Is Time Truly Continuous or Discrete?

[Tachyon son]

Ive been reading different points of view and theories regarding this topic. Wich is, currently, the most reliable one?

P.S: Had red a nice one explaining that time, in human perception terms, is discrete, because the brain needs at least the change of the smallest quanto (1 bit?) of information to work (to be able to perceive anything).

 

[mathman]

Whether or not time is continuous or discrete has nothing to do with human perception. Humans have been around a relatively short time (modern humans less than 200,000 years) compared to the universe. Time existed before there was any life.

As far as time being continuous or discrete from physical theory, the question is open. For example, loop quantum gravity has time as discrete. General relativity operates in continuous time. Only time will tell.

 

[Dissident Dan]

Originally posted by mathman

As far as time being continuous or discrete from physical theory, the question is open. For example, loop quantum gravity has time as discrete. General relativity operates in continuous time. Only time will tell.

har har...

 

[Chi Meson]

Check this old thread regarding "chronon vs. Plank time."
www.physicsforums.com/showthread.php?threadid=6174

Chronons are a theoretical discreet particle of time. Plank's time is a very tiny amount of time; it seems to be the smallest meaningful amount of time.

 

[avemt1]

Whether or not time is continuous or discrete has nothing to do with human perception. Humans have been around a relatively short time (modern humans less than 200,000 years) compared to the universe. Time existed before there was any life.
As far as time being continuous or discrete from physical theory, the question is open. For example, loop quantum gravity has time as discrete. General relativity operates in continuous time. Only time will tell.

Yes, and when time stopps we will percieve that it has stopped and the discovery will be made. TIME HAS STOPPED. It will be broadcasted over the entire world network next year.

HA HA YEAH RIGHT...

we cannot percieve time as stopping, because we would stop percieving in the process of time stopping, therefore time is continuous IN THE PERSEPTION OF THE HUMAN MIND.
The only way to percieve time as stopping is to isolate ourselves from whatever time is, and measure it without having the isolated (controlled) time interfere with the experiment.

 

[avemt1]

Now any other ideas?

 

[Mk]

Yes, we could not tell, because we are contained in it, if it stopped we wouldn't notice, as far as we know, it could stop all the time, and/or speed up whenever, since we're contained in it. If you were to imagine a closed container, you are suspended in the middle, floating, with no way to communicate with the outside world. The box could be going trillions of miles an hour, abruptly stop, to zero, then speed up to 7,000, you wouldn't know because you can't see it from the outside, or watch the outside.

Could we in any way, ok, this is crazy... perceive time from outside time. Watch a parallel universe from another one?

 

[s3nn0c]

"Could we in any way, ok, this is crazy... perceive time from outside time. "

In a specific sense it's a natural thing in noncommutative geometry :-)

 

[avemt1]

Yes, we could not tell, because we are contained in it, if it stopped we wouldn't notice, as far as we know, it could stop all the time, and/or speed up whenever, since we're contained in it. If you were to imagine a closed container, you are suspended in the middle, floating, with no way to communicate with the outside world. The box could be going trillions of miles an hour, abruptly stop, to zero, then speed up to 7,000, you wouldn't know because you can't see it from the outside, or watch the outside.

Could we in any way, ok, this is crazy... perceive time from outside time. Watch a parallel universe from another one?

I am not sure, but it seems possible. Alternate dimensions is not in my list of interests.

 

[CeeAnne]

Has time been proven to actually exist? It's a measurement; a comparison of events; the swing of a pendulum or vibrations from the atoms in caesium vapour; whatever, it's counted and compared to other events. Time exists mathematically and is very useful, as are other dimensions, but a meter exists only in the sense that we have a stick designated as that long and stuff to compare. Is time any different?

 

[avemt1]

Has time been proven to actually exist? It's a measurement; a comparison of events; the swing of a pendulum or vibrations from the atoms in caesium vapour; whatever, it's counted and compared to other events. Time exists mathematically and is very useful, as are other dimensions, but a meter exists only in the sense that we have a stick designated as that long and stuff to compare. Is time any different?

Well, if you look at time in Relativity, time is able to be distorted. This, for me, is proof enough that it is real.

 

[sigma]

Yes, we could not tell, because we are contained in it, if it stopped we wouldn't notice, as far as we know, it could stop all the time, and/or speed up whenever, since we're contained in it. If you were to imagine a closed container, you are suspended in the middle, floating, with no way to communicate with the outside world. The box could be going trillions of miles an hour, abruptly stop, to zero, then speed up to 7,000, you wouldn't know because you can't see it from the outside, or watch the outside.

Could we in any way, ok, this is crazy... perceive time from outside time. Watch a parallel universe from another one?

I would disagree. I think you'd hit the wall if the container was abruptly slowed down or accelerated. What this make in the analogy with time is an open question.

The question is wheter we can divide time into infinitly small pieces or not, right?
What is time anyway? Can we divide something if we don't even know what it is?

Well if there's an definite smallest particle/string/loop/wave whatever you like that cannot be divided into smaller components, maybe time is of the same nature?

lol.

 

[avemt1]

hittting a wall is only an effect of inertia.
we can divide mass by volume to get density, so we obvioulsy can divide time into some quantative value. By my experience time is continuall due to human perseption, but it is continuous at a rate. This states that time can be split into values such as seconds, hours, minutes, days, months, etc...

 

[Les Sleeth]

Has time been proven to actually exist? It's a measurement; a comparison of events; the swing of a pendulum or vibrations from the atoms in caesium vapour; whatever, it's counted and compared to other events. Time exists mathematically and is very useful, as are other dimensions, but a meter exists only in the sense that we have a stick designated as that long and stuff to compare. Is time any different?

I agree with you CeeAnne. There is no "time" with existential qualities. I've argued at PF many times that time is simply how we measure the rate of the universe's entropy (as in: overall rate of disorganization). What we do is use situations or things that cycle, almost like a metronome keeping beat. Why that works is because if the universe continues heading toward disorganization, it will evenually destroy all regularity. Since regularity is what allows cycles, it makes sense to use the regularity of cycling things as yardsticks.

If that is true, it gives us the means to decide this thread's question. I say time is both discrete and continuous. Because the last cycling thing to go will be the oscillation associated with quantum processes, and because we know quantum processes occur in discrete units, then we also know that time progresses in discrete steps. But since there is no known circumstances where entropy fails to prevail overall, time is continuous too. In other words, micro-time proceeds discretely, and macro-time proceeds continuously.

 

[Mk]

I would disagree. I think you'd hit the wall if the container was

hittting a wall is only an effect of inertia.

Sorry, my analogy was incomplete, if there was no smashing into walls inertia... heh, I think you know what I mean. No?

I agree with you CeeAnne. There is no "time" with existential qualities. I've argued at PF many times that time is simply how we measure the rate of the universe's entropy (as in: overall rate of disorganization). What we do is use situations or things that cycle, almost like a metronome keeping beat. Why that works is because if the universe continues heading toward disorganization, it will evenually destroy all regularity. Since regularity is what allows cycles, it makes sense to use the regularity of cycling things as yardsticks.

If that is true, it gives us the means to decide this thread's question. I say time is both discrete and continuous. Because the last cycling thing to go will be the oscillation associated with quantum processes, and because we know quantum processes occur in discrete units, then we also know that time progresses in discrete steps. But since there is no known circumstances where entropy fails to prevail overall, time is continuous too. In other words, micro-time proceeds discretely, and macro-time proceeds continuously.

What is the other side of the arguement? How is time not a measure of process comencing in the universe? And I see micro-time compared to macro-time as an interesting thought...

 

[Les Sleeth]

What is the other side of the arguement? How is time not a measure of process comencing in the universe?

I don't think two sides are implied in what I said. If time is what I say it is, then I should be able to use that model to describe time in terms of your question, ". . . is time not a measure of process commencing in the universe?"

I assume you are referring to the fact that time is said to commence with the Big Bang (if not, then forget what I'm about to say ). From the very first moment of the universe's inception we can now see entropy was in charge. At first of course it looked like everything is getting organized, which it was. But just like if you look at life during the formation of the fetus you might say the law of entropy is being violated (but later when the person dies it is clear overall it wasn't), so too can we now see that the universe appears it was fated for disintegration from the moment it came into being.

It would have been exceedingly difficult to measure the rate of entropy in those opening moments. Now we can do it by averaging all the entropic change since the Big Bang.

Why is time so hard to understand? One reason could be relativistic effects, as avemt1 mentioned, "Well, if you look at time in Relativity, time is able to be distorted. This, for me, is proof enough that it is real."

Let's try out the time-as-entropy-rate model on that. If time is the rate of entropic change in the universe, how could it be altered? Well it turns out, for example, that gravity and acceleration tend to retard entropy because they slow particle oscillation rates. Since, according to the entropy rate model, there are only so many oscillations remaining in matter before the universe disintegrates, a slower oscillation rate at some spot (like an accelerating spaceship or neutron star) means "time" (i.e., entropy rate) proceeds more slowly than frames of reference not subject to acceleration or the intense gravity of a neurtron star.

 

[avemt1]

I would disagree. I think you'd hit the wall if the container was abruptly slowed down or accelerated. What this make in the analogy with time is an open question.

The question is wheter we can divide time into infinitly small pieces or not, right?
What is time anyway? Can we divide something if we don't even know what it is?

Well if there's an definite smallest particle/string/loop/wave whatever you like that cannot be divided into smaller components, maybe time is of the same nature?

lol.

all right you caught me, but we are talking about time here not inertia.

 

[avemt1]

Why is time so hard to understand? One reason could be relativistic effects, as avemt1 mentioned, "Well, if you look at time in Relativity, time is able to be distorted. This, for me, is proof enough that it is real."

Let's try out the time-as-entropy-rate model on that. If time is the rate of entropic change in the universe, how could it be altered? Well it turns out, for example, that gravity and acceleration tend to retard entropy because they slow particle oscillation rates. Since, according to the entropy rate model, there are only so many oscillations remaining in matter before the universe disintegrates, a slower oscillation rate at some spot (like an accelerating spaceship or neutron star) means "time" (i.e., entropy rate) proceeds more slowly than frames of reference not subject to acceleration or the intense gravity of a neurtron star.

This sounds like the properties of the wave of light: As the vibration increases energy is decreased, but as vibration decreases energy is increased. If you substitute acceleration for energy and vibration of wavelength for vibration of matter you get the same result. Correct?

 

[Les Sleeth]

This sounds like the properties of the wave of light: As the vibration increases energy is decreased, but as vibration decreases energy is increased. If you substitute acceleration for energy and vibration of wavelength for vibration of matter you get the same result. Correct?

That's how I see it. In a thread I started a long time ago I asked if light ever spontaneously lost energy. Marcus was kind enough to explain how the microwave background radiation still hanging out in the universe since the era after the Big Bang appears to "stretch" in wavelength as the universe expands, which of course means it surrenders energy. That, in the rate-of-entropy-as-time model I've suggested, would be considered the "aging" of light.

I wonder if background microwave radiation would serve as the best timer possible in our universe since if we had our clocks tuned to its frequency, our clocks would be slowing pretty close to the rate the universe is winding down.

 

[sigma]

That's how I see it. In a thread I started a long time ago I asked if light ever spontaneously lost energy. Marcus was kind enough to explain how the microwave background radiation still hanging out in the universe since the era after the Big Bang appears to "stretch" in wavelength as the universe expands, which of course means it surrenders energy. That, in the rate-of-entropy-as-time model I've suggested, would be considered the "aging" of light.

I wonder if background microwave radiation would serve as the best timer possible in our universe since if we had our clocks tuned to its frequency, our clocks would be slowing pretty close to the rate the universe is winding down.

Does the "aging" of light oppose relativity?

 

[selfAdjoint]

Does the "aging" of light oppose relativity?

There is no "aging" of light.

 

[Les Sleeth]

Does the "aging" of light oppose relativity?

Well, in light of SelfAdjoint's comment I will defer to his judgement since he is the expert. The only thing I feel somewhat confident about is describing time as the rate of entropy. I wouldn't care to venture any opinions about relativity.

But what I meant was, if background radiation loses energy as the universe expands, then when the universe was younger, background radiation possessed more energy. So I used the term "aging" metaphorically. Since background radiation has been around longer than just about anything, and has been adjusting energy-wise all that time, it's "age" is always showing by in its oscillation rate (which is why I wondered if it might not be the best clock we have available).

By the way, today I bought an atomic clock! (Well, as close to one as I can afford.) After my PDA burnt out, I wanted a clock with a weekly alarm (not a watch, which is easy to find) because I have to call to reserve a court at my racquetball club EXACTLY on time or some other turkey will get the court. It only loses something like a second every million years, so if you ever want to know exactly what time it is, just ask me.

Of course, make sure you don't ask me when I am taking off from SFO International because then my clock will seem a little slow to you. Hmmmmmm, or will it? That's a good question for SelfAdjoint. Since time on the clock is actually maintained by a radio signal it receives from the US atomic clock in Fort Collins, would that be affected the same way as if it were keeping time all by itself on board the plane?

P.S.
Here's the clock: http://www.weatherconnection.com/product.asp?itmky=213391

 

[hitssquad]

9,192,631,770 vibrations of a Cesium 133 atom in a vacuum

Since time on the clock is actually maintained by a radio signal it receives from the US atomic clock in Fort Collins, would that be affected the same way as if it were keeping time all by itself on board the plane?

No. Your clock will run slow while on the plane, but that will not affect the synchronism of the time updates. Every time your clock receives an update from the Fort Collins WWVB 60kHz atomic-clock radio station, it will revert to Fort-Collins-synced time.

Apropos link:
http://store.newadventures.com/wirelessclocks.html

 

[Philocrat]

Ive been reading different points of view and theories regarding this topic. Wich is, currently, the most reliable one?

P.S: Had red a nice one explaining that time, in human perception terms, is discrete, because the brain needs at least the change of the smallest quanto (1 bit?) of information to work (to be able to perceive anything).

If you can mathematically reconcile SEQUENTIALISM with SIMULTANEITY, and, perhaps, successfully freeze SPATIO-TEMPORAL HISTORIES into a 'MONOPOIDAL FRAME' then the diverse senses of time that you are describing should, like natural forms, everporate!

 

[Les Sleeth]

No. Your clock will run slow while on the plane, but that will not affect the synchronism of the time updates. Every time your clock receives an update from the Fort Collins WWVB 60kHz atomic-clock radio station, it will revert to Fort-Collins-synced time.

Apropos link:
http://store.newadventures.com/wirelessclocks.html

Here's what I wondered about. Why wouldn't the Fort Collins signal, once entering the plane's frame of reference, be affected and so give a relativity-adjusted impulse to the clock?

P.S.
By the way, those clocks at your link do not have a weekly alarm! :tongue2:

 

[Philocrat]

On the issue of the spooky and illusive nature of Time, I wrote an Informal Piece last month and posted on this Forum called 'THE STANDARD UNIVERSAL NOW: A Philosophical Analysis of time' in which I informally showed how the notion of omnipresency is conceptually possible, without any intention of formalising it, but unfortunately it was removed and locked up in the Theory Devevlopment section of PF by Schroot and the Mount Everest Crew of this forum, and which has now completely vanished from there. The point I was trying to make in that two-part informal piece was to show how time can equally be illusive by looking at the notion of omnipresence in a quantitative and logical way. The equations that I used there were never meant to serve any formal purpose. It was only an informal illustration of the notion. The challenge that I posed in that piece to the formalist is this: if you can succeed (which I know you all can - it's your field) in formulating a better and formally correct matheamtics for describing the notion of Omnipresence, your result will never fundamentally deviate from the original point that I was trying to make. The mathematical formula you devise should conceptually violate the notions of past and future and suspend the activities of a timeless traveller into a perment present. This would be a conceptual violation, and not necessarly founded in reality since there are already so many physical restrictions already imposed on physical events by science. Only in this cenceptual sense can one say that time may have an illusive twist to its nature. However, science must not pride itself and bet too mush on this, as there is currently no concrete grounds for completely ruling out the translation of conceptual possibility into a real possibility.

 

[Mk]

I don't think two sides are implied in what I said. If time is what I say it is, then I should be able to use that model to describe time in terms of your question, ". . . is time not a measure of process commencing in the universe?"

I assume you are referring to the fact that time is said to commence with the Big Bang (if not, then forget what I'm about to say ). From the very first moment of the universe's inception we can now see entropy was in charge. At first of course it looked like everything is getting organized, which it was. But just like if you look at life during the formation of the fetus you might say the law of entropy is being violated (but later when the person dies it is clear overall it wasn't), so too can we now see that the universe appears it was fated for disintegration from the moment it came into being.

It would have been exceedingly difficult to measure the rate of entropy in those opening moments. Now we can do it by averaging all the entropic change since the Big Bang.

I ment, you say you argue against "something," but you didn't say what the other ideas are, what are they?

 

[Les Sleeth]

I ment, you say you argue against "something," but you didn't say what the other ideas are, what are they?

I see. I was agreeing with CeeAnne about seeing time merely as a measurement, and not seeing it like some suggest as, say, an actual dimension one can move around in or as being "real" in any other way. Time is just the name we give to the rate of change and the regularity found in that; since change overall is disintegrative in the universe, that is why I said time is a measurement of the rate of entropy.

 

[Les Sleeth]

Here's what I wondered about. Why wouldn't the Fort Collins signal, once entering the plane's frame of reference, be affected and so give a relativity-adjusted impulse to the clock?

I just want to add to my question, which if anybody knows the answer I'd like to know.

I can see how light speed of the signal wouldn't be affected, but wouldn't the signal's oscillation rate be affected?

 

[Ludwig]

If I may offer a different point of view...

Time cannot possibly be continuous because events happen in time. For instance, when we flip a switch and turn a light bulb on, there is no time in which the bulb is neither on nor off. So for a certain period of time the bulb is off, and for another period it is on. You can make the periods as short as you want, at least in principle, but you can't make them as short as zero. Not even in principle. So time must be necessarily made of small "quanta", tied together one after the other with no "gaps" in between.

 

[jackle]

If time did come in small lumps, it doesn't follow that all these lumps are synchronized so that they march forward like billions of tiny clocks that all tick together. It seems likely that one "clock" or lump of time might tick (pass by), then another somewhere else, then the first one again. So it could be nothing like a video sequence where all the tiny dots that make up the picture "jump" from one frame to the next at the same moment.

Each dot in the TV analogy (or sub-atomic particle in the real world) might jump between states independently and with some random factor as well. When studying particle radiation, I never encountered any suggestion that there are "allowed times" and "disallowed times" for the radiation to be detected. I suspect you could prove that there is no such thing.

If time was discrete, but asychronized with a random variance at the microscopic level, it could give a macroscopic impression of continuity which would emerge from billions of tiny lumps of time that pass endlessly in no particular order throughout a given volume of space.

 

[Les Sleeth]

The discrete arguments seem like pretty good thinking to me. But there seems to be another aspect too, one which does not negate the quantum way of describing time. Using an analogy, say you blow a balloon up and then connect the opening to a device that pressure causes to open and close (releasing a "quanta" of air). As the air pressure decreases in the balloon, the device takes longer to open up, but it will still function as long as any air pressure is inside the balloon. Looking at the point of the opening, there the process is discrete; but looking at the whole ballon, the process is continuous in the sense that is will continue non-stop until all the air pressure in the balloon is gone.

 

[CeeAnne]

Let's look for a reason for time. The Theory of Relativity makes the equivalence principle obvious, and the primary equivalence in this case is time/space. Although space may be thought of as void, with the ideas of quanta it has become usual to think of it as very particulate. The fabric of space comes to mind. Perhaps it becomes no smaller than quark size, but nonetheless something very tiny represents the fabric of space between stars as well as between the parts of atoms making up the stars. In addition to being the underlying substance, space fabric would also be the vector of energy transfer and propagation. The total energy of the Universe is tied to this space fabric. It is the natural tendency of anything in motion to continue in motion and this is the thing we call energy. Energy is change, and at the quanta level there definitely is a lot of change. Think of the change as a structural pattern, such that the rate of energy transfer can be depended on for everything, from a macro object such as a rock to the vibrations of atoms. However, motion affects this transfer of energy, and clocks, whether windup or atomic, are timed by the transfer of quanta. Atomic behaviour depends on it. So it seems plausible that at light and sublight speeds the rate of transfer would be slowed considerably. Could this be what we are measuring and callling time? Why is the speed of light what it is? Try it this way: Accelerate an object. As the object is pushed faster, what happens? It moves away from the energy source (this is true of rockets, too) and the faster it moves away, the less energy is transfered. This effect is usually equated as an increase in mass requiring more and more energy to accelerate, by I think mathematically if we calculate the difference in transfer rate due to motion, the result would be the same increased energy requirement as given by mass increase calculations. So, anyway, if time is a transfer rate, the rate would be different for things at rest compared to when they are in motion. Continuous or discrete? Look at the quanta.

 

[Sho'Nuff]

http://www.utm.edu/research/iep/t/time.htm