What is time??
- Thread starter Shadow1
- Start date
No it hasn't been cleared up. All the evidence points to the circadian rythm of the SCN as being responsible for any time perception, it does afterall govern ''awarness''.
How about: is there a description of time which is not tautological?river said:
Or: is time fundamentally different to space? If so, how is it different if in Minkowski spacetime, a time interval is a distance?
Or: why is time symmetrical in physical theories, but can't be 'reversed' physically?
There is more... even better, on the perception of time from wiki
''Although the sense of time is not associated with a specific sensory system the work of psychologists and neuroscientists indicates that human brains do have a system governing the perception of time,[4] composed of a highly distributed system involving the cerebral cortex, cerebellum and basal ganglia. One particular component, the suprachiasmatic nucleus, is responsible for the circadian (or daily) rhythm, while other cell clusters appear to be capable of shorter-range (ultradian) timekeeping.''
More or less proves my point.
''Although the sense of time is not associated with a specific sensory system the work of psychologists and neuroscientists indicates that human brains do have a system governing the perception of time,[4] composed of a highly distributed system involving the cerebral cortex, cerebellum and basal ganglia. One particular component, the suprachiasmatic nucleus, is responsible for the circadian (or daily) rhythm, while other cell clusters appear to be capable of shorter-range (ultradian) timekeeping.''
More or less proves my point.
Right ok, so how can we model time as a dimension of space?
Quite simply really. The phenomenon of the Spacious Present is what gives us the impression that time is a physical component of the vacuum. Let me elaborate:
''The concept was further developed by Harvard professor of philosophy William James.[3] James defined the specious present to be "the prototype of all conceived times... the short duration of which we are immediately and incessantly sensible". C. D. Broad in "Scientific Thought" (1930) further elaborated on the concept of the specious present, and considered that the Specious Present may be considered as the temporal equivalent of a sensory datum.''
http://en.wikipedia.org/wiki/Specious_present
''Through a series of declarative sentences (or "propositions"), one can affirm the existence of the specious present. For example, to see a second-hand moving is quite a different thing from seeing that an hour-hand has moved.''
So we ''see'' motion, we attribute it as a ''flow'' on things. Naturally things move in space, so if you can attribute some kind of time-keeping with objects, it seems only obvious that one could create some kind of four dimensional vacuum.
The vacuous rubbish of such a statement however, is that time cannot be physically measured. Only space has any physical meaning, while time is one of those ghostly concepts that we have clung to just because we all come to agreement on it. It should be of no surprise that we might imprint some psychological perception of time on the universe at large. However there is no real proof to suggest such an approach is a correct one.
Take your own advice:
Wrong.
The SCN is responsible for us having a 24-hour cycle.
Glorious fail (please see your own comment about actually reading what you link to);
The topic is spEcious present, not spAcious present (i.e. false present).
It's "vacuous rubbish" because you say so?
We can't measure time? Er, what do clocks do?
Nor any proof to suggest that your inane ramblings have any validity.
So?
A minute ago you said it had nothing to do with the perception of time. I'd say one which governs us on a daily basis (the short range) is one which indeed has a lot to do with our perception of time.
And a glorious fail is not a spelling mistake. And you don't seem two have to brain cells to rub together this morning, because I said ''we have not physically measured time...''
..then you mention clocks on the wall. Wrong kind of science dywydder. Wrong kind of science. A clock on the wall has been built. It measures time because it was designed that way not because time itself is a physical entity lol
A minute ago you said it had nothing to do with the perception of time. I'd say one which governs us on a daily basis (the short range) is one which indeed has a lot to do with our perception of time.
And a glorious fail is not a spelling mistake. And you don't seem two have to brain cells to rub together this morning, because I said ''we have not physically measured time...''
..then you mention clocks on the wall. Wrong kind of science dywydder. Wrong kind of science. A clock on the wall has been built. It measures time because it was designed that way not because time itself is a physical entity lol
I mean, shall I rehash what you said,
''B) not (to what evidence we have) responsible for us "sensing time".''
notice the contradiction?
do have a system governing the perception of time,[4] composed of a highly distributed system involving the cerebral cortex, cerebellum and basal ganglia. One particular component, the suprachiasmatic nucleus, is responsible for the circadian (or daily) rhythm,
''B) not (to what evidence we have) responsible for us "sensing time".''
notice the contradiction?
do have a system governing the perception of time,[4] composed of a highly distributed system involving the cerebral cortex, cerebellum and basal ganglia. One particular component, the suprachiasmatic nucleus, is responsible for the circadian (or daily) rhythm,
Really?
And yet you quote me in a later post:
I did not say "nothing to do the perception of time".
Then you should learn how to read.
It doesn't need much to do with the perception (since that can be handled elsewhere), it's to do with the scheduling (i.e. the "check-list").
Hmm, you mentioned
And then go on to make the "spelling mistake": as if you were trying to shore up some sort of argument about spac[e/ious] time.
Please try to be consistent.
And you don't have two brain cells AT ALL.
I quoted your words directly. I'll do it again:
So what?
A tape measure was designed its way, yet we measure space with it.
Got any actual arguments?
Actually, forget replying to me (unless you want to do your previous dishonest trick of replying when you know there's no chance of a rebuttal). Letting you back was merely a symptom of what's gone wrong with Sci - I'm out of here.
You really are a slow one... so what about a measuring tape, difference is we know space is physical because we can measure it, observe it if you like. We don't observe time, so were is the evidence it is physical? And you said:
''B) not (to what evidence we have) responsible for us "sensing time".''
You can't even deny it dywydder, so why are you? NOT RESPONSIBLE FOR US SENSING TIME. These are your own words. Yet the wiki article does a fantastic job at contradicting you.
''It doesn't need much to do with the perception (since that can be handled elsewhere), it's to do with the scheduling (i.e. the "check-list").''
I beg to differ immensely! If the base of perception is awareness, and alertness is just another name for awareness, then
''circadian rhythmicity includes sleep, physical activity, alertness, hormone levels, body temperature, immune function, and digestive activity.''
Now... most of all... this is a complete and utter straw man you have drawn today, from spelling, to basically spouting crap about the SCN not being responsible for any kind of perception of time. The reason why it's a straw man is that the original idea presented here by me was that time has a biological explanation, which it does. I mean, the wiki article even states that the awareness of time is due to a spread out stucture in the brain, were one of them is called the SCN, which also regulates our sense of time, irrespective of your little outburst on my post. So whether anyone likes it or not, time does not have to be part of the physical vacuum. There are more biological reasons which may explain why we sense any time at all. We do afterall all experience awareness, the perception of time when awake, not asleep. Therefor the alertness explains why we may have any perception of time on a daily basis at all!
Now go back to sleep dywdder... coz' am not answering you anymore. You are a massive waste of my time.
''B) not (to what evidence we have) responsible for us "sensing time".''
You can't even deny it dywydder, so why are you? NOT RESPONSIBLE FOR US SENSING TIME. These are your own words. Yet the wiki article does a fantastic job at contradicting you.
''It doesn't need much to do with the perception (since that can be handled elsewhere), it's to do with the scheduling (i.e. the "check-list").''
I beg to differ immensely! If the base of perception is awareness, and alertness is just another name for awareness, then
''circadian rhythmicity includes sleep, physical activity, alertness, hormone levels, body temperature, immune function, and digestive activity.''
Now... most of all... this is a complete and utter straw man you have drawn today, from spelling, to basically spouting crap about the SCN not being responsible for any kind of perception of time. The reason why it's a straw man is that the original idea presented here by me was that time has a biological explanation, which it does. I mean, the wiki article even states that the awareness of time is due to a spread out stucture in the brain, were one of them is called the SCN, which also regulates our sense of time, irrespective of your little outburst on my post. So whether anyone likes it or not, time does not have to be part of the physical vacuum. There are more biological reasons which may explain why we sense any time at all. We do afterall all experience awareness, the perception of time when awake, not asleep. Therefor the alertness explains why we may have any perception of time on a daily basis at all!
Now go back to sleep dywdder... coz' am not answering you anymore. You are a massive waste of my time.
Time is observed and measured via changes of state or via changes in a given status quo. The second hand on the clock change position in space to reflect time. A change in the status quo is also a definition of entropy.
If the entropy of the universe increases over time, then the status quo of the universe needs to be in a flux of change. The brain interprets this change as the flow of time. The pacer cell will generate cyclic rhythms that are extrapolated, in conjunction with observed changes in the status quo, to create a relative system of time. The net entropy of the universe cannot decrease, but has to constantly increase, therefore the parallel flow of time is one directional.
Entropy increases but needs energy for this to occur. This is provided for, by the natural flow of energy from higher to lower potential, with the difference going into entropy. Locally, we can alter the flow of time (change in the status quo) by altering the flow of energy. We can refrigerate food, and thereby take away the energy needed for entropy, slowing the normal passage of time (rate of change in the status quo), locally. This will rot slower in time. But since we can not reach absolute zero, there is always a slightly flow of entropy and time.
In GR or general relativity, mass is a form of energy. Paradoxically, the more mass/energy there is the slower time appears to flow. This appears to contradict everything I said above, since the mass/energy is higher. However, the force of gravity is an ordering principle, that lowers local entropy, causing the flow of time to slow.
For example, higher gravity will increase pressure, causing water to condense into liquid. This pressure induced transition results in an entropy decrease locally. The flow of time slows thereby still associating time to entropy.
Below is data from the entropy change for water going from gas to liquid. The higher the GR or gravity, the material entropy slow its rate. For example fusion and neutron density are very limiting to changes of in the status quo needed for entropy.
If the entropy of the universe increases over time, then the status quo of the universe needs to be in a flux of change. The brain interprets this change as the flow of time. The pacer cell will generate cyclic rhythms that are extrapolated, in conjunction with observed changes in the status quo, to create a relative system of time. The net entropy of the universe cannot decrease, but has to constantly increase, therefore the parallel flow of time is one directional.
Entropy increases but needs energy for this to occur. This is provided for, by the natural flow of energy from higher to lower potential, with the difference going into entropy. Locally, we can alter the flow of time (change in the status quo) by altering the flow of energy. We can refrigerate food, and thereby take away the energy needed for entropy, slowing the normal passage of time (rate of change in the status quo), locally. This will rot slower in time. But since we can not reach absolute zero, there is always a slightly flow of entropy and time.
In GR or general relativity, mass is a form of energy. Paradoxically, the more mass/energy there is the slower time appears to flow. This appears to contradict everything I said above, since the mass/energy is higher. However, the force of gravity is an ordering principle, that lowers local entropy, causing the flow of time to slow.
For example, higher gravity will increase pressure, causing water to condense into liquid. This pressure induced transition results in an entropy decrease locally. The flow of time slows thereby still associating time to entropy.
Below is data from the entropy change for water going from gas to liquid. The higher the GR or gravity, the material entropy slow its rate. For example fusion and neutron density are very limiting to changes of in the status quo needed for entropy.
http://www.lsbu.ac.uk/water/phase.html
I guess only good can come of posting this which I am about to do... It is part of a chapter of a book I have been writing, this chapter is named ''what is time?''
What is Time?
"The distinction between past, present, and future is only a stubbornly persistent illusion" - Albert Einstein
So we now arrive at a question that is important because it will have a lot to do with consciousness which I will attempt to tackle in it's own chapter after this one. Time is something we all usually tend to agree exists. It is part of how the world is allowed to evolve over some length of time. Time seems to encompass every physical event, so maybe it should not be too hard to imagine why time has been a serious question for early man. One example would be the Mayan Civilization who were obsessed with the idea of time.
And even to today, time seems to be a very important question because on the whole of things, we really don't know too much about time, other than what physicists have prescribed into their theorems. Then, knowing this it seems that time is calculational tool we use to catalogue events over a series of moments. Time in the much deeper sense is something we feel flow inexorably from our past and into our future and we are somehow sandwiched in the middle.
Well time has had some serious new dresses to wear when quantum theory came about. It had something to say about some universal flow of time; such as, it didn't exist! It also said that time was not really a river. It also had some strange counterintuitive things to say about the past and future as well, so much that they were really illusions, most probably created by the human mind. We shall discuss these new concepts soon.
The biggest accomplishment of relativity in a mathematical sense (created by Einstein's teacher, Minkowski) was probably the realization that space and time where in fact a single object. That time turned out to be an imaginary dimension of space, that the whole spacetime metric we call the 'vacuum' was really composed of four spatial dimensions. This was huge because it gave time a physical appearance as well. Space was known as a bubbling sheet of particles, which became a dynamical aspect of what a vacuum was really all about, so if time truely was a dimension of space, then time must be just as physical as the vacuum.
It ultimately made sense to do this, because in the end of the day it did still require that to travel a distance in space meant to move through time as well. An interesting note was that we were to move through time, time does not move through us, hence why there is no flow. Also, if space was geometrical then it meant that time could not be linear either.
One of relativities biggest contributions was it's theoretical idea that time and space had some distant origin in our pasts. Known as the big bang, since time is primal, part of the dimensional set-up of the vacuum, then if time just began we can assume that space just began as well, including matter, energy, gas and plasma. The beginning of time was a wonderful insight that was created by the equations of General Relativity (the study of our universe in terms of gravity and curvature). However, like with so many beginning's, will there be an end?
This has been a question that we will explore at the end of this chapter. For now, I am going to explain what get's physicists ticking when we talk about time.
Timelessness
Now I come to a subject that most physicists tend to be quiet about, apart from a few maveriks. Time becomes part of the odd unanswered questions of quantum mechanics, but while quantum mechanics describes time in a certain way, General Relativity has something else to say about the nature of time entirely. This was so prominent at the time, it was eventually named the ''time problem'' of quantum mechanics and Relativity.
The way we apply time is not how you apply time to theory like quantum mechanics. Quantum mechanics tends to treat time like starts and stops instead of any linear feature (a progressive evolution of a single frame of reference. Instead, you can have loads of little fragments of time, just mometary fleeting flashes of existence. In our existences, in reference to the world of perception (what we see and sense) including the perception of time is very linear sometimes. In fact, the time we feel is one which tends to flow from some past and into some future.
This is called the psychological arrow of time. There are in fact several arrows of time in physics, but we shall only cover this one as that would take up a lot of space to describe them. The psychological arrow of time can be thought of as the illusion brought about by having the ability to catalogue information in a linear process. This is not a loose speculation, but a matter of observation, since the brain is ''aware'' of a past if it will have the ability to catalogue events and remember them in a certain order. In doing so, it will attach a meaning to it, which we call time. It also means that we attach a ''flow'' to time as well, so maybe it is not surprising then to find out that there really is no flow to time either in physics. [1]
I say it is an illusion however, but in quantum mechanics, there is no such things as a past or future. (If one finds that claim slightly hard to believe, the explanation of time in General Relativity is even bolder). Einstein was famous for stating that the past and future were illusions.
However, his theory would emit the appearance of time completely from the equations! This model came to be known as the timeless theories. In fact, timelessness was a Cosmological theory and used a global wave function (a wave function of the universe) in an equation called the Wheeler-deWitt Equation. Since it uses a global wave function, one can maybe hyothesize that if there was a time derivative in the equation, it would therefore relate to a global time as well. It might be interesting to note that there seems to be no such thing as a global time in relativity, but there is some evidence that the impossibility of finding a global time [2] may actually imply a singularity in spacetime, according to E. Minguzzi (cited).
What makes this interesting, (before we cover the Wheeler-deWitt equation) is that it is generally considered that the presence of a singularity is a sign of the breakdown of our theory, as I am sure I mentioned before in our second chapter. If theories which omit the global existence of time lead to singularities, then we must consider that they may have some kind of time description to avoid the singularity problem.
The Wheeler-deWitt equation has the form
$$\hat{H}|\psi> = 0$$
On the right, we would usually see $$i \hbar \partial_t \psi$$ but there is none because it does not apply. Whilst it is true we can use clocks as measuring devices, that requires the description of local time. Indeed, there are many who believe that time is strictly a local phenomenon, such as Prof. Lee Smolin has criticized the timeless theories:
''All that is real is real in a moment, which is a succession of moments. Anything that is true is true of the present moment. Not only is time real, but everything that is real is situated in time. Nothing exists timelessly.''
However, while Prof. Smolin may be technically correct, there does not seem to be any indication why time is necesserily real and he seems to be making the large assumption that anything to exist requires the description of time; but maybe Smolin was meaning something else? Maybe someone who takes Relativity very seriously and says that time is a dimension of space, then there is the question that time is actually something we have attached to the world outside based on our experiences. We do afterall, only experience the outside world by taking in two dimensional images which are transported to our brains through a series of complex bio-chemical disturbances all the way to the brain, where the information is further analyzed and somehow recast into the three dimensional phenomenon called ''perception''.
Observation's are real time events and so they cannot be described in imaginary terms however. Observations may cover a wide-range of interactions however, from a human being tentively watching an atom in the lab, to individual particles observing each other.
The world we see is not quite the world at large, yet the world we see is governed by logical changes which require the notion of some kind of time which the outside world may not be part of. After all, as far as we can tell, time is a subjective phenomenon which governs our perception in the way we sense a moment pass by. This subjective relationship might be deep enough to suggest it has something inherent to do with consciousness itself rather than thinking time is a real world phenomenon it's own right.
Another point that should be made, is that our sense of time is itself attached to the perception of a past and a future. The brain is the perfect instrument which manages to retain unthinkable amounts of information which it catalogues and places it as our past. The information is usually well documented in the nueral networks, that if one remembered an event, the sense of the information is ''ordered'' when it is being thought about. It is like we are re-living the experience all over again, but in a new present time frame.
This is the thing. We do no such thing as going back in time when remembering an event, we are simply recreating that event inside of our minds to the standards of how we remembered it in the past. Time is stuck inside the sphere of the present, always. The future is some unknown time yet to occur, but the past doesn't exist either because it remains as an experience, not a true physical artefact of the world any longer.
The Wheeler-deWitt equation then requires a new solution to understand why it seems to be predicting why the universe at large is timeless. If consciousness is treated as the only system which can experience local time, then if timelessness ceases to exists in the global sense, then time would still remain part of the subjective experience, which would kind of bring a new importance on the human individual for once.
Consciousness is a local phenomenon to our frame of references and we can all generally agree on the same time, this is called Asymoptotic time, so it is as if our brains are designed to generally keep in tune with our surroundings, the people we interact with. It is also governed by day's and nights, where internal biological clocks determine when we sleep, even eat and drink. We can actually tamper with the gene responsible for the perception of time called the Suprachiasmatic Nucleus. So already, we can see there is some genetic, physical interpretation for the experience of time. One might use this as evidence for the case of believing that time is really just a subjective phenomenon and not a real world case.
Whatever the solution to the cosmological problem of time is, it does not stop one obvious fact that seem's to be staring us in the face. That is that consciousness not only requires the subjective experience of time to be allowed to work, but consciousness also requires the distinction of a past and future. As Fred Alan Wolf put it one time, ''a mind without a past is no mind at all.'' [3] So the state of mind is heavily dependant on the structure of how we experience time, the symmetry of past and future which our collective subconscious feels inexorably woven into.
One interesting question which still get's raised today, is the question of whether backward causality phenomenon exist in nature. These objects can be described as something moving backward in time. In the formulation of quantum field theory and the idea of antiparticles, they could be modelled as though the were moving back in time because all of the parameters where just as would be found in a time-reversed object. Usually however, today atleast, physicists do not take this as a true physical representation of reality. However, there is a theory suggested by prof. John Cramer called the Transactional Interpretation.
The way the transactional interpretation treats the wave function is the idea of a positive time wave and a negative time wave are able to move from the future to the past and from the past to the future. The wave moving forward in time is an advanced and moving back the retarded wave functions; and as you may guess, the waves are solutions of different quantum information packets which upon the absolute square amplitude they will define real existing things.
The emmiter could be an electron, radiating a photon, which is caused by producing a field. The field is time-symmetric under the Wheeler-Feynman description which and as John Cramer describes it ”time-symmetric combination of a retarded field which propagates into the future and an advanced field which propagates into the past.”
He considers a net field which consists of a retarded plane wave form F1
$$F_1 = e^{i(kr - \omega t)}$$
for t1 ≥ 1. Here, t1 is the instant of emission. The advanced solution G1 is simply
$$G_1 = e^{-i(kr - \omega t)}$$
for t1 ≤ 1. The idea is that the the absorbing electron responding to the incident of the retarded field F1 in such a way it will gain energy, recoil, and produce a new retarded field F2=-F1 which exactly cancels the incident field F1. The net field after such a transaction is zero.
$$F_{net} = (F_1 + F_2) = 0$$
Applying this to a universe can be beneficial. It can help explain how the early universe came into existence, because the future implied it through probability. The future of our universe can shape the early universe in such a way that it can define parts of the universe which are smeared by possibilities and out of which only one true history can survive. So there is the chance that the wave function in our universe is sending information back to points in our universes history where the early universe is just being formed.
There are some retrocausal implications as well, but some of these can be avoided using reinterpretation rules. None of this however fixes the problem of time in quantum mechanics but if we were to assume that somehow the problem of time arises from a dodgy theory then quantum physics may allow such a theory like the Transactional Interpretation which allows quantum wave's to undulate time in a symmetric fashion, both in the positive and negative time directions.
If time did exist, then the universe would be self-contained in respect to it. Self-contained time just means that universe experiences it's own unique time. One consequence of quantum mechanics that some physicists look into is parallel universe theory. In these universes, the meaning of self-contained time becomes important. To have so many universes, it would not make sense to say they were all ticking off the same proverbial clock. Time has been argued however to make more sense in a parallel universe picture.
So, as we have seen, time is not linear and it is not necesserily a real quantity. Nor does it necesserily have to exist outside of perception. It may be purely a subjective phenomenon. We have also seen that time may not even exist in the universe at large and how time is a series of starts and stops in quantum mechanics so there was no flow to time either. Now we are going to ask if there is a symmetry in time which physicists call the ''Collapse.''
The Specious Present
The Specious Present is the phenomenon of local perception, the tagging of the evolution of events associated always to the present moment. Indeed, it seems evident that we human beings are inexorably stuck in this drift we call present time, but the strange illusion of past and future still persists in the psychology of the human being. It is psychological because of the identification it has been classed under. The psychological arrow of time purports to the linear nature of time in the subjective psyche, in other words, we can feel a past before us, and expect a future to happen. It creates the strange concept that somehow thoughts and feelings exist beyond the observer.
How does time not flow, we move from the past, present to future, right?
No.
Time cannot move us, it has no flow. If time is a real thing, and not a subjective phenomenon then surely we move through time, not the other way around?
There are two main reasons why time does not have an arrow, a directionality or a flow. Serious reasons no less:
1) To define some definate arrow from the past into the future, there needs to be a point in where everything came from to define some direction in space. Direction does not exist in space. Equally there is no center to the universe according to current understanding, every point on the spacetime map would be the center to the universe.
2) Time does not have a flow according to current physics belief.
The last concept I found out was used in a strong arguement against the arrow of time:
http://www.motionmountain.net/download.html
"Time is a concept introduced specially to describe the flow of events around us; it does not itself flow, it describes flow. Time does not advance. Time is neither linear nor cyclic. The idea that time flows is as hindering to understanding nature as is the idea that mirrors Page 71 exchange right and left. The misleading use of the expression ‘flow of time’, propagated first by some flawed Ref. 36 Greek thinkers and then again by Newton, continues. Aristotle (384/3–322 bce), careful to think logically, pointed out its misconception, and many did so after him. Nevertheless, expressions such as ‘time reversal’, the ‘irreversibility of time’, and the much-abused ‘time’s arrow’ are still common. Just read a popular science magazine chosen at random.''
Finally, how can time move us from past, present to future, when by definition the present time is all there is? We don't exist in the past, nor do we exist in the future, we are always stuck in the present moment.
Energy is related to Time and Space
Bernoulli's equation is a representation of the law of "the conservation of energy" which is related by Noether's Theorem to the geometry of time - this basically means that it does not matter when you might conduct an experiment, there is a symmetry of a systems action which should imply a conservation law each time.
What is Time?
"The distinction between past, present, and future is only a stubbornly persistent illusion" - Albert Einstein
So we now arrive at a question that is important because it will have a lot to do with consciousness which I will attempt to tackle in it's own chapter after this one. Time is something we all usually tend to agree exists. It is part of how the world is allowed to evolve over some length of time. Time seems to encompass every physical event, so maybe it should not be too hard to imagine why time has been a serious question for early man. One example would be the Mayan Civilization who were obsessed with the idea of time.
And even to today, time seems to be a very important question because on the whole of things, we really don't know too much about time, other than what physicists have prescribed into their theorems. Then, knowing this it seems that time is calculational tool we use to catalogue events over a series of moments. Time in the much deeper sense is something we feel flow inexorably from our past and into our future and we are somehow sandwiched in the middle.
Well time has had some serious new dresses to wear when quantum theory came about. It had something to say about some universal flow of time; such as, it didn't exist! It also said that time was not really a river. It also had some strange counterintuitive things to say about the past and future as well, so much that they were really illusions, most probably created by the human mind. We shall discuss these new concepts soon.
The biggest accomplishment of relativity in a mathematical sense (created by Einstein's teacher, Minkowski) was probably the realization that space and time where in fact a single object. That time turned out to be an imaginary dimension of space, that the whole spacetime metric we call the 'vacuum' was really composed of four spatial dimensions. This was huge because it gave time a physical appearance as well. Space was known as a bubbling sheet of particles, which became a dynamical aspect of what a vacuum was really all about, so if time truely was a dimension of space, then time must be just as physical as the vacuum.
It ultimately made sense to do this, because in the end of the day it did still require that to travel a distance in space meant to move through time as well. An interesting note was that we were to move through time, time does not move through us, hence why there is no flow. Also, if space was geometrical then it meant that time could not be linear either.
One of relativities biggest contributions was it's theoretical idea that time and space had some distant origin in our pasts. Known as the big bang, since time is primal, part of the dimensional set-up of the vacuum, then if time just began we can assume that space just began as well, including matter, energy, gas and plasma. The beginning of time was a wonderful insight that was created by the equations of General Relativity (the study of our universe in terms of gravity and curvature). However, like with so many beginning's, will there be an end?
This has been a question that we will explore at the end of this chapter. For now, I am going to explain what get's physicists ticking when we talk about time.
Timelessness
Now I come to a subject that most physicists tend to be quiet about, apart from a few maveriks. Time becomes part of the odd unanswered questions of quantum mechanics, but while quantum mechanics describes time in a certain way, General Relativity has something else to say about the nature of time entirely. This was so prominent at the time, it was eventually named the ''time problem'' of quantum mechanics and Relativity.
The way we apply time is not how you apply time to theory like quantum mechanics. Quantum mechanics tends to treat time like starts and stops instead of any linear feature (a progressive evolution of a single frame of reference. Instead, you can have loads of little fragments of time, just mometary fleeting flashes of existence. In our existences, in reference to the world of perception (what we see and sense) including the perception of time is very linear sometimes. In fact, the time we feel is one which tends to flow from some past and into some future.
This is called the psychological arrow of time. There are in fact several arrows of time in physics, but we shall only cover this one as that would take up a lot of space to describe them. The psychological arrow of time can be thought of as the illusion brought about by having the ability to catalogue information in a linear process. This is not a loose speculation, but a matter of observation, since the brain is ''aware'' of a past if it will have the ability to catalogue events and remember them in a certain order. In doing so, it will attach a meaning to it, which we call time. It also means that we attach a ''flow'' to time as well, so maybe it is not surprising then to find out that there really is no flow to time either in physics. [1]
I say it is an illusion however, but in quantum mechanics, there is no such things as a past or future. (If one finds that claim slightly hard to believe, the explanation of time in General Relativity is even bolder). Einstein was famous for stating that the past and future were illusions.
However, his theory would emit the appearance of time completely from the equations! This model came to be known as the timeless theories. In fact, timelessness was a Cosmological theory and used a global wave function (a wave function of the universe) in an equation called the Wheeler-deWitt Equation. Since it uses a global wave function, one can maybe hyothesize that if there was a time derivative in the equation, it would therefore relate to a global time as well. It might be interesting to note that there seems to be no such thing as a global time in relativity, but there is some evidence that the impossibility of finding a global time [2] may actually imply a singularity in spacetime, according to E. Minguzzi (cited).
What makes this interesting, (before we cover the Wheeler-deWitt equation) is that it is generally considered that the presence of a singularity is a sign of the breakdown of our theory, as I am sure I mentioned before in our second chapter. If theories which omit the global existence of time lead to singularities, then we must consider that they may have some kind of time description to avoid the singularity problem.
The Wheeler-deWitt equation has the form
$$\hat{H}|\psi> = 0$$
On the right, we would usually see $$i \hbar \partial_t \psi$$ but there is none because it does not apply. Whilst it is true we can use clocks as measuring devices, that requires the description of local time. Indeed, there are many who believe that time is strictly a local phenomenon, such as Prof. Lee Smolin has criticized the timeless theories:
''All that is real is real in a moment, which is a succession of moments. Anything that is true is true of the present moment. Not only is time real, but everything that is real is situated in time. Nothing exists timelessly.''
However, while Prof. Smolin may be technically correct, there does not seem to be any indication why time is necesserily real and he seems to be making the large assumption that anything to exist requires the description of time; but maybe Smolin was meaning something else? Maybe someone who takes Relativity very seriously and says that time is a dimension of space, then there is the question that time is actually something we have attached to the world outside based on our experiences. We do afterall, only experience the outside world by taking in two dimensional images which are transported to our brains through a series of complex bio-chemical disturbances all the way to the brain, where the information is further analyzed and somehow recast into the three dimensional phenomenon called ''perception''.
Observation's are real time events and so they cannot be described in imaginary terms however. Observations may cover a wide-range of interactions however, from a human being tentively watching an atom in the lab, to individual particles observing each other.
The world we see is not quite the world at large, yet the world we see is governed by logical changes which require the notion of some kind of time which the outside world may not be part of. After all, as far as we can tell, time is a subjective phenomenon which governs our perception in the way we sense a moment pass by. This subjective relationship might be deep enough to suggest it has something inherent to do with consciousness itself rather than thinking time is a real world phenomenon it's own right.
Another point that should be made, is that our sense of time is itself attached to the perception of a past and a future. The brain is the perfect instrument which manages to retain unthinkable amounts of information which it catalogues and places it as our past. The information is usually well documented in the nueral networks, that if one remembered an event, the sense of the information is ''ordered'' when it is being thought about. It is like we are re-living the experience all over again, but in a new present time frame.
This is the thing. We do no such thing as going back in time when remembering an event, we are simply recreating that event inside of our minds to the standards of how we remembered it in the past. Time is stuck inside the sphere of the present, always. The future is some unknown time yet to occur, but the past doesn't exist either because it remains as an experience, not a true physical artefact of the world any longer.
The Wheeler-deWitt equation then requires a new solution to understand why it seems to be predicting why the universe at large is timeless. If consciousness is treated as the only system which can experience local time, then if timelessness ceases to exists in the global sense, then time would still remain part of the subjective experience, which would kind of bring a new importance on the human individual for once.
Consciousness is a local phenomenon to our frame of references and we can all generally agree on the same time, this is called Asymoptotic time, so it is as if our brains are designed to generally keep in tune with our surroundings, the people we interact with. It is also governed by day's and nights, where internal biological clocks determine when we sleep, even eat and drink. We can actually tamper with the gene responsible for the perception of time called the Suprachiasmatic Nucleus. So already, we can see there is some genetic, physical interpretation for the experience of time. One might use this as evidence for the case of believing that time is really just a subjective phenomenon and not a real world case.
Whatever the solution to the cosmological problem of time is, it does not stop one obvious fact that seem's to be staring us in the face. That is that consciousness not only requires the subjective experience of time to be allowed to work, but consciousness also requires the distinction of a past and future. As Fred Alan Wolf put it one time, ''a mind without a past is no mind at all.'' [3] So the state of mind is heavily dependant on the structure of how we experience time, the symmetry of past and future which our collective subconscious feels inexorably woven into.
One interesting question which still get's raised today, is the question of whether backward causality phenomenon exist in nature. These objects can be described as something moving backward in time. In the formulation of quantum field theory and the idea of antiparticles, they could be modelled as though the were moving back in time because all of the parameters where just as would be found in a time-reversed object. Usually however, today atleast, physicists do not take this as a true physical representation of reality. However, there is a theory suggested by prof. John Cramer called the Transactional Interpretation.
The way the transactional interpretation treats the wave function is the idea of a positive time wave and a negative time wave are able to move from the future to the past and from the past to the future. The wave moving forward in time is an advanced and moving back the retarded wave functions; and as you may guess, the waves are solutions of different quantum information packets which upon the absolute square amplitude they will define real existing things.
The emmiter could be an electron, radiating a photon, which is caused by producing a field. The field is time-symmetric under the Wheeler-Feynman description which and as John Cramer describes it ”time-symmetric combination of a retarded field which propagates into the future and an advanced field which propagates into the past.”
He considers a net field which consists of a retarded plane wave form F1
$$F_1 = e^{i(kr - \omega t)}$$
for t1 ≥ 1. Here, t1 is the instant of emission. The advanced solution G1 is simply
$$G_1 = e^{-i(kr - \omega t)}$$
for t1 ≤ 1. The idea is that the the absorbing electron responding to the incident of the retarded field F1 in such a way it will gain energy, recoil, and produce a new retarded field F2=-F1 which exactly cancels the incident field F1. The net field after such a transaction is zero.
$$F_{net} = (F_1 + F_2) = 0$$
Applying this to a universe can be beneficial. It can help explain how the early universe came into existence, because the future implied it through probability. The future of our universe can shape the early universe in such a way that it can define parts of the universe which are smeared by possibilities and out of which only one true history can survive. So there is the chance that the wave function in our universe is sending information back to points in our universes history where the early universe is just being formed.
There are some retrocausal implications as well, but some of these can be avoided using reinterpretation rules. None of this however fixes the problem of time in quantum mechanics but if we were to assume that somehow the problem of time arises from a dodgy theory then quantum physics may allow such a theory like the Transactional Interpretation which allows quantum wave's to undulate time in a symmetric fashion, both in the positive and negative time directions.
If time did exist, then the universe would be self-contained in respect to it. Self-contained time just means that universe experiences it's own unique time. One consequence of quantum mechanics that some physicists look into is parallel universe theory. In these universes, the meaning of self-contained time becomes important. To have so many universes, it would not make sense to say they were all ticking off the same proverbial clock. Time has been argued however to make more sense in a parallel universe picture.
So, as we have seen, time is not linear and it is not necesserily a real quantity. Nor does it necesserily have to exist outside of perception. It may be purely a subjective phenomenon. We have also seen that time may not even exist in the universe at large and how time is a series of starts and stops in quantum mechanics so there was no flow to time either. Now we are going to ask if there is a symmetry in time which physicists call the ''Collapse.''
The Specious Present
The Specious Present is the phenomenon of local perception, the tagging of the evolution of events associated always to the present moment. Indeed, it seems evident that we human beings are inexorably stuck in this drift we call present time, but the strange illusion of past and future still persists in the psychology of the human being. It is psychological because of the identification it has been classed under. The psychological arrow of time purports to the linear nature of time in the subjective psyche, in other words, we can feel a past before us, and expect a future to happen. It creates the strange concept that somehow thoughts and feelings exist beyond the observer.
How does time not flow, we move from the past, present to future, right?
No.
Time cannot move us, it has no flow. If time is a real thing, and not a subjective phenomenon then surely we move through time, not the other way around?
There are two main reasons why time does not have an arrow, a directionality or a flow. Serious reasons no less:
1) To define some definate arrow from the past into the future, there needs to be a point in where everything came from to define some direction in space. Direction does not exist in space. Equally there is no center to the universe according to current understanding, every point on the spacetime map would be the center to the universe.
2) Time does not have a flow according to current physics belief.
The last concept I found out was used in a strong arguement against the arrow of time:
http://www.motionmountain.net/download.html
"Time is a concept introduced specially to describe the flow of events around us; it does not itself flow, it describes flow. Time does not advance. Time is neither linear nor cyclic. The idea that time flows is as hindering to understanding nature as is the idea that mirrors Page 71 exchange right and left. The misleading use of the expression ‘flow of time’, propagated first by some flawed Ref. 36 Greek thinkers and then again by Newton, continues. Aristotle (384/3–322 bce), careful to think logically, pointed out its misconception, and many did so after him. Nevertheless, expressions such as ‘time reversal’, the ‘irreversibility of time’, and the much-abused ‘time’s arrow’ are still common. Just read a popular science magazine chosen at random.''
Finally, how can time move us from past, present to future, when by definition the present time is all there is? We don't exist in the past, nor do we exist in the future, we are always stuck in the present moment.
Energy is related to Time and Space
Bernoulli's equation is a representation of the law of "the conservation of energy" which is related by Noether's Theorem to the geometry of time - this basically means that it does not matter when you might conduct an experiment, there is a symmetry of a systems action which should imply a conservation law each time.
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kx000
Valued Senior Member
Time isn't anything, but the measured distance between the first event to occur in the universe recorded by man, going until this very second, and to keep being recorded until we are gone. At which point time will continue unrecorded. A hour will always be a hour, its just that time isn't aware, nor does it need the recording of a hour for it to exist. Or, time is a rhythmic extra universal force that naturally occurs through some sort of heat powered catalysis, that runs on the same even spread beat for all of ever for ever and ever. These beats that occur on rhythm time after time would be the smallest possible measurement of time.
Going out on a limb, time is a man made idea, and we have a better chance at stopping it, than traveling it.
Going out on a limb, time is a man made idea, and we have a better chance at stopping it, than traveling it.
Exactly!
Time is a human concept that describes a rate, having no real existence in the universe.
If I had to go out on a similar limb, I would say that my studies have shown the same things. Time is purely a human concept, maybe part of the psyche, not objective and not having any real physical application in the world. It is merely a tool which we attach to measurements.
Over 1000 posts to this thread, involving unnecessary complexity. Various digressions not pertinent to the question: “What is time?”
Einstein made it very simple: See post 19, which is repeated below with a few added remarks.
First: If you need a definition for before & after, you are not able to understand time & can forget about this thread.
Einstein once wrote something like the following about time, which I think is very succinct and pretty much describes it.
His view does not require a reference to motion or any physical processes: It merely uses the concept of events.
What is missing from the above view/definition of time?
The above is a description of proper time for a single observer in an inertial frame. It gets more complicated when it is necessary to consider multiple observers, difference inertial frames, accelerated motion, & gravity.
It is interesting that Albert used bold or italics for before & after, implying that they should be considered primitive terms, not definable via the use of simpler terms or concepts.
Note that an axiomatic system requires undefined primitive terms to avoid various problems associated with circular definitions.
It is interesting that Albert did not mention the concept of the flow of time from past through the present into the future, which does seem to be a construct (illusion?) of the human mind rather than an objective process associated with reality.
Einstein made it very simple: See post 19, which is repeated below with a few added remarks.
First: If you need a definition for before & after, you are not able to understand time & can forget about this thread.
Einstein once wrote something like the following about time, which I think is very succinct and pretty much describes it.
When an individual ponders his experiences, he can order the events in his life using the criteria of before & after. He can assign a number to each event in such a way that events assigned a lower number occurred before events assigned a higher number.
It is convenient to use a device called a clock to provide a consistent set of numbers for use in ordering events.
In describing the laws of physics using the language of mathematics, it is convenient (if not necessary) to use a continuous variable called time. This variable similarly orders events based on the criteria of before and after.
There is little (if anything) more that can be said relating to time.
The above is not a quote: It is a paraphrase based on my not infallible memory. I Think it is from the preface to one of his books or essays on Relativity. I have read several articles & books containing very lengthy & confusing verbiage which did not seem to describe the concept of time any better than the above.It is convenient to use a device called a clock to provide a consistent set of numbers for use in ordering events.
In describing the laws of physics using the language of mathematics, it is convenient (if not necessary) to use a continuous variable called time. This variable similarly orders events based on the criteria of before and after.
There is little (if anything) more that can be said relating to time.
His view does not require a reference to motion or any physical processes: It merely uses the concept of events.
What is missing from the above view/definition of time?
The above is a description of proper time for a single observer in an inertial frame. It gets more complicated when it is necessary to consider multiple observers, difference inertial frames, accelerated motion, & gravity.
It is interesting that Albert used bold or italics for before & after, implying that they should be considered primitive terms, not definable via the use of simpler terms or concepts.
Note that an axiomatic system requires undefined primitive terms to avoid various problems associated with circular definitions.
It is interesting that Albert did not mention the concept of the flow of time from past through the present into the future, which does seem to be a construct (illusion?) of the human mind rather than an objective process associated with reality.
BTW: Einstein's remark about past, present, & future was not intended to be taken at face value.
That remark was made in the context of a discussion of World Lines, which model the laws of physics as static geometry.
Most people do not realize that the mathematics of both Special & general relativity treat physics as geometry. A moving particle is viewed as an unchanging curve. The actions of a person is viewed as a collection of related world lines.
Since the model is geometric, there is no motion. There is no past, present or future. Consideration of motion, past, present, & future require translating the geometric model into concepts compatible with the world of our ordinary senses.
Special relativity is a flat space model (plane geometry), while General Relativity is a curved space model (spherical or other non Euclidean geometry).
That remark was made in the context of a discussion of World Lines, which model the laws of physics as static geometry.
Most people do not realize that the mathematics of both Special & general relativity treat physics as geometry. A moving particle is viewed as an unchanging curve. The actions of a person is viewed as a collection of related world lines.
Since the model is geometric, there is no motion. There is no past, present or future. Consideration of motion, past, present, & future require translating the geometric model into concepts compatible with the world of our ordinary senses.
Special relativity is a flat space model (plane geometry), while General Relativity is a curved space model (spherical or other non Euclidean geometry).
Everything you have said correlates with my understand Dinosaur. I applaud your post for how accurate it is.
It is very true as well what you write. In fact, some particular catches my eye:
''Since the model is geometric, there is no motion. There is no past, present or future. ''
This could not be closer to the truth and the main reason why the past and future do not exist in physics. In fact, what you state above is the main reason why a timeless model exists. It is because Einstein's equations generate a motion in time that is a symmetry of the theory, it is not a true time evolution.
Again, nice set of posts!
It is very true as well what you write. In fact, some particular catches my eye:
''Since the model is geometric, there is no motion. There is no past, present or future. ''
This could not be closer to the truth and the main reason why the past and future do not exist in physics. In fact, what you state above is the main reason why a timeless model exists. It is because Einstein's equations generate a motion in time that is a symmetry of the theory, it is not a true time evolution.
Again, nice set of posts!
Big Chiller
Registered Senior Member
Not this again do you guys have something to gain from showing that time isn't real perhaps you have something to gain by disclosing the argument that time isn't real to the laypeople. Note that time is fundamentally change and change is what makes measurement possible.