An Infinite Cosmos: Part Two

The nature of, the size, the shape and the duration of our Universe has been speculated and debated upon ever since humans gazed in wonder at the night sky. Though ideas have waxed and waned, and though modern cosmology is more focused than ever on actual observations, speculations, well that’s still the case today. My take, albeit slightly more philosophically inclined, is that our Universe is just part of an overall infinite in space and infinite in duration cosmos. 

Continued from Part One.

As we noted in the example of the fridge and your body, it takes energy to reverse entropy or at least hold it at bay. A reversal of entropy is sort of like that closed box with Maxwell’s Demon (representing energy) that controls a slot that the Demon can either open or close that’s in the middle of that closed box that’s of a uniform temperature.  The Demon opens the slot whenever a rapidly moving (hot) molecule heads toward the left side or when a slower moving (cold) molecule heads toward the right side. After a while, the left side of the box will be containing just hot stuff (rapidly moving molecules) and the right side cold stuff (slowly moving molecules). Maxwell’s Demon is like a kid expending energy sorting a bag of 1000 various coloured marbles (maximum disorder) into piles of reds and greens and blues and yellows (maximum order).  Of course our infinite cosmos contains no demons, and marble-sorting kids need not apply if there’s ever a job ad for restoring order to an infinite cosmos.

Okay, without demons (or entropy reversing kids), our infinite cosmos heads towards a state of maximum entropy or maximum disorder or maximum uniformity. The cosmic temperature will be the same everywhere; matter will be evenly distributed. But, can an infinite cosmos ever reach such a state? It could or should take an infinite amount of time, but that’s also assumed. 

Yet alas, what even an infinite cosmos needs is a Maxwell’s Demon. The cosmos, if it is to retain a state of vitality for an infinite duration, needs something that recycles stuff that’s at maximum entropy (maximum disorder) back to the basics of minimum entropy (or minimum disorder) where useful things can continue to happen.

* The Role of Gravity

Gravity seems to be a Maxwell Demon’s kind of force that keeps on keeping on. As long as you have two bits of matter, even just two electrons, you have gravity. Radiation (electromagnetism) could be dispersed evenly in infinite space over infinite time, but it is hard to imagine that situation with gravity. The only real way gravity could be rendered inert and useless as an energy source would be if it was 100% concentrated in just one place – like a super ultra mother of all cosmic Black Holes. The only other way gravity could be nullified would be in matter were distributed so absolutely evenly such that every bit of matter were being gravitationally pulled on absolutely evenly in each and every direction. But the slightest nudge or deviation from this ideal theoretical state (inevitable given quantum fluctuations) would throw everything out of equilibrium. But because matter is energy and energy is matter, if gravity can disrupt the distribution of matter from a state of near perfect uniformity, then energy will follow the short and curly material bits. Light (photons) reacts to gravity as much as electrons do. Further, the one extra nice property that gravity has is that it can’t be blocked. You can block out light or shield yourself from electromagnetic effects, but nothing will shield you from gravity.

* The Recycling Role of Radioactivity

Fortunately, there are several basic ways of recycling complex cosmic stuff back into the cosmos in the form of simple stuff. The first of these however has issues. Gravity can contract and pull together interstellar gas and dust into a proto-star which will ignite under pressure via thermonuclear fusion to form a radiant star. Stars however fuse lighter elements into heavier elements, and when a star goes nova, or becomes a supernovae, those heavier elements increasingly form the next generation of interstellar gas and dust. Eventually, after many generations of enrichment, interstellar gas and dust is lacking in those lighter elements (mainly hydrogen and helium) which easily undergoes fusion. Heavy elements, like iron, just won’t fuse any more and so the continued formation of radiant stellar stuff grinds to a halt. But, there is an escape clause.

Among the heavy elements; elements that stars manufacture, are radioactive elements with unstable atomic nuclei. Radioactive decay re-releases back into the cosmos those fundamental bits and pieces that can reform into those lighter elements that are the basic building blocks for forming radiant stellar objects. There is cosmic recycling from the simple to the complex and back to the simple again.

* The Recycling Role of Cosmic Black Holes

The second way of cosmic recycling is, believe it or not, via cosmic Black Holes. Astronomical Black Holes, via the vacuum energy (quantum foam or fluctuations) and quantum tunnelling, can release elementary particles back into the cosmos. As mentioned earlier, this is known as Hawking Radiation, after theoretical cosmologist/astrophysicist Stephen Hawking. Complex stuff can go into a Black Hole, but just very simple stuff ultimately comes back out again.

* The Recycling Role of Life

Life can be an entropy buster as in the case of Maxwell’s Demon, the kid who sorts the marbles, the mum who does the housework, the bird or beaver who gathers up forest debris to make a nest. But, it takes outside energy to accomplish these things and at the end you haven’t decreased complexity – the marbles are still marbles; twigs are still twigs. But microbes like bacteria, etc. can break down complex stuff (like twigs) and turn it into less complex stuff which can be recycled into hundreds of new and different complex things. So, when our home planet eventually meets its Waterloo, and gets scattered back into the cosmic winds, thanks to bacteria, there will be more simple stuff floating around than would otherwise be the case

So complex stuff gets recycled back into simple stuff, all brought together again by gravity to ultimately form complex stuff again. The cosmos receives recycled stuff back, from which it can keep on keeping on!    

* A Fly in the Ointment

In a cosmos that’s both infinite in space and infinite in duration, here’s an interesting ‘angels on the head of a pin’ question. There are two forces which in theory can extend their influence indefinitely, that is, unto infinity. They are electromagnetism (of which light is a prime example) and gravity. So, can the influence of a force cross an infinite space if it has an infinite amount of time to do it in?

Perhaps Maxwell Demon’s ‘closed box’ isn’t really an appropriate ‘container’ for an infinite cosmos. If the cosmos is infinite, can it be described as a closed system? 

The Multiple You

And so finally, consider and reconsider the quantum mantra: “Anything that isn’t forbidden is compulsory; anything that can happen will happen”. That’s even more the case when you have infinite time and space to play around with! So, I add to that mantra “and will happen again and again and again, an infinite number of times”. That actually means, or at least very strongly suggests that every possible scenario, every possible history, and every possible variation on each and every scenario or on any theme that you care to think of or think up will happen again and again and again. That, by the way, includes you. You are a scenario, and you, and every possible variation of you and your history will transpire numerous times; actually an infinite number of times. If that isn’t spooky, I don’t know what is, but it’s a logical consequence of having an infinite cosmos. 

An Infinite Cosmos: Part One

The nature of, the size, the shape and the duration of our Universe has been speculated and debated upon ever since humans gazed in wonder at the night sky. Though ideas have waxed and waned, and though modern cosmology is more focused than ever on actual observations, speculations, well that’s still the case today. My take, albeit slightly more philosophically inclined, is that our Universe is just part of an overall infinite in space and infinite in duration cosmos. 

In the infinite beginning there was something rather than pure nothing – a finite amount of something in an infinite void of nothingness. This scenario eliminates the philosophical quandary of what’s beyond the boundary - that only other alternative. This eliminates the philosophical quandary of how much stuff there is. An infinite amount of stuff doesn’t leave you much elbow room.

In the infinite beginning, well there was no beginning; there can ever be an end. No Alpha – no Omega. This eliminates the philosophical quandary of what comes before the ‘beginning’ and what comes after ‘the end’. 

Okay, having postulated an infinite cosmos in space and in duration, well, other certain and not so philosophical issues come to the fore. If they can be addressed, well that’s all to the good. If not, well it’s back to the drawing board.

I’ll start with…

Olber’s Paradox

The night sky should be as bright as the daytime sky since in whatever direction you look, sooner or later you should see a star or galaxy that’s in your line of sight. That’s Olber’s Paradox because the night-time sky isn’t as bright as the daytime sky. One resolution is that our observable Universe is finite and there are only a finite number of stars and galaxies and thus, there will be lines of sight that do not intersect with an object that’s emitting light.

But what if the cosmos is infinite in size and has existed for an infinite amount of time? Does that resurrect or reinstate the validity or viability of Olber’s Paradox? Not necessarily.

Why is there something rather than nothing? That’s been a prime philosophical question that has raged for eons. But, on reflection, overall, there is a great deal more of nothing than of something. If everything was something, it would be rather difficult to move. There would be no elbow room. In other words, just because the cosmos is infinite in duration and in volume doesn’t mean that there has to be an infinite amount of something within.

Let’s say that pure nothing is a perfect vacuum. Then something within that nothing makes for an imperfect vacuum. One could image a cosmos so dilute that there could literally be gaps of pure nothingness between the bits and pieces of something. Or, one could imagine a universe that contained just one final cosmic Black Hole that had over all the infinite eons gobbled up everything else that had been a something within the cosmos, and thus 99.99999% of that cosmos would contain absolutely nothing. 

That aside…

Stars, like people, are born, and thus their light may not have yet reached us.

Stars, like people, die, and thus their light has ceased to reach us. It has all now passed by.

In an infinite space, stars maybe so far distant that by the time their light reaches us, it’s so diluted or spread out that only one photon per hour hits the eye and that threshold is too low to stimulate the optic nerve and thus register.  

Ever present cosmic Black Holes have gobbled up a lot of the radiation that is emitted and reflected. In fact, in a cosmos that’s infinite, why haven’t those astronomical Black Holes sucked up everything that can be sucked up thus terminating any and all evolving universes within that cosmos? Well the answer is Hawking radiation which theoretically predicts, on pretty substantial grounds, that eventually Black Holes will radiate away their mass. Once input is less than Hawking radiation output, the Black Hole will slowly, ever so slowly, radiate away, giving back to the cosmos what it once took away. There will be more on the significance of that shortly.

Entropy and Cosmic Recycling

Another concept that needs addressing is entropy or the Second Law of Thermodynamics, otherwise known as the ‘arrow of time’ or sometimes as ‘time’s arrow’. If one considers an infinite universe to be a closed box or closed system, then over time, and we have an infinite amount of it, that closed box should reach absolute equilibrium and no further cosmic evolution would be possible. There would be a maximum amount of disorder, and there would be no further energy available to reverse that level of disorder.

It should be noted from the outset that in any closed box or closed system, entropy rules. Things will go from a state of order to a state of disorder without outside interference, that being an external source of energy to reverse the natural trend. The commonly cited example is if you have a closed box (the kitchen), and you turn off the fridge, the kitchen and the fridge will eventually reach absolute equilibrium, the same temperature. The kitchen warms up the fridge; the fridge cools down the kitchen, until both are at the same temperature – maximum disorder. It takes an outside energy source – electricity – to keep the fridge colder than the kitchen and thus in a state is disequilibrium or a state where entropy has not been maximalized. Trouble is, once energy is evenly spread out throughout a closed system (like the fridge in the kitchen), no matter how much of it there is, it’s useless in terms of doing useful things – like initiating change.

Another example: Your own body is a closed system. Your body’s energy is in equilibrium. You are at 98.6 degrees Fahrenheit from head to toe. Within that state of affairs, your body can not do useful things. Fortunately, there’s a larger closed system that your body is a part of (like the fridge is part of the kitchen) that enables you to disrupt your body’s equilibrium and thus provide the means for your body to initiate change. Your outside energy source is food, which is good since once you invoke that larger closed system that contains you, that larger system absorbs your body heat that gets radiated away into it. So the fridge needs outside energy to replenish its supply of cold; you need energy to replenish your body heat and to provide the ways and means to keep you keeping on. Of course as we all know, that’s just postponing the inevitable. Sooner or later the fridge breaks down with wear; ditto you too. But in the meantime, and for a little while, you can keep your body’s entropy under control.  

Now any attempt to tunnel around various laws, principles and relationships of physics might be in vain, but not a total waste of time. The laws, principles and relationships of physics are constantly being refined, even overturned as in Einstein refined Newton’s gravity; the Sun going around the Earth got overturned by Copernicus. However, anyone attempting to tunnel over, around, or through the Second Law of Thermodynamics should abandon all hope. If you try to butt heads with entropy you’ll just end up with a sore head. You’d have better luck patenting a ‘perpetual motion’ machine, itself a violation of the ways and means of the entropy concept. In fact entropy is why you can’t construct a perpetual motion machine and why any patent officer worthy of the name would refuse you a patent for one.

Still, in an infinite cosmos, a cosmos that keeps on keeping on, there probably needs to be a way to go from a state of disorder (high entropy) back to a state of order (low entropy).

  

To be continued…

Time To Question Time: Part Two

Time is the most mysterious concept that you are likely to think about. You know exactly what time is, unless you actually have to explain it and then things bog down. If you admit that time is pure puzzlement, well you’re not alone as the nature of time has been endlessly debated by thinkers, good, bad and average, ever since humans had the ability to think. Okay, I’m a thinker, so here are my thoughts in Q & A form about time.  

Continued from yesterday’s blog…

Q. Is time travel to the future possible?

A. Time travel to the future is easy – you’re doing it right now at the rate of one second per second – boring – or when you fall asleep (or pass out drunk), next thing you know you are in the future, ahead by several hours. You’ve skipped or jumped over some interval of time. That’s what one usually means by travel to the future. It is jumping over some significant interval of time without having to experience or live through it, like say going from 2013 to 2015 and avoiding 2014 entirely. Of course when you arrive in the ‘future’, be it the following morning or by skipping 2014, it’s no longer the future but the present – the ‘now’. It’s actually impossible to be in or to exist in the future, it’s only possible to head towards the future, which you do anyway at the rate of one minute per minute. 

I guess you could construct a philosophical argument that relative to your point of view of yesterday, if you say skipped a day and landed in tomorrow, you are now in the future, but such convolutions don’t get us very far since the you that existed yesterday no longer has any existence or meaning either today or tomorrow or post tomorrow. In fact, the person you call “you” that existed one second ago has now come and gone and passed away into history. The only you that has any reality is the person you call “you” that exists right now.

Apart from your normal modes of time travel into the future, you can accelerate the process. There’s also Einstein’s Relativity twin paradox whereby relative to an outside observer, time, as in rate of change, slows down for someone who is travelling at velocities that are approaching some goodly fraction of the speed of light. So, a twin who heads off at a rapid rate of knots and boldly goes, when returning to meet and greet her stay-at-home twin, will find that though twins they might be, their ages are now different. The stay-at-home twin has aged more quickly, or the boldly going twin has aged more slowly depending on your ‘relativity’ point of view, which isn’t really a paradox, rather the consequences of what happens when you travel at a very rapid rate of knots relative to someone who doesn’t.

However, the same philosophy or argument from those several paragraphs above applies in that you, in this case the you that’s the boldly going twin, is never in the future, only in the now or existing in what passes for the present (along with your stay-at-home twin). That applies even if that present is tens of thousands of years after you were born, which is possible (and thus your stay-at-home twin has long since died and returned to dust). No matter which way you slice and dice things, you only have reality in the present that you find yourself in. 

Q. And what do you conclude about the viability of time travel to the future from the above?

A. Ultimately, to my way of thinking, time travel, even to the future (by skipping over periods of time), is impossible since again time is a concept and not a thing, like a road or a river you have to travel continuously on, up and down on. If time is just a concept, then time travel is illogical.

Q. Is there any other likely impediment to time travel?

A. Yes there is. When you visualise standard time travel stories or films to the past or to the future, your time machine or device keeps you firmly attached to the same set of terrestrial coordinates from which you started, so if you say start in New York City (2013) and go plus or minus say 200 years either to the future (2213) or to the past (1813), you’ll end up in the New York City of that time. That’s bonkers! In that 200 years, either way, Planet Earth on which New York City is attached, but you are not, has moved. Planet Earth is attached to the Sun (gravitationally) and the Sun is in orbit around the Milky Way Galaxy, which itself is moving in space, so when you materialize 200 years in the past or future, the odds are extremely likely that you will materialize into the depths of outer space! Even if you ignore all that, the Earth will not make an exact number of solar orbits and axis revolutions over 200 years to bring you back into exact alignment with the terrestrial coordinates you started out from. So, you just might materialize smack dab in the middle of the Atlantic Ocean. Oops! What one really needs is a time and space machine like the Doctor’s TARDIS where you can also set spatial coordinates. 

Q. Have all billionaires been time travellers to the past?

A. Maybe! It’s easy to imagine looking up say all the long shot horses who won their races in say over one particular year. Now travel back in time to that year and start placing reasonable bets on each ‘long shot’ (that proved a sure thing), make a super-bundle of loot, and hop back to your own era; your own present day and start living the good life. Of course there are many, many variations on this go-back-in-time and get-rich-quick schemes.

Q. We spend our entire lives in the “now” moment, and eternal “now”, yet each “now” moment lasts way less than a nanosecond before the “now” you vanishes into the limbo-land of the past only to be replaced by the future you that was just a theoretical probability that now becomes reality, for just a nanosecond before that you too slips away into the unreachable past. That’s confusing!

A. There’s no real mystery here. There are many examples from daily life of the difference between the continuum and the part of the continuum.

You’re driving along the road in your car. Your car is the continuum since you’re always in your car for the duration (that eternal “now”); the specific section of road you are travelling over is your nanosecond “now” which changes from nanosecond to nanosecond.

You’re swimming with the current in a river. The surrounding water is your eternal “now”; the section of riverbed you’re passing over is your nanosecond “now”. Or, you can reverse the scenario. If you swim exactly against the speed of the river current or flow, the part of the riverbed you are stationary over is now your eternal “now”, while the patch of water around you is ever changing and thus becomes your nanosecond “now”.

If you walk across the stage with the spotlight on you, the light is your eternal “now” but your place on the stage is constantly shifting – your nanosecond “now”.

If you lie in bed all day (and night), the bed is your eternal “now”, but the ticking of the clock, even if only via the changing position of the sun (in the day) and the stars (in the night), or that change from sunrise to sunrise, is your nanosecond “now”.

Note that all of the examples involve motion. Motion is change and change is what the concept of time is all about.  

Q. Does God exist within time or outside of time?

A. There is no God (or gods) so the question is immaterial, irrelevant and has no bearing on the proceedings. But if there is a God(s) they would exist inside of time since to exist is to undergo change and time is nothing but a measure of change. 

Q. When do I exist?

A. Now, and only now. The “you” that existed an hour, even a minute ago is no longer. That past you, actually all those entities you called you (plural) that existed in the past have been consigned to the history books. The “you” that (probably) will exist an hour or even a minute from now, actually all those entities you will call you (plural) that will exist in the future do not yet have reality of any substance.

Q. So again, what is time?

A. One heck of a metaphysical mess!

Time To Question Time: Part One

Time is the most mysterious concept that you are likely to think about. You know exactly what time is, unless you actually have to explain it and then things bog down. If you admit that time is pure puzzlement, well you’re not alone as the nature of time has been endlessly debated by thinkers, good, bad and average, ever since humans had the ability to think. Okay, I’m a thinker, so here are my thoughts in Q & A form about time.  

Are you confused about time? If so, join the crowd. I’m part of that crowd, and I’m confused, but I’ll try to work through my befuddlement via this hypothetical question and answer session which hopefully will enlighten me and you too. 

Q. What is time?

A. Time is a concept, like Wednesday is a concept.

Q. A concept of what?

A. Change. Without change the concept of time is meaningless.

Q. What properties does time have?

A. Time has no properties, just like Wednesday has no properties. Time has no structure or substance; no mass or energy, no colour or spin or charge, it has no associated field, and it exerts no force and has no fundamental particles associated with it. 

Q. Does time have a beginning? Will time ever end?

A. No. Time is eternal. An eternal time removes those nasty philosophical questions of what came before; what comes after?

Q. Can time be created?

A. The concept of time can be created, but only by the mind blessed with some degree of sophistication, but that does not give substance and structure to time itself, any more than the JFK concept of ‘landing a man on the Moon and returning him safely to Earth before the end of the decade’ in and of itself made it so. The concept of a lunar landing is not a real lunar landing. Time itself cannot be created like a soufflé since there are no ingredients that collectively comprise time.

Q. Can time be destroyed?

A. Since time cannot be created, time cannot be destroyed. While that is similar to existing conservation laws, there is no conservation law in existence for time like there is for matter and energy since, unlike matter and energy, time cannot be altered from one form to another, since time is not a thing.

Q. Was the Big Bang event 13.7 billion years ago the start of time?

A. No. Since time cannot be created, the Big Bang banged in existing time which means there was a before the Big Bang. Something had to cause the Big Bang (a change) and that something could only have been an earlier event which happened in already existing time, since an event, a change, defines what time is.

Q. Where does time exist?

A. The concept of time exists only where change exists, and change only exists within that ongoing, yet ever paper-thin slice that we can the “now”. Change neither exists anymore in the past nor does it exist yet in the future.

Q. Are time’s related terms also concepts?

A. Absolutely. None of the following can be placed on the lab’s slab; none of the following are ‘things’, just mental concepts and conventions: past, present, and future; when, now and then; before and after; second, minute, hour, day, week, month, seasons, year, decade, century, millennia, and eon; any of the named days of the week; any of the names of the seasons; any digit that represents a year (i.e. – 2013); any date; yesterday, today and tomorrow; birthday, anniversary and holiday; weekend and weekday; noon and midnight.  A clock or calendar or metronome can be put on the lab’s slab, but a clock, etc. isn’t time, just like a thermometer isn’t temperature, and a Geiger counter isn’t radioactivity.

Q. Is time travel to the past possible?

A. Yes and no.

Einstein’s concepts of General and Special Relativity allow for time travel to the past (and the future), the usual scenario is via a rapidly rotating massive object that can twist space-time around in a loop where the starting point that joins up with itself to form the loop, like a snake swallowing its tail, isn’t any longer at the same point in time. However, the flaw I find with all of that is that this requires space and time, or space-time, to be a thing, which IMHO it is not. Space-time is a concept without substance and structure because both space and time are concepts without substance and structure. Be that as it may.  

The basic argument against going back in time is the creation of a paradox, something along the lines of killing your mother when she was a young girl thus preventing your very existence which means you couldn’t have gone back in time and murdered your mother, etc. Hells, bells, why not just do the suicide properly and go back in time a few months and kill your own self! But any trip back in time will create conditions back then that did not originally exist, and however minor, not only will they become an established part of history, but have that butterfly or ripple effect on down the line – chaos theory. If those new conditions, thanks to your time travelling presence, did not originally exist and now they do, that’s also a paradox as something cannot be and yet be at the same time, and that contradiction extends on down the line as history unfolds differently.

Further, you MUST go back in time (no free will in the matter) to ever create and ensure the conditions that came to pass back when, new conditions that you initially caused – only you never initially caused them since there’s an infinitely recycling causality loop here. You went back in time which caused a certain set of conditions which become a part of established history which means at some point in your life you are required to go back in time to create that certain set of conditions which become a part of established history, all to be endlessly repeated for all eternity. Presumably you couldn’t even commit suicide before you travelled back in time and thus break the cycle.

Of course if the past were somehow changed, then presumably you’d never know it since all records, including those of your memory, would be altered accordingly. But things would be messy if millions of people each travelled back in time and altered this, that and the next thing. History textbooks and other records would be rewritten and altered to conform to all those alterations every second. Then too, what if someone went back in time and altered history to the extent that mankind went extinct as a result – that’s the ultimate going back in time and killing your mother as a young girl!

Here’s a novel concept. Say it is the 10^th of the month. Go back in time to the 1^st of the month and meet and greet yourself. The both of you now wait until the 10^th of the month and then go back in time to the 2^nd of the month where you both can now meet and greet and join up with the other two of you that existed then. Then the four of you wait until the 10^th of the month and the four of you travel back in time to say the 3^rd of the month where the four of you link up with the four of you that existed on the 3^rd. The eight of you now wait until the 10^th of the month and then travel back in time to the 4^th of the month where you group together as a crowd of sixteen. Wait until the 10^th of the month and the sixteen of you travel back to the 5^th and join up with the other sixteen to form a mob of thirty-two, and so on and so on. Starting with just you, you could create an entire army of you!

Q. Where’s the paradox in creating an army just out of you?

A. The paradox here is that you are getting something for nothing, in this case extra copies of you. Where in fact does the extra matter and energy come from that creates that you army?

Q. Anything else?

A. Another reason time travel to the past is suss is that we don’t see any time travellers from our future paying us a visit. Though Einstein’s Special and General Relativity allows time travel to the past, and although the laws of physics are time invariant (they are valid from past to future and future to past), no visitors. Either our descendents don’t have any interest in us, or perhaps there aren’t any – descendents that is – if we go extinct or go back to the Dark Ages sooner rather than later. Or, perhaps time travel just isn’t possible after all or is in the too hard basket.

Q. You lie! What about the Second Law of Thermodynamics?

A. Ah yes, what about the Second Law of Thermodynamics which is held responsible for time’s arrow or the arrow of time (i.e. – things proceed from past (which you remember) to future (which you don’t remember). But the Second Law of Thermodynamics is misnamed since the second ‘law’ isn’t really a ‘law’, just a statement of probability, albeit extremely high probability. When things happen in a statistically probable way (eggs break or scramble; eggs don’t un-break or unscramble) that’s the arrow of time that we perceive. Put in a more thermodynamic context, a boiled egg cools off and heats up the kitchen until both are at the same temperature; the kitchen doesn’t cool down and transfer that energy to the raw egg and cook it.

Q. Anything else?

A. Yes, another postulate has it that one cannot travel further back in time than the time the time machine was constructed. So if our descendents come up with a first ever time machine in the year 2113, they couldn’t come visit us in 2013, though those living in the year 2213 could go back to 2113 (but no farther back).

The way out of that is what about an advanced extraterrestrial civilization’s time machine, say built in 2013 BCE, or over 4000 years ago. Say, what about those pesky UFOs? Instead of ET coming here from out there in their and our present, they come here from there in our present but from their future! The only problem with that is that UFO events and flaps are not clustered around what we would call historically important events, like say the Trinity A-Bomb test in 1945 or the launch of Apollo 11 in 1969 or the sinking of RMS Titanic in 1912. Of course, that they are conspicuous by their absence, well that just maybe our parochialism coming to the fore. Time travelling aliens may have a differing agenda. 

Aliens aside, you could easily imagine a time travelling Travel Agency existing several hundred years from now conducting guided tours to important historical events of their (and our) past, say tours in groups of one hundred per. After several thousand such tours, say to the battle of the Alamo or to Custer’s last stand at the Little Big Horn, things would be getting a mite crowded since each tour has to show up at the same place and date!

Q. And what do you conclude about the viability of time travel to the past from the above?

A. Ultimately, to my way of thinking, time travel, at least to the past, is impossible since time is a concept and not a thing, like a road or a river you can travel up and down on. You can travel in a car, but not in the concept of an automobile.

To be continued…

The Physics and Philosophy of Time: Part Two

“What is time?” That is a question that has been pondered and debated for probably thousands of years by some of the finest philosophical and scientific minds ever produced, without any definitive resolution. So, I’m NOT going to pretend that this is THE ANSWER – the be all and end all to the question. It’s some of my thoughts, which hopefully are as valid as anyone else’s!

Continued from yesterday’s blog…

How Old Are You? Well that’s obviously an easy question. You were born on such-an-such a date; today’s date is such-an-such; therefore you are such-an-such old.  Well ‘yes’, and well, ‘no’. The late astronomer Carl Sagan noted that we are all made of ‘star stuff’. That is, with the exception of hydrogen, all the higher chemical elements, which ultimately comprise us (carbon, nitrogen, oxygen, iron, etc), were cooked up in the heart of stellar interiors, at extreme temperatures and pressures. When stars explode (nova and supernova) those elements get spewed out into the cosmos, ultimately to clump together as the stuff from which new solar systems, planets, and life are formed.

However, we can go one step beyond that since, on the other hand, you are ultimately comprised of  fundamental particles like electrons and quarks which in turn make up those chemical elements (atoms) which can combine to form molecules, even the complex biochemical molecules which make you, you. 100% of you ultimately consist of these elementary particles, all of which were created or spewed out when the Universe was created. That’s currently estimated at 13.7 billion years ago, in the cosmological event called the “Big Bang’. In other words, you, being formed out of the elementary particles that collectively make up ‘you’, are the same age as the Universe, some 13.7 billion years old!  So, get in contact with your inner self, meditate with your inner electrons, quarks, hadrons, fermions, leptons, bosons and baryons, and discover the history of the universe, for they were there!

“Play It Sam. Play ‘As Time Goes By’”:  We’ve all heard of the ‘arrow of time’ which points in one direction – from past to present and present to future. It’s related obviously to the concept of entropy, that this left to themselves, things go from an orderly state to a disorderly state – a clean desk gathers dust! A teenager’s bedroom loses neatness as time goes by. One way of dramatically illustrating this concept is to look at a film of some event which runs from past to present to future, and thus looks normal, and then look at the same film running backward – i.e. from the present to the past. We’ve all seen films of a broken egg and associated mess on the kitchen floor mysteriously reassembling, leaping up into the air, and gently landing on the kitchen table top. We KNOW we’re seeing the wrong arrow of time; we know we’re seeing entropy as it isn’t – going from a disordered state to an ordered state. Nature doesn’t happen that way. Or does it?

We’ve all seen paint dry. We can film paint drying. We can tell if that film is running backwards because we know dry paint doesn’t turn into wet paint.

We’ve seen films of a thunderstorm. The lightning flashes, the thunder rumbles, and wind howls, and the rain pelts down. That film in reverse would be obvious, because the thunder rumbles, then the lightning flashes, and though the wind still howls, the rain is pelting upwards!

What if you had a lump of coal? It obviously has some amount of radioactive carbon-14 in it, which slowly but surely decays. If a film showed the amount of radioactive carbon-14 increasing in the lump of coal, you’d guess that the film was being run backwards.

Take a piece of paper and set it on fire. If you saw a film showing the reverse, ashes burning and turning into paper, you’d be pretty dense not to know something wasn’t quite right.

Take a container with a divider in the middle. In one half, fill it with hot coffee. In the other half, fill it with hot cream. Lift out the divider and start filming. Pretty soon the white cream and the black coffee produce a uniform brownish/grey mix. If you saw that film in reverse, you’d be bewitched, bothered and bewildered, because things don’t happen that way.

Lastly, let’s film your life – birth, childhood, teenager, young adult, adult, mature aged citizen, elderly, [until death was finally on the near horizon]. Again, you’d immediately know someone put the film in backwards of you saw yourself growing ever more visibly younger.

Now, instead of filming the BIG PICTURE – drying paint, a thunderstorm, radioactive carbon-14 in coal, burning paper, that nice cup of coffee with cream, and this is your life, let’s film just one elementary particle or atom or molecule contained within each of those events. If you focused on just that one bit particle / atom / molecule, and then ran the film backwards, would anything seem strange? The answer is ‘NO’.

The molecule of paint is there whether of not the wetting agent is arriving or leaving, and the wetting agent, say an alcohol molecule, can potentially arrive just as readily as leave as a molecule of same.

A water molecule (making up a rain drop) can rise into the atmosphere just as readily as it can descend.

Atomic particles can impact and turn an ordinary non-radioactive carbon atom into a radioactive (carbon-14) one. I mean radioactive carbon was somehow created in the first place, so the reverse process obviously can happen. So, even if a particle decays into other particles, the reverse is not anomalous as particles can merge – think of hydrogen fusing into helium (plus energy) in the Sun for example.

The carbon in a molecule of cellulose (paper) will, when the paper is burned, remain an atom of carbon, either as carbon ash or as carbon dioxide. But then carbon, or carbon dioxide, can be incorporated into cellulose, so filming in reverse breaks no laws of physics or chemistry. In other words, chemical reactions are reversible. Hydrogen and oxygen can combine in a ratio of two to one for form water. Water in turn can be broken down by electrolysis into hydrogen and oxygen.

There’s nothing unusual if a molecule of cream goes to the left and a molecule of coffee right next to it goes to the right (i.e. – cream and coffee components separate).

Lastly, each and every particle, atom or molecule in your body doesn’t age. Film any particle, atom or molecule that’s part and parcel of your body, view it backwards, and you wouldn’t notice anything anomalous from the time it becomes part and parcel of you until it leaves. Viewed forward or backward, particles, atoms or molecules enter your body, do their thing, and ultimately get replaced by other particles, atoms or molecules.

So, if the micro components of these macro systems don’t exhibit any preferred arrow of time, or exhibit entropy, or have some sort of inevitable destiny, then in theory, the macro systems can defy the arrow of time or entropy or their inevitable destiny. Paint can un-dry; rain can pelt upwards; atomic particles can make something non-radioactive, radioactive; carbon atoms can participate in reversible chemical reactions; creamy coffee can separate into coffee and cream; and lastly, you don’t apparently have to age (but you probably will anyway). Or, put another way, an electron is immortal, so even though you will age and die, not that its much of a consolation, but all your component particles, etc. ultimately live on (and on, and on) to strut their stuff again, and again.

In conclusion, it would appear that there is a very fundamental difference between time in the macro-universe and time in the micro-universe. It’s almost as if there were two highly different software packages written in order to run the overall Universe, one with an arrow of time and entropy, and one without!

Further recommended readings about time:

Carroll, Sean; From Eternity to Here: The Quest for the Ultimate Theory of Time; Dutton, New York; 2010:

Davies, Paul; About Time: Einstein’s Unfinished Revolution; Penguin Books, London; 1995:

Hawking, Stephen & Penrose, Roger; The Nature of Space and Time; Princeton University Press, Princeton, New Jersey; 1996:

Le Poidevin, Robin; Travels in Four Dimensions: The Enigmas of Space and Time; Oxford University Press, Oxford; 2003:

Lockwood, Michael; The Labyrinth of Time: Introducing the Universe; Oxford University Press, Oxford; 2005:

Mahid, Shahn (Editor); On Space and Time; Cambridge University Press, Cambridge; 2008:

It’s About Time – For a Change: Part One

Introduction: The real nature of what we call ‘time’ is one of the Big Questions. It’s been debated ever since humans evolved thought and language. That puzzlement remains true to the average person today, although ‘time’ has become the professional subject or province of philosophers, metaphysicists, and theoretical physicists, not to forget many a science fiction author! Here’s my two cents worth – ‘time’ is an illusion!

What Is Time? Time is, IMHO, an illusion. Time has no real independent existence – it can’t stand by itself. If you removed all the matter and energy from the Universe, would there be left anything we could address as time? Time is just our way of keeping track of, and measuring rate of change in matter and/or energy. If nothing ever changed it would be nonsense to talk about time. The flow of time; the arrow of time; is just the flow of macro things changing. If everything were somehow ‘frozen in time’ – like a single frame from a film – then there is no actual time that can be discussed or measured. So we don’t in any sense measure something that is time, we measure rate of change and call that time.

Actually you measure rate of change by another rate of change. For example, the rate of change from birth to death is usually measured by the rate of change in position of the Earth orbiting the Sun (years and fractions of years) and rate of change of position of the Earth rotating around on its axis (days and fractions of days). Another example: The rate of change between the beginning of your lunch hour and the ending of your lunch hour is usually measured by the rate of change of the hands of a clock (sixty 360 degree sweeps of the minute hand or a 30 degrees clockwise change in the hour hand) or the rate of change in the numbers on your digital watch, say from 1:00 to 2:00. Translated, a variable or uncertain rate of change (lifespan; length of a lunch ‘hour’) is usually measured by a standard, invariable, predictable rate of change.

Now rate of change is affected by gravity – a function of mass – the greater the mass the greater the gravity and the slower things change from A to B in that gravitational field, but that slowness is only relative to someone else also measuring A to B but who is in a lesser gravitational field. A clock at the top of a tall building (lesser gravity being further from Earth’s centre) ticks at a faster rate than an identical clock at street level (which has higher gravity due to being closer to Earth’s centre). Rate of change is also affected by velocity. The faster you go, the slower things change from A to B, again however it’s relative to someone else also measuring A to B but who is moving at a lower velocity relative to you. That’s why it’s the theory of relativity! The standard example is the twin paradox – if your identical twin zooms off in a spaceship at extreme velocities to the distant stars, stops, reverses direction, and returns at that high rate of speed to Planet Earth, and to you, you’ll find your twin has aged to a far lesser degree than you. You now have grey hair and wrinkles; your interstellar travelling twin is still in her youthful prime of life.

Time vs. Time Travel: I’ll poor water on this fire at the outset by stating again that time is but an illusion. Time doesn’t exist; therefore time travel isn’t possible. Time is but a label, like your own name is but a label, and has no more reality than the label ‘Wednesday’. We just arbitrarily call every 7^th ‘day’ Wednesday, but you can no more hold Wednesday in your hands and you can time. Time, repeating myself, has no independent reality. You can’t assign any physical properties to the concept. I mean time isn’t a solid, it isn’t a liquid, and it isn’t a gas. Time has no size, weight, colour, texture, density, it doesn’t vibrate or have a wavelength, ditto no odour or flavour, it has no temperature or pressure, it doesn’t consist of any known combination of known forces and/or elementary particles, it corresponds to no known element or compound. You can’t pour time into a bottle and store it; you can’t confine time in a force field or in a prison cell or trap it on a piece of sticky fly paper. Therefore, if time has no substance, one can not actually travel through time.

What we perceive as ‘time’ is, again repeating myself, nothing but change – change in our environment; in our natural world; in our mechanical devices; and even in ourselves and associated companions (animal and human). Repeat – time is but an illusion. Change is real (cause and effect) since it involves forces and particles; energy and matter, the sorts of things that when you kick them, they kick back. We measure ‘time’ by the rate things change; rate of change is what we call ‘time’. Repeat - it’s the change (in something) that is real. 

Now on the macro scale, that is scales we interact with on a day-to-day basis, change appears to all intents and purposes to go one way (usually from a state or high order to a state of disorder) and so we view time as flowing from past to present to future – in one direction; order to disorder – past to present to future. But change in just one direction (order to disorder – past to present to future) is ultimately a function of numbers and probability. The simple illustration is to introduce a drop of ink into a bowl of water. That’s a high order situation. Now left to itself, there will be a change. The ink will disperse throughout the bowl of water. That’s a state of disorder. If a disordered uniform mix of ink and water separated all by itself into a drop of pure ink and a bowl of pure water (high order), that too is change, but we would interpret or view such an event as going backwards in time. If you viewed such a happening on film, you’d immediately conclude the film was being run backwards.

There’s a far greater probability for individual ink particles to spread out throughout a large volume than to come together in a small space. There’s lots of pathways to spread out; far fewer pathways to come together. But at the micro level, the level at which those individual ink particles do their thing, they don’t care where in the bowl of water they are. They are just as ‘happy’ to be all together as a drop of ink, as dispersed and diluted. If they do come together as a drop of ink from a dispersed/diluted state, that’s statistically unlikely, but such an event violates no laws of physics. It would be going from a state of maximum disorder to a highly ordered state; or, from an apparent future to present to past ordering. Such a change would appear for all practical purposes as apparent time travel – going backwards in time.

The catch – there’s always a catch – is while all those ink particles are defying statistical probability and undergoing apparent time-reversal, the rest of the cosmos is acting in a statistically normal way – going forward in ‘time’. So, perhaps we have a Universe where for 99.9999% of the time, 99.9999% of events within the Universe march to the beat of the standard past – present – future ordering of things. That is, in terms of change happening in a statistically probable way. While now and again tiny pockets of the Universe reverse direction, they do so at least just temporarily.  One can only defy statistically probability for only so long. So the ink particles come back together again as a drop of ink within a bowl of water – then what? They no doubt reverse direction again and proceed normally.

An analogy might be that while some individuals are winners while playing the slot machines (high order), the club still rakes in the profits from the vastly greater majority of (disordered) losers, and that no doubt the few highly ordered winners will eventually descend into a state of disorder and contribute ultimately to the club’s profit margin! It’s more statistically likely for a winner to become a loser than for a loser to become a winner.

Consider electrons. On average, any given electron has a very high probability of participating in a changing set of circumstances consistent with statistically probability. That is, the electron is moving forward in ‘time’. But if in those rare (loser to winner) occasions the changing set of circumstances goes against the grain of statistically probability, then we would view that electron as moving backwards in ‘time’. But there ultimately is no backwards or forwards in time, just change which statistically goes or moves in one general direction (order to disorder), but which can now and again, albeit briefly, go the reverse direction (disorder to order).

To belabour the point, what we call the past is change which has already happened; the present is change which is happening; the future is change that will happen.

To be continued…

Time Reversal: Studies in Time and Motion: Part Two

Time reversal is not the same as actual time travel, rather its pseudo time travel in the sense that time reversal is more akin to a thought experiment yet one you can often perform with a motion picture camera. I’ll explain…

Continued from yesterday’s blog…

Things left to the natural way of things tend to go downhill not uphill. That’s gravity for you. Things traveling uphill better be expending energy, if they aren’t then you are probably in The Twilight Zone. It’s the old saying ‘what goes up, must come down’, and thus Newton’s apple bonked him on the head instead of doing a Superman imitation. Film a waterfall. Reverse the film. Oops!

Things that don’t have front-back symmetry left to the natural way of things tend to move in one direction, and if you see the reverse, it looks odd. Humans and companion animals tend to move forward, not backward. The same applies for most modes of transport – you don’t normally pedal a bicycle backwards just like you don’t drive to work in reverse, and aircraft certainly don’t fly backwards. But things with front-back symmetry can, like a balloon or a rocket taking off vertically. [But said rocket, once it turns on its side loses front-back symmetry and hence looks weird flying backwards.]

The key to all of this interpretation of time reversal, IMHO, is motion, or change (there can be no change without motion and vice versa). Filming something that’s standing still (no motion; no change) and playing the film backwards is a no-brainer for ‘there’s nothing strange happening here’.

Motion (or change) can be exhibited as left-right (LR), forward-back (FB), down-up (DU) or bottom-top (BT) or a mix of the three. Since time is a measurement of rate of change (or motion), all motion (or change) must have in addition a time dimension to it. If it didn’t have a time dimension to it, it’s rather silly to talk about a time reversal!

Motion of course can also be constant per unit of time, or variable per unit of time. Reversing the former is not as strange as reversing the latter.

Now for some general observations - first and foremost with respect to all things anomalous or weird, might I suggest that all else being equal, time reversing objects with high symmetry or no symmetry tends to be less weird than something in-between. So filming an amoeba, an asteroid rotating or a cloud forming, moving and dissipating (no symmetry) or a sphere in motion (a ball, a balloon) or a cube (say a dice), or a rotating tire or a Black Hole (high symmetry) isn’t likely to appear strange.

Time reversing things with LR and FB symmetry, or BT asymmetry, like rockets, pencils, trees/plants (in the abstract), dry spaghetti, mountains (in the abstract), tornadoes (in the abstract), and CDs/DVDs, don’t tend to appear too anomalous over the short term, at least if they aren’t moving. If they are moving, then things might look odd, but within bounds of reasonableness. Of course the CDs/DVDs might be rotating the wrong way and playing from outer edge to inner edge; the rocket might be landing with all motors firing instead of taking off. Of course if filmed for a long enough period, as in time-lapse photography, you’ll find it odd that plants shrink instead of grow, mountains don’t erode away but grow higher, and pencil points don’t become blunt but ever sharper.

Time reversing objects with only LR symmetry (vertebrates; most modes of transport like cars and planes and boats) tends to look odd. Land animals and automobiles don’t tend to walk/drive backwards; fish and boats don’t tend to swim/tread water backwards; birds and planes don’t tend to fly backwards.

Time reversing a change in symmetry from high to low is not overly anomalous, but low to high is usually considered strange. Examples: A punctured tire (originally LR, BF, BT) deflating to (LR, BF) isn’t strange; the reverse is. A pencil (LR, BF) falling over from the vertical (its radial symmetry broken) isn’t anomalous, but the view in reverse is. When a car (LR symmetry) crashes (zero symmetry), that’s normal – a car un-crashing most certainly isn’t.

Time reversing inanimate objects (still life – natural or man-made) tends towards the less anomalous, so filming, over the short term, a cliff face, or a painting, doesn’t look all that strange in reverse.

However, most artificial, man-made objects, tend to have a purpose(s) which for the most part doesn’t include just sitting there looking pretty, like a painting. If such objects have a purpose, then they tend to have a before and after aspect to them - if before and after tends to be the same as after and before, then things will look the same in reverse. However, the nature of the before tends to be different than the nature of the after, so reversing the two will probably be noticed – and odd. For example, place the white bread in the toaster and toast. The bread pops up toasted. Now reverse and you go from toasted bread to un-toasted bread. Or, throw your dirty dishes in the dishwasher and wash them. Take your nice clean dishes out. Reverse the film and you now put clean dishes in the dishwasher, apparently ‘wash’ the dishes, and take out dirty dishes!

Time reversing simple animate objects is less anomalous than time reversing complex organisms. If I viewed a bacteria’s behavior for an hour, and my cat’s behavior for an hour, filmed same and reversed same, I bet I could tell that the film of the cat had been reversed, but not nearly as certain about the bacteria.

Things get odd if you time reverse events dependent upon not space, but on time itself, so time reversing objects that by their nature are affected by the passage of time will be more anomalous than objects that aren’t. Film an electron for a million years and reverse – yawn. Film a rock for a million years and reverse. Over a million years, a rock will tend to erode, so the reverse is an apparent violation of entropy. Film a drop of blue ink placed and entering a glass of water at its surface and let time strut its stuff. Reverse the picture and you have a glass of pale blue water becoming clearer as all the blue bits come together at the surface in what appears to be a drop of blue ink. That’s odd. Film a hot cup of coffee and place a thermometer in it. The mercury in the coffee thermometer goes up and levels off. Place another thermometer next to the cup of coffee. Over time, the coffee’s thermometer registers lower and lower temperatures as the coffee cools; the outside thermometer gains a bit in temperature as heat from the coffee warms up the surrounding area. Now reverse. The coffee appears to get warmer and warmer; the adjacent area cooler and cooler. That’s also odd.

Time reversing objects moving LR or FB will tend to exhibit less anomalous behavior relative to DU/BT. So, two tennis balls, one each entering upper right and lower right move towards the centre, collide, and rebound each moving off stage towards the upper left and lower left. Reverse the film – nothing strange. But, drop a tennis ball and it goes top bottom, bounces bottom top, stops, goes top bottom, etc. until friction takes its toll and the ball comes to rest on the surface. Played in reverse, a motionless ball starts vibrating, jiggling, and then bouncing ever higher and higher. That looks very odd indeed. Or, Humpty Dumpty shuffles across the garden wall left to right – reverse and Mr. Dumpty shuffles right to left. But, if someone pushes Mr. Dumpty off the garden wall and Humpty falls down and shatters, the reverse looks odd. Why? Basically, I think its because top bottom/bottom to (or up down/down up) is associated with gravity and gravity is a one way (pull) force. Time reversal makes gravity a push force, something that’s well outside our day-to-day experiences.

Time reversal of steady-as-she-goes motion (constant velocity) is bound to be less anomalous than accelerated motion. A tennis ball moves at constant velocity left to right; ditto right to left in a reversal. A tennis ball hit by the server decelerates (due to friction) as it moves toward the opposite court. If the opposing player returns the ball in the normal course of events, then the ball will also be decelerating as it approaches the original server. Reverse the film, and when you get to the original beginning, the original server finds the ball accelerating as it approaches. How very odd. 

Time reversal in the micro world is a lot less anomalous than in the macro. Drop a uranium atom and a piece of dry pasta in a pot of boiling water. Reverse the picture. Which now looks odd – the micro or the macro? In the world of the micro, an electron and a positron meeting up for a date will quickly find their relationship in strife as they mutually annihilate and give off energy. But, the reverse is also possible. The vacuum energy can spontaneously produce matter-antimatter particle pairs. Now look at a chemical macro situation. An acid plus a base will react to form a salt and water. For example, the base sodium hydroxide (NaOH), will react with hydrochloric acid (HCl) to form table salt (NaCl) and water (H2O). But note that salt water, brine – our oceans – don’t revert naturally back into sodium hydroxide and hydrochloric acid. Chemical reactions that proceed of their own accord in one direction can of course be reversed, but it takes a bit of prodding. Without evidence of that prodding, the reverse reaction looks odd. So, running a film of that chemistry experiment backwards will look odd.

Summaries:

There’s nothing strange happening here: Still life. Motion too can be within this category. Toss a ball up in the air and it comes down again. If you reverse that, you still get an up and then down trajectory. Dig a hole and make a pile of dirt; take a pile of dirt and drop it into a hole.

That’s possible: A rocket ship can blast off and head straight up; a rocket ship, all engines blasting, can descend and land. While that’s certainly not the way the Redstone, Atlas, Saturn rockets and space shuttle worked, it’s possible, as the Lunar Surveyors and LEM and how the Mars Viking surface craft, landed. It’s possible to film the launch of a V-2 and reverse the film and conclude that such an event was possible.

That’s odd: Events showing objects without front-back symmetry moving contrary to expectations is certainly odd, but possible. Humans can walk backwards. Cars can travel in reverse gear. Birds can fly backwards if the wind is strong enough; ditto fish if the current is strong enough. Seeing a plane fly backwards is probably odd enough as to send you heading off to see the optometrist, the shrink, or attend AA meetings. 

That’s really weird and highly improbable: You’d place viewings of apparent violations of the 2^nd ‘law’ of thermodynamics (like a box of air molecules all moving in such a fashion that the faster/warmer molecules congregate in one half of the box and the slower/cooler molecules get together in the opposite half); and events hinting at antigravity, in such a category. Another case might be relativities so called ‘twin paradox’. Take two identical twins. One stays at home and the other boldly goes and travels at near light speed to a faraway destination somewhere out there, then reverses direction and heads for home. Upon arrival home, the boldly going twin appears a lot younger than her stay-at-home twin sister. Reverse the chain of events and you’ll have the stay-at-home sister growing younger as a result of her twin gallivanting around the cosmos! Take an inflated balloon and pop it, or let go of the end and watch it fly erratically around. Reverse that image. You’re sure to bet your life’s savings which viewing is forwards and which is backwards.

That’s impossible: There’s only one real example here. Film a macro object entering a Black Hole. Reverse the film. Since nothing (except Hawking radiation) can escape from the gravitational pull of a Black Hole, any film showing such an event is not just suspect and highly improbable – it’s flat out impossible.

Conclusion: Watching film in reverse can be fun and if you think about what you’re watching – the behind the scenes – educational.

Time Reversal: Studies in Time and Motion: Part One

Time reversal is not the same as actual time travel, rather its pseudo time travel in the sense that time reversal is more akin to a thought experiment yet one you can often perform with a motion picture camera. I’ll explain…

The laws of physics do not recognize the arrow of time, at least on the micro or quantum scale. The fundamental particles do not age. Their interactions can proceed in either time direction – past to present to future, or, future to present to past. Since the macro (like us), is made up of the micro, how come we age? Macro relationships often tend to be unidirectional, past to present to future only, what we call time’s arrow or the arrow of time. 

Make a film. Run it backwards. That’s what I call a pseudo time reversal thought experiment. We’ve all seen them. They are usually funny, not so much funny ha-ha, but funny peculiar. So, at what point do you go from a viewing where there’s ‘nothing strange happening here’, to ‘that’s possible’ to ‘that’s odd’ to ‘that’s really weird and highly improbable’ to ultimately ‘that’s impossible’. Or, at what point do you go from acceptance of what you are seeing, albeit back-to-front, to suspecting a time reversal, to knowing you’re watching a film backwards, and are their any generalities that can be drawn from this? Let’s look at some ordinary examples.

There’s a man sitting in his living room with the lights on, crossing and uncrossing his legs. Reverse the film – no anomaly. The man now picks up a book and reads it from front to back. Reverse the film – It’s now slightly odd in that the book is being read from back to front. The lights go out. Reverse the film and the lights come on – nothing strange. The lights go out and the man picks up a flashlight and turns it on. Reverse the film – this is very strange as the light from the flashlight is instead now entering the flashlight from somewhere stage left (or right). The lights come back on and the man lights up a cigar and smokes it. Reverse the film – Now you absolutely know the film is the reverse because the cigar smoke and ash turns into cigar which grows ever longer!

Let’s film that same man sitting in his chair for one hour. Run the film backwards and the odds are you won’t see anything too strange. Now film the man for one second each day over the course of a decade – roughly the amount of film. Reverse the latter film – you should now certainly see something strange. The man is getting visibly younger!

Let’s film a military person standing at attention for say ten minutes. Now that’s not exactly an exercise in still life because the person is still moving – the eyes are blinking, the person is breathing, the heart is beating, etc. So, run the film backwards and there’s nothing overly unusual. The eyelids open and close; the chest expands and contracts, the heart beats. But if you could look a bit deeper, beneath the surface, you’d note a lot of strange activity. Photons aren’t entering the person’s eyes; they are exiting (so in the reverse film, the person is blind). The person is breathing in lots of carbon dioxide and exhaling lots of oxygen. The heart may be beating, but the blood is flowing in the wrong direction! Food in the stomach is becoming undigested. Those are odd happenings indeed.

You’re standing on the railway platform filming as the express train, the ‘4:50 from Paddington’ (thanks Agatha) thunders by blowing its whistle. Reverse the film. There’s nothing odd to be seen here. Well, trains can travel in both directions (especially if they have an engine at both ends) and you can’t tell standing on and filming the platform which direction Paddington is in as there is no signage to that effect visible. But, the change in pitch of the train’s whistle (the Doppler Effect*) will not be the same regardless whether it thunders by left-to-right or right-to-left. As you are filing, as the train approaches and passes you, you go from hearing a high pitch (the sound waves are compressed) to a low pitch (the sound waves are now spread apart). Reverse the film, and the order is low pitch to high pitch, even though the train is approaching (in the reverse film viewing) and receding (in the reverse film viewing). That’s contrary to expectations. Ah, but also in the film frame is the station’s clock, the hands of which are now going counter-clockwise! That gives the game away – unless you assume that’s due to an electrical fault! [*Contrast with the filming of a galaxy moving ever faster away from us – the expanding Universe – with insert of the galaxy’s spectrum lines shifting ever further towards the red. Reverse the film and the galaxy is now approaching us and the spectrum is moving in the other direction – towards the blue. That’s exactly according to expectations.]

Say there’s a tree swaying in the breeze. Reverse the film – no anomaly. Keep filming, and note the clouds are moving from right to left. Reverse the film – still nothing unusual. Keep rolling the film and watch the light get dimmer and dimmer as dusk approaches. Reverse the film – okay, so it’s now dawn dawning. You see a bird fly away from one of the tree branches. Reverse the film – now that’s odd. The bird is flying toward the tree branch, but tail first. Still, maybe it’s just a very strong gust of wind blowing the bird backwards. The bird is flying away from the tree branch because the wind has cracked and broken the branch and it falls to the ground. Reverse the film – now you know its time reversed as the branch moves from the ground up and attaches itself to the tree.

Film the city late at night. The office lights go on and off; the neon signs are flashing, and the traffic lights are doing their red-green-amber-red-green-amber-red thing. Reverse the film – it’s now slightly odd in that the traffic lights are going red-amber-green-red-amber green-red. That’s not the normal sequence. Still, maybe its an electrical fault. Resume forward filming and see this lone automobile cruise on up the street. Reverse the film – so the car is now moving backwards. Well, it’s odd but cars can move in reverse. Resume normal filming. The car is actually being driven by a drunk driver and he hits a pedestrian killing same before crashing and totally destroying his car by driving at speed into a building. Now reverse the film. Now you know it’s a reversal because cars don’t un-crash and the dead don’t come back to life.

Film a clear sky that slowly over time shows a cloud developing and turning into a traditional storm cloud with anvil top. Reverse what you just filmed. There’s no anomaly as clouds can dissipate as well as form. Continuing filming and watch the storm cloud develop a funnel and turn into a waterspout hitting the water before running out of puff and returning to its parent cloud. Reverse – nothing unusual to be seen, the water looks the same before and after regardless of time flow. Resume filming and note the funnel reforming and becoming a waterspout again, but there’s this unfortunate ship that’s caught up in the event and sinks. Reverse the film and because you rather suspect that ships don’t un-sink, you know it’s a time reversal image you’re watching. Continue normal filming and see this cloud produce ball lightning that dances and floats around. Reverse the film, and I’d suspect you wouldn’t suspect anything. Resume filming, and see the ball lighting go ‘poof’ and disappear. Now reverse the film and see the ball lighting ‘un-poof’ and appear from out of nowhere and out of nothing. That’s very odd, but you’re no expert on ball lighting so maybe it’s possible. Now our cloud, in normal filming mode, produces a traditional sideways, cloud-to-cloud lighting bolt and crash of thunder. Reverse the film. What’s odd, and a giveaway that the film is running back-to-front, is that you’ll hear the thunder before you see the lightning. [It’s also slightly odd in that the thunder starts off faint and builds in intensity, finally cutting out fairly abruptly – not in a fade-away fashion as per norm.] If that doesn’t cinch it, continue filming while the cloud produces a hailstorm that batters the waters below. Reverse the picture – hail doesn’t go from the ground up (hail can go up and down and up and down again and again within its parent cloud due to updrafts and downdrafts, but once it reaches the surface, that’s the end of the journey).

Finally, film a symphony orchestra playing a concert. Reverse the film. There’s probably nothing unusual to be witnessed. Now add the sound of the music and reverse the film – now that’s weird (the ‘music’ that is), but maybe it’s just some of that highly modern experimental atonal ‘music’ – except the concert program said it was to be an all Mozart concert, not that that is definitive proof – maybe it’s a different Mozart! Now resume filming in the normal way and get the audience’s applause. Reverse the film. There’s nothing too odd here except, like the thunder example above, the applause started off softly, softly, builds up in intensity, and cuts off fairly abruptly.

One can easily come up with thousands or ordinary everyday scenarios that can evolve from being time reversible without question to ‘whoa’ – that’s funny peculiar.

Things left to the natural way of things tend to go from order to disorder. If you see the reverse, it’s suspect, probably highly improbable, but not impossible. It’s just the second ‘law’ of thermodynamics in operation, but it’s a statistical ‘law’ that can be broken, but rarely is, due to chance. There are lots of possible arrangements for disorder; few arrangements for something in a ordered state, so statistically, the odds favor disorder and thus you have to go to a lot of time and effort (energy expenditure) to go from disorder to order. Thus, seeing a film of a nuclear explosion in reverse, or a firearm shooting bullets in reverse or a plane un-crashing is suspect.

For example, pour out a really hot cup of coffee then start filming. Reverse the film. Apparently there’s nothing odd to look at – just a cup of coffee - except, if you’ve filmed in infrared. If you run that infrared film backwards, you’d have the coffee get ever warmer, and the surrounding environment get ever cooler. In real life, the coffee would cool down and the immediate environment would warm up slightly. So, this is a case of things appearing normal, backwards or forwards in the visible spectrum, yet odd indeed with viewed backwards in the infrared.

To be continued…