Time Explained

[Farsight]

TIME EXPLAINED

Time is very simple, once you get it. But “getting it” is very very difficult. That’s because your current of time is so deeply ingrained. You think of time as a length:

Q: How long will it take to get to London?
A: What do you mean long?

We form a mental map of the world using our senses and our brains. But the map is not the territory. We use time to think, but we’ve grown so accustomed to thinking the way we do, that we don't think about time any more. We don't see time for what it is.

But let’s start with something easier. Let’s start with colour. Follow the link below to conduct an experiment:

http://www.echalk.co.uk/amusements/O...erception.html

This demonstrates something important about colour perception. What you thought was yellow is in fact grey. It really is. It isn’t a trick. Tear a small hole in a piece of paper to make your own mask to remove context. Hold it up to one image after the other, and you realise that the effect is genuine. It comes as a shock, but genuine it is. Yellow is grey. What does this tell you? It tells you that colour is perception rather than reality. Imagine a super-evolved alien bat with a large number of ears, like a fly’s eye. This bat would “see” using sound, and if it was sufficiently advanced it would see in colour. This should be a reminder that in the subatomic world there is no such thing as colour. A photon has a wavelength, an electromagnetic oscillation, a motion.

Next let’s take a look at heat. Put your hand on the griddle and sizzle, you know heat is real. But we talk about heat exchangers and heat flow as if there’s some magical mysterious fluid in there. And yet we know there isn’t, because junior-level physics tells us that heat is atomic or molecular motion. It’s a “derived effect”, or a macro effect if you prefer. Sure, heat is a real thing. But you know it's motion.

Pressure is similar. You can’t measure the pressure of an atom, because pressure isn’t a fundamental property of the sub-atomic world. It’s another ”derived effect”, and the Kinetic Theory of Gases tells us it’s derived from motion.

How about Kinetic Energy? A cannonball in space travelling at 1000m/s has Kinetic Energy. Oh sorry. I made a mistake. It isn't the cannonball doing 1000m/s. It's me. So where's the kinetic energy now? Nowhere. Because it's just a mathematical expression of stopping distance. There isn't any. All there is is motion.

We’re all familiar with Sound. It’s like light because it’s waves, and like pressure because they’re pressure waves. And when you look beyond this at the molecules that make up the air around us, you see that sound is motion.



Did you know that smell is really shape? Nevermind, because you should be getting the drift by now. We are accustomed to thinking about the world in terms of how we experience it, rather than the scientific, empirical, fundamental, underlying things that are there. And nowhere is this more so than with Time.

What is Time? Let’s start by looking up the definition of a second:

"Under the International System of Units, the second is currently defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium-133 atom. This definition refers to a caesium atom at rest at a temperature of 0 K…”

OK, a second is nine billion periods of radiation, of light. Now, what’s a period? We mentioned light, so let’s have a look at frequency:

Frequency = 1 / T and

Frequency = v / λ

Flipping things around, I see that period T is wavelength λ divided by velocity v.

A wavelength is a distance, a thing like a metre:

“The metre is the length of the path travelled by light in vacuum during a time interval of 1/299 792 458 of a second...”

And a velocity is a distance divided by a time. So:

A period T is a distance divided by a distance divided by a time. That’s a another period, another time. OK, so that definition of time is circular. We can’t see the empirical fundamental definition. The axiom warning light is flashing, so let’s look at frequency again:

Frequency is the measurement of the number of times that a repeated event occurs per unit of time.

And the penny drops. We measured nine billion oscillation events and then we defined that as a second. We counted events. We counted motions.

That’s what time is. It’s counting. One two three four five… nine billion. Mark that down as a second. One two three four five… nine billion. Another second. And you don’t have to count the motion in an atomic clock. You could count the motion of beans in a a bucket. Ping, ping ping, chuck them in, regular as clockwork.

But now you should notice something: the only direction that is actually there, is the direction of the beans' motion. "More beans" is not a direction. There is no direction for the “Arrow of Beans” to point to. It’s just a mathematical notion, as imaginary as the direction you take when you count along the set of integers.

So why on earth do we say things like Clocks slow down as if a clock is something that moves like a car? It isn't travelling. There's no slow or fast or up or down to it. We say The day went quickly but it didn’t go anywhere, and it didn’t go quickly at any speed at all. It isn’t travelling and there is no direction. The only directions that are there are the directions of the internal cyclic motion. And they’re being counted, incremented, added up.

We count this regular motion to use as a ratio against some other motion, be it of light, atoms, buses, or brains. All of these things have motion. Some have more of it than others. And all those motions are real, with real directions in space. But the time direction isn't real. It's as imaginary as that direction you take when you count along that set of integers.

That's why the past is only in your head and your records. It's the places where things were. All those places are still here, now. It isn’t a place where you can go. The past is the sum of all nows, and now lasts for zero seconds because there is no time. Only motion. A second is nine billion motions of a caesium atom. Accelerate to half the speed of light and a second is still nine billion motions of a caesium atom. But there's only half the local motion there used to be, because the other half is already doing the motion through space. Look again at the definition of the second and the metre, and you will understand Special Relativity. Time didn’t begin fifteen billion years ago. Because it never started in the first place. It was motion that started in the first place. And it was fifteen billion light years a go-go.

Let’s go over it again. Motion is a change of place in space. We measure this by comparing it with some other motion, and use the term "time" in our measuring. It's a measure, so by definition it's a dimension in the proper sense. But that only makes it a parameter, not a spatial, linear dimension that we can move along. So why do we say how long when we're thinking about time? We imagine a length of time. We imagine that we travel along this imaginary length at a speed of one second per second. When you "get" time, you realise just how ridiculous this is. We don't travel anywhere. Our atoms and everything else are in motion, but there's no travelling through the measure of this motion. To travel backwards in time we'd need negative motion. Motion is motion whichever way it goes. You can’t have negative motion.

So What do we do with SpaceTime? Ah, Einstein. He knew all right. He found his Hole. Einstein’s Hole. Look it up. Talking of Einstein, let’s look at Simultaneity, and a little thought experiment called the “Cylinder and the Nail”.

The cylinder is the same length as the body of the nail. At the far end of the cylinder there's a sheet of paper stretched across it like a drumskin. If you were to slide the nail into the cylinder, the pointy end of the nail just touches the paper, but it doesn't penetrate because the head of the nail is too wide to fit into the cylinder.

You mount collision detector A on the head end of the cylinder, and collision detector B on the paper end of the cylinder. Now with a very special gun, you can fire the nail at the cylinder, or the cylinder at the nail, and monitor your collision detectors.

From the cylinder's perspective, the nail is a shortened spike. So the first detector to fire is A at the front end of the cylinder. The nail doesn't stop (in reality we're talking gamma-ray plasma jets here) so detector B at the paper end fires later.

From the nail's perspective, the cylinder is a flattened doughnut. The first detector to fire is B at the paper end. Detector A at the front end of the cylinder fires later.

From the cylinder's perspective A "happens before" B, whilst from the nail's perspective B "happens before" A. The time experience is therefore subjective to each object and its motion, and is not an objective experience independent of motion. Ergo our experience of time is a subjective experience that is the product of motion, and our treatment of time as a length and a travel direction is incorrect.

The correct concept of time has to defer to velocity. Velocity is not distance over time. Instead velocity determines your measure of time and space, because spacetime is fundamental, not space, and not time. Velocity is motion, more absolute than distance, more absolute than time. We measure the motion of the molecules of a gas using temperature. There is no time in temperature. And while we talk of a “high temperature”, we cannot travel a “height of temperature”, because there is no height. And we cannot travel a “length of time”, because there is no length. I’ll show you a picture:



What can you measure? OK you can measure height. And width. And if it wasn't just a picture you could also measure depth. That's three Dimensions, with a capital D because we can move in those dimensions. What else can I measure? What is the fourth dimension? Well, the picture comes from the Wikipedia Temperature page, so I can also measure the temperature. The motion. The velocity. It's a measure of change of place rather than a measure of place, and it has no absolute units, because you can only measure one change of place against another. It's a fourth dimension, but you can't move in this dimension so it's a dimension with a small d. And because there are no absolute units, the units are relative, which is what Special Relativity is trying to tell us.

And Special Relativity is also trying to tell us something about the speed of light. Speed is distance over time. But light experiences no time, so talking about speed doesn’t make sense. Light doesn’t travel at any speed. It is a constant, because it is constant. And that constant c has its own units of velocity that we should liken to temperature. Velocity should be defined by degrees, not by metres and seconds, because it defines metres and seconds. And because it defines metres and seconds it but a short step from there to telling the children that the speed of light is the speed of time.

Strange but true. Because when you get down to the subatomic nitty-gritty, there is no colour. There is no heat. There is no sound. There is no pressure. There is no time, not the way you think. Now try to imagine a particle, without a surface please. And you see why the quantum world, the real world of physics, is oh so very strange.

If you don't believe me, if you think I'm wrong, show me the maths. But make sure you kick t out of all of your equations. And note that there are physicists who think like me. Julian Barbour. Carlo Rovelli. And more. Ever heard of a book called A World Without Time: The Forgotten Legacy of Godel and Einstein, by Palle Yourgrau?

"It is a widely known but insufficiently appreciated fact that Albert Einstein and Kurt Goedel were best friends for the last decade and a half of Einstein's life. They walked home together from Princeton's Institute for Advanced Study every day; they shared ideas about physics, philosophy, politics, and the lost world of German-Austrian science in which they had grown up. What is not widely known is that in 1949 Goedel made a remarkable discovery: there exist possible worlds described by the theory of relativity in which time, as we ordinarily understand it, does not exist. He added a philosophical argument that demonstrates, by Goedel's lights, that as a consequence, time does not exist in our world either. If Goedel is right, Einstein has not just explained time; he has explained it away..."

Time Travel is bunk. Sleep tight.

[Farsight]

All: I've worked hard on this essay, and hope it's sincere, logical, and reasoned. Please can I have your considered feedback. Craig, I'd especially value your input. Can you find some flaw?

[GAHD]

Can you actually DO and refrence the nailgun 'experiment'?

[Boerseun]

I think you're confusing reality with figures of speech.

Nobody disputes the fact that temperature isn't 'high' or 'low', but merely an indication of atomic vibrations, but everybody knows what you're talking about when you say the mercury's 'high' (or low). It's a figure of speech, traceable to the first mercury-filled thermometers, with the high and low levels indicative of the thermal expansion of the mercury inside the tube. That's about as technical as it gets. Same with the 'arrow of time', it's a figure of speech. Disproving that is more of a linguistic exercise than anything else.

Also, saying that history exist only in our heads and records, is simply flat-out wrong. The information of what I've been up to ten years ago, exist in a spherical shell around me with a radius of ten light-years. History is real, and in order to view it, you have to be as far away (in light-years) as you want to view. Problem being that we can't travel faster than light, else we might have eventually brought the whole study-field of history into the realm of science! We view galaxies as they were millions of years ago. History is real, but we can never view or interfere with our own. Apart from demanding faster-than-light travel, it would raise paradox issues that Nature simply doesn't allow. There's no penalties for breaking Laws of Nature, the fact is that you simply can't.

Time travel is bunk not because of some specific difficulty in describing exactly what time is, but because of the limits placed upon us by Nature.

Your nail-gun experiment is a variation of the thought experiments that made Einstein realise that time dilation would prevent such paradoxes. If these objects are flying at such a velocity that the dimension in which they're travelling gets shortened, then time dilation would sort your problem out. Besides, if the cylinder looks to be a flattened doughnut to the nail, you should keep in mind that the nail itself is shortened - the only reason that this is not visible from the nail's perspective is that c is still viewed as perfectly c in all directions as far as the nail is concerned.

Smell a shape...? I'm not completely with you there...

Originally Posted by popular

And because it defines metres and seconds it but a short step from there to telling the children that the speed of light is the speed of time.

Not quite, but the speed of light is certainly the speed at which the effect I have on the universe is propagating. If I pick up a jelly-bean, that fact is propagated at c in an expanding sphere around me. 4 years from now, astronomers at Alpha Centauri can attest to the fact that I did, in fact, pick up a jelly bean on this day. They will have no inkling about it a moment before.

Information spreads at c. Time is the name we give to the sequencing of sets of information. And if we talk about time running, or slipping or sliding or bouncing or smelling or whatever, it's simply a figure of speech. Disproving that is a linguistic exercise.

Okay - I'll make you a compromise. As of now, time won't run any more. As of now, time will fitzdoodle. Problem solved.

[ronthepon]

This is a great essay, Popular! Excellently written.

However, the cylinder experiment is probably the weak point. The unsatisfactory part, infact, of your peice of work. From what I can find, it requires the concepts of S.R.

I strongly suggest that, after you compile this totally and excellently, you put this up in the articles section also.

[ronthepon]

And... er, whoops, I did'nt see your post, Boerseun, but I gotta defend Popular in this little aspect:

Originally Posted by Boerseun

I think you're confusing reality with figures of speech.

I think thaty he's trying to show how in general we have a wrong... well maybe not wrong, but imaginary and axiom-based concepts of some features or reality.

EDIT:

About the history thing, we can observe what happened, see it. We can see the first photons that were involved with it, we can hear the sound waves the event generated, but we cannot re-play it for real.
History exists in exactly that form. Records. The records are real, and the event they showcase were real. heck, I can't poke around with that 'were' concept now, not in this thread, but ... er... do you get what I'm saying? I sense my communication skills failing here...

[Jay-qu]

Originally Posted by Popular

TIME EXPLAINED
Time is very simple, once you get it. But “getting it” is very very difficult.

Its like "I could explain to you fully what infinity is, but it would just take me forever..."

In all seriousness, nice job, I can see you have put a lot of time into it and I dont mean to make fun

[Farsight]

Thanks guys. Yes Ron, maybe I need to rework or replace the cylinder and the nail. Perhaps I need to insert a few more illustrations and give the whole thing an overhaul.

Boerseun:

I'm at work, and I've lost all my cookies and I can't remember my "Popular" password and my email address is different. I hope it's OK to use this second userid for today. Thanks for your feedback. In reply:

I think there's more to this than "figure of speech". The concepts we use are deeply rooted in the way we think, and it's very hard not to use them. Try talking about time without using any past or future tense, and without any of those "time is a length" figures of speech, and it's incredibly difficult.

Hmmn. Maybe I used the wrongs words when talking about history. We all know history really happened. And the information about an event is real enough. But it the history of the event isn't the actual event. I put it to you that there's not a huge difference between an electromagnetic shell ten light years across and a ten-year old videotape. Both contain information about the event, but neither is the event. The event is where things were and how they met, and they're not there now whatever information you have to hand.

As regards the nail gun, the cylinder looks shortened from the nail's perspective, and the nail looks shortened from the cylinder's perspective. We don't know which one of them we fired. This aspect of the thought experiment is like the Twin's Paradox. The crux of the matter is that event A happens before event B for the nail, yet event B happens before event A for the cylinder. They can't both happen before each other, so the "passage" of time has to be subjective to motion rather than an objective reality.

See wikipedia Olfaction for what I meant about smell being a shape.

You were talking about c as a speed. Our experience of distance and time varies with our speed, and while we always measure c as 300,000 metres per second, our metres vary and so do our seconds. The units we're using for c aren't constant, so to express it absolutely it seems like we need some new units based on spacetime rather than space and time. That's why I was talking about velocity and degrees. (I like 0 degrees for motionless and 90 degrees for c, but I'm not proud of it).

Yes, information spreads at c. And yes, time is the name we give to the sequencing of sets of information. The events occur in a sequence, and we record these events. Like a video tape I guess. What we've already recorded is the past, what we're recording now is now, and what we haven't yet recorded is what we call the future. The tape "runs". But there is no absolute measure of length on this tape, no absolute measure of speed, no fundamental units of time. Because our VCR and the tape is itself a series of events, just like the events we're recording. Sure, the tape provides a record of events, it's information, but it isn't the actual events. They're in the world, not in the sequence, not on the tape. You can rewind the tape to review the history, but there's no way to rewind the tape to visit the past. You can't travel down the tape.

You can use your tape to measure time, and time is therefore a dimension in the generic sense of the word. But all this "figure of speech" stuff has turned the measure into the sort of dimension that people think is physically accessible like the dimensions of space.

I must buy that book.

[Boerseun]

Originally Posted by Popular2

I think there's more to this than "figure of speech". The concepts we use are deeply rooted in the way we think, and it's very hard not to use them. Try talking about time without using any past or future tense, and without any of those "time is a length" figures of speech, and it's incredibly difficult.

No disagreement there, but the mere fact that we can't properly describe it without resorting to speech more fitted to other things, like 'length', for instance, don't change anything about the nature of time. It is simply a linguistic shortcoming.

Originally Posted by Popular2

I put it to you that there's not a huge difference between an electromagnetic shell ten light years across and a ten-year old videotape. Both contain information about the event, but neither is the event. The event is where things were and how they met, and they're not there now whatever information you have to hand.

That's true, and very well put, too. And you can't interact with a recording.
But even if you're sitting across the room from someone, talking to them, you're still not 'interacting' in 'real time' - there's a lag of a few nanoseconds before your friend's 'universe' intersects with yours. You can't even participate in real time interaction with your own body - where you see your foot is where it was a little while ago, not where it is now. The only thing that might say that it's in 'real-time connection' with all of its constituents, is a photon. From there on, it's a matter of scale, and debating the nature of time is moot.

Originally Posted by popular2

As regards the nail gun, the cylinder looks shortened from the nail's perspective, and the nail looks shortened from the cylinder's perspective. We don't know which one of them we fired. This aspect of the thought experiment is like the Twin's Paradox. The crux of the matter is that event A happens before event B for the nail, yet event B happens before event A for the cylinder. They can't both happen before each other, so the "passage" of time has to be subjective to motion rather than an objective reality.

Time dilation should sort this issue out, I guess.

Originally Posted by popular2

You were talking about c as a speed. Our experience of distance and time varies with our speed, and while we always measure c as 300,000 metres per second, our metres vary and so do our seconds.

Yes, but only from a third party's vantage point. In your frame of reference, a meter is always a meter, and a second is always a second, regardless of your v.

Originally Posted by popular2

The units we're using for c aren't constant...

They are - in the same frame of reference...
[quote=popular2...so to express it absolutely it seems like we need some new units based on spacetime rather than space and time. That's why I was talking about velocity and degrees. (I like 0 degrees for motionless and 90 degrees for c, but I'm not proud of it). [/quote]
I think I see what you're getting at, but like the old man said, it's all relative.

Originally Posted by popular2

Yes, information spreads at c. And yes, time is the name we give to the sequencing of sets of information. The events occur in a sequence, and we record these events. Like a video tape I guess. What we've already recorded is the past, what we're recording now is now, and what we haven't yet recorded is what we call the future. The tape "runs". But there is no absolute measure of length on this tape, no absolute measure of speed, no fundamental units of time. Because our VCR and the tape is itself a series of events, just like the events we're recording. Sure, the tape provides a record of events, it's information, but it isn't the actual events. They're in the world, not in the sequence, not on the tape. You can rewind the tape to review the history, but there's no way to rewind the tape to visit the past. You can't travel down the tape.

I agree 100% with that - but it does make for excellent sci-fi, though...
Your point about there not being any absolutes in measurements is quite correct, as a matter of fact every single atom in the universe exists in its own unique universe, with its own definitive 'spacetime' in which that atom's measurements are definitive and absolute. And his (the atoms) set of measurements will only be definitive for itself, and will not mean much anywhere else. I only use the term 'atom' here as a convenience - it goes right down to the most elementary particle there is. They all exist in their own unique 'universe'.

Originally Posted by =popular2

You can use your tape to measure time, and time is therefore a dimension in the generic sense of the word. But all this "figure of speech" stuff has turned the measure into the sort of dimension that people think is physically accessible like the dimensions of space.

Which, of course, it isn't.

I might sound like an old pain in the posterior orifice, to tell the truth I like this thread and what you have to say. I'm just being the devil's advocate that any good thread needs. Even on Mondays.

[Farsight]

Thanks Boereun. I'll try to respond to each point you raised:

..the mere fact that we can't properly describe it without resorting to speech more fitted to other things, like 'length', for instance, don't change anything about the nature of time. It is simply a linguistic shortcoming.

Yes, time is whatever it is, but when I try describe it without using "length" the fallout feels so dramatic that simply a linguistic shortcoming doesn't sound adequate. I struggle to demonstrate this to your satisfaction.

But even if you're sitting across the room from someone, talking to them, you're still not 'interacting' in 'real time'

Yep, I agree with that. When you measure to an absolutely fine degree you find you can't have any interaction in true "real time", because real time has a zero duration. I think there's a truism in there somewhere.

The only thing that might say that it's in 'real-time connection' with all of its constituents, is a photon.

But a photon doesn't experience any time. The real time is again of zero duration.

Time dilation should sort this issue out, I guess.

Time dilation is the sort of thing I'm now having trouble with. I imagine myself as a metronome. Each tick is a thought in my head. If I'm travelling with a forward motion of c I can't tick, because any transverse motion would cause c to be exceeded. If however my forward velocity is zero I can tick with a transverse motion of c. My time experience changes, but I can't find any actual time out there that's dilating.

Yes, but only from a third party's vantage point. In your frame of reference, a meter is always a meter, and a second is always a second, regardless of your v... They are in the same frame of reference

Noted and agreed. But I've got to confess that even basic things like "frame of reference" are starting to give me trouble. I see an inertial frame of reference translates at a constant vectorial velocity and I'm thinking it's just the motion, the velocity, the thing that defines the time rather than some point of view.

Oh you're not a pain. You should see some of the grief and abuse I've copped elsewhere. Please do play devil's advocate. I'd like to see this float, but if it doesn't I'd rather know. The thing is, if it does float you might be having fun playing devil's advocate elsewhere. I see somebody like Kip Thorne on TV talking about time travelling wormholes, then I think of that Arrow of Beans and my eyes kinda narrow...