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:

A Perfect Vacuum, Not

I recall the movie “Alien” had a tagline along the lines of ‘In space, no one can hear you scream’. Why? Because space is a vacuum, and sound (as in screaming) cannot travel from point A to point B if there’s a vacuum in-between. But the question really is, is space a perfect vacuum? Can one achieve a perfect vacuum? If not, why not?

One of the big scientific oops often depicted in Hollywood (and other country’s equivalents) sci-fi space operas is an external view of spaceships, etc. in deep space chug-chug-chugging along with all appropriate sound effects, and/or blasting away with laser cannons or photon torpedos, ditto with appropriate sound effects. Of course, if you really were an external viewer, what would you actually hear? - Absolutely nothing. It would be, or should be, like viewing a silent film from the pre-talkies era. But, for the sake of dramatics, Hollywood (etc.) ignores the physics of it all. ‘Artistic licence’ is what it’s called I believe. 

However, in the physics classroom, where artistic licence isn’t allowed, I’m sure we can all recall from our student days a demonstration of the ringing alarm clock inside the bell jar. As the air was pumped out from the bell jar, the ringing got softer and softer and softer until you heard nothing at all, even though the alarm clock was still jangling away. Of course the science teacher or physics professor told you there was now a total vacuum inside the bell jar and thus no sound could travel from point A – the alarm clock inside the vacuum inside the bell jar, to point B – your ears which were outside the bell jar.

Of course it should be obvious to blind Freddy that there was no such thing as a total or perfect vacuum inside the bell jar. Firstly, no pump is good enough or efficient enough or strong enough to remove each and every last molecule of air from the bell jar. [Of course there is no such thing as a molecule of air, rather atoms and molecules of the various substances that together make up what we call air, but for the sake of simplicity let’s make believe there are molecules of air.] Even discounting those rarefied air molecules left within the bell jar, molecules few and far enough in-between as to prevent the sound of the alarm clock from reaching your ears, the inside of the bell jar still wasn’t a total vacuum.

Why? Well assuming the bell jar was made of glass; light was pouring through the bell jar, and light is a something. The inside of the bell jar was full of visible light. Okay, let’s make the bell jar out of solid lead. That blocks out the light – right? Wrong. Visible light is but a small part of the entire electromagnetic spectrum. Radio waves (a form of non-visible ‘light’) will probably pass through the leaden bell jar, or gamma rays. Even if you succeed in blocking out all of the wavelengths and frequencies of the electromagnetic spectrum, there are still cosmic rays. If you make the leaden bell jar thick enough you might block out all of the cosmic rays, but that still leaves neutrinos, and in order to block all of those, you’d need a bell jar that had a lead thickness of hundreds of light years. Neutrinos can pass through leaden walls as easily as Casper the Friendly Ghost – even easier!

Okay, so you’ve got a perfect pump to remove all the air molecules and sufficient shielding to prevent even neutrinos from entering and passing through. That’s that; now you have your perfect vacuum – right? Wrong again.

You still have gravity not only surrounding but inside the otherwise perfectly shielded bell jar. Even if there were no other matter in the entire Universe, the bell jar itself is made of matter and has its own gravity which resides inside the jar as well as extending to infinity outside of it. Since nothing we know of can block the force of gravity, well that alone puts the kibosh on the perfect vacuum. Gravity is really a real thing, and if you doubt it, I invite you to try to leap tall buildings at a single bound!

Now a perfect vacuum would have to have a temperature of absolute zero, given the total absence of any material substance within. Temperature of course is just a measurement of the average molecular or atomic motion of molecules, atoms, even their fundamental particles. No stuff means a temperature of absolute zero. However the Universe isn’t lacking in stuff which moves around from place to place

For quite another reason however, absolute zero, zero degrees on the Kelvin scale, (or minus 273.15 degrees Celsius or minus 459.67 degrees Fahrenheit) is only theoretical and can never be obtained. That’s because the concept of absolute zero violates the Heisenberg Uncertainty Principle which states that it is impossible, no matter how good your measuring instruments are, to simultaneously know the position and momentum of anything, because the very act of measuring something must alter both parameters. That’s because something must bounce off what you are trying to measure and hence interact with your measuring device, but that bounce alters the position and momentum of that in which you are interested. At a theoretical absolute zero, nothing moves and thus you would know both the position and momentum of that or any object, even say an electron, with absolution precision. The momentum is zero and thus your object is in, and stays in, a fixed location – and besides, there’s nothing to bounce off it anyway, because that something (usually a photon) must also have zero energy and is thus at rest.

And thus we have the concept of the vacuum energy, or quantum fluctuations or the quantum jitters. That is to say, at the extreme micro level, there is always activity and thus motion and thus temperature above the theoretical minimum of absolute zero - thus, no perfect vacuum is possible. Even the best vacuum will have the quantum jitters. Oh, and by the way, the quantum jitters or the vacuum energy has been experimentally verified.

So, if you were somehow expecting that there was such a thing as a perfect vacuum, you’re out of luck, not that that I’m sure will cause anyone any loss of shuteye. However, that doesn’t alter the fact that in space, no one can hear you scream! You don’t need a perfect vacuum for that to be true.

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…

The Quantum Life, the Universe and Everything

Is life, the Universe and everything a smooth as silk continuum where everything is deterministic, or are we ruled by little ultimately indivisible quantum Lego blocks of time and space and matter and energy with all is determined by the throw of a cosmic dice? Apparently it’s the latter and the realm of the quantum makes “The Twilight Zone” seem downright normal by comparison. Is the realm of the quantum really spooky? You bet it is. Welcome to more of the world of the quantum mess!

Quantum physics is a total mess, not because it doesn’t represent at least a part of reality because it has been experimentally verified to incredible degrees of precision and no experiment has disproved any of it; not because the quantum is a fundamental part of and behind much of our established technology; but because nobody really understands what it all really means. What does quantum physics actually tell us? The science of the quantum is rock solid – it’s the philosophy underlying it that’s the mess. The comprehension, the meaning behind quantum physics is difficult, not just for the public but for professionals as well. From discontinuities and uncertainties and super-positions of all possible states, to entanglement and all things left to chance and probability, and where a cat can be both dead and alive at the same time and universes split and duplicate at the drop of a hat, where the elementary bits and pieces of the micro exhibit both wave and particle properties (though at least not at the same time), and last, but certainly not least, the absolutely essential role of the observer and the observer’s measurement in all of this quantum mess.

The philosophy and meaning and reality behind quantum (micro) physics is diametrically in contrast to that of classical (macro) physics, yet classical physics (the physics of Galileo and Newton that we were all taught in high school) must ultimately be derived from micro physics a.k.a. quantum physics.

Science is often more about what happens and how it happens rather than why it happens just that way. Many physicists just get on with their experiments, get results, but don’t worry too much about any ultimate meanings – why they got the results they did – so that practical everyday interpretation of all things quantum tends to be called the ‘shut up and calculate’ interpretation. It works; just do it; don’t worry about what it means.’ Fortunately, some scientists are deeper thinkers than others and do ponder – in this case, our quantum mess.   

As to the big picture, the Universe at large may seem smooth and continuous but it’s anything but on the micro-scale. In fact, I’d suggest the Universe is akin to being constructed of Lego blocks of different colours (each reflecting basic realities like time, mass, energy, length, etc.) In other words, the entire Universe, all the bits and pieces, are really indivisible bits and pieces. That is, quantum physics underlies all of cosmology and all of physics. Now Lisa Randall (Professor of Physics, Harvard University), defines ‘Quantum’ as “A discrete unbreakable unit of a measurable quantity; the smallest unit of that quantity”.  For example, you can have one electron, or two electrons, but not one and a half electrons. An electron can orbit an atom in this orbit, or in that orbit, but not one in-between. The electron can jump from one orbit to another and absorb or give off energy, but in discrete indivisible units, such that you can have one fundamental bit of energy (or the particle responsible for that energy – a photon in the case of electromagnetism; a graviton in the case of gravity), or two bits, but again, not one and a half bits. There is such a thing as the shortest unit of length possible (hence area and volume), called the Planck length as well as the shortest most fundamental unit of time called Planck-Wheeler time. So, all these various quantum Lego blocks ultimately make up life, the Universe and everything. On the macro-scale these blocks aren’t noticeable. But when dealing with cosmological issues that involve small spaces, or large densities or tiny time frames or other physical extremes, then one needs to abandon ‘smooth and continuous’ for quantum’s Lego blocks.  

But just when you think it safe to go back into the now quantum waters, along comes one tiny little exception to the quantum rule just to make life either difficult, interesting or both; that exception is gravity, which just refuses to have it’s own little Lego block. If life, the Universe and everything can’t make up its mind to be either/or, then things are really messed up. 

Time & Time Travel: Part Two

Continued from yesterday’s blog…

“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 left to themselves, things go from an orderly state to a disorderly state – a clean desk gathers dust! 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 the macro- and micro-verses. It’s almost as if there were two highly different software packages written in order to run the Universe, one with an arrow of time and entropy, and one without!

TIME TRAVEL: Time travel is a staple in sci-fi stories, novels, films and TV series. And, time travel is possible – in theory. We all know about journeying to the future if one travels at close to light speeds relative to your destination (the twin paradox). Travel to the past is apparently allowed to, via rotating worm holes. The problem there is that theory predicts worm holes, if they exist at all, will exist for nanoseconds and be very tiny to boot.

Anyway, the fun bit about time travel is the various paradoxes that arise, the most famous one being the grandfather paradox. That is, what if you travel back in time and kill your grandfather before he sired your father. If you did that it means that you could never have been born, but if you were never born you couldn’t go back in time to kill your ancestor. This is the sort of stuff sci-fi authors (and philosophers) love – ditto physicists! My favorite time travel paradox however is the one where you get something for nothing. Say you have this edition of “Hamlet”, and you want Shakespeare to autograph it. So back you go in time to Shakespeare’s era. You knock on his door, but the housekeeper says he’s out for the day but if you leave the book he’ll autograph it and you can come by and collect it next morning. When Shakespeare comes home, he sees the book, reads it, and is so impressed he spends the night making a copy. You come back the next morning, collect your now autographed edition of “Hamlet”, and return to the present day with your now very valuable book.  The question now becomes, where did the original “Hamlet” come from? You didn’t write it; but Shakespeare didn’t either as he plagiarized your copy hence passed it off as his own.

Another favourite is you meeting yourself. Say you’re 50 and not all that well off. You get the brilliant idea to travel back in time and convince your younger self to invest in some stocks you know will pay off later on big time. And so it comes to pass that your younger self so invests, and becomes filthy rich, only, in leading such a high life, dies of a heart attack at the age of 45! Or you always regretted not proposing to the love of your life when you were young, and thus go back and convince your younger self to muster up the courage and do so. He does, but as they fly off on their honeymoon, the plane crashes with no survivors. Sometimes you don’t know when you’re well off.

Or if you can travel back in time, then of course others can to. Naturally there’s going to be lots of people interested in particular events, maybe even at the time, seemingly trivial events (yet which turn out in the long run to have had major impact(s)). And so you might have any number of people going back to particular historical focal points, each with their own particular agenda (most of which will be mutually exclusive), and ultimately causing havoc. I mean if person one goes back and influences an event producing a new outcome, then person two might go back and has a go at that result and things get altered again, which will then prompt person three to go back and influence things more to his liking, etc. In other words, history would never be fixed, rather always be fluid. Since we believe that history (or the past) is fixed, that what’s written on your history book page today will not alter overnight. Thus, you have probably concluded that time travel cannot happen, will not happen, and has not happened, however much you yourself might wish to go back in time yourself and change something. (Don’t we all really wish some past something, personal and trivial, or perhaps something of major significance could be changed and you’d be that instrument?)

It’s paradoxes and situations such as the above that prompted Stephen Hawking to postulate that there is as yet an undiscovered law of physics which prohibits time travel to the past – he calls it ‘chronology projection conjecture’. Since we have never seen – to the best of our knowledge – any time travellers from our future, he’s probably right.