The Arrow of Time

[ygolo]

I want to start a discussion about the science that gives direction to the way time "flows."

It is fascinating to me. Why does the 2nd Law of thermodynamics hold? Why does quantum entanglement increase over time? Why does electromagnetic radiation follow only retarded solutions instead of advanced solutions?

To put it in simpler terms:
Why is the Past different from the future?

Some examples:

• Objects spontaneously fall towards the earth, but not the other way around.
• A vase can spontaneous break or shatter, but the reverse doesn't happen spontaneously.
• Waves radiate outwards from a point spontaneously, but don't converge to a pont spontaneously.

Some indication is that the Second Law of Thermodynamics comes from going from states that are less probable to states that are more probable.

In fact, the entropy associated with a certain macro-state is porportional to the ln of the number of micro-states associated with that macro-state.

Still that doesn't completely explain things like the radiation, or even the gravity direction (though the gravity related issues are expalined by Gibbs-Free Energy, but what explaines Gibbs-Free-Energy).

So lets speculate. I think it'll be interesting.

Einstein and Ritz had an argument over with was more primary--Einstein believed Thermodynamics explained the directionality of radiation, while Ritz believed that the direction of radiation was primary and lead to thermodynamics.

Note some other issues, like the topology of the universe will prohibit time-like curves that meet themselves without violating the laws of thermodynamics. Hawking had a theory that entropy (and perhaps our associated notion of time) would start going backwards at some point in history to allow such topologies.

 

[nozflubber]

I recently found philosophical inspiration to bolster an idea i've toyed with recently: time is meaningless and nothing itself. I found it in a strange author that most physicists would be unfamiliar to: Kant.
"All phenomena, that is, all objects of the senses, are in time, and stand necessarily in relations of time" ... "If we drop our manner of looking at ourselves internally, and of comprehending by means of intuition... then time is nothing". Time is intuitive and perceived only because the human mind seeks to project, predict, and "roll" as best it can.

This proposition also explains why we cannot define infinite very well (conceptually nor mathematically) - because infinite by itself cannot be conceptualized outside the realm of Time and Change. It requires an understanding of the "rate of change" of infinite when we have an infinite series, for example, as we can't examine infinite divided by infinite anymore than we could examine Jrogrols divided by Jrogrols (random word I made up to demonstrate epistemological unawareness)

What need be crucially understood here is that time is meaningless without change - it is interesting to point out how simply this is demonstrated in popular film. What happens when we "freeze time" in Star Trek or twilight zone? Changes stop occuring, that's it. Freezing time can't be understood any further beyond that because time IS change. In the sci-fi world, freezing time is essentially the same as being able to change while nothing else changes around you (which I think is impossible but it nonetheless demonstrates how common this idea is)

Now, since I have conveniently redefined the nature of the question by eliminating the appeal to "time itself" (time doesn't FLOW - in fact it doesn't DO anything at all) to explain the sequential nature of events, it must be restated:

Why is thermodynamics a one way arrow? Why does change always occur according to the rules of entropy? What don't we see really ODDBALL shit, like a basketball falling upwards?

I must admit that question bugs the hell out of me, because there's no obvious reason it SHOULD be just like that. Physicists and metaphysics just have to swallow the bitter "that's the way it is" pill at this juncture. To be bold, I don't think it DOES absent of some "divine engineer"(and this hypothesis is dubitable no doubt), it just appears to us that way. I think there is infinite chaos and infinite possibility to the universe... just for whatever reason, entropy applies to us 100% of the time. or at least it SEEMS to... I can conceptualize a universe where our "quantum mechanical garbage" (IE the results we DON'T see), get dumped into some sub-realm, something ala Everet's model...

If a portion of the basketball falls upwards.... there's gotta be a reason we can't observe that portion.

 

[nozflubber]

Maybe God likes to play "segregation" with energy and results, 1950s American style? It's absurd to group the chaotic universe with the nicely ordered, converging universe! Maybe hell is just a bunch of refuse.



EDIT: actually analyzing through Energy and a particular statistical result doesn't do "justice" to time..... time must be summarized in ALL of the changes in effects we see in a system. Thermodynamics does this very well, much better than time.

 

[yenom]

woah i was just thinking about this.

I suspect time is just a projection of information from our brains. but I am not sure.
Time is one of the undefinable things and mystery in nature.

 

[matmos]

Why is thermodynamics a one way arrow? Why does change always occur according to the rules of entropy?

I rather like Bolzmann's theory. It has interesting implications.

If a portion of the basketball falls upwards.... there's gotta be a reason we can't observe that portion.

How do you know it hasn't? When you weren't looking.

 

[ygolo]

Ah. Good. People are participating. Time ans space are artificial concpets we made to explain the universe, but the notions to correspond to something.

It's tricky though, because I know of no way to objectively place the "present moment."

It seems like the present moment is absolutely subjective. Though the directionality from past to future seem to have some arrows.

Boltzman's theory is the micro-state macro-state theory I slated earlier. if w is the number microstates for a particular Energy state, then the entropy S is proportional to ln(w). So "disorder" is really kind-of analogous to loss of information--anctually in information theory, "bits of information" are actually called negentropy.

Interesting, huh?

 

[yenom]

So is there a way for time to flow backward? Time and energy I think are pretty intertwined.

 

[entropie]

yea it works like my brain, it constantly dissolves .

I am not a big fan of giving the entropy too much credit concerning our definition of time. Time is an illusion and therefore our understanding of it is just an interpretation of the real mechanics.

But what is indeed really intresting would be the reactions that take place to dissolve a theorethical perfect system. That goes down the bigbang route, like what initiated the bigbang ?

 

[JocktheMotie]

yea it works like my brain, it constantly dissolves .

I am not a big fan of giving the entropy too much credit concerning our definition of time. Time is an illusion and therefore our understanding of it is just an interpretation of the real mechanics.

But what is indeed really intresting would be the reactions that take place to dissolve a theorethical perfect system. That goes down the bigbang route, like what initiated the bigbang ?

I disagree with you here. I think entropy has to do with everything concerning time. Entropy gives matter and energy rules for how it should behave. Time is simply the rate at which those processes behave, and it is not an illusion, because we can change the rate at which it moves across different reference frames by manipulate the energy of the system. While our idea of seconds, minutes, hours and years are certainly arbitrary and based on how our minds experience time, that doesn't mean time itself is created by our minds.

 

[yenom]

I disagree with you here. I think entropy has to do with everything concerning time. Entropy gives matter and energy rules for how it should behave. Time is simply the rate at which those processes behave, and it is not an illusion, because we can change the rate at which it moves across different reference frames by manipulate the energy of the system. While our idea of seconds, minutes, hours and years are certainly arbitrary and based on how our minds experience time, that doesn't mean time itself is created by our minds.

time is not an independent cvariable of energy. As for time being a vector quantity and energyt being scalar. I do not know how this works.

 

[JocktheMotie]

time is not an independent cvariable of energy. As for time being a vector quantity and energyt being scalar. I do not know how this works.

Time responds to the mass and kinetic energy of a system in that as the speed or mass increases, the system's spacetime "footprint" is altered, thereby affecting time's rate.

Also, maybe my explanation of time as vector component is misleading. Hopefully this site may help:

One of the easiest ways to understand this effect is to think of objects with mass as traveling through space-time, instead of just space. All objects with mass travel with a constant "speed" through space-time (It's not really velocity, as velocity is motion over distance, not distance and time). If an object is stationary in relation to its surroundings, it is traveling only through time, at it's constant speed. In fact, the object is traveling through time alone at the speed of light. If the object begins to move, it's speed through space-time remains constant, but it's speed through time must slow down to compensate. If the object moves through space at a speed approaching the speed of light, it's speed through time diminishes significantly. If it moves through space at the speed of light, it will stop "moving" through time altogether.

 

[ygolo]

time is not an independent cvariable of energy. As for time being a vector quantity and energyt being scalar. I do not know how this works.

In addition to what Jock mentioned, there is a quantum mechanical link as well. Tme and Energy are conjugate to each other. Therefore, just like momentum and postion, there in an uncertainty principle involving time and energy.

The Energy-Time Uncertainty Principle

 

[entropie]

I disagree with you here. I think entropy has to do with everything concerning time. Entropy gives matter and energy rules for how it should behave. Time is simply the rate at which those processes behave, and it is not an illusion, because we can change the rate at which it moves across different reference frames by manipulate the energy of the system. While our idea of seconds, minutes, hours and years are certainly arbitrary and based on how our minds experience time, that doesn't mean time itself is created by our minds.

Yes I know spacetime.

I meant I dont like to tamper with mind constructs concerning for example time travel. I rather like to tamper with mind constructs based on entropy for example. I meant a mere definition thing, because I have been confronted with meta-physics in the past and though they are great philosophers, they tend to bend something they heard from physics into a philosophical issue and expand the theory.

I like that and its cool but I cant follow their ideas without mathematical proof. Most of the times; I have been confronted with them, I got bored because they used a lot of fantasy and interpreted but lacked to care about any physical / mathematical proof.

I am sorry, this is off-topic, I just got some issues with philosophers

 

[BlueScreen]

This might be too much of a simplification but...

As time moves forward, more events occur; more things interact. It takes more information to describe the order of the system, because more has happened to put the system in its current state. Hence on a universal level, a move toward chaos is ensured.

 

[yenom]

things in the universe can only exist in two forms : matter and energy.
If time is not matter, then it kmust be energy.

sorry, ygolo and jock, the article seemed a little difficult to understand but I will try my best.

 

[FDG]

I always thought about the arrow of time as the central limit theorem of life/universe, so to speak. With each second (we may use another measure - particle interaction, maybe) we are "rolling a dice" with every interaction. If we roll a million of dices at once, then we would be extremely surprised to find an expected value different than 3 (assuming a 6-faced dice).

 

[yenom]

There is also the question why only time has an infinite quality while other properties of the universe does not. Perhaps we can include space.

 

[sunset5678]

`

it is kind of ironic how you remember certain things
that had escaped your memory for years then they help you figure out a solu
tion to a current situation, or you find a long-missing object when you get th-
is twinge and an urge to check a certain place even though you really don't
know why after you'd forgotten about them entirely and weren't thinking of anything related, and it inspires you to change some situation in your life. On one side of the coin it seems coincidence and rationally explainable, but on the other it doesn't. I'm not sure how much stock I put into this stuff but it
can raise an eyebrow sometimes. The fact that the past can affect the pre-
sent and the past in between can be affected by those things being forgott-
en then you remember those things and it feels like time flows more normally,
but then you realize the stuff in between must have had some kind of purpo-
se like people you meet and things you wouldn't have gotten to know about
them if things would have been different and experiences you might have sur-
passed entirely if you were where you were 'supposed' to be. If they could
figure out those mysteries perhaps time travel could be fathomable.

 

[yenom]

What if all the watches in the world go anticlockwise? What will happen to time?

 

[Fluffywolf]

I still see time as nothing more then a mere perception of movement, but time itself isn't an existential factor. It's not manipulative, it's not there.

Clocks measure themselves, we use time to measure our movement and ourselves. But there is, has and always will be only the present.