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What Is Time? One Researcher Shares His Exploration
Physicist Sean Carroll has built up a bit of a name for himself by tackling one of the age old questions that no one has been able to fully explain: What is time? Earlier this month he gave an interview with Wired where he tried to explain his theories in layman's terms. "I’m trying to understand how time works. And that’s a huge question that has lots of different aspects to it. A lot of them go back to Einstein and spacetime and how we measure time using clocks. But the particular aspect of time that I’m interested in is the arrow of time: the fact that the past is different from the future. We remember the past but we don’t remember the future. There are irreversible processes. There are things that happen, like you turn an egg into an omelet, but you can’t turn an omelet into an egg."
We remember the past but we don’t remember the future.
In a way you can "remember" future, it's called deja vu. The few times I've had it, everything matched perfectly what I already knew. I knew what was going to happen and what there was around me and what was different than how it usually is, ie. what items were in different location or not there. Like most people, I attributed it to a past dream. I am certain it didn't happen before in reality nor was it some anomaly from memory.
This leads me to believe there is a timeline. Everything happening all the time has a position and state on that timeline. We try to explain time with physics and our current knowledge. This is somewhat related to physics - if you're moving faster, you're aging slower (your time is going slower). This is true on airplanes and true when moving at light speed. If you moved fast enough, everyone on Earth could age 70 years while you only aged a few minutes.
But this only works towards future. Nevertheless, if it works towards future it must also work towards past. I think the plain movement speed isn't what's causing the differences in passing time, but it triggers something else. We as humans have (admittedly bad) memory of everything that has happened in the past. There is our own state and time. Why there couldn't be global state and time, a timeline? A timeline you could warp within, even if you did exactly the same things again.
About half past ten, give or take a couple of minutes.
Entropy
On the Oregon Cost born and raised, On the beach is where I spent most of my days
that connects state one to state two.
Please do not read this sig. Thank you.
FORD: No, No listen. Just imagine that you’ve got this ebony bath, right? And it’s conical.
ARTHUR: Conical? What kind of bath is -
FORD: No, no, shh, shhh, it’s, it’s, it’s conical okay? So what you do, you fill it with fine white sand right? Or sugar, or anything like that. And when it’s full, you pull the plug out and it all just twirls down out of the plug hole but the thing is
ARTHUR: Why?
FORD: No, the clever thing is that you film it happening. You get a movie camera from somewhere and actually film it. But then you thread the film in the projector backwards.
ARTHUR: Backwards?
FORD: Yeah, neat you see. So what happens is you sit and you watch it and then everything appears to swirl upwards, out of the plug hole and fill the bath amazing.
ARTHUR: And that’s how the universe began?
FORD: No. But it’s a marvellous way to relax.
TRILLIAN: Funny man.
FORD: Well it broke the ice didn’t it?
Maybe not directly, but you can feed that omelet to a chicken, and then take the resulting egg.
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http://discovermagazine.com/2010/mar/02-the-real-rules-for-time-travelers/article_print
We remember the past but we don't remember the future. There are irreversible processes. There are things that happen, like you turn an egg into an omelet, but you can't turn an omelet into an egg.
But if time is non-monotonic, wouldn't we un-remember, un-break things, during the backturns?
How would anyone know if time isn't always forward?
Sheesh, evil *and* a jerk. -- Jade
Time is an artificial construct of the Human mind that allows us to mark our pitiful existence in an uncaring universe.
I've got your sig, right here.
time is the bi-product of change
A physicist I'm not, nor mathematician, but 'TIME is CHANGE' in my book. No change- no time. What else can you measure it against?
"We remember the past but we don’t remember the future. There are irreversible processes"
I am in NO WAY qualified to argue on the subject, but the quoted statement seems like a problem with words and definitions. You can't 'remember' the future because the word 'remember' doesn't apply very well to the word (or usage of the word) 'future.'
I'll probably be blasted out to hell by an expert in 3...2...1...
v = s/t therefore vt = s therefore t - s/v: Time is simply distance over velocity!
Honestly it's all very well to swindl^H^H^H^H convince people to give you grant money by investigating "time". I mean, the prospects of having one's very own time machine are incredible.
Yet one has to ask, (and this is where tenses get complicated, I will resort to the Douglas Adams trans-temporal convention) if anything practical wioll have come from such a study, we would have been receiving visitors from "the future" for a long time now! Heck, wars and genocides could have been prevented as far back as ancient Egypt. In fact, human nature being what it is, history will would have become pretty boring...
Seven puppies were harmed during the making of this post.
Time is our word for every dimension that exists besides the first three... not sure how many there are though.
Humpty Dumpty sat on a wall,
Humpty Dumpty had a great fall.
All the king's horses and all the king's men
Couldn't put Humpty together again.
A more apt question is this: What is Entropy?
Hello. I am a time traveler. Be not afraid. I come from the past and I travel into the future at a rate of one second per second.
From St. Augustine's Confessions, Book XI:
CHAP. XIV. -- NEITHER TIME PAST NOR FUTURE, BUT THE PRESENT ONLY, REALLY IS.
17. At no time, therefore, hadst Thou not made anything, because Thou hadst made time itself. And no times are co-eternal with Thee, because Thou remainest for ever; but should these continue, they would not be times. For what is time? Who can easily and briefly explain it? Who even in thought can comprehend it, even to the pronouncing of a word concerning it? But what in speaking do we refer to more familiarly and knowingly than time? And certainly we understand when we speak of it; we understand also when we hear it spoken of by another. What, then, is time? If no one ask of me, I know; if I wish to explain to him who asks, I know not. Yet I say with confidence, that I know that if nothing passed away, there would not be past time; and if nothing were coming, there would not be future time; and if nothing were, there would not be present time. Those two times, therefore, past and future, how are they, when even the past now is not; and the future is not as yet? But should the present be always present, and should it not pass into time past, time truly it could not be, but eternity. If, then, time present -- if it be time -- only comes into existence because it passes into time past, how do we say that even this is, whose cause of being is that it shall not be -- namely, so that we cannot truly say that time is, unless because it tends not to be?
We spend too much time on the subject of time. How can we really ever know the true nature of time if we are limited by our perception of it as human beings? All we can see is the Entropic version of time this guy discussed; things are in state one, the state changes with chemical reactions and energy release, then they are in an irreversible state. Time is a byproduct of this basic law of Thermodynamics. Personally I'm of the mind that the true nature of the universe eludes it because there are forces or concepts we are yet incapable of perceiving. But I'm only a novice in Physics, I could be wrong.
Sure baby, I'll give you my phone number...in Hex
There is no past, there is no future, there is only the present.
Which I came up with so long ago is: Time is a measurement of location and actions.
Location: The relative point you were at in space, includes local (Earth) and/or celestial location.
Actions: What you were doing at the time.
In history, we measure where we were and what we were doing.
In present, where we are now and what we're doing.
In future, where we will be and what we will be doing.
Larry Niven wrote that "A man who can make fire burn backwards is mighty wizard indeed", or words to that effect. One of his short stories, I forget which.
-kgj
Thermodynamics is one of two sets of phenomena that are irreversible. The other is rather obscure, but is related to the fact that "ordinary" matter seems to be so much more abundant in our universe than anti-matter.
All other phenomena in our universe are reversible in time, which raises an interesting question: are we unable to see the future because our brains work on thermodynamic operations?
Not only biologic brains, but digital computers also depend on non-reversible operations. A two-input AND gate has a "0" output in three different input conditions: "00", "01", and "10". Now imagine a computer that uses a reversible logic system that is reversible, would that computer have a time-symmetric operation?
fruit flies like a banana.
I just took a linear algebra course, and to perform a translation on a matrix (each column is a coordinate set, each row is x, y or z coordinates), you first add a dimension, and multiply your matrix by an identity matrix with the wanted translation in the extra dimension. In other words, to move stuff using matrix multiplication, you have to add a dimension. It makes no physical sense, but it is interesting to think of time as this added dimension simply facilitating movement.
As for the math I am talking about, I can't format it nicely, but translating by (5,6) looks like this:
Format is [[row 1],[row 2],[row 3]]:
A=[[2 3],[4 5]]
A'=[[2 3 0],[4 5 0],[0 0 1]]
T=[[1 0 5],[0 1 6], [0 0 1]]
A'(translated)=T*A'
A'(translated)=[[7 8 0],[10 11 0],[0 0 1]]
My webcomic
It will be, quite literally in every sense of the phrase, the end of time.
STOP . AMERICA . NOW
The direction of time is order to chaos (with a few exceptions). The universe is more chaotic than it used to be, but with packets of order.
Fundamentally, it takes a little energy to turn order to chaos but a lot of energy to turn chaos to order. Like breaking an egg, or thermodynamic laws (energy moving from hot objects to cold objects, due to hot objects having more entropy).
This sounds like the steady state theory. Back then Hoyle was pushing it the idea was that mass comes from nowhere continuously. In this idea entropy just appears in a quiet universe for no reason.
http://michaelsmith.id.au
Prove me wrong.
The future obviously does not exist. The past? Doesn't exist either. Hence, only this present moment exists.
You can't even prove that the past existed. The only thing we have is present-moment memories, etc. I remember typing "Prove me wrong" but my memory is hardly reliable. If thirty seconds ago you spilled milk on your pants, all you have now is wet, soggy pants, not any "chain of events". Even if you filmed it, all you have is the present-moment series of images, not some actual piece of the past.
Only this present moment exists. All else is wild speculation and fantasy. Time does not exist.
Advice: on VPS providers
Time is what you are wasting right now.
synchronizing location and actions. Time allows members of society to harness shared cognitive storage capabilities in the interest of collaboration and synchronization, which allows humans to produce the incredibly complex world that we have produced.
STOP . AMERICA . NOW
Baby don't hurt me... Don't hurt me... no more...
Time will never have an arrow. Spacetime will, from the space part. If you take Minkowski's advice, that one should only think about spacetime, not time or space, then Carroll's question is poorly formed. It is good English, bad mathematical physics. Since Minkowski's observation was based on work with special relativity, people presume is observation applies only for relativistic systems. Sorry, Nature is more consistent than that: one needs to think about spacetime always, even if it contributes squat. Newton's 2nd law can be written F = m (d/dt. 0, 0, 0)^2 (0, x, y, z). What makes it classical are all the zeroes that appear in the spacetime operators.The handedness of times arrow comes from the space part whose contributions are stupidly small, but add up enough of them, and they are irreversible.
Working on new views of old physics at http://VisualPhysics.org
you do the math. time is what we have (yet another gift) here, &/or hereafter.
You're either a Philosophy student, or you just watched Donnie Darko for the first time, right?
This is Slashdot. This must be a dupe.
Set your phasers on "funky"!
Time is the fire in which we burn...
The Islamic view of time and the universe in general is that what has happened, is happening and will happen has already been determined ("it is written"). What has happened can never be undone and this is mentioned many-many times in the Quran. This means that time travel is impossible. In fact, the belief in fate and predestination and accepting the outcome whether good or bad, is one of the core of iman or Belief. What is happening and what will happen also cannot be avoided. To some extent, mankind has the ability of self determination on the small scale but in the larger scheme of things, God had determined everything. For example, the time of death for a person is already determined(though we will not know it) even before birth and mankind could not avoid or add or subtract even 1 second to this. Similarly, the time of Qiamat or Armageddon where the entire universe will fold upon itself is also already determined. Many Muslim scholars have dwelt on this subject, particularly its impact on the concept of sin and reward. The Prophet Muhammad actually discourages too much dwelling on this matter because human minds could not fathom the will of God. God is not some bearded Caucasian with long hair and wearing a white robe. God exist outside of time and the universe and thus is unfathomable. "He" is nothing that any human mind could ever imagine or grasp any more than a bacterium in a petri dish could grasp the concept of a sentient human being.
Some of you may remember Uncle Rico from Napoleon Dynamite. He was the uncle that lived in his van, taping himself throwing a football to himself, and was constantly wishing he could go back in time so he could relive one of his football moments and his life would be perfect. I've been having some similar moments (except in my case, there was an ex gf I had in HS, parents kicked me out, and she thought I abandoned her, 20 years later I find her and she's still makes me sigh but she's married with kids, like I am)
So with my slightly smarter than Rico brain I've been exploring the possibility of time travel. I have no physics background, etc.
It started off with a dream I had. I saw what looked like torus's made of water flying past me, like distortion waves. After they passed, I was in the past. I think the inspiration came from the Atlas 5 rocket going through the sundog last month.
http://www.youtube.com/watch?v=SsDEfu8s1Lw&feature=player_embedded#
The next day I read up on bending time/space into a torus. I found out that at the speed of light, this is what happens to time/space naturally.
http://www.scribd.com/doc/17397008/SPINORS-TWISTORS-QUATERNIONS-AND-THE-SPACETIME-TORUS-TOPOLOGY-Paper
I also know a bit about relativity. If I travel from earth at lightspeed, from my perspective on my spaceship time has stopped on earth.
So I started questioning what would happen if a torus of space time flew past me at the speed of light, and I was in the center of the torus as it passed. Would time stop around me while I remain in a normal time space? What if it went beyond light speed, would time begin to slowly go backwards?
If space/time travelling at 0 = our perceived passage of time.
If space/time travelling at 299,792,458 mph = time stopped
Then wouldn't space/time travelling at 599,584,916mph = our perceived passage of time in reverse?
Basically saying that at 599,584,916mph it would take me 22 years to get back to my sweetheart. If I wanted to get there in a few hours I'd be looking at getting space time to pass me by at 13,190,868,152,000mph
I'm not trying to say this is a valid theory, like I said I have no physics background at all. It's just something I've been thinking about a lot. The whole torus thing like I said, it was a dream and my thought was the reason you would want to bend space/time into a torus is to keep a region in the center of non bent time/space so you, the traveler would be safe.
From TFA:
Entropy goes up with time, things become more disorderly
Basically, our observable universe begins around 13.7 billion years ago in a state of exquisite order, exquisitely low entropy. It’s like the universe is a wind-up toy that has been sort of puttering along for the last 13.7 billion years and will eventually wind down to nothing.
So, if entropy goes up with time, and things become more disorderly, how is it that species and advanced life forms become more orderly?
It’s very easy to prove that time is abstract. Time cannot change because changing time is self-referential. Why? Because velocity in time would have to be expressed as v = dt/dt, which is nonsensical. It’s that simple, folks. But I am tilting at windmills, I know.
The abstract nature of time is the reason that a time dimension is bunk and that nothing can move in spacetime, a revelation that always comes as a surprise to most relativists. But here it is from the mouth of a relativist:
From Relativity from A to B by Prof. Robert Geroch, U. of Chicago
By the way, physics is about to enter a revolutionary phase because Aristotle was right about motion.
Rebel Science News
So let me see, if I understand this correctly: :)
Time has the ballistic and aerodynamic properties of a medieval wooden projectile?
May I suggest nursing home aide or politician?
Think about it. You are sitting still on a chair, in your house, on the Earth. The Earth is moving around the sun. The sun in moving around the Milky Way Galaxy. The Milky Way Galaxy is moving in whatever direction it is moving in the Local group. The Local Group is moving in whatever direction it is moving. Heck, the entire universe might be moving through some other medium. Who knows. The point is that we are always moving, even when we are sitting still.
is easy to understand - Data goes back in time and meets Mark Twain, who utters amazing one liners. This is important so that we can get the TNG version of Spock and Kirk going back into the past and trying to juryrig some technobable.
Oh wait, you weren't referring to The Next Generation episode?
To perceive truly is to be aware of all reality through the awareness of your own. But for this no illusions can rise to meet your sight, for reality leaves no room for any error. This means that you perceive a brother only as you see him now. His past has no reality in the present, so you cannot see it. Your past reactions to him are also not there, and if it is to them that you react, you see but an image of him that you made and cherish instead of him. In your questioning of illusions, ask yourself if it is really sane to perceive what was as now. If you remember the past as you look upon your brother, you will be unable to perceive the reality that is now.
You consider it "natural" to use your past experience as the reference point from which to judge the present. Yet this is un-natural, because it is delusional. When you have learned to look on everyone with no reference at all to the past, either his or yours as you perceived it, you will be able to learn from what you see now. For the past can cast no shadow to darken the present, unless you are afraid of light. And only if you are would choose to bring darkness with you, and by holding it in your mind, see it as a dark cloud that shrouds your brothers and conceals their reality from your sight.
--ACIM
Thermodynamics is one of two sets of phenomena that are irreversible. The other [CP violation] is rather obscure
CP violation isn't obscure if you visit the seedier corners of the Internet. It's called a USB line; I'll show you later.
Now imagine a computer that uses a reversible logic system that is reversible
Reversible computing exists.
A far out yet compelling video on time and inertia can be found at http://www.keithclemens.org/ . Very reminiscent of Einstein style thought experiments, such as riding a beam of light.
What I would like to have explained is why photons have no time. Since they travel with the speed of light, from their perspective, they come anywhere instantly. It's as if two points in space get connected at that time. Also, from their perspective, the whole universe gets contracted into a giant vertical pancake. Yet we somehow measure that they travel for some time. What is going on there?
Also, what's with the entropy in a single event, lets say that two electrons "colide", lets say that a photon is created, then absorbed in the other electron. Does this increase entropy or not? Can this be answered without mention gases? At what point some stuff becomes gas? 5 particles or more? Does that mean that time direction only exists if you look at more than 2-3 particles?
Yesterday's history -- tomorrow's a mystery
Just as the chessmaster remembers the future of their games, we just need to think infinite steps ahead.
Time is just a measurement, nothing more. It is a useful construct, much in the way that idea of free will or the illusion of "self" are useful constructs.
I'm sure there are other universes that are tuned to other frequency's and they would see time as faster or slower because whatever energy they can "see" will be their speed of "light". They could have smaller particles as atoms or larger. Honestly I think time is directly a function of the rate at which our universe is tuned. Our matter is "vibrating" with universe energy(Radiated with light etc).We exist because we can capture energy. And the passage of time can be explained by the laws of entropy. So to summarize the speed of light is our understanding of time. Hawking for a while thought we would reverse at the end of the expansion of matter in the universe; "And be crushed like spaghetti". Kinda funny really!
C-A-T really spelled DOG?
I have the same thing happen to me all the time. I think it's some kind of observer bias or selection bias. I don't remember all the times I pulled out my phone and no one called. Maybe they don't exist and there is some kind of weirdness, considering the extreme limitations imposed by our biology I do not feel qualified to trust my own judgment. This sort of thing has been studied scientifically, at least a little bit. To my knowledge no evidence of "precognition" has been found. What has been found is that our perspectives on reality, our subjective experience of existence, is fundamentally flawed. We're watching shadows on cave walls still.
Strangely, this kind of explains everything:
http://www.youtube.com/watch#v=gaaf_9TqPL8&feature=fvw
"What is time?" The question is so difficult. I'm always surprised when people offer glib answers along the lines of "time is change" or "time is entropy". This says to me that most people don't even understand the question.
Feynman said it best:
"What is time? Don't even ask me. It's just too hard to think about."
Moving 'backwards' in time and being able to see your future ahead of seems just as reasonable as walking forwards and looking where you're going. What I mean is that the Universe is what it is irrespective of Man and the fact that we experience time as we do doesn't imply that's how the Universe actually works.
Not sure about the capital U but being the only one (we know about) it probably deserves a proper noun.
So... you've either got deja vu, or EM really does influence the brain, and your subconscious has figured it out?* Both seem quite unlikely, but you're the one describing the phenomenon...
(Yes, there is an uptake in EM just prior to receiving a call. Holding a cell phone next to certain speakers will often let you hear this.)
I won't join Slashcott. OTOH, If Beta goes live, I just won't be back until it's fixed. Sorry Dice.
What would Newtonian Mechanics be like if it were seriously reconfigured to having Time as a constant of 1? Interesting conjecture this is...
what happens at 88 MPH?
Time is the gap between observation and comprehension.
Time is the children of parents.
Time is the helplessness that ensues, when you realize what you cannot do over.
And so on and so forth...
The other [wikipedia.org] is rather obscure, but is related to the fact that "ordinary" matter seems to be so much more abundant in our universe than anti-matter.
Sorry but you are confusing CP (matter/antimatter) symmetry and T (time reversal) symmetry. These are not the same. In addition time reversal violation does NOT mean that a process is irreversible it just means that it prefers to go in one direction over the other.
Both have been independently shown to be broken: CP in K and B meson decays and T in K and B meson oscillations which might be the source of your confusion. It is also worth pointing out that the combination of all three, called CPT, is expected to be conserved since it is a symmetry of relativistic space-time. If this is an unbroken symmetry then CP and T symmetries will be closely associated with each other but even then they will still be different.
If the CPT symmetry is broken then we end up with weird effects like Lorentz-violation, antiparticles with different masses to particles and really fundamental things like Quantum Field Theory break down. This makes it very hard to even construct CPT-violating models (although they do exist).
Time is man-made. It is a product of consciousness and perception. Space-time is utter nonsense. Time is not a dimension of space. It is not tied to space in anyway. It is not a physical property. It is a chronological series of events. It is a measure of rate of change. The only way to alter time is to alter the rate of change in the physical world or the consciousness and perceptions of the mind.
It's not necessarily a glitch. The brain just always tries to take the path of least resistance. Consider this:
You see a ball, and you've recognized a ball before, so it must be another ball that you're seeing right now.
Now consider people trying to spot the Loch Ness monster on that very lake in Scotland. People who come to the lake often see shapes in the distance and interpret those as the monster. But really, the brain is just trying to match those shapes to the pattern that represents the Loch Ness monster.
Deja Vu is no different. The brain senses something and wants to recognize it as something it already knows. Dega Vu is just an effect of the brains pattern recognition system.
Notice how people never have Deja Vu of extraordinary events? It's really no wonder why that is.
Time is just natures way of keeping everything from happening at once.
=-=-=-=-=-=-=-=-=-=-=-=-=-=-
Friends don't let friends enable ecmascript.
Timey-wimey ball.
Quidquid latine dictum sit, altum videtur.
The only time that exists is now. The universe is everywhere and always engaged in creating its next local state from its current local state within whatever supervenient constraints apply (like being part of a ball of rock).
The past is an extremely useful and widely deployed conception of pattern recognising systems based on traces left in the current state, largely through the necessarily conservative* nature of the universal update function. That conception of past grounds intentional action in the forever now.
It also makes a complete nonsense of predeterminism.
*This is an almost circular argument. If it wasn't conservative, pattern recognition would be impossible and we would not exist.
-- Our systemic servants do not good masters make.
Everything moves, thus everything has time. The trick is in the measuring. One must observe, which on a large scale is easy, but as you get to basic particles the energy of watching is always slightly greater than the energy of movement so you will always be behind in measuring "time". You can certainly predict what might happen but I don't think it's ever possible to see it happen or measure it at this scale.
There are things that happen, like you turn an egg into an omelet, but you can’t turn an omelet into an egg.
Why would you want to? I like the fact that I can poop and that's it. I don't want it working in reverse.
Can I bum a sig?
Everyone knows time is a cube. What are you all, educated stupid or what?
"I assumed blithely that there were no elves out there in the darkness"
Time=change
Except for ending slavery, the Nazis, communism, & securing American independence, war has never solved anything.
n/t
Warning: this article may contain humor, sarcasm, parody, and perhaps even irony. Read at your own risk.
Perhaps time does flow back and forth. . . except that we, caught in time, would never know the difference, yes? If "time" represents the configurations of matter and energy in the universe, if time ever did flow backwards, our minds would seem to reset back to that point in time, and we would never remember having been in the future (of if it rolled back far enough, we would no longer exist, waiting yet again to be born)?
Can Science really ever say, with a certainty, that time never does go backwards? All we can say is that if time does go backwards, we would never be able to detect it. You'd need an observational point outside of time to see such ebb and flow (if it happened to exist), wouldn't you?
I got zero new information about time in the article.
From wikipedia:
http://en.wikipedia.org/wiki/Entropy
"Entropy is the only quantity in the physical sciences that seems to imply a particular direction for time, sometimes called an arrow of time. As we go "forward" in time, the second law of thermodynamics states that the entropy of an isolated system tends to increase or remain the same; it will not decrease. Hence, from one perspective, entropy measurement is thought of as a kind of clock"
Bad car analogy:
This is silly in a same way if you had an indicator light that would turn on only if you are going forward, and then call that light "a speedometer".
- - From the movie "Beat the Devil" (1954), directed by John Huston,
written by John Huston and Truman Capote
Shoes for Industry. Shoes for the Dead.
If you want to reverse the time of a spacetime event, you use this member of the Lorentz group, diag{-1, 1, 1, 1}. Have that act on a 4-vector (t, x, y, z) and you get (-t, x, y, z). Now how are you going to get time back to were it started? Use exactly the same element. The Lorentz group is a global symmetry. It is to all levels of accuracy the same darn thing. Makes much math easier, but it is why physicists say the laws are identical if time goes backwards or forwards.
The important laws in physics are local. Both the standard model and general relativity depend on the values of t, x, y, z. Let's construct a local time reversal operator, call it B, such that B (t, x, y, z) = (-t, x, y, z). This can be done by presuming all three of these are quaternions, a 4D rank 1 tensor upgraded to also be able multiply and divide like real and complex numbers (full disclosure: I own quaternions.com). R can be calculated, it is (x^2 + y^2 + z^2 - t^2, 2 t x, 2 t y, 2 t z)/(t^2 + x^2 + y^2 + z^2). That will work every time, but if you want to reverse something, then reverse it again, the second B will not be identical to the first B. The first term is identical, but the 3-vector part flips signs, not magnitudes. When one makes time reversal local using quaternion operators, the arrow of time is not a problem because there is a mathematical difference between reversing the reverse of time.
Working on new views of old physics at http://VisualPhysics.org
http://www.youtube.com/watch?v=QER_yqTcmjM
A physicist I'm not, nor mathematician, but 'TIME is CHANGE' in my book.
The following is speculation ...
Not quite. To us, time is the recognition of change, or that -a- change occurred. The brain machine is wired such that sensory information generates impulses, which after these impulses have travelled through the matrix, and if the new impulses are "different" than the previous (compared against the previous physical re-wiring), a new physical re-wiring occurs. The "comparison" is done by "negative" feedback, in much the same way a "negative feedback" operational amplifier configuration works. This process is "recursive", such that the "changes of previous change" are compared in an exactly the same way. Ultimately the brain "weights" those "comparison re-wirings" such that the "most important" differences have the largest feedback weight. And this is the important part. The whole recursive feedback process solely exists to keep the machine at a stable equilibrium with its sensory input, hence the environment of the machine. Memories are just the meta-level artifact of this process. Machine self awareness spontaneously occurs at the negative feedback "node" of input sensory impulses reacting with all previous weighted comparisons re-wirings. The "feeling" of being "within", and as "separate from", yet a "part of" the external physical world occurs at the "comparison impulse frequency", and -is- the actual re-wiring process, per unit-impulse-time.
As for "the arrow of time", we are asking why does change happen at all, and especially in only one direction, and not the other. Well it seems that would be the case because that is the way the universe is already "loaded up". Certainly most particle interactions "could" mathematically happen the other way around, but the existing physical state values for velocity vectors already exists. You might as well ask "Why are the values already loaded?" Or, alternatively "Why does the physical universe already have state?"
This last question leads inevitably to the concept of a universe without end because anything that has state(s) cannot "lose it (them)". The word "state" here is used fluidly, instead of iteratively. A substance of a "infinitely continuous and un-sub dividable" nature, is probably what the universe is made of. And this "substance" is probably not "static". It is likely the "substance" fluctuates with "wildly and unfathomable" properties, yet provides "wells" of quantitative meta-zones that define "location and size" for our purposes. If you consider for example that the equation "y=mx+b" defines a line, yet is completely continuous, then it becomes odd that we expect our measuring instruments to ever tell us the exact nature of the universe beyond the "minimum" scale for the quantum environment. There may very well be a "boundary", or "interface level" scale by which we can never penetrate, beyond which lies an even deeper physical manifestation. Think of it this way. Legos are building blocks by which you can build things at their "interface level". That is our "minimum scale". However we know that Legos are actually made of a smaller substance yet. It may be that things going on at the deeper level can cause our interfaces to "break" occasionally, which leads to things like radioactivity or spontaneous creation via vacuum fluctuation. In this way, the universe is probably infinitely sub-divided into zones of higher and conversely ever deeper scale. All the observable features of the universe that we know about appear to us at "our scale" because we simply exist at a nearer "relative scale" to be able to experience those features.
If black holes are entropy producers. Then we establish that the universe had more order in the past then it does now. If time is the accumulation of entropy then a place without entropy is a place without time.
... the moments that make up the dull day.
If you liked Primer, read Larry Niven's "Singularities make Me nervous" Quite a few of the ideas in primer were in Niven's short story.
"it's just something that comes to your mind and because of the noise ratio you only notice it later"
The human brain is very good at creating non-existant patterns in random noise. There is a classic phycological experiment (IIRC by Skinner), showing that pigeons do exactly same thing (ie: engage in superstisious behaviour).
In the experiment a feeder was set up so that it would drop a pellet of food randomly with a mean time between pellet drops of a few minutes. The feeder was placed in the pigeon cage for an hour or two at normal feeding times.
The hungry pigeon would just happen to make some random movement just before the pellet happened to drop. It then mentally connected that movement with food and would repeat it a few times in the hope another pellet would appear.
Occasionally it would make a different movement just before the pellet appaeared. It would then mentally connect this new movement with food and join the two movements together in the hope of getting more food. After a while the pigeon(s) had all created their own unique an complex dance that they would start endlessly performing whenever the dispenser was introduced to their cage.
The really interesting part is that the time it took to perform a fully developed pigeon dance was always equal to the mean time between random pellet drops, meaning the pidgeon was virtually garenteed to recieve the reward after one or two performances of it's dance. Connecting random dreams to future events after the fact is just one of the many human forms of the pigeon dance.
And did you exchange a walk on part in the war for a lead role in a cage? - Pink Floyd.
For a fraction of a second I hesitated to check your Wikipedia link, fearing Chris Hansen would sneak up from behind the moment I clicked it.
Time has more than 1 dimension too... just like space. Every possible outcome of any event creates a branch and the universe splits and follows every path.
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I have a copy of Future Memory, which posits that events can be pre-experienced (mostly non-volitionally, similar to a 'near death experience').
This does not imply that the future is ordained. By knowing what's going to happen in advance, we have the ability to choose a better outcome.
Learn the rules so you know how to break them properly.
www.teslabox.com
Interesting how he put a quiet universe in the middle with two universes coming out in two directions. Some years ago, I got this idea that the arrow of time is different in each location of the universe. Or in other words our 3-dimensional world is actually an expanding 3D-'sphere' in a 4D-space. Of course, I have no idea if this 'model' fits the observations in any way. I just thought it to be an interesting idea. It also means that the time is not going in two directions but in an infinite number of directions.
... is pretty good at least. Good presenter and obviously knows his stuff. Sits in a room with Feynman's desk or something at Caltech.
http://blog.slaingod.com
Theories that involve the multiverse are, in my opinion, nearly as unscientific and embarrassing as religion or theories that involve "god": you can "explain" nearly everything and you can prove nothing. Give me a break with multiverses.
How is the question why there is a multiverse that spawns off universes randomly so much nicer that the question why there is a universe? It is equally unanswerable but introduces complexity: let occam's razor cut away the multiverse part until there is anything that is falsifyable about the story.
My pet theory is that time is an ordering on the set of possible worlds (the phase space of the universe), from less entropic to more entropic. That is, for a given possible world, any of its "nearest neighbors" (those possible worlds differing from it by the smallest possible amount, one bit) which are less entropic are chronologically prior to that possible world, and any "nearest neighbors" which are more entropic are chronologically posterior to it. And likewise, any world prior to a prior world is itself prior to the initial world under consideration, and any world posterior to a posterior world is itself posterior, such transitivity being the nature of an ordering relationship.
Any possible world which is neither prior or posterior to a given world is not a part of that world's timeline, though timelines may have possible worlds in common (much like how, if you are neither an ancestor nor a descendent of mine, you are not a part of my genealogical lineage, but my lineage and your lineage can share a common ancestor). Since there are, practically by definition, more high-entropy possible worlds than low-entropy possible worlds, a given possible world will typically have fewer possible pasts than possible futures, and thus timelines will tend to converge in the past and diverge in the future.
The reason we perceive time as moving from the past to the future (from less to more entropic states) is that any process of acquiring, processing, and storing information about the world necessarily consumes energy (if nothing else, it discharges the energy storing the information, though that energy may then be replenished from elsewhere), that energy doing the work of stimulating whatever sensors are being used to acquire this information, thus reducing the amount of usable energy (but not total energy) in the universe; that is, reducing the amount of useful work that can be done in the universe; that is, increasing the amount of entropy in the universe.
In order words, the process of perception creates entropy (though other things create it as well), so we necessarily perceive time as moving toward more entropic states. To put it another way: we can only remember lower-entropy states of the universe, since by acquiring memory of those states we increased the subsequent entropy of the universe. When we model these memories, we observe the pattern of entropy increasing in later memories, and in turn we anticipate, generally correctly, that later states will be higher entropy. Thus our mental model of time acquires its directionality.
Thoughts along these lines, and attempts to integrate relativistic elements of time into this model, have previously lead me to ideas similar to Erik Verlinde's recent model of gravity as an entropic force, though not being a physicist by profession my ideas were far less developed and rigorous than his. I'm watching the developments in that area closely, hoping to see someone develop a more rigorous presentation of something like the above out of it...
-Forrest Cameranesi, Geek of all Trades
"I am Sam. Sam I am. I do not like trolls, flames, or spam."
You can turn an omelette into an egg - just feed the omelette to a hen and she will do it for you.
It's called an elephant's trunk whereas it is in fact, an elephant's nose, a nose by any other name would smell as sweet
Time is not the "4th dimension" - that's a completely arbitrary and illogical statement. May as well say "thought" is the fourth dimension. Time is not "sideways to" the 3 dimensions of space.
Time is not necessarily a property of the universe at all. All we can directly measure is CHANGE. We cannot directly measure TIME, however we do measure change *as a function of something*. That sometime is, basically, other changes. That is to say, our perception of what we call "time" is just our brains comparing one set of changes with another.
Time is something that we, as humans, agree on. If we did not all have some kind of common "ticker" in the brain, which measures a beat we all have in common, the effect would be that we would not agree with each other on how fast time is going.
Time is relative in a much more encompassing way than Einstein meant (I won't say more "subtle" or "profound", that's silly talk). Drugs can change our perception of time, yet we say, "no - time is more or less constant". But that's only because the vast majority of us run at the same "speed". Whatever changes in the brain allow us to measure time, it's the same for all of us most of the.. er, time. So to speak.
There is no time. There is only change. You might say there can be no "change" without time - something to measure change against. So I say time is all about *perception*. If we had no memory at all, we would not be able to experience time. Time is the experience of change in relation to what our brains said was the state of things a second ago.
So I think Adams was right, and time is an illusion, in the most timeless sense.
Time flies likes an arrow - fruit flies like a banana.
Now imagine a computer that uses a reversible logic system that is reversible, would that computer have a time-symmetric operation?
Well, quantum computers work something like that.
You may want to think of the state of a classical computer as a bit vector, a member of {0, 1}^n for some n. In the same vein, the state of a quantum computer is a member of C^{2^n} for some n; it's a 2-to-the-n-dimensional complex vector. Oh, and it has length 1.
The state transformations you can do are described by unitary matrices; in particular, they are invertible. Say you apply U to a state x and get a state y. Applying U^{-1} to y will still take time, though (is my understanding; but I'm not certain). And you can do a measurement which loses information.
So, quantum computers are maybe not exactly what you want, but you might want to look into them.
This is just a statistical argument. There are simply far more ways to be disorganised than organised. So it's just very, very unlikely (but not impossible) for large numbers of things to behave in a way that looks like "time-reversal" to us. This is why you get the difference between the scales - it's just the combinatorial explosion you get when arranging large numbers of things.
I seriously wonder why anyone think this provides any deep explanation of time itself - glad to be enlightened if I'm missing something deep (or obvious) here...
There was an article a couple of months ago. I think I saw it also here on slashdot. From a phisicist from MTI I think, who had a very nice idea. He was introducing a concept of negative information, as something that has the ability to remove/delete information from a system. He was also saying that this negative information is "generated" when time travels backwards and in such a way that it erases the information that was generated while it was traveling forward. So this could explain why we don't remember future. So we only remember the results of processes that have not been reversed (...yet? on the state we experience right "now"?). If this is true, then it also breaks second law of thermodynamics. Not that it matters in the way we experience world. It would only matter if someone could be unaffected by the negative information. But then he is probably outside of this system, if such "place" exists. The law will then have to be restated as "the entropy on a closed system can decrease, but nobody in the system can notice it". :-)
If for example we had a closed system with some creatures in it and we were holding it in our hands and we were observing it. Some processes would look "reversible" to us. But for a creature in this closed system, would it be able to understand that this "reversible" process is being actually reversed? Keep in mind that the reverse will also reverse the states of the creatures mind about the time at which the process went forward...
To be honest I liked this idea. At least it's less crazy than the idea of bozons that try to kill the machine that tries to reveal them... ;-)
Remember kids, you can't break a few eggs without making an omelet.
K.
Not discrediting the physicist at all - but the analogies and abstractions used to explain this to a reporter really don't add anything or mean much to anyone, other than to make people think of wild ideas that really have nothing to do with the idea itself.
Fluff piece, in other words.
You can't explain every little thing.
Some concepts have to be "basic concepts".
Time seems like an excellent candidate for a basic concept.
According to the Russian astrophysicist Nikolai Aleksandrovich Kozyrev, who has done some very interesting research, time is a form of spiraling energy.
http://en.wikipedia.org/wiki/Nikolai_Aleksandrovich_Kozyrev
Which ties in to torsion physics (Tesla, Schauberger, etc), the zero-point energy field or (do I dare say it? yes!), the aether! **
CHAPTER 01: THE BREAKTHROUGHS OF DR. N.A. KOZYREV
http://divinecosmos.com/index.php/start-here/books-free-online/20-the-divine-cosmos/95-the-divine-cosmos-chapter-01-the-breakthroughs-of-dr-na-kozyrev
http://divinecosmos.com/index.php/start-here/books-free-online/20-the-divine-cosmos/103-the-divine-cosmos-chapter-09-harnessing-torsion-waves-and-consciousness
Even seems to connect to the time-wave theory of Terence McKenna..
**
"Concerning the Silvertooth experiment: The Michelson-Morley experiment, which did not show any translational motion through an aether or other medium of propagation, was later shown to have a fundamental flaw: The standing waves that are reflected back onto a mirror become phase locked on the mirror, and hence to its motion through space. Silvertooth built a standing wave experiment that avoids the phase locking encountered in the Michelson-Morley setup. It uses a configuration similar to the Sagnac experiment, which many years ago did detect motion relative to an aether. Silvertooth's addition was a sensor capable of measuring the spacing between standing wave nodes.
This spacing is dependent upon the orientation of the apparatus relative to the Earth's motion, and this fact made the Earth's motion measurable. Silvertooth measured the 378 km/s motion of the Earth in this experiment. Some references are: Silvertooth, E.W., "Experimental Detection of the Ether", Speculations in Science and Technology, Vol.10, No.1, page 3 (1987) In that same issue beginning on page 9, is an excellent "Plain English" summary by H. Aspden entitled 'On the Silvertooth Experiment'." [We are heading toward the Constellation Leo.]
Wibbly wobbly timey wimey.
I am tired, and of limited brain power right now, but couldn't time be described as a series of linear states, continually changing, but never repeating in a deterministic way?
Then if we go on to say what we know of Quantum Theory is correct, that things may exist in more than one state and any point in its existence, might this not prove (in a limited way) that time at least in the physical manifestation of "states" does not exist, at least at a certain level. Perhaps that is the "problem" with Quantum theory and its multiple alive/dead cat states, is that at the quantum level time ceases to exist, and we as humans are trying to describe that relationship through the lens of perception that is the human experience with time.
Or what I said, makes no sense to someone who knows what they are talking about. Pass me the hydro spanner...
Also we all know that Canadian Sir Sanford Fleming invented time, at least the standard kind.
Here is my theory.
Consider a small object falling towards a very massive object (like a planet or a star). Although in theory movement is possible in any direction in space, from the point of view of the small object, it only seems possible in one direction. Furthermore the movement is inexorable and automatic. It seems like a fundamental property of space. (Lets keep it simple here, bendy space and gravitons aside, that's how we would experience it).
Sounds somewhat similar to the way we experience time. What, then is the very massive object that we are falling into (in the direction of the percieved flow of time)?
To answer that, ask yourself about your perception of time. Isn't it the case that we only know about the flow and passage of time because we are conscious of it? If we were able to percieve time in the reverse direction, then all physical time-related or time-bound events would unfold in THAT direction. In other words, it is not that space or events or objects move in time, it is that our consciousness moves in time. So what would cause our consciousness to move inexorably in only one direction. The answer should by now be obvious. In the direction that we call the future is a very massive body of consciousness. That is what our consciousness is falling towards.
So, to conclude: The good news is that our union with God is just a matter of time (or is it that time is just a matter of God?). :) http://offsider.sourceforge.net/ - proof that anything is possible with *nix.
"It's an herb!"