change in the phase speed of the wave, while its group speed is unchanged. At angles greater than zero this also causes the direction of the wave to change (because one end of the wave-front, or ripple, enters before the other giving a varied speed across the wave-front and thus twisting it round). Beyond a critical angle Refraction becomes total internal Reflection.
Reflection – Defuse Reflection is produced by the photonic emissions of resonantly vibrating atoms or electrons in an appropriate medium on the incidence of a light beam. If Refraction occurs half the emission will follow the refraction while the other half is reflected as randomly scattered light. If the reflected emission is coherently aligned a spectral reflection will occur (mirror image). If the Refraction incident angle passes a critical angle Refraction become Reflection and total internal Reflection is achieved.