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.
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