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What is the Nature of Time?

19 Answers
We can build a clock to measure elapsed time. This could be mechanical or atomic, or we could use planetary motion. All these clocks assume that there is a uniform passage of time. In Einstein's relativity, measurement of time depends on relative motion and the effects of gravity (or inertial mass). Some scientists have speculated that the passage of time is illusory. Yet we are born, appear to age, and eventually die, which suggests that something is passing.
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Hello Angels55

Let's see how much confusion I might add to the answer!

The argument for time being a mere illusion does hold some weight, in that time is defiantly not as it seems at all! Is there truly ever a wave of the 'present' that we are RIDING across space in our own time-frame, or is this just a mathematical curiosity that is interpreted by us in the classical manner? I can't spot any moment that IS the present, even though it seems to always be here and now - I cant touch it or it is no longer the same present, things have changed.

The mere act of observation requires not input, but change. We of course only observe changes to the present, so we therefore must never observe it IN THE PRESENT oddly enough. And every moment that I can remember has been the present, but all events have not taken place simultaneously. The coffee was brewed this morning and after some short period of time (10 minutes) I poured the coffee into my glass. Time must then only be a placeholder, a series of constructed labels that allow comparative memories from this moment (yet to be experienced!) to the first we remember. I can easily use it to explain my coffee experience or even, in the case I have no memory of something, reconstruct the past time (I think INTERNALLY) to draw the logical conclusion that the coffee brewing must not have been carried out after the pouring or drinking of it.

Of course this would be quite strange in a time reversed universe (assuming CPT-symmitry). Our experience wold seem very strange,but why would it be more strange than ours to them? They might be used to experiencing the stimulant effect of caffeine, quenching it by removing coffee from their stomach and preforming a handful of new beans from the coffee machine which are then stored until they can get paid for a full bag at the end of each week!

I do believe our personal experience through time is closely related to our personal trip through the parallel universes that branch forward from past to future in the many-worlds interpretation of quantum physics. The essential relation being that a specific path for ever viewer is created independent of all else. All other universes go on with altered states and all other observers continue on out of sync with one another to some small degree (extremely unless you've traveled at high subliminal speeds lately!). Still this separation defines our personal experience of reality, and yet does not effect anyone else's unique experience.

If we view spacetime in it's true form, there are no movements or oscillations, in the traditional sense. a sine wave in space would appear as a point that was basically dashed (although the spaces are connected, just further away. Everything is merely geometric illusions that seem to present as classical time to us. I realize your asking a deeper question, but I have no complete answer yet! I do believe that light is a type of bridge between space and time. Creating the dilemma of mathematically being able to interchange the two, but when many equations involve a "time-like" movement in spacetime, this does not hold true in most cases as a valid solution anymore.

Sure relativistic movement is simply motion is simply a change in angular geometry in the temporal-dimension, and using natural units of equivalent space and time this looks very pretty, but the truth is that it requires either a super-time to experience, or to observe the motion of time - either way it is a damaging request to all laws of physics as well as ends up being cyclically redundant requiring a new super-suppertime to observe it's predecessor properly.

Of course there is always the unfavorable and useless, but difficult to deny possibility that I (you) am all that is, and time is a purely internal experience that we are looking outward for while it is not there at all.

Finally, I'll end by saying that in addition to your question, I?d be curious to better understand the need for time, and why the specific rate? What is the significance of not watching this movie at super-speed, or as a extra dimensional image - devoid of time? It would seem to be easier, this seems to imply that indeed there is a "reason" as we call it, and I would suspect that we need to be able o make he observations and decisions that determine our unique life, otherwise we would see every outcome (nearly infinite branches per "moment" or per unit of planks time, or every "Jiffy" infinite undeniably deterministic endings and paths would exist o see! We would lose free will, or God forbid quantum uncertainty (which I believe to be hiding a deeper concept. While a quantum wave function can be defined in real numbers the probability that leads to a collapsed wave function (or the resulting universe it selects) requires time, although how the outcome is decided is still hidden at the "moment", I believe it will be removed essentially from our interpretation of reality, thus time. (each requires the other - but that means in the absence of an observer, pre-life, and post-life, that there is no reality, also leading to the tree falling in the woods paradox, which most of us find difficult to deal with objectively!)

Oh, and to reply to on of your last posts...I can honestly say I can' see the things you mentioned happening now, because that again means that all time is now since at every moment there seems to exist a here and now, because everything I see just happened, so I can't rule it out as a mere memory of something that never occurred. I prefer to though!

I'm sure time is clear now to everyone! (laughs) Thanks for the interesting question and ongoing dialog (and from a rather old question I must say too!)

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Scientific measurements indicate some very specific facts about time, and they can be briefly summarized: time seems to function in one direction from past to future in which the past is fixed and unchangeable; time can be quantized as a hypothetical "chronon" (6.97 x 10 ^-24) or "Planck Unit" (5.39 x 10 ^-44) rather than as a continuous "flow" in quantum mechanics or general relativity; time may be described as a fourth dimensional function of the three spatial dimensions; time and space may be combined into a continuum where the distance between points is time and the time between events is distance; and time may be sequenced or cyclical based on the recurrence of observed events such as heartbeats or sunrises.

For human activities on Earth, time is customarily defined by chronology. Time is one of the seven different measurable functions within the System of International Units, as in seconds, minutes, hours, days, years, etc.

The nature of chronology is based on principles of physics that are actually ignored in the course of human lives. Earth spins at 1,070 miles per hour (1,670 kph) at the equator, orbits the Sun at 66,611 mph (107,200 kph), and the Sun apparently orbits the center of the Milky Way Galaxy at about 486,000 mph (782,000 kph), as the Galaxy rotates at 503,310 mph (809,976 kph), and the Milky Way moves through space as part of the Local Group of galaxies at 1.34 million mph (2.16 million kph). We are blissfully unaware of these velocities, yet they have major impacts on relative time for our planet.

Even though unaware of the actual speeds, humans measure the Sun's positions and establish that it gives the appearance of "rising" every morning as Earth spins. We divide the cycles into a sequence of time. It is the "nature" of the solar day and year that we use to measure separation of events on Earth.

Comparatively, an observer, with powerful instrumentation, near the center of the Milky Way would notice that the Sun orbits once every 225 to 240 million years, which would be a galactic year for the center of our solar system. That represents 1/65 of the estimated age for the cosmos. Even so, the galactic speed of 1.34 million mph is not even a significant fraction of the speed of light, which is about 670,616,629 mph, so all that movement through space does not have much effect on either mass or relative time. As a result, for all practical purposes, our usages of chronological, tick-tock clock time fits very well within the physics of our galaxy. Temper fugit.

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S

I think if we can look at "time" from the perspective of something more tangible, I expect we'd learn that time is really nothing more than the process of "decay" (living and dying?). That is, we know everything in our universe is slowly, but surely, decaying, as our earth orbits our sun (which is expending its energy all the time) and as earth rotates on its axis and as our whole galaxy is in motion, and as so many other galaxies are in motion...and as our entire known universe is in motion...at some point, everything we know of is destined to "end"...to "run out of energy"...to "cease to be"...or so we think.

Science tells us that everything we now know and see and touch, taste, smell, or otherwise experience all began from "nothingness", in an instant of "time". Beyond that, science is still trying to figure it out. They call it the "Big Bang", but they have no clue what was before that...if anything. Really? Hmmm...

Science also tells us that our universe is "alive", in that it is constantly changing; new stars being "born", old ones "dying", and that galaxies actually "dance" with one another; and we're learning more and more that there are many other "planets that might possibly support life" out there (in my humble opinion, I think our universe if full of other life, but I surely can't prove that).

All I know is that when I think of "time", I perceive it to be simply the duration that elapses while "everything" we know of slowly, but surely, decays; or erodes, or decomposes, or dies...however we wish to describe the process of "life", I guess. I'm just sayin'...

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So I imagine that time is a measurable speed of an object. As objects are moving through space time is flowing, it is sort of a measure in the change in space 1 second = x feet traveled etc. Starting with the big band the universe began to expand essentially starting time as we all travel outward from the event horizon. So time will essentially end when the speed runs out.
The reason we probably age is because our molecules are moving while our environment is moving and everything moving at slightly different paces around us affects everything else etc and it results in aging.
Also in order to travel through time we would have to travel faster than the expansion of the universe in order to break it's effects on us and reach another point in time. That is also assuming that essentially every point in time exists at the same time which is complicated...

Overall none of this makes sense and time is just too complicated to understand, I say we just enjoy what we have of it.

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J

The nature of time is relative. That is why time seems to stop when you are stuck in boring meeting or class. Just kidding. I think it really is just theory. Who knows if we will ever know the nature of time. On earth it seems constant. However, with speed time slows down. This is why satellites or object that orbit the earth have have their clock off. Some people think if we could go faster than the speed of light then we could go back in time. I don't know if that will ever happen. Science fiction has discussed the nature of time in Terminator, Back to Future, Stargate, and Star Trek. Maybe time travel will be possilbe someday. If will ever be then we need to understand the nature of time. I don't think we understand it enough to do time travel. Maybe we will in the future because some people think that UFOs are really time travelers from the future. They can't talk to us because they would change history and their future may not exist. Hope this answers your question. Thank you.

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All of us for all our life NEVER travel at speeds that will affect the flow of time.
Neither do we come close to such a massive object that time will slow down!.
For all lives and objects on earth, time passes at the same rate for all practical purposes.
I said that becaise there are some exceptions.
Particles doing the rounds in the cyclotrons and linear accelerators do experience time dilation.
But they represent an extremely narrow snapshot of life on earth.

Yes something passes, and we call that time.
To my mind it is the movement of space in a higher dimension which we experience as time.
Since we cannot see that dimension, we only feel passage against it.
At low velocities, this flow is linear and "almost same" for all objects arouns us.
By low velocity is meant velocity in range that does not bring in Einstein's relativistic phenomena into effect, such as lorentz contraction, increase in inertial mass etc. ...

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I don't see any evidence for time. Events occur such as the ticking of a clock, day and night and the seasons, radioactive decay and the breakdown and disintegration of atoms, motion of objects.
We measure time by the number of constant duration events which occur in a measurement device. This could be the swing of a pendulum in a mechanical clock or cycles of a quartz oscillator in a quartz clock or microwave oscillator in an atomic clock. Also Special Relativity would seem to indicate that the duration of these events is shortened if we approach the speed of light. When "time flies" is something going on in our brains which has the same affect as traveling very fast?
Does motion plus events = time ? If there is no motion nor change, has time paused?
Sorry I'm asking more questions than providing answers!

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I

The nature of time is limited to that which defines it. For example, time can be measured in hours, minutes, and seconds, or it can be defined by a lifetime: birth, youth, adulthood, middle age, elderly, etc.

Einsteins theory of relativity even states that time can be measured by the observer, offering the example that if you sit next to a pretty woman, time flies, but if you sit on a hot oven, time slows.

Time can be set by our bodies, such as circadian rhythms, and can be set by our bosses: lunch time, break time, work time.

In other words, time is, well, what ever you make it to be, and how you wish to measure it. Whatever you define as time, it will be, but no matter how you define it, your time is not infinite. Make the most of it.

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S

Time is what we call the orderly process that keeps everything from happening at once. We really don't know the mechanics behind it, and only have a vague idea of how it works.

We have Rubibium based atomic clocks in orbit, which have to be adjusted frequently to keep our GPS system in sync.

Now the question is, is it actually the velocity that effects the slowing of the clock ticking, or the reduced gravity that causes the Rubidium to decay more slowly?

Your query really does result in more questions than answers, but I guess that's one of the joys of science.

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A

"Science" does not tell us that the universe is alive. However, scientists tend to use anthropomorphic descriptions which may not add meaning or clarity to their statements.

You seem to be equating the passage of time with the increase in entropy. This is a thoroughly discussed scientific argument but is rather unhelpful in that it does not really promote understanding of anything we experience. However, this may be the final word on the subject. In this case, what is time and why do we experience it?

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I think I read something about Einstein having been working on a different theory before he died. It was about the idea that all time was really the same. Meaning as if you could go from one time age to another as in the Time Machine. I can't find anything on that right now but it is interesting. It was as if something was missing that he had and then he added that on to it.

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You don't see any evidence for time? If we look around us we see people aging, crops growing, arrows moving through the air, radioactive decay, as you wrote. What is that? We measure the ?passage of time by measuring oscillations of some sort: clocks, atoms, planets, the sun. What is that?

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You guys have all read the question and answered with the same wording. Is there such a thing as time? What is it? What does a clock measure? The way the second is now defined, in terms of atomic wavelengths, we basically have lost the whole idea of passage of time.

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Tabodi45 If nothing is moving then there is no time? That may be so. Is time just another spatial dimension? In Einstein's relativity you can mathematical use time as a 4th dimension, but what does that mean?

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C

Well i just did a bit of research and wow how complex is this but here is what i have taken away hope it helps..
Seems to me time is based on our consciousness and our ability to perceive it.

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A

Well the fellow sure doesn't give away very much of any consequence, does he. He is, no doubt, a cousin of Lewis Carroll, don't you think? That sure was a bowl of pablum.

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C

This link should help you out allot more than i can
http://www.wired.com/wiredscience/2010/02/what-is-time/

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P

I see change and motion. Is this what you mean by time or the passage of time?

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Please reread the first post which is the question asked.

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