Antimatter and the One Electron Universe: Part Three

It’s a saying that’s been quoted by others, usually scientists and science writers, thousands of times by now, yet it retains the element of a profound insight. And that is ‘the Universe is not only far stranger than we imagine, it’s far stranger than we can imagine’. Every time you turn a corner, there’s an unexpected and rather shocking surprise staring you in the face! Mother Nature never seems to run out of curve balls. Anyway, one such imagination could have our Universe’s strangeness level increased a notch or so in that it allows for micro (quantum) time travel and that perhaps can lead to a Universe that consists of way less stuff than that contained in the smallest speck of dust.

Continued from yesterday’s blog…

Associated Cosmology:

A better output of the antimatter-going-back-in-time as pseudo-matter concept is that – as hinted above - it explains the lack of antimatter in our current cosmos. Theory suggests that at the time of the Big Bang event, equal amounts of matter and antimatter should have been created. Of course had that been the case, all matter would have annihilated all the antimatter (and vice versa), and our cosmos would be nearly just pure photon energy. Now some of that photon energy would now and again spontaneously turn into a matter/antimatter particle pair, but overall there would be relatively little solid stuff at all. We note that this Universe would still contain equal amounts of matter and antimatter – but it doesn’t. The accepted way around that is the assumption that there was ever a slight excess of matter created vis-à-vis antimatter, so after all the annihilations; matter was the winner and dominated the cosmos, which is what we see today, and what little photon energy transmutes back into matter and antimatter hardly is enough to alter the ratio.

However, what if equal amounts of matter and antimatter were created at the Big Bang event? If antimatter has a slightly greater affinity for backwards time travel, then maybe even hardly any matter-antimatter annihilation could occur, as much of the antimatter separated from the matter by fleeing backwards in time (as pseudo-matter), or the matter separated from the antimatter by fleeing forward in time – same thing. Just as all matter (our Universe) is travelling forward in time (from our perspective) at one second per second, there must be another antimatter (pseudo-matter) universe travelling backward in time (again from our perspective) at one second per second.

That leads to a new novel cosmology, courtesy of yours truly. Assume that antimatter (as pseudo-matter) travels into the past at the same rate as ordinary matter travels into the future – one second per second. There’s a separation between the Big Bang’s antimatter component and the matter component. Or, in other words, the Big Bang event created two universes, one each of charged matter, uncharged matter (the neutral particles of matter), photons and the other neutral force particles (like the graviton); one of charged antimatter, uncharged antimatter (the neutral antimatter particles), anti-photons and other antimatter neutral force particles (like an anti-graviton). Oh, as per CPT, each universe is the mirror image of the other. Perhaps the concept of a mirror universe (as seen in several Star Trek episodes) might not be quite so sci-fi after all! Our Universe, say is a left-handed Universe; our antimatter counterpart is a right-handed universe. So, one has total symmetry between the two cosmos’s. That should please physicists! Of course each cosmos is in itself asymmetric with respect to their matter-antimatter ratio.

Each universe appears to be retreating or going backwards in time from the perspective of the other, (in a similar way that you are getting further and further away in time from any event in the past you care to identify, which equally applies from the point of view of that event contemplating you – if it could). Anyway, that’s all academic since there’s no longer any actual contact between the two universes. Each universe is in isolation and all is as it should be within each self-contained cosmos.

Of course in each universe, some particles reverse charge due to photon energy, and then reverse again, perhaps again and again and again, so that the matter universe has a small but continuous creation component of antimatter – which doesn’t last long; the antimatter universe has a small continuous creation component of matter – which doesn’t last long.

The vast majority of all these zillions of photons created at the Big Bang event, and present in each of the dual universes, including those we are awash with in the here and now, don’t constantly mutate into a matter/antimatter pair, so that’s a rarity in the cosmic scheme of things. If we’re matter by a vast percentage, then the few photons that temporarily create a bit of antimatter doesn’t amount to a hill of beans, and in any event, that antimatter will meet quick smart matter and it’s photon time again, regardless whether the antimatter bit came from our future to our now, or was created in our now and has skipped back to our past, all at the rate of one second per second. Antimatter doesn’t stick around in our here and now, but if it travelled back in time, turned into an electron, that electron would be in forward time step with us. In fact, that electron would exist in our here and now since matter that existed in our past, exists now.

I wonder whether or not a further consequence of all this time travelling is that we need a wave equation for position in time as well as position in space. All particles (for that matter, all macro objects made up of particles) have a quantum wave function associated with them that gives the probability that that particle (or macro object) will be at some location or other (the quantum uncertainty principle dictates that we can only know the probability that a particle will be a location X). So, if we want to know where a specific electron is, we can say (for example) it’s 90% likely to be within one radius from a specific position, or 99% certain to be within two radii, or 99.9% to be within three radii, etc.  Do we now need a wave equation to tell us that a positron/electron is say 90% certain to be within one time unit in the past/future, 99% certain to be within two time units in the past/future, or 99.9 % certain to be within three time units in the past/future, etc.? I would assume so since the positron/electron can U-turn at any unknown time in the past/future.   

An Analogy:

When everything is moving together forward (or backward) in time, there’s relatively less scope for interactions and associated baggage compared to head-on (past hits future) interactions. Past-future interactions are bound to be pretty inevitable. It’s only the relative rarity of opposite direction past-future interactions that make them harder to detect.

Analogies are useful when the going gets sticky. Let’s say we have 1000 cars in the (present time) parking lot. There are 500 black cars (call them antimatter cars) and 500 white (or matter) cars.

Now say 500 cars head toward the north (future time) exit, 99% of which are matter cars and 1% antimatter cars. In keeping with symmetry, we have 500 cars head for the south (past time) exist, of which 99% are black antimatter automobiles and 1 % are the white matter automobiles. Apart from a few possible bender-benders as the cars jockey for the two exits (I’ll assume here that the black cars only bump fenders with other black cars and white cars vice versa), I’ll take it as given that 495 white and 5 black cars make it to the north exit and the northbound freeway, and 495 black and 5 white cars ditto than heading southbound, towards the past.

In fairly quick order, you have two separate groups heading away from each other, never to interact with each other again. (See my potential cosmology example above.) Alternatively, you could just have all 1000 cars head out of the north exit and travel on the northbound (heading towards the future) freeway. But, you’d need 99% of  your cars to be matter white cars (990 of them) and 1% antimatter black cars (10 of them) to reflect the fact that because they represent the matter/antimatter distribution of our Universe, and there’s way more of the former than the latter. 

In our Universe, it’s the northbound traffic on the freeway that’s the parallel analogy. We’re heading towards the future in a predominately matter based Universe. (I’m ignoring ‘dark matter’ and ‘dark energy’ here since we don’t have much of a handle on what exactly they are.)

Because the northbound traffic is all travelling at the same speed, one second per second, there’s not too much interaction between the cars going on, apart from those inattentive drivers who drift sideways. So, cars can interact, explosively if a black car drifts into the pathway of a white car (or vice versa), but not that often, relatively speaking.

Now in our northbound freeway traffic of 495 matter cars and 5 antimatter cars, every now and then one of the cars does a U-turn - now something interesting is bound to happen, keeping in mind that a black car becomes pseudo-white and a white car, pseudo-black. Cars travelling all in the same direction don’t interact much; but if a rogue car starts travelling down the wrong way, going south in the northbound lane (or vice-versa), well headlines are bound to be made. You have the following options: A wrong way pseudo-white car meets head-on a white or black car; a wrong way pseudo-black car meets head-on a black or white car. If pseudo-black meets white, or pseudo-white meets black, that’s like matter-antimatter annihilation. But if pseudo-black meets black, or pseudo white meets white, then things are more complicated.

Value-Adding:

So, when ‘interesting’ things happen, how do these interesting events actually explain spooky physical (quantum) phenomena? Well one possibility, as given above, is that it explains why all electrons or positrons or protons or antiprotons or neutrons or antineutrons, etc. are the same. There’s just one of each! Apart from that, it can explain Einstein’s objection to quantum entanglement – spooky action at a distance, where apparently, two particles can ‘communicate’ or interact at faster-than-light speeds. For example, say an elementary particle leave the Sun’s visible surface at say 6 a.m. your local time. It then reverses time direction back to say 3 a.m. your local time. It reverses time direction again and since it’s now had plenty of time to travel the distance, hits your particle detector at 6 a.m. your local time. That particle has travelled from the Sun to the Earth, not in the normal eight light minutes, but instantaneously. One other bit is that if a particle travels into the past that adds to the collective amount of stuff at some point in space as well as in the past. Again, say a particle at 6 a.m. in Sydney reverses time direction and ends up back at 3 a.m. in Canberra, where a double slit experiment is being carried out by shooting particles one at a time, yet producing traditional wave interference. Well, one way to explain where all these extra unexpected particles come from that can account for the strange interference effect is that they have not come from so much as a where as from another when. The experimenter thinks he is firing one particle at a time, when in reality there are lots of others around, all from different times! Remember, zigzagging back and forth in time again and again and again produces lots of particles at a particular time, but it’s the same particle. So, so-called wave interference is explained where logic dictates there shouldn’t be any at all!

Conclusions:

Either you accept that at the micro (quantum) level time can flow in either direction, or you stick steadfastly to the arrow-of-time of the everyday macro world as something that applies equally as well to all things micro. Either way apparently is a valid point of view. Different strokes for different folks.

Some additional references are:

Davies, Paul; The arrow of time; (in) About Time: Einstein’s Unfinished Revolution; Penguin Books, London; 1995; p.196-218 (esp. 204-207):

Fraser, Gordon; The back passage of time; (in) Antimatter: The Ultimate Mirror; Cambridge University Press, Cambridge; 2000; p.77-93:

Gott, J. Richard; Time travel to the past; (in) Time Travel in Einstein’s Universe: The Physical Possibilities of Travel Through Time; Phoenix, London; 2002; p.76-130 (esp. 128-129):

Oerter, Robert; The bizarre reality of QED; (in) The Theory of Everything: The Standard Model, the Unsung Triumph of Modern Physics; Plume, N.Y.; 2006; p.93-120 (esp. 114-120):

Some further readings about antimatter in general:

Close, Frank; Antimatter; Oxford University Press, Oxford; 2009:

Fraser, Gordon; Antimatter: The Ultimate Mirror; Cambridge University Press, Cambridge; 2000:

Nir,Yossi & Quinn, Helen R.; The Mystery of the Missing Antimatter; Princeton University Press, Princeton, New Jersey; 2008:

Antimatter and the One Electron Universe: Part Two

It’s a saying that’s been quoted by others, usually scientists and science writers, thousands of times by now, yet it retains the element of a profound insight. And that is ‘the Universe is not only far stranger than we imagine, it’s far stranger than we can imagine’. Every time you turn a corner, there’s an unexpected and rather shocking surprise staring you in the face! Mother Nature never seems to run out of curve balls. Anyway, one such imagination could have our Universe’s strangeness level increased a notch or so in that it allows for micro (quantum) time travel and that perhaps can lead to a Universe that consists of way less stuff than that contained in the smallest speck of dust.

Continued from yesterday’s blog…

The One Electron Universe:

So here is where things get interesting. According to Michio Kaku* (and other sources – see further readings), Feynman speculated (whether seriously, or tongue-in-cheek I know not) that perhaps the Universe consisted of only one electron (and presumably one proton**, one neutron, etc.). The logic goes something like this – at 10 AM an electron travels in the normal future direction. At 10 PM the electron reverses its time direction and heads back towards the past. At 10 AM it bounces back towards the future. At 4 PM, you freeze-frame and ‘see’ three particles, two travelling from the past to the future; one traveling from the future to the past. But in reality, all three are the same particle, two are matter electrons, one appears as a pseudo-positron. Now multiple that zigzag by zillions and extend some of the time frames from the Alpha to the Omega. One can reach the conclusion that the Universe consists of just one each of all the elementary particles!

This electron/pseudo-positron pair, bouncing forever forward and backward in time between Creation and Armageddon, is in fact the sum total of electron-ness in the Universe, which explains why all electrons are identical clones; ditto positrons since one travelling backwards would then appear to be a pseudo-electron.

The same would apply to a proton. There’s only one bouncing forward in time (as a proton) and backwards in time (as a pseudo-antiproton**) between the Alpha and the Omega. And real antiprotons, going backwards in time would appear as pseudo-protons.

In short, the Universe (including you), from beginning to end, consists of just a very few (one of each) particles and antiparticles, which makes the Big Bang event more believable! Any ‘now’ moment is just one slice of that forever ping-pong ball back-and-forth endless journey. It all happens so fast that for all practical purposes, one particle is everywhere at once. You think you consist of zillions of particles – alas, it’s only a few going zip, zigzag, zoom, zigzag, zip, zigzag, zoom, zigzag, zip, zigzag, zoom, zigzag, zip, zigzag, zoom, zigzag, zip, zigzag, zipping & zigzagging & zooming, etc. – back and forth – so rapidly it’s the illusion of many.

Now, personally, I think it’s one of the biggest crock-o-shit ideas I’ve come across (the lone particle idea, not the antimatter or the time reversal concepts – but then again Feynman may have been just shooting the bull and tossing out ideas just for the sake of speculating). I have to admit however, it’s a damn appealing idea in its simplicity! The cosmos all of a sudden is a lot less complex and perplexing. But…

The problem, as I see it, is that the zip/zoom time for electrons/pseudo-positrons (and positrons and their pseudo-electrons), or protons/pseudo-antiprotons (and antiprotons and pseudo-protons) is relatively slow (less than light speed) because they have mass. Even if they travelled at light speed, be it backwards or forwards in time, it would take, say zipping back to the Big Bang event, some 13.7 billions of years to do so (and another 13.7 billion years to return to our time). That would mean an awfully long duration when our ‘now’ was devoid of stuff and energy. The mirror of that is the time these few and far between particles would take to cross the Universe from side-to-side (assuming a finite Universe), even neglecting any further expansion while that crossing was going on. The crossing would take far longer than you could hold your breath for (and then some). Maybe that’s why the ‘one electron, one positron, one proton, one antiproton, etc. Universe’ isn’t discussed much. As a science fiction idea, it’s great. As a practical example of how our Universe is constructed – well you don’t see it proposed in any astronomy textbooks!

Or could it? Keep in mind that the side-to-side and top-to-bottom (or ultimately volume) crossings of the Universe was easier/quicker in the past when the Universe was smaller (recall our Universe is not only expanding, but that the expansion rate is accelerating due to something we know nearly nothing about called ‘dark energy’). Alas, the time distance between Creation and Armageddon (assuming there is an actual final end which is doubtful given an ever ongoing expanding Universe) remains fixed, so there’s no way to compress that part of the journey. Now here I keep assuming that the maximum ‘velocity’ through time is one second per second in either direction.

Oh wait, I’ve neglected to take relativity theory or effects into account. The velocity of electrons and positrons (and protons and antiprotons) through space could affect their ‘velocity’ through time. However, I’ve no hard information on how fast in space electrons/positrons, protons/antiprotons will travel. Elementary particles can stand still – well wiggle and jiggle in places somewhat uncertain according to quantum principles.  Or, they might really floor the petal to the metal and zip and zoom around – as opposed to being laid back. If they zip and zoom around at close to light speed, their ability to transverse the cosmos in quick-smart time is increased. Recall the so-called ‘twin paradox’ where the twin in the fast lane ages a lot slower than her stay-at-home laid back sister. Lacking hard information, I’ve really not neglected relativity; I just can’t figure it into the scenario.

An analogy in something less than cosmic terms, would be to think of a river which has length, depth, and width. Each fundamental particle, or let’s be generous and say one water molecule, would have to go from top to bottom, bank to bank, and headwater to river mouth so quickly so as to give the illusion of a ‘solid’ continuously flowing river.

What ever so slight worries me here is that there is an actual known example of how Mother Nature presents us with an illusion. Solid matter (or liquid matter or gaseous matter for that matter) isn’t solid at all. Matter is nearly all empty space, be it an ice cube, a drop of water, or water vapour. Since that’s not an everyday common example, you’re more aware of how a film strip of individual images when moving rapidly create the illusion of a picture in motion, or a motion picture. Another common example is your TV screen or newspaper photograph. Those apparently solid continuous images are in reality just a composite of hundreds of individual dots.

Anyway, still, it’s a real stretch to imagine a river, far less our cosmos, as being composed of just a few bits and pieces! Actually that brings up a more fundamental problem in the case of one water molecule zipping and zapping so fast as to create an illusionary river – one water molecule, far less any single elementary particle or combination of particles has no property of wetness. So how could a one water molecule alone give a river its wetness property? [The same applies to other properties of matter – say colour, or texture. How could a one electron universe have colour?]

Ultimately it matters little if there is only one electron/positron (and proton/antiproton) dual-particle or entity zipping and zooming and zigzagging back and forth, or an umpteenth zillion. There’s still an observational lack of antimatter and there should be near equal amounts of both matter and antimatter. That imbalance is strange in that with equal probability a photon should create both an electron and a positron (and electron-positron annihilation should create a photon – symmetry all around).

The Missing Antimatter:

So why don’t we see significant quantities of antimatter today? Well, it’s nearly all travelled into the/our past in the form of pseudo-matter. Of course, if it were all that simplistic, you’d think textbooks would be full of pages outlining how the mystery of the missing antimatter has been solved. Since they’re not, maybe I’ve missed out on an elusive point or ten, or maybe the penny hasn’t dropped for the rest of the physics community yet!

Anyway, ‘what if’, and I have no specific reason in mind why this should be the case, but ‘what if’ antimatter has a greater affinity for travel backwards in time than matter? Antimatter exists – that’s established fact. Now antimatter can be created in labs and is used in medicine and it normally travels in a forward time direction at one second per second - normally. Therefore it doesn’t follow that any particle of antimatter must immediately upon its creation start heading towards The Creation, only that all else being equal, more antimatter particles than matter particles reverse time’s arrow.

Since antimatter doesn’t disappear immediately (if properly contained in a magnetic field away from ordinary matter), disappearing as in a backwards in time Houdini trick, there appears to be no observational evidence for this backwards-in-time-travel stunt by antimatter. I mean, if 100 antimatter particles are created in the lab, yet a few minutes latter there are only 98, that should constitute evidence, but apparently that’s not observed. For that reason, if I were a gambler, I’d bet against the antimatter-traveling-back-in-time theory; but why spoil a good scenario? But then as illustrated above, there’s nothing incorrect about viewing all of matter and all of antimatter, the sum total of stuff, just moving forward in time and in step at the rate of one second per second.

Still, we have to account for a Universe where matter rules and antimatter is the minority.

Maybe the affinity for antimatter travelling backwards in time is a slow (by human standards) process that however over cosmic time periods takes on significance.

But wait, you might think that a positron starting its journey back in time at one second per second would be thwarted in that the physical world it exists in is itself moving forward in time at one second per second. The two, a plus one second per second and a minus one second per second would cancel out and thus the positron is stuck in place and ain’t going no-where! But that doesn’t work either. Here’s our river analogy again to clear things up (I hope).

So say you’re floating in a river (representing time), moving downstream (the arrow of time) at one meter per second. Where ever you are, that’s your ‘now’. Downstream is your future; upstream is your past. Say a fish (representing the positron) is swimming upstream (back in time) at one meter per second. The fish is just standing still relative say to a tree on the bank of the river. You, on the other hand, are floating by that tree (which is standing still while you’re moving relative to it a one meter per second) and leaving it behind (in your past). Likewise, you and the positron-fish are getting farther and farther apart in distance, or separated in time!

To be continued…

*Parts of this topic were sparked off by reading several pages in Michio Kaku’s chapter on Precognition, contained in his latest book Physics of the Impossible: A Scientific Exploration of the World of Phasers, Force Fields, Teleportation and Time Travel; Penguin Books, London; 2009:

**Old learning’s die hard. Of course both the neutron and the proton are no longer considered to be fundamental particles. Rather, both are composed of a trio of quarks, and thus it is proper to have quarks and anti-quarks rather than protons and antiprotons/neutrons and antineutrons.

Antimatter and the One Electron Universe: Part One

It’s a saying that’s been quoted by others, usually scientists and science writers, thousands of times by now, yet it retains the element of a profound insight. And that is ‘the Universe is not only far stranger than we imagine, it’s far stranger than we can imagine’. Every time you turn a corner, there’s an unexpected and rather shocking surprise staring you in the face! Mother Nature never seems to run out of curve balls. Anyway, one such imagination could have our Universe’s strangeness level increased a notch or so in that it allows for micro (quantum) time travel and that perhaps can lead to a Universe that consists of way less stuff than that contained in the smallest speck of dust.

Symmetry: The Yin and the Yang:

Symmetry, or two ways of looking at things, or dual solutions or just plain duality is quite familiar in our world and has lots of parallels in mathematics and physics too. I mean we have wave – particle,  forward - back, left - right, east - west, top - bottom, north - south, push - pull, either – or, positive charge - negative charge, matter – antimatter, spin-up – spin-down, mass (matter) – energy, clockwise – counter clockwise, for every action there is an equal and opposite reaction, the irresistible force vs. the immovable object, odd – even, zero – infinity, male – female, mind – body, alive – dead, black – white, night – day, dawn – dusk, right down to heads or tails, old vs. new, war and peace, a glass half full vs. a glass half empty, perhaps Coke vs. Pepsi in that glass! 

We’re aware that there are mathematical equations that have two solutions. For an easy example, what is the square root of four? There are two solutions: +2 and -2. Of course the concept of -2 is usually considered to be irrelevant or nonsense (can something be minus two feet in height?), so normally only the positive values are considered justified. One tends to always assume and use +2, which, when squared, is four.

Likewise, the general form of a quadratic equation always has two solutions at its core, again, one that is usually a plus value, one that is usually a minus value, but in any event dual solutions.

Symmetry and the Flow of Time:

So, with all this symmetry and dualism in our lives, in physics and in mathematics, why not add in one more – say the flow or arrow of time. But surely time can only flow in one direction, from past to present to future. Or then again, maybe that’s an unwarranted assumption.

At the micro (quantum) level, there is no physical law or principle equivalent to the one-way macro ‘arrow’ of time. Every micro (quantum) action in what we would term the direction towards the future can be equally valid in what we would term the direction towards the past. If time has no significance at the micro (quantum) level, then all particles and all antiparticles can go both backwards and forwards in time, and in doing so, become pseudo-antiparticles or pseudo-particles respectively. The concept that the arrow of time can reverse must be among the most difficult of ideas to wrap your gray matter around if for no other reason than that our grey matter has only ever actually experienced a unidirectional time’s arrow.

Translating what a dual-solution, a minus or a positive value solution, could mean in real physics, Maxwell’s equations predict the existence of two sorts of light waves, a (positive value) ‘retarded’ light wave (the normal kind that travels from past to present to future), and (you guessed it) a (negative or minus value) ‘advanced’ light wave (a decidedly un-normal variety that would in theory travel from future to present to past). 

In physics, one normally has something called CPT symmetry, where C = charge, P = parity (left vs. right), and T = time. To conserve symmetry, if a particle is assumed to be travelling backwards in time, then its handedness is reversed, and so is its charge. It takes on the appearance of that particle’s antimatter counterpart.

In other words, you have to reverse the charge, reverse left-right handedness, and reverse the arrow of time to conserve symmetry. When this is done, an electron, going backwards in time, must take on the appearance of, and be interpreted as, a positron – but of course it’s a pseudo-positron in that’s it’s a normal electron wearing a Halloween mask even though it’s indistinguishable from the real positron McCoy. 

Feynman’s Idea:

When (future) Nobel Laureate Professor Richard P. Feynman (albeit starting this track while in his graduate days) looked at physicist Paul Dirac’s equation for electrons, he noticed that if one reversed both the electron’s charge and the time element, then there was perfect symmetry. An electron with normal negative charge going forward in time (one solution), seemed to be identical to an electron with positive charge – a positron – going backwards in time (a second solution)!

A positron is termed an electron’s antiparticle, or equally an electron could be termed a positron’s antiparticle, but in common terms, an electron and a positron are examples of matter and antimatter.

Now all matter particles have an antimatter twin. Their charges are opposite. Particles having no overall charge (like a neutron** or a neutrino) are their own anti-particles (in that their charge is the same – zero). Even so, these particles and their antimatter counterparts differ in other respects, have differing quantum numbers, so particle physicists still talk about such things as an antineutron** or antineutrino, and you’ll find references to them in the antimatter literature. Antimatter isn’t an ivory tower fairy tale concept. Positrons have been created; Mother Nature can create antimatter. In fact, gram for gram, antimatter is the most valuable stuff in existence, worth hundreds of times its weight in gold or diamonds because it’s both naturally rare and can only be manufactured in miniscule quantities at exorbitant costs in particle accelerators.  And, as we all are aware, when matter meets antimatter it’s annihilation time – ka-boom – electromagnetic energy (photons) is given off***.

The upshot of all this is that Feynman proposed that antimatter was just ordinary matter but ordinary matter going in the opposite time direction! Perhaps at this juncture I’d be better off to quote Feynman directly:

“We begin with a photon and an electron, and we end up with a photon and an  electron. One way this event can happen is: a photon is absorbed by an electron, the electron continues on a bit, and a new photon comes out. This process is called the scattering of light. When we make the diagram and calculations for scattering, we must include some peculiar possibilities. For example, the electron could emit a photon before absorbing one. Even more strange is the possibility that the electron emits a photon, then travels backwards in time to absorb a photon, and then proceeds forward in time again. The path of such a “backwards-moving” electron can be so long as to appear real in an actual physical experiment in the laboratory.

The backwards-moving electron when viewed with time moving forwards appears the same as an ordinary electron, except it’s attracted to normal electrons – we say it has “positive charge”. … For this reason it is called a “positron”. The positron is a sister particle to the electron, and is an example of an “anti-particle”.

This phenomenon is general. Every particle in Nature has an amplitude to move backwards in time, and therefore has an anti-particle.”

[Feynman, Richard P.; QED: The Strange Theory of Light and Matter; Penguin Books, London; 1990; p.97-98.]

Or, in the words of British science writer Jenny Randles:

“Indeed, it is now widely accepted that the best way to interpret a positron – which is the antimatter version of the electron with identical mass but opposite charge – is to view it as an electron that moves backwards through time.”

[Randles, Jenny; Breaking the Time Barrier: The Race to Build the First Time Machine; Paraview Pocket Books, New York; 2005; p.116.]

So, here’s my understanding of what happens, and apparently there are two ways of looking at the picture. What if an electron is going forward in time and for some reason emits or absorbs a photon which would cause it to alter direction, perhaps to the extent of reversing direction in time as well thus taking on the appearance of a pseudo-positron (because charge is reversed). At some later time, the pseudo-positron emits or absorbs a photon, and reverses time direction again turning back into your everyday electron. That’s one way of looking at things.

The other way is to abandon time reversals and just assume that all electrons and all positrons go forward in time, full stop. In either scenario, you have no physical contradictions – two solutions to the same equation as it were. But if you accept the time reversal concept, it’s a sort of micro Dr. Jekyll and Mr. Hyde transformation.

Let’s run that by again.

Reality one: A real electron travelling forward in time absorbs a photon, bounces back in time as a pseudo-positron (because charge has to be reversed) and absorbs a photon and reverses time direction again, back to that of an electron moving forward in time.

Equally, a real positron travels forward in time, absorbs a photon, goes back in time as a pseudo-electron (charge goes from plus to minus), absorbs a photon and reverses time direction. In this picture there is no matter-antimatter annihilation.

Reality two: A real electron (or positron) going forward in time meets its opposite number (caused by an earlier forward time travelling photon energy that disintegrated producing a matter-antimatter particle pair) and that annihilation produces (emits) a photon (energy) also travelling forward in time which can then disintegrate back into an electron-positron pair travelling forward in time. In this view there is annihilation (matter meets antimatter), and energy (photon) producing a matter-antimatter particle pair, but no time travel. In either picture, the total number of electrons, positrons and photons remain the same. 

 To be continued...

**Old learning’s die hard. Of course both the neutron and the proton are no longer considered to be fundamental particles. Rather, both are composed of a trio of quarks, and thus it is proper to have quarks and anti-quarks rather than protons and antiprotons/neutrons and antineutrons.

***I’ve never actually seen an explanation as to why matter and antimatter annihilate on contact giving off pure energy. It just does in the same, but opposite way (symmetry again) as pure energy can create matter and antimatter particle pairs. The annihilation and creation of matter – antimatter, to and from energy, is not the problem since matter (including antimatter) and energy are two sides of the same coin. [It’s interesting that you have matter and antimatter, but not energy and anti-energy.] So, I’ll just accept that when an electron meets a positron – ka-boom. Also ditto that in that a ka-boom can create an electron – positron pair. But presumably an electron and an antiproton, if meeting up, won’t annihilate because the antiproton is not the antimatter equivalent of an electron. Also ditto that in that energy cannot create an electron – antiproton pair of particles.