The Dark Arrow of Time

by Massimo Villata

  Accordingly, the interpretation of antimatter as matter going backward in time (and in space) is practically immediate. We thus discover that there is probably a totally inverted space-time, where ordinary matter can evolve contrariwise, and the existence of antimatter would prove that this inverted space-time is possible.

  We know that many of the most familiar physical laws are invariant for P and T (together and singly). This is true of such laws of classical physics as Maxwell’s equations for electromagnetism and the laws of gravitation, both in the simplistic Newtonian formulation and in Einstein’s relativistic formulation. Maxwell’s equations, as well as considering the usual electromagnetic waves traveling in a vacuum at speed c , or in other words, the so-called retarded radiation that propagates forward in time, also contemplate the possible existence of advanced radiation propagating backward in time, though this is usually considered merely a mathematical curiosity with no physical meaning. In our interpretation, however, it is the radiation emitted by matter going back in time.

  For gravity, neither the classical nor the relativistic formulation distinguishes between the two time directions. Running backwards a film of a perfectly elastic ball bouncing on the ground or of a satellite orbiting its planet would show nothing unexpected. But it would be different if the ball were not perfectly elastic (balls never are in reality), such that each successive bounce would lose a bit of kinetic energy to heat or deformation, and the backward film wouldn’t work. And this is what happens whenever we’re dealing with thermodynamics and entropy: a film of a broken glass on the floor that puts itself back together and jumps up onto the table would give rise to considerable suspicion, to say the least. Not that it’s physically impossible. Just highly unlikely.

  This is why people don’t usually believe that another arrow of time exists. But maybe an antimatter glass, in our eyes, would behave in exactly this way.

  In conclusion, then, going backward in time is relatively easy (in theory…). All we need to do is what the electron in Fig. 1 does: we transfer an amount of energy equal to twice our mc 2 , and there we are, traveling merrily backward in time, and maybe waving to ourselves, our other selves who still have to be inverted. Obviously, in the moment when we “belong” to the other arrow of time, the energy we transferred for inversion is interpreted as energy gained, because now the Feynman diagram is overturned. And the people in the lab where all this happened saw a matter-antimatter annihilation, while for those of us who have been inverted it’s a pair creation.

  Clearly, there’s a problem. There always is when you go backward in time.

  Let’s suppose we’ve been inverted, together with the spaceship in which we went through the inversion process. Now, for those who remained faithful to the usual arrow of time, we’re made of antimatter (actually, from their point of view we disappeared with the “annihilation”, and so we should say “we were made of antimatter”). We “travel” back a bit in time, enjoying ourselves as we watch what’s already happened as it unfolds in the opposite sequence, with people walking backwards, getting out of the shower nice and dry with no need of a towel, regurgitating their meals back on the plate, appetizingly untouched. Then we go to one of those instantaneous interplanetary transmission arrival stations we were talking about earlier. Let’s say we’re on the planet Alkenia and people arrive, or in other words are transmitted, from Earth. And then comes the “trick” hinted at by Mattheus Bodieur! We take the place of part of that antimatter that separates from the matter, which is to say the spaceship and passengers arriving from Earth, after the instantaneous transmission from there to here. For us, that transmission still has to take place, and we “live through it” backwards. And so we end up on Earth at the moment of their departure. So we can not only move from one planet to another in subjectively zero time, but we can also return to the moment of our departure, or at least the same period, without having to go through the dozens of years that light needs to make the round trip. A pretty good deal!

  And caroming back and forth, we could even return to Earth in the past, but no further back than the time when the first transmitting station (which for us is the receiving station) was set up. But in the novel, these little jaunts in the past are strictly forbidden by Thaymite law.

  But scofflaws, as always, abound. And not only. The book’s plot, in fact, revolves around scheming and intrigues, with the theft of secret plans and software that make it possible to travel freely back in time, to any period.

  Once transmitted back in time, we find ourselves in a world that flows in the opposite direction, like before the transmission, a world where we’re made of antimatter. So we have to invert again if we want to participate in that world’s events, and not just watch them like a film being rewound. That calls for another lab for time inversion, or in other words for annihilation-creation; but now it’s all more complicated, because we come from that lab’s future, unlike when we were inverted before the transmission. It’s a far from trivial problem, which in the novel is resolved with special antimatter devices. The lab staff, with no way of knowing what’s about to happen, will only detect a massive loss of energy, and an identical pair of spaceships appearing out of nowhere, one “arriving from the future”, and the other “going back to the future”.

  And this is where we run into the problems that we mentioned earlier, the well-known problems that always crop up with trips in the past.

  Let’s suppose that before being re-inverted, we saw events that happened, say, on Tuesday; maybe events in which we took an active part, as is the case with the characters in the novel. We’re inverted twenty-four hours later, on the Monday preceding those events. We already know where we’ll be and what we’ll be doing the next day… Our fate, it seems, is sealed, and there’s no getting away from it… And so goodbye free will!… Or we witnessed events where there’s no trace of our presence; or again, we know that on that Tuesday there will be an attack in which many people will be killed—we know because we come from the future. But we can’t do anything about it, we can’t be there in a place where we weren’t seen, nor can we prevent something that’s already taken place.

  And this is why people don’t usually believe that trips in the past are possible. Or at least it’s one of the main reasons. Because it would mean abandoning the idea of free will.

  Nobody can say for sure whether free will exists or not. We’ll never know whether the “choices” we think we make could have been different. At bottom, the physical laws that govern the macroscopic world and thus much of our brain are deterministic. Who can say that the “will” to do this or that is not just a presumption-fueled illusion, and that in fact everything does not play out along a predeterminable chain of causes and effects that we have no real power to change? If I type an “s” on the keyboard now, and then I scratch my itchy eye, how can I ever know whether I could have done differently?

  We can invoke quantum indeterminacy, and the fact that in the world of quanta the evolution of a physical process is never certain, but can only be probable at most. And we can think this gives us some room for manoeuvre, but the “how” would be entirely unknown.

  Unknown. And in any case, we still know so little about how our own brain works.

  Or we can invoke some sort of abstract entity, possibly not physical, like the “conscience”, or the “soul”, or whatever, and hang the whole burden of free will on it. But we would be hard pressed to say where along the evolutionary ladder from the amoeba to Homo sapiens such an entity was injected into the organism. Unless we deny the theory of evolution, and there are those who do just that.

  But we’ve gone well beyond the physical explanations we set out to provide. And all of this, anyway, is entirely outside our own wheelhouse.

  Let’s go back, to whether it’s possible to choose between doing or not doing what we saw ourselves do; or between foiling or not foiling an attack that has already happened. The latter case is easy: clearly we can try, it’s just that we don’t suc
ceed. It’s not as if there was news footage somewhere showing whether or not we were there with our rental car trying to block the road the terrorists are going to take, but getting to the intersection one second too late, or not getting there at all because the traffic cops flagged us down.

  But on to the harder case. The one where we not only know exactly what’s going to happen down to the last detail, but since we’re protagonists, we have to repeat exactly the same actions that we’ve already seen. Here, it really would seem that there’s no room for free will. It would seem that our destiny is that of well-programmed robots who can do absolutely nothing that’s not written in their program. Who can’t even dig in their heels and say “No, I’m not going there…”.

  Let’s suppose, though, that there’s some way we can introduce a change of some kind, large or small. Then we would have two different realities at one and the same time, as it were. With two different futures. Parallel universes? Where only one is the universe we knew and that we come from, while from that moment onwards we’ll belong to another? As in the “grandfather paradox”, where the grandson goes back in time to when his grandfather was still a boy, and kills him before he can conceive his father (bloodthirsty but effective, more than any other birth control method). And so, after the dire deed is done (or maybe even before, since going back in time), he finds himself in a different universe than the one he came from, and in whose future he’ll never be born.

  The novel explores all of these different alternatives, where free will may or may not exist, but the view that seems to prevail at the end is that of “bifurcations of reality”, where actions in the past give rise to new stories in parallel realities. All of these musings on time travel paradoxes, and others in the novel, spring from the author’s speculations, but are often borne out by existing theories, 9 as in the case of the Novikov self-consistency principle. 10

  Or perhaps Professor Borodine was right. When he said that what happens in each instant is, yes, the effect of past causes, but is also the effect of future causes: all you have to do is shake off a single-time outlook on reality. Maybe then there would be no more paradoxes, no more parallel universes. Maybe even the probabilistic nature of the quantum world would gain a meaning: it exists only because we don’t take the future causes into account.

  Lastly, the novel also deals with other issues, which we might call less scientific, like mind reading and healing powers. “Less scientific” because there is no solid scientific proof that such faculties exist. On the contrary, a number of experiments appear to indicate that they don’t, at least for the participants in the experiments. Obviously, this doesn’t mean that other people (who maybe weren’t interested in the experiments in question) do not have these gifts.

  After all, there’s also no scientific proof that time travel can exist—far from it—but the scientific literature on the question is extensive and authoritative. So where’s the difference? Given that in all three cases there do not appear to be ironclad arguments against them.

  The human body, or even any other animal or non-animal organism, is a marvelous machine that can interface with the outside world in ways that are truly incredible. We almost never notice, because we’re used to it. A couple of extra faculties like reading people’s thoughts or being able to heal wounds would be very small beer indeed, compared with what we’ve already got: eyes, ears, the immune system, cell regeneration and all the rest. It might be objected that eyes and ears exist because there are electromagnetic waves and sound waves that, if correctly received, transmitted and interpreted by the brain, provide information of vital importance to the organism. In other words, they exist for reasons of selective pressure.

  But the brain emits signals too, in the form of brain waves and so forth. And there are a number of methods for “reading” these signals, the best known being electroencephalography and functional magnetic resonance imaging. Computers can analyze and interpret these signals: it probably won’t be long before we have machines that are able to detect whether we’re thinking of an apple or a banana. Maybe the difference between these signals and those involving light and sound lies in the fact that thought and brain activity in general have not been around for long, and perceiving them is of less importance to survival (unless somebody is sneaking up on us from behind with lethal intent), and so there has not (as yet) been any real selective pressure in this direction.

  The above-mentioned brain imaging through functional magnetic resonance reveals what regions of the brain are activated at a given time, thanks to the increased flow of oxygen-rich blood, which is closely related to neural activity. From the information on the activated brain areas, dedicated software can reveal something of the actual thoughts of the brain owner. This is a very indirect route to mind reading, but it is what we have actually got so far. It would be very different if some people were endowed with the appropriate sensory apparatus, something like the third eye of dharmic spiritual tradition, possibly located in some layer of the neocortex or below. This is, of course, purely speculative, but is a very good topic for fiction.

  In addition, the human body emits plentiful infrared radiation. Who knows, in some individuals certain components of this radiation might have beneficial properties. Or there could be some other kind of “radiation”, that we’ve never even dreamed existed because we don’t have the right “detectors”. Just like when we didn’t suspect that there could be such things as radio waves, X-rays, alpha, beta and gamma radiation, neutrinos or gravitational waves.

  On more scientific grounds, there is evidence of mind-body connections where some induced mental state can affect healing. The most famous example is the placebo effect. In this sense, a healer would be a person capable of inducing positive and reassuring moods against the disease, thus helping the natural healing process, just as the consolatory effect of a mother relieves her child's suffering. Moreover, if mind reading is possible in the future, maybe mind influencing to heal is also possible. However, this does not explain why some of us, putting our hand on the belly of our newborn baby who suffers from bowel colic, can (almost) immediately make them stop crying upon the release of a great fart.

  But then, as we were saying, why is time travel different? Why can it be classified as a scientific topic, and the other things can’t? And who ever saw a trip in time? Faith healers and mind readers, real or presumed, legendary or historical, have always existed; what’s more, people often believe in them.

  The fact is that time travel is harmless (or at least until it actually happens), while paranormal powers aren’t, seeing that there has always been a horde of self-proclaimed magicians ready to prey on the gullible. And so, even if only as a question of public health, serious research in this area does not go down well with anyone. Certainly not with the pharmaceutical companies. Nor with the church, whose “spiritual” enemies, heretics and healers, real or presumed, were burnt at the stake only a few centuries ago.

  In the novel, the ability to read minds, and perhaps also certain healing powers, arises from a genetic mutation (this is obviously highly speculative, an invention of the author's imaginative mind). The selective pressure on a prehistoric population that brought this mutation about, and the resulting historical repercussions, will be discussed at length in connection with the time trips in the second novel in this series, entitled “The Other Messiah”.

  Footnotes

  1 Morris, Michael S.; Thorne, Kip S.; Yurtsever, Ulvi (1988). “Wormholes, Time Machines, and the Weak Energy Condition”. Physical Review Letters. 61 (13): 1446–1449. Bibcode:1988PhRvL..61.1446M. doi: 10.​1103/​PhysRevLett.​61.​1446 .

  2Stueckelberg, E. C. G. (1942). “La mécanique du point matériel en théorie del relativité et en théorie des quanta”. Helvetica Physica Acta. 15: 23–37.

  3 Feynman, R. P. (1948). “A Relativistic Cut-Off for Classical Electrodynamics”. Physical Review. 74 (8): 939–946. Bibcode:1948PhRv…74..939F. doi: 10.​1103/​PhysRev.​74.​939 .

 
4 Feynman, R. P. (1949). “The Theory of Positrons”. Physical Review. 76 (6): 749–759. Bibcode:1949PhRv…76..749F. doi: 10.​1103/​PhysRev.​76.​749 .

  5 Villata, M. (2011). “CPT symmetry and antimatter gravity in general relativity”. EPL. 94 (2): 20001. doi: 10.​1209/​0295-5075/​94/​20001 .

  6 Villata, M. (2013). “On the nature of dark energy: the lattice Universe”. Astrophysics and Space Science. 345 (1): 1–9. doi: 10.​1007/​s10509-013-1388-3 .

  7 Villata, Massimo (2015). “The matter-antimatter interpretation of Kerr spacetime”. Annalen der Physik. 527 (7–8): 507–512. doi: 10.​1002/​andp.​201500154 .

  8Kaiser, David (2005). “Physics and Feynman’s Diagrams”. American Scientist. 93: 156–165.

  9Lewis, David (1976). “The Paradoxes of Time Travel”. American Philosophical Quarterly. 13 (2): 145–152.

  10 Friedman, John; Morris, Michael S.; Novikov, Igor D.; Echeverria, Fernando; Klinkhammer, Gunnar; Thorne, Kip S.; Yurtsever, Ulvi (1990). “Cauchy problem in spacetimes with closed timelike curves”. Physical Review D. 42 (6): 1915–1930. Bibcode:1990PhRvD..42.1915F. doi: 10.​1103/​PhysRevD.​42.​1915 .