# Thread: What is the simplest definition for time?

1. How can be time defined in the simplest way? According to my theory, time can be defined as 'change' in any form, any place in the universe. Any type of change in the real universe is called time. It can be changing of state, shape, size, color, temperature, force applied or the place etc.

So we can say that if there no change in the universe, there is no time in the universe. Because time is the 4th dimension, so if time is not there, the whole universe becomes 3 dimensional. Then the universe will stay like a paused video if there is no time. Can you prove it is not?

2.

3. The simplest definition of time:

Time is that which stops everything from happening at once.

4. Time is that which clocks measure: relative movement. Everything moves relative to something else. Entropy just shows the arrow of time, but is not in itself time. Or that is how I think of it.

5. My opinion of this matter is this! (im on my phone so excuse errors please) Time is the natural process of aging, in the universe. A relative quantity that has an inverse relationship, relative to the observers speed. The ultimate goal being the ability to reach the speed of light. At which point time would ultimately stop progressing, for that entity.. Time is specific to each individual thing, no two entities have the same perceptions of time; unless placed at an equal constant speed for a set period (aka eliminate variables). Time is relative, relative to the natural process of time perceved by a fixed object.(fixed object being used as a reference point)Hope this helps

6. Time is a concept of man

7. Originally Posted by fizzlooney
Time is a concept of man
So, without man, everything would happen simultaneously?

8. i got it!

time is the speed at which thing happen.

The unit is the second per thing

9. Simplest explanation - that makes sense to me - is "Time is the passage of events". Which is close to the original poster's view.

Used to be time was measured by the rising and setting of the Sun, phases of the Moon, flow of water, a candle burning, pendulum swinging, a clock ticking and so forth. Now, the most accurate means of measuring time is radiation of - something, I don't recall right now. If one watches the television show "CSI", one can tell time - meaning the time since death occurred - by looking at decomposition. In all instances, events passed.

As far as humans are concerned, time must be measured somehow. For instance - in the case of a conventional wind up clock, one can only get down to half a second. That's a 'tic' or a 'tok', depending on which half of the second is in question.

That's why there's no way to tell how 'long' the Singularity sat in place prior to the Big Bang. Nothing happened. Since no one was there to start and stop the stopwatch, or turn the calendar, there's no way to tell how much time was involved.

The same with the end of the Universe. At some point, entropy will absorb (for lack of a better word) all the energy in the Universe. No more heat transfer, no more light, no more movement. Again, no one with a stopwatch - no stopwatch, either. Time will end. At least it will end in any sense humanity can comprehend.

Eternal, Omnipotent Beings who's existence is not predicated on the Universe excluded, of course.

10. Originally Posted by sreeramavarmaraja
How can be time defined in the simplest way? According to my theory, time can be defined as 'change' in any form, any place in the universe. Any type of change in the real universe is called time. It can be changing of state, shape, size, color, temperature, force applied or the place etc.

So we can say that if there no change in the universe, there is no time in the universe. Because time is the 4th dimension, so if time is not there, the whole universe becomes 3 dimensional. Then the universe will stay like a paused video if there is no time. Can you prove it is not?
"What is the time" is rather popular topic, at that – since the time is an ontological category (isn't "Time is that which clocks measure") - the discussions haven’t some substantial results. That isn’t surprised; any ontological category cannot be "understandable" outside the informational model, though. When the model is proven as be true, complete and self-consistent and so must be used in any ontological analysis.see, e.g., [1004.3712] The information as absolute )

In the model notions "Time" (and "Space") are some logical conditions/ rules that control multielement informational systems (IS) [in this case – IS "Matter"] and have two main sides: (i) – they are possibilities for the elements to be separated, and (ii) – rules "how the separation must be realized in given IS".

Space, first of all, separates fixed elements, when Time is a sequential of that logical (cause - effect ) chains are inherent for the information and in a chain a cause is always before the effect. In the absolutely infinite Set "Information" (see arXiv link above): (i) - all Its elements are connected (interact) between each other, (ii) – every element contains all other elements (the Set totally), and (iii) the information in the Set spreads with infinite – but not absolutely! - speed.

An example (relates somewhere to a discussion in http://www.thescienceforum.com/1-0-25473t.php ; posting "SSDZ – Guitarist" ). Every infinitesimal volume of space (including, e.g., in a human’s brain) outside Andromeda nebula contains full absolutely exact information about the nebula. When, e.g., an electron from outer space falls in the nebula, immediately in every Set’s element – including in a brain’s space volume – the information appears "an outer electron fell into the nebula". At that corresponding "time interval" for this information is infinitesimal, but isn’t equal to (is more then) zero, since "the electron’s arrival – creation of corresponding information – obtaining the information by another Set’s element" is a cause-effect chain.

In the IS "Matter" Space and Time as "possibilities" are realized as the "spacetime". Besides – what seems rather reasonable – for Matter to exist as some "stable" dynamic IS (i.e. something like a computer) is necessary to be built from very stable primary logical elements (FLEs), so informational exchange between material elements (interaction of particles, bodies, etc.) is determined by "speed of flipping" of the FLEs, which becomes be not infinite; and is, as a reasonable work suggestion, equal to Planck time. If the FLE’s dimension is equal to Planck length, then maximal speed of the information in Matter is equal to the speed of light, c.

Since any changes in material elements (further - particles) reduce eventually to the FLEs flips, in Matter a variable appears - "the time", which has natural scale unity – Planck time; and since all material processes are totally "standardized" the time can be - and is - used to describe how different material IS evolve. The Space is an analogues to time.

As outer possibilities and rules for Matter’s elements, space and time are "absolute" and don’t depend on the elements. At that – since after some cause Matter became be a dynamical system (be evolving) and because of there isn’t a "friction" at the FLEs’ flipping they don't stop, – for the Matter evolution one can apply the notion "time flows"- down to "Matter time flow" in "absolute time" with speed c.

But though space and time are analogues and FLE dimensions and "flip times" are equal in both – space and time – directions, they aren’t identical, first of all because of logically the flips I a "not-time" direction is also the flips in time.

An example – a straight line flipping of FLEs along time and space directions. Though in second case FLE doesn’t flip in the time direction, it, nonetheless, is in the same "absolute time" as the time flipping FLE.

But flip time in any direction cannot be lesser then Planck time, so (more see the arXiv links) if there is a flipping in both directions, flip rate in the time direction becomes be lesser - for a particle "time dilation" happens. But all in Matter remains be in "absolute time".

An example. Let a fast particle in an accelerator hits in a target and give rise to a particle – let famous mu-meson - having speed near c at time t1, then the meson hits into detector at t2, where t1 t2 and (t2-t1)are laboratory’s times. Though the meson at that is "time dilated", it doesn’t "come out of the laboratory time" – all (including meson’s) times are the same (eventually the same absolute times).

Again – more see the arXiv links,

Cheers

11. Time arose because we compared any two natural phenomenon. Time is based on the sexagesimal system used by the sumerians. The Sumerians started measuring time in seconds and minutes. Thus 60 seconds became 1 minute and 60 minutes became 1 hour. After observing the movement of the stars the Sumerians concluded that 1 day is made up of 24 hours. For calculating the year they took help of seasons and movement of constellations. Thus we have TIME now.

12. Originally Posted by sreeramavarmaraja
How can be time defined in the simplest way? According to my theory, time can be defined as 'change' in any form, any place in the universe. Any type of change in the real universe is called time. It can be changing of state, shape, size, color, temperature, force applied or the place etc.
How about this: Time exists like heat exists, being an emergent property of motion. It's a cumulative measure of motion used in the relative measure of motion compared to the motion of light, and the only motion is through space. So time doesn’t really flow and we don’t travel through it. Note thought that I consider this merely a restatement of the "time is change" theme which goes back as far as ancient Greece. See for example Time for Aristotle // Reviews // Philosophical Reviews // University of Notre Dame

Originally Posted by sreeramavarmaraja
So we can say that if there no change in the universe, there is no time in the universe. Because time is the 4th dimension, so if time is not there, the whole universe becomes 3 dimensional. Then the universe will stay like a paused video if there is no time. Can you prove it is not?
Nope. Press the freeze-frame button and you stop motion. That's what a clock clocks up, be it a mechanical clock, a quartz clock, or an optical clock. A clock doesn't actually clock up "the flow of time" or "the passage of time". Phrases like that are just a figure of speech. A moving clock that that passes through two events is said to measure "proper time", but look closely and it all comes down to motion, whether it's local motion in the mechanism of the clock or macroscopic motion through space.

13. Time is a method of measure, in and of itself it would have no definition , like a ruler if its purpose wasnt to equate distance then the ruler would be nothing more then the material its made of, like wise time is a mesure, if it didnt serve its fuction of regulating days, events, etc etc etc. then its fuction would be nothing more then a word.

14. Time is a frame of reference, compared to another reference, through a series of change(s) in any form, and is also a fundamental property of the universe.
As 3d beings, we cannot see time; however, we do have the ability to acknowledge and perceive time: for Δtime its relative to Δposition and Δspeed. (v=d/t)

I hope this satisfies your request, i wouldn't know how it simplify it any further.

*edit: i just realized that our views of are almost identical (i only replied to the title and didn't actually read your post until after)

15. Time is the velocity of the progression of events such that existence itself is an element of the set of events.

16. Originally Posted by the old man
Time is the velocity of the progression of events such that existence itself is an element of the set of events.

Correct me if I am wrong, but if time is the velocity of events, and as others suggest that velocity to be the speed of light itself, does not time stand still at the speed of light?

17. Tempus fugit. (As good a definition as most I've read here.)

I have read better by Hawking et al.

18. Originally Posted by sreeramavarmaraja
How can be time defined in the simplest way? According to my theory, time can be defined as 'change' in any form, any place in the universe. Any type of change in the real universe is called time. It can be changing of state, shape, size, color, temperature, force applied or the place etc.

So we can say that if there no change in the universe, there is no time in the universe. Because time is the 4th dimension, so if time is not there, the whole universe becomes 3 dimensional. Then the universe will stay like a paused video if there is no time. Can you prove it is not?
You are right. Time (of something) means change (of something); motion (of something). There is no possibility to describe time without adducing to itself, in other words use its synonyms.

19. [As an addition to SSDZ post of August 31st, 2011]

Now a special paper relating to Space-Time problem appeared in arXiv: [1110.0003] Space and Time

Cheers

20. In its simplest form, I would define 'time' as a functional term (entity), which shows temporal relation between a cause and its effect.

21. There are various, equally valid ways to define the concept of "time". Please refer to :

Time - Wikipedia, the free encyclopedia

This is actually a very complex topic, but I personally favor the mathematical/physical definition :

Spacetime - Wikipedia, the free encyclopedia

22. A number of posts have been split off to a new thread in New Ideas and Hypotheses named "Time cannot dilate", as these posts deal with the personal theory of one particular poster.

23. Time, like space, are words we use to identify quantitative entities calibrated most simply along linear singularities to "measure" reality. Space or time is not reality. They are words for dimensions. It just so happens space is 3 dimensional, and time 1 dimensional. "Reality" will never cease to amaze, inspire, and confuse, even those who think they understand it entire, yet in using "dimensions", "dimensio", Latin for "to measure", time most simply appears to be the way things "change" in space, seemingly to our perception in a undirectional fashion, like there;s no undoing what has been done, unless you know what you are doing and what you want (which is another discussion entirely).

24. Originally Posted by theQuestIsNotOver
Originally Posted by the old man
Time is the velocity of the progression of events such that existence itself is an element of the set of events.

Correct me if I am wrong, but if time is the velocity of events, and as others suggest that velocity to be the speed of light itself, does not time stand still at the speed of light?
If so, then the CERN neutrinos have gone into the future or into the past? Yet they are still here.

25. Originally Posted by theQuestIsNotOver
Time, like space, are words we use to identify quantitative entities calibrated most simply along linear singularities to "measure" reality. Space or time is not reality. They are words for dimensions. It just so happens space is 3 dimensional, and time 1 dimensional. "Reality" will never cease to amaze, inspire, and confuse, even those who think they understand it entire, yet in using "dimensions", "dimensio", Latin for "to measure", time most simply appears to be the way things "change" in space, seemingly to our perception in a undirectional fashion, like there;s no undoing what has been done, unless you know what you are doing and what you want (which is another discussion entirely).
Space is also said to be a physical reality, with physical realities having at least three dimensions and probably many more. Time is said to consist of at least three dimensions .. past, present, future.

26. Originally Posted by theQuestIsNotOver
Time, like space, are words we use to identify quantitative entities calibrated most simply along linear singularities to "measure" reality. Space or time is not reality.
Time is reality when we refer it to matter (which is in constant motion). If measured, or as considered as measure of motion then it is not reality. Space belongs to physical reality otherwise would be illusion.
They are words for dimensions. It just so happens space is 3 dimensional,
Dimensionis a measure of spatial extent.
and time 1 dimensional.
Time/ motion / change does nor appear autonomously in nature in contrast to any material entities. If any form of matter travels in any of 3dimensions, that means it needs time to beat a distance and that is why time as a dimension does not exist.
"Reality" will never cease to amaze, inspire, and confuse, even those who think they understand it entire, yet in using "dimensions", "dimensio", Latin for "to measure", time most simply appears to be the way things "change" in space, seemingly to our perception in a undirectional fashion, like there;s no undoing what has been done, unless you know what you are doing and what you want (which is another discussion entirely).
Time(of sth) / motion (of sth) / change (of sth) does not need our perception. It exists, existed and will exist as long as matter is,was and will be.

27. Time is just the fourth dimension. It's just like the other three, except most objects change state as they pass/extend through it.

Motion is an illusion created by our evolved tendency to value one of these dimensions over the others, and inability to see more than just a cross section of it at any moment. For a being able to see more than just the cross section, a human would look like a big snaking line that has a baby on one end and an old person on the other.

If they progressed through the "up/down" axis instead of the "past/future" axis, then that snaking line would appear to be moving back and forth across the "up/down" axis. If, like us, they were only capable of traveling through their chosen dimension in one direction (changing states as they went, so they could only see one cross section at any moment), they would think we were violating the laws of physics by doing what we do.

28. Think about this

If a stopped clock (by this I mean broken)is right two times every day
how many times is a working clock right

29. Originally Posted by Bad monkey
Think about this
If a stopped clock (by this I mean broken)is right two times every day
how many times is a working clock right
Depends on its boss. Most bosses told me I never did anything right, so I clocked them.

30. Such an unChristian thing to do, tsk, tsk.

31. Originally Posted by MeteorWayne
Such an unChristian thing to do, tsk, tsk.
It's unchristian to activate a stopwatch? Nowhere in the bible doth it saith "thou shalt not activate a stopwatch."

32. Originally Posted by kojax
Time is just the fourth dimension. It's just like the other three, except most objects change state as they pass/extend through it.
I don't agree. Time is not dimension. You can move in any of three dimensions, but cannot move in time.
Motion is an illusion created by our evolved tendency to value one of these dimensions over the others, and inability to see more than just a cross section of it at any moment. For a being able to see more than just the cross section, a human would look like a big snaking line that has a baby on one end and an old person on the other.
Motion (of sth) is not illusion. It's real. Any physical entity is in a constant motion and we can observe and experience it.
If they progressed through the "up/down" axis instead of the "past/future" axis,
The“past/future” axis does not exist in nature. It's simply Now.
then that snaking line would appear to be moving back and forth across the "up/down" axis. If, like us, they were only capable of traveling through their chosen dimension in one direction (changing states as they went, so they could only see one cross section at any moment), they would think we were violating the laws of physics by doing what we do.
It'snot clear. We can travel only in one direction (it does not exclude possibility of changing direction/s during the travel of course). That also means we cannot travel in time (neither to the past nor in the future).

33. Originally Posted by fizzlooney
Time is a concept of man
Fizzlooney is dead right, a few words say a lot to those who think from first principles.

Time isn't a fundamental component of reality, it is just a concept of man. It is used to attempt an explanation in layman's terms for observed changes to the world we see. 'Time' is just light and other stuff passing us by, and observed by the individual.

OK .. we can use this concept of time in a practical way, it's a rule of thumb, it isn't fundamental. All is relative. Your blue can be my red.

If I could move along with the light then would I effectively cease to exist to any static observer? I'm not a light emitter, and light wouldn't be reflecting off me, because it wouldn't be catching me up or racing away from me. If was a space traveller, maybe you wouldn't see me coming and you wouldn't see me going. I could be a finite mote, in an infinite stream of stuff heading your way.

34. Originally Posted by niebieskieucho
Originally Posted by theQuestIsNotOver
Time, like space, are words we use to identify quantitative entities calibrated most simply along linear singularities to "measure" reality. Space or time is not reality.
Time is reality when we refer it to matter (which is in constant motion). If measured, or as considered as measure of motion then it is not reality. Space belongs to physical reality otherwise would be illusion.
They are words for dimensions. It just so happens space is 3 dimensional,
Dimensionis a measure of spatial extent.
and time 1 dimensional.
Time/ motion / change does nor appear autonomously in nature in contrast to any material entities. If any form of matter travels in any of 3dimensions, that means it needs time to beat a distance and that is why time as a dimension does not exist.
"Reality" will never cease to amaze, inspire, and confuse, even those who think they understand it entire, yet in using "dimensions", "dimensio", Latin for "to measure", time most simply appears to be the way things "change" in space, seemingly to our perception in a undirectional fashion, like there;s no undoing what has been done, unless you know what you are doing and what you want (which is another discussion entirely).
Time(of sth) / motion (of sth) / change (of sth) does not need our perception. It exists, existed and will exist as long as matter is,was and will be.

Dimensio: Latin, "to measure".

Why make this a linguistics thread?

35. Originally Posted by foxbat
Originally Posted by fizzlooney
Time is a concept of man
Fizzlooney is dead right, a few words say a lot to those who think from first principles.

Time isn't a fundamental component of reality, it is just a concept of man.
How then do you answer the question posed by Speed Freak, in post 6 of this thread, where he asked, "so, without man, everything would happen simultaneously?"

36. Who's to say that time is (in certainty) an absolute, physical quality or a subjective, man-made concept? ...considering our very limited and fallible perception of the world.

The way I see it is like the 4th dimension idea.

We have three spatial dimensions, in which objects can change *form* over space (distance). A banana doesn't have the same shape throughout its entire length. But an object can't change shape in the same place because there is no time.

Time is an additional dimension, in which objects can change *form* over time, in the same place. A banana doesn't stay fresh and firm throughout its entire lifetime.

37. Originally Posted by niebieskieucho
Originally Posted by kojax
Time is just the fourth dimension. It's just like the other three, except most objects change state as they pass/extend through it.
I don't agree. Time is not dimension. You can move in any of three dimensions, but cannot move in time.
Think of the Earth in inertial motion around the Sun. Consider how much energy it would take to stop it and make it go backwards. Now imagine if the Earth were moving in a straight line with the same inertia. Since nobody had ever observed the Earth to move in any other direction, we might come to believe that this motion in this direction is a fundamental constant of nature.

What if our progress through time is similarly based on a kind of inertia, rather than a fundamental law? We move at a constant pace in a constant direction.

Motion is an illusion created by our evolved tendency to value one of these dimensions over the others, and inability to see more than just a cross section of it at any moment. For a being able to see more than just the cross section, a human would look like a big snaking line that has a baby on one end and an old person on the other.
Motion (of sth) is not illusion. It's real. Any physical entity is in a constant motion and we can observe and experience it.
True, but there's no guarantee that any two observers will perceive it the same.

then that snaking line would appear to be moving back and forth across the "up/down" axis. If, like us, they were only capable of traveling through their chosen dimension in one direction (changing states as they went, so they could only see one cross section at any moment), they would think we were violating the laws of physics by doing what we do.
It'snot clear. We can travel only in one direction (it does not exclude possibility of changing direction/s during the travel of course). That also means we cannot travel in time (neither to the past nor in the future).
You can travel to the future merely by cryogenicly freezing yourself. I know that's kind of cheating in a discussion like this one, but it's likely that time travel into the past would work in very much the same way. Instead of setting up your metabolic processes so that they come to a halt, you'd make them go backwards (with respect to the rest of the world), while you yourself continue to go forwards (by which I mean you still perceive yourself to be going forwards.)

More likely, all humanity will ever achieve is the ability to send messages back in time, rather than whole people. Sending a message to the future is unbelievably easy. Just write a letter and put it in a safe place to be opened later.

Originally Posted by Halliday
Originally Posted by foxbat
Originally Posted by fizzlooney
Time is a concept of man
Fizzlooney is dead right, a few words say a lot to those who think from first principles.

Time isn't a fundamental component of reality, it is just a concept of man.
How then do you answer the question posed by Speed Freak, in post 6 of this thread, where he asked, "so, without man, everything would happen simultaneously?"
A being that saw the Fourth dimension as merely being a dimension, rather than a progression, probably would perceive all events to be simultaneous.

The universe would be a beautiful 4 dimensional sculpture.

38. Any ideas on what that might look like, 3-d space held by 1-d time?

39. We already have 3 spatial dimensions, and many believe in a 4th temporal dimension.

In spatial one dimension, you can only move forward or back, it'slinear.

In spatial two dimensions, you can move forward, back, left, or right (thinking "flat"). Actually, these are only the main axial directions, you can move anywhere within 360 degrees.

Then there's 3 dimensions.

So if time acts in similar manner, then we should be living in linear, one-dimensional time. Considering we look at time as future (forward), past (backwards), and the present (point-location).

But I'm not sure of this, since we use square units of time for acceleration.

40. Originally Posted by sreeramavarmaraja
How can be time defined in the simplest way? According to my theory, time can be defined as 'change' in any form, any place in the universe. Any type of change in the real universe is called time. It can be changing of state, shape, size, color, temperature, force applied or the place etc.

So we can say that if there no change in the universe, there is no time in the universe. Because time is the 4th dimension, so if time is not there, the whole universe becomes 3 dimensional. Then the universe will stay like a paused video if there is no time. Can you prove it is not?
I think you have it concerning the simplest definition: In one word it is simply"change" or in two words it's "change and motion."

My simplest definition of time goes like this. Time is : an interval of change between two time frames. Its unit of measure is the second and its ruler is called a clock which is designed to be congruent with the rotation rate of the earth. A clock is used as a standard for comparison to measure the duration of an event or interval. Clocks come in versions such as sun dials, water clocks, sand clocks, pendulum clocks, spring winding clocks, light clocks, atomic clocks, etc. A "time frame" on the other hand does not involve time itself because to is an interval. Instead a time frame is a snapshot of an event/matter at a point within time where no change is involved.

Unfortunately today few physicists ascribe to a simple idea of time for a number of reasons. Sean Carrol in his book "From Eternity to Here" suggests that it might take as long as a century before we have enough information and understanding to formulate a valid theory of time. That's a very big difference between the simple definition and explanation embolden above. In my opinion in a hundred years the definition of time will be much closer to the above simple definition/explanation/understanding (if not exactly the same) than it will be to a book of complicated theory

41. i cant understood that most of the people say that there is no 4th dimension called time.
may there is no proof to travel in time but some peoples says is impossible like they are sure 100%
traveling on way trip to the future its kind of time travel.

42. Because the meaning of “time” varies depending on the context in which it is used, the question: “What is time?” is not legitimate if it presupposes that time is some kind of thing(See Pitcher on Wittgenstein’s philosophy). For example the “time” in the formula for speed is a standard motion used to measure motion: you compare the motion of one thing (a moving standard; a Swiss watch, a light beam) to the motion of some other moving thing. So in the case of speed, time measured is the motion of a single moving body relative to an observer used as a standard to which that observer can compare other motions relative to him/herself. Change, on the other hand, is a result of varying geometrical relations of all physical bodies that exist in the world.“Measured time” cannot embody that change—as Einstein’s SRT thought experiments showed [Thought experiments based on the “Sagnac Effect” can also show that change in the geometrical relations of all bodies cannot be measured by a single moving body (a tick tock, or the motion of an electromagnetic wave front)].So the idea that “time” could be defined in the “simplest way” seems to presume that there is a single thing to which one could point and say: “See? There isTime”. I think a better approach is to demand that anyone using the term “time”clarify what they mean in any given context, rather than leaving the listener to harbour unwanted meanings or guess what the author might mean by the term. Another alternative, one I find appealing (but unfortunately impractical because the word “time” is so entrenched, is such an integral part of so many day to day idioms) is to restrict or narrow the usage of the word so that it has a more ostensive definition: We could define “time” as all motion and use a different word for the measured time of physics or vice versa.

43. Originally Posted by Vexspits
Because the meaning of “time” varies depending on the context in which it is used, the question: “What is time?” is not legitimate if it presupposes that time is some kind of thing(See Pitcher on Wittgenstein’s philosophy). For example the “time” in the formula for speed is a standard motion used to measure motion: you compare the motion of one thing (a moving standard; a Swiss watch, a light beam) to the motion of some other moving thing. So in the case of speed, time measured is the motion of a single moving body relative to an observer used as a standard to which that observer can compare other motions relative to him/herself. Change, on the other hand, is a result of varying geometrical relations of all physical bodies that exist in the world.“Measured time” cannot embody that change—as Einstein’s SRT thought experiments showed [Thought experiments based on the “Sagnac Effect” can also show that change in the geometrical relations of all bodies cannot be measured by a single moving body (a tick tock, or the motion of an electromagnetic wave front)].So the idea that “time” could be defined in the “simplest way” seems to presume that there is a single thing to which one could point and say: “See? There is Time”. I think a better approach is to demand that anyone using the term “time”clarify what they mean in any given context, rather than leaving the listener to harbour unwanted meanings or guess what the author might mean by the term.Another alternative, one I find appealing (but unfortunately impractical because the word “time” is so entrenched, is such an integral part of so many day today idioms) is to restrict or narrow the usage of the word so that it has a more ostensive definition: We could define “time” as all motion and use a different word for the measured time of physics or vice versa.
Your idea makes sense. The sum of time in general could be defined as "relative motions," of matter and field, and a definition of "a time interval" could be very simple such as my definition above, or more/ very complicated as otherwise argued by physicists having differing opinions of it This might equate to defining space as the confined absence of matter, or space as a quantitative distance, area, or volume.

44. Time just "does", maybe that's why we just leave it alone?

45. too bad time does not leave us alone
but instead tortures us with its intrusive and constant molestation
yet we crave more
are we addicted to time
interrogative punctuation

46. Originally Posted by theQuestIsNotOver
Time just "does"
Or better said, time just IS. We have assigned space 3 dimensions.

Time seems to work, partially, in an analogous manner. Our time seems to be similar to the 1st spatial dimension, which is of lines.

Although we move forward as a point on the linear time model, we are very very limited in the sense we cannot at will move at a faster or slower pace. Nor can we pause time, or move backwards. Even less are we able to teleport from one point of time to another.

47. Originally Posted by archy
too bad time does not leave us alone
but instead tortures us with its intrusive and constant molestation
yet we crave more
are we addicted to time
interrogative punctuation
You really should keep this stuff out of the hard science fora. Or supply the salad dressing...

48. Time is the measurement that quantifies the transition periodbetween the occurrences of events. It can be used to identify the occurrence ofa specific event among the occurrence of other events. Time marks the distinctoccurrence of an event.
Time is a measurement that can be used to quantify thetransition period from one event to another. Time strings together all events inthe sequence of their occurrence; for an observation of time to be valid, thesequence of events must represent the sequence of their occurrence.
Time is the essence of existence. There is no beginning oftime; there is no end of time. There is only a continuous flow of time; frombeyond the beginning to beyond the end.
When an event occurs in time it is locked in the sequence ofits occurrence. It cannot take place before or after that point in time. It is maintained in its sequence ofoccurrence through eternity.
For an observation of a time related even to be true it mustbe held in its sequence of occurrence.

49. what
pray tell
is hard
about time
or salad dressing
interrogative
are we addicted to time or not
and if not why
are we always running out of it
like ants on crack
further interrogative

time is not hard at all
it oozes away
silently
sneakily
before you realize it it
has fled
utterly
like an octopus through
a drainpipe

50. Originally Posted by theQuestIsNotOver
Any ideas on what that might look like, 3-d space held by 1-d time?
Imagine what 3d space would look like to a two dimensional being (like Pac Man in the Pac Man video game), and then work from there.

Suppose Pac Man progresses through "time" by moving "upward" at a constant speed into a third dimension. Every 2 cm he moves upward is 2 seconds of time in the game. The map of all his positions if he sat still would look like a straight bar rising out of the TV screen. If he moves around, the map of his positions would look like a curving bar rising out of the screen. The speed he's moving at would determine how flat the angle of that bar was relative to the screen.

Special Relativity basically tells us that there's a minimum angle. The bar can never be totally flat to the screen (because that would mean he was moving at infinite speed.)

51. archy
most
annoying
poster
on
forum
with
bad
poetry
signifying
nothing

52. Originally Posted by sreeramavarmaraja
How can be time defined in the simplest way? According to my theory, time can be defined as 'change' in any form, any place in the universe. Any type of change in the real universe is called time. It can be changing of state, shape, size, color, temperature, force applied or the place etc.

So we can say that if there no change in the universe, there is no time in the universe. Because time is the 4th dimension, so if time is not there, the whole universe becomes 3 dimensional. Then the universe will stay like a paused video if there is no time. Can you prove it is not?
I would rather say 'Time' is a functional entity that measures interval between two events. It is always measured in relation to motion with respect to motion of a reference body. 'Time' is not a (physical) real entity and it has no real existence. Changes of state, shape, size, color, temperature, force applied or the place etc. are results produced by relative motion of fundamental/primary particles of a body. Without motion (in the universe), there will be no 'time' (in the universe). In fact 'time' is not present in the universe, but in the minds of rational beings.
'Time' is not a spatial dimension. Universe always (in our present concept) remain three-spatial dimensional. 'Time' is used as an additional dimension (not spatial) to indicate interval between two events.

53. Thank you for your colorful feedback.
Time is misused because of a missing universal comprehension of the essence of time. It plagued Einstein and led to his misguided attempt to relate it to space. I would like to improve the situation with the clarity of truth.
I hope you enjoyed my hypothesis, it was intended to stimulate or understanding with the clarity of truth.

54. Originally Posted by Jack1941
Thank you for your colorful feedback.
Time is misused because of a missing universal comprehension of the essence of time. It plagued Einstein and led to his misguided attempt to relate it to space. I would like to improve the situation with the clarity of truth.
I hope you enjoyed my hypothesis, it was intended to stimulate or understanding with the clarity of truth.
I'm not sure what you mean by "colorful feedback".
I don't agree with your statement that Einstein was "misguided".
I find it difficult to understand how you have improved "the situation with the clarity of truth".

55. Originally Posted by Jack1941
.......Time is misused because of a missing universal comprehension of the essence of time. It plagued Einstein and led to his misguided attempt to relate it to space..............
Space-time is in essence a very simple and necessary concept which is needed for any mathematical on-going explanation of a point in space anywhere. Example: When describing a point in intergalactic space, for instance, you might wish to set up a Cartesian coordinate system X,Y, and Z. You may wish to have the zero point of your coordinate system based upon the observable centers of three surrounding galaxies that are close to being on the same plane. But what is the meaning of this calculated point, will it always remain in the same position? You might realize that there is no such thing as such a stationary point since the three galaxies are all moving relative to each other, and that all three are moving relative to a background of much more distant galaxies. So you add time into the equation as "T." Now you can calculate the relative position of your zero point and its changing position over time relative to your chosen galaxies.

Therefore spacetime can simply equate to a point in space at a particular point in time, and nothing more. The collective of all points in space at a given point in time can also be called spacetime. The concept of Spacetime is independent of Einstein's work. It was developed by Minkowski many years before Einstein, based upon his realization of its need. For the concept of spacetime to also provide for the concept of "warp" one needs additional but totally separate factors and equations added to the simple spacetime concept. Einstein made this addendum when formulating General Relativity by using the Ricci tensor to mathematically explain his concept concerning the warpage of space. The collection of all points in space at any point in time when referring to Einstein's inclusion of his warpage equations, can also be called Spacetime. This concept of spacetime may be the most common use of the word, but it is also the most complicated concept of it. Is this concept of spacetime warping valid? Time will tell

Is spacetime something real by itself? It is no more real than space or time separately. Both distances in space and time relate to a relative and quantitative interval involving a mental perspective. By paraphrasing a Einstein statement into a question I think the correct answer to this question can be best understood. The question is: What would be the meaning of space, time, and gravity in the total absence of matter? His actual quote was "Time and space and gravitation have no separate existence from matter." This was his one sentence summation of his theory of General Relativity.

56. Originally Posted by Jack1941
Time is the measurement that quantifies the transition periodbetween the occurrences of events.
I think your definition makes sense until "transition period between the occurrences of events". Before you measure the period between the occurrences of the events, by what do the events occur in the first place? As niebieskieucho said, it's difficult to define time without already implying time in the definition. For your idea to work, there first has to be something by which one would differentiate two events in order to measure in between them. The events have to first exist within some abstraction.

57. Maybe we're all misguided in trying to define time? It seems to me to be one of those self-defining concepts, in which we could only use synonyms. Maybe fundamental and irreducible?

58. Originally Posted by brody
Originally Posted by Jack1941
Time is the measurement that quantifies the transition period between the occurrences of events.
I think your definition makes sense until "transition period between the occurrences of events". Before you measure the period between the occurrences of the events, by what do the events occur in the first place? As niebieskieucho said, it's difficult to define time without already implying time in the definition. For your idea to work, there first has to be something by which one would differentiate two events in order to measure in between them. The events have to first exist within some abstraction.
The determination of time is measured by a counting mechanism called a clock. What we attribute the passage of time to are changes which can be attributed to matter, or the speed of light. The primary foundation particles for matter which determines the elements are protons. Protons have an internal clock that counts the passage of time for a proton in any time frame. So one could say: time and its unit of measure the second, could be ultimately understood and defined as a function of proton spin in any examined location. Since we have not developed an ongoing counting mechanism for the revolutions that a single or group of protons make (that I know of), 10^23 revolutions per second, we instead use the atomic spin as it relates to emissions by cesium atoms which is a function of nuclear spin, which is a function of proton spin. Proton spin progresses at a constant rate when matter is stationary, and also a constant but different rate when matter is maintaining a constant velocity within a gravitational field.

Optical clocks are the latest thing in the accuracy of time. They are based upon laser light concerning emission and absorption rates of matter.

http://physicsworld.com/cws/article/news/41696

Light clocks have been made based upon the speed of light but so far it seems that they cannot match the accuracy of atomic clocks.

https://www.google.com/search?q=ligh...iw=911&bih=399

59. If time were not a real dimension we wouldn't be able to travel in it. Some theories say we can travel in it. Therefore time is more than measurement.

60. Originally Posted by Aristarchus in Exile
If time were not a real dimension we wouldn't be able to travel in it. Some theories say we can travel in it. Therefore time is more than measurement.
Of course time is more than measurement. Just like the length of something is different form its measurement by using a ruler. Time can be easily understood as the duration of an event we are observing, such as the time it took for us to drive somewhere, three o'clock PM -- the time since the beginning of the day. The concept of time is very simple to understand I believe, and it is separate from our measurement of it. For us on Earth it is the progression of change in the world that can be measured. All those claiming something more complicated I think will someday be edified concerning time's very simple nature. Yes time dilation is a little more complicated but think that it too can still be explained and readily understood by most in secondary school.

61. Perhaps one could define Time as the distance between two objects?

62. Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
I think you will find that is "space".

63. Originally Posted by Strange
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
I think you will find that is "space".
Ha, well that certainly is true, would like to humour me though? It certainly is a moot point I am making, but I think it's relatively interesting.

I agree distance implies a physical measurement between two objects, but is time not something that is physically measurable, both in its length and in its effects? Take into consideration that the person you are today won't be the exact same person you are tomorrow, maybe not mentally or in your own concept of yourself - but physically you will be different (even if minute). Does that not mean that tomorrow you will be a different object? If time is a medium that is travelled, and if the destination travelled to is always different does that not mean there is a distance?

64. Originally Posted by stander-j
I agree distance implies a physical measurement between two objects, but is time not something that is physically measurable, both in its length and in its effects?
Well, time can be measured, that much is true. But, of course, it is (potentially) measured differently by everyone depending on speed, acceleration, gravity, etc.

Does that not mean that tomorrow you will be a different object?
I have always thought that the Trigger's Broom "paradox" is one of those fairly empty and unproductive philosophical questions.

65. Originally Posted by forrest noble
time and its unit of measure the second, could be ultimately understood and defined as a function of proton spin in any examined location.
Is that to say that time is a product of proton spin? And without the property of spin, time would cease to exist?

I agree that it can be accurately measured by such, but not that time is directly caused by the such.

66. Originally Posted by brody
Originally Posted by forrest noble
time and its unit of measure the second, could be ultimately understood and defined as a function of proton spin in any examined location.
Is that to say that time is a product of proton spin? And without the property of spin, time would cease to exist?

I agree that it can be accurately measured by such, but not that time is directly caused by the such.
The interpretation that time is solely change/ motion and nothing more, is well accepted by many such as myself. That all changes ultimately are a function of particle spin is solely a hypothesis that I adhere to, but according to the standard model all the so called "forces of nature" also motivate change and would accordingly be most of the combined causes of it.

To think of proton spin as defining time I believe is a simple but valid understanding of it since accordingly the spin correlates with the tick of a clock, and dilates in the same way for the same reasons.

Is that to say that time is a product of proton spin? And without the property of spin, time would cease to exist?
Without particle spin atomic matter of any kind and the visible cosmos including ourselves, would probably not exist since spin/ angular momentum is an integral quality of fermions.

67. Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
Not in non-locality.

68. Originally Posted by Aristarchus in Exile
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
Not in non-locality.
Hmm, I'm not too versed in the Quantum world, or the scientific world for that matter.. Would that be along the lines of Entanglement?

69. Time is...when your alarm clock goes off in the morning !!

70. Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
Or perhaps one could define time as the distance between two events?

71. Originally Posted by stander-j
Originally Posted by Strange
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
I think you will find that is "space".
Ha, well that certainly is true, would like to humour me though? It certainly is a moot point I am making, but I think it's relatively interesting.

I agree distance implies a physical measurement between two objects, but is time not something that is physically measurable, both in its length and in its effects? Take into consideration that the person you are today won't be the exact same person you are tomorrow, maybe not mentally or in your own concept of yourself - but physically you will be different (even if minute). Does that not mean that tomorrow you will be a different object? If time is a medium that is travelled, and if the destination travelled to is always different does that not mean there is a distance?
It is wrong to assume that the term “measurement” means the same or has the same sense regardless of the methods by which one measures. What does “length” mean when one measures distance? What does “length” mean when one measures time? Similarly, does “traveling” a distance have the same sense as “traveling” through time? The gramatical similarities are misleading. Consider the following proposition: “Motion needs (or requires) time”, and “A running engine needs (or requires) fuel.” Does the verb “to need” signify a genuine dependency between the subject nouns and the predicate nouns in both propositions? I think not!

Different “times” are more a matter of differences rather than distances.

72. Originally Posted by Vexspits
Originally Posted by stander-j
Originally Posted by Strange
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
I think you will find that is "space".
Ha, well that certainly is true, would like to humour me though? It certainly is a moot point I am making, but I think it's relatively interesting.

I agree distance implies a physical measurement between two objects, but is time not something that is physically measurable, both in its length and in its effects? Take into consideration that the person you are today won't be the exact same person you are tomorrow, maybe not mentally or in your own concept of yourself - but physically you will be different (even if minute). Does that not mean that tomorrow you will be a different object? If time is a medium that is travelled, and if the destination travelled to is always different does that not mean there is a distance?
It is wrong to assume that the term “measurement” means the same or has the same sense regardless of the methods by which one measures. What does “length” mean when one measures distance? What does “length” mean when one measures time? Similarly, does “traveling” a distance have the same sense as “traveling” through time? The gramatical similarities are misleading. Consider the following proposition: “Motion needs (or requires) time”, and “A running engine needs (or requires) fuel.” Does the verb “to need” signify a genuine dependency between the subject nouns and the predicate nouns in both propositions? I think not!

Different “times” are more a matter of differences rather than distances.
See, that's where I would disagree. By suggesting that they are not the same, you would suggest there is a visible difference between a physically travelled distance, and a distance travelled through time. This however is not the case: An engine that burns fuel is travelling towards becoming an engine that can no longer run. The engine it will become, the engine that is out of fuel, no longer had the same use, and therefore time is the distance in between these two differentiating uses, and therefore differentiating objects. When I say distance I am not referring to what we would consider a tangible measurement. I am referring to a distance that we can understand, but cannot see (this would also stress that we do not understand time - we only understand the notion of it).

73. Time is abstract, but not that abstract. It's tangibly measured by temporal units on a varying scale, as there are units of spatial distance, there are seconds, minutes... etc. And because of time's very essence, of course we cannot measure it physically, as in stretching out a tape measurer. And a linear time model of an arrow serves as the representation of "distances" between occurences.

74. Originally Posted by brody
And because of time's very essence, of course we cannot measure it physically, as in stretching out a tape measurer.
And yet we can measure it to amazing accuracy.

And a linear time model of an arrow serves as the representation of "distances" between occurences.
Except those "distances" (and even the ordering) depend on who measures them. So your "linear arrow" is flexible and can point in either direction!

75. Originally Posted by stander-j
Originally Posted by Aristarchus in Exile
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
Not in non-locality.
Hmm, I'm not too versed in the Quantum world, or the scientific world for that matter.. Would that be along the lines of Entanglement?
Yes. In non-locality/entanglement time and space seem eliminated .. either that or there is one universal time, the infinite now where if something happens 'now' here it also happens 'now' 1 zillion googolplex light years away.

76. Hm, I personally think that a lot of these attempts at redefining "time" make things more complicated than they need to be. In my humble opinion the geometrical definition of time as being an oriented coordinate in a manifold appears to be easiest and most intuitive ( maths aside for the moment ). I can picture space and time as a stretched fabric; I can bend and twist the fabric, add masses to it, and immediately visualize what happens. It seems really intuitive...but maybe that's just me

77. Originally Posted by Aristarchus in Exile
Originally Posted by stander-j
Originally Posted by Aristarchus in Exile
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
Not in non-locality.
Hmm, I'm not too versed in the Quantum world, or the scientific world for that matter.. Would that be along the lines of Entanglement?
Yes. In non-locality/entanglement time and space seem eliminated .. either that or there is one universal time, the infinite now where if something happens 'now' here it also happens 'now' 1 zillion googolplex light years away.
I have a pretty big question about Wave Function Collapse, which I'll make a thread for eventually. For the time being however, I don't think I can defend my posed definition against non-locality. Well I somewhat can, but the only way I would be able to is to suggest that particles being entangled would have to be looked at in the way that they are now the same object - just on different sides of the spectrum (if they were to be opposing in nature). Therefore being affected instantaneously is subject to those two particles being one and the same when entangled. Now, what is the cause for one of the particles being disturbed? Surely that must've been in the mail, so the point where the particle flips is the point of becoming a new object - and time is then seen as the distance between when a particle is disturbed and when a particle is not.

78. Originally Posted by Markus Hanke
Hm, I personally think that a lot of these attempts at redefining "time" make things more complicated than they need to be. In my humble opinion the geometrical definition of time as being an oriented coordinate in a manifold appears to be easiest and most intuitive ( maths aside for the moment ). I can picture space and time as a stretched fabric; I can bend and twist the fabric, add masses to it, and immediately visualize what happens. It seems really intuitive...but maybe that's just me
I think you're seeing it fairly well .. if spacetime can be bent and twisted it can be circled (Mobeus twist?) .. so that the end is the beginning .. (non-locality?)

79. Originally Posted by Aristarchus in Exile
Originally Posted by Markus Hanke
Hm, I personally think that a lot of these attempts at redefining "time" make things more complicated than they need to be. In my humble opinion the geometrical definition of time as being an oriented coordinate in a manifold appears to be easiest and most intuitive ( maths aside for the moment ). I can picture space and time as a stretched fabric; I can bend and twist the fabric, add masses to it, and immediately visualize what happens. It seems really intuitive...but maybe that's just me
I think you're seeing it fairly well .. if spacetime can be bent and twisted it can be circled (Mobeus twist?) .. so that the end is the beginning .. (non-locality?)
Yes, in theory at least this is indeed possible - it's called a closed time-like curve, and is permissible in certain solutions of the GR field equations :

Closed timelike curve - Wikipedia, the free encyclopedia
http://en.wikipedia.org/wiki/Kerr-Newman_metric

Unlike the Moebius strip, a closed time-like curve should be orientable, though. Whether such curves are physically possible or not remains to be seen. Remember, only because they are mathematically compatible with the field equations does not necessarily mean they are physically possible.

You are actually raising some interesting points for further thought - can the Moebius strip be generalized into higher dimensions ( the Klein Bottle immediately comes to mind here ), and if so, would such a manifold be a valid solution of the Einstein equations ? I don't have an immediate answer to this, but it's certainly an interesting question.

80. Originally Posted by SpeedFreek
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
Or perhaps one could define time as the distance between two events?
Events works too, I'd actually say that works better. I intended 'objects' to mean anything that is relative to change through time.

81. Originally Posted by fizzlooney
Time is a concept of man
Yes indeed. We invented this quantitative concept to describe durations.

Ludwik Kowalski (see wikipedia)

82. Originally Posted by stander-j
Originally Posted by Vexspits
Originally Posted by stander-j
Originally Posted by Strange
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
I think you will find that is "space".
Ha, well that certainly is true, would like to humour me though? It certainly is a moot point I am making, but I think it's relatively interesting.

I agree distance implies a physical measurement between two objects, but is time not something that is physically measurable, both in its length and in its effects? Take into consideration that the person you are today won't be the exact same person you are tomorrow, maybe not mentally or in your own concept of yourself - but physically you will be different (even if minute). Does that not mean that tomorrow you will be a different object? If time is a medium that is travelled, and if the destination travelled to is always different does that not mean there is a distance?
It is wrong to assume that the term “measurement” means the same or has the same sense regardless of the methods by which one measures. What does “length” mean when one measures distance? What does “length” mean when one measures time? Similarly, does “traveling” a distance have the same sense as “traveling” through time? The gramatical similarities are misleading. Consider the following proposition: “Motion needs (or requires) time”, and “A running engine needs (or requires) fuel.” Does the verb “to need” signify a genuine dependency between the subject nouns and the predicate nouns in both propositions? I think not!

Different “times” are more a matter of differences rather than distances.
See, that's where I would disagree. By suggesting that they are not the same, you would suggest there is a visible difference between a physically travelled distance, and a distance travelled through time. This however is not the case: An engine that burns fuel is travelling towards becoming an engine that can no longer run. The engine it will become, the engine that is out of fuel, no longer had the same use, and therefore time is the distance in between these two differentiating uses, and therefore differentiating objects. When I say distance I am not referring to what we would consider a tangible measurement. I am referring to a distance that we can understand, but cannot see (this would also stress that we do not understand time - we only understand the notion of it).
Contrary to the opening sentence of your reply, clearly you do agree that the analogs borrowed from the language of space (namely the words “length”, “distance”, and “travel”) have a different sense when used with respect to time. You even went on to give examples of how you use those words and what you mean by them in that context, explaining in the end that by“distance” you are not “referring to what we would consider a tangible measurement” (as opposed to the visible distance between two events). Good! So essentially we are on the same page—I’m hoping you are at least willing to consider the possibility that we are.

Now, there is nothing wrong with choosing to say that a running generator in a shed out in my backyard is “travelling towards” being a generator that will not be running when it no longer has fuel; or that there is a “distance” between the engine when it is running and when it no longer is. But to what end should we apply this rather “forced” usage? It seems to me to be a fruitless endeavour. How does it help clarify our thoughts vis a vis the concept of time? In my opinion it only further mystifies instead of providing us with any explanatory power. Such an approach is more likely to lead us to resign, to say things like: “…we do not understand time—we only understand the notion of it.”

83. Originally Posted by SpeedFreek
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
Or perhaps one could define time as the distance between two events?
Two events in time. As one could equally likely see it spatially as two events (in terms of place) e.g. the national parade happened 62 miles away from the big earthquake. It's obvious what you meant and that you knew it but I just wanted to point that out :P

84. Originally Posted by brody
Originally Posted by SpeedFreek
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
Or perhaps one could define time as the distance between two events?
Two events in time. As one could equally likely see it spatially as two events (in terms of place) e.g. the national parade happened 62 miles away from the big earthquake. It's obvious what you meant and that you knew it but I just wanted to point that out :P
An event is always 4-dimensional - it has a spatial and a temporal component. The national parade took place in Dallas, Texas ( spatial ) on Jan 1 at 8am ( temporal ). You need both pieces of information to exactly pinpoint the event. Two events can therefore be separated spatially ( in miles ), temporally ( minutes, hours, days,... ), or both.
This, btw, brings us back to the geometrical definition of time which I first proposed to be useful in post 20.

85. Originally Posted by Markus Hanke
Originally Posted by brody
Originally Posted by SpeedFreek
Originally Posted by stander-j
Perhaps one could define Time as the distance between two objects?
Or perhaps one could define time as the distance between two events?
Two events in time. As one could equally likely see it spatially as two events (in terms of place) e.g. the national parade happened 62 miles away from the big earthquake. It's obvious what you meant and that you knew it but I just wanted to point that out :P
An event is always 4-dimensional - it has a spatial and a temporal component. The national parade took place in Dallas, Texas ( spatial ) on Jan 1 at 8am ( temporal ). You need both pieces of information to exactly pinpoint the event. Two events can therefore be separated spatially ( in miles ), temporally ( minutes, hours, days,... ), or both.
This, btw, brings us back to the geometrical definition of time which I first proposed to be useful in post 20.
I agree. Though I was treating the temporal and spatial part separately, time does, in a way, cooperates with space to make our universe work. And as such location and time are both used for events. Thanks for pointing that out.

86. Instead of trying to define what time is, its often easiest just to agree on a way to measure it. Find something in nature with a constant periodic motion, get everyone to build a device with the same periodicity. That way, one can just start counting out the number of periods that happen between any two events and define time to be the measure of the number of periods that this device goes through between the two events. We are fortunate to be able to find what we believe to be a perfectly constant periodicity in nature, the vibration of certain crystals appears to be exactly regular for example. Taken right from wiki, the second is defined to be "the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom".

To say that time is an invention of man is silly. Sure, we have the freedom to choose the period we use to measure time in i.e. the units (seconds,days, ect.), and in that sense we have invented a means of measuring time, but as pointed out above, everything isn't happening at once, there is certainly some notion of time that we are observing.

For a more formal definition of time some pretty interesting maths is involved.

87. Originally Posted by TheObserver
For a more formal definition of time some pretty interesting maths is involved.
Then show us this "interesting maths". We are all grown-ups here (well mostly), so we can take it.

88. I'm not really there yet but I'm pretty sure they do it with differential geometry and some other crazy stuff. We were studying manifolds in my analysis class and my prof was talking about it very briefly.

89. Originally Posted by TheObserver
I'm not really there yet but I'm pretty sure they do it with differential geometry and some other crazy stuff. We were studying manifolds in my analysis class and my prof was talking about it very briefly.
For a given connected manifold with metric g we define

thus

and therefore

which defines the "distance in time" between two arbitrary events A and B.
This ought to do the trick, no ?

90. The measurement and comparison of relative rates of change

91. Measuring events is at this point the only sure thing about time, whether it even exists or not, unless you happen to believe certain time-honoured spiritual writings which say time does exist. The best brains of science are divided as to whether time is a reality or a measurement.
Personally, I see time created in the vortex of spiral galaxy spin. But that's just one aspect.

92. Time is that which drives forward all processes and therefore all change.

A clock is a process that includes a periodic subprocess, whose periods the clock counts in some way. Thus, a clock does not directly measure time; it counts periods. A clock, being a process, is driven forward by Time. Time is common to all clocks just as it is common to all processes.

The identification of Time with the "local time" as indicated by clocks is, philosophically, an unfortunate mistake introduced during the development of relativity theory. It is clearer to think of different "local times" as reflecting differences in the rate at which local processes proceed, such differences being caused by differences in velocity and gravitational potential.

93. Here's my two cents worth: Time is money and a one-way street.

94. Time is that which drives forward all processes and therefore all change.

A clock is a process that includes a periodic subprocess, whose periods the clock counts in some way. Thus, a clock does not directly measure time; it counts periods. A clock, being a process, is driven forward by Time. Time is common to all clocks just as it is common to all processes.
Maybe the problem is in applying time universally as a fixed, absolute continuum. Are you seeing it's not ubiquitous? Unless it is truly subjective, and each perspective holds its own scale of time. Then there's really multiple fixed, absolute continua. I'm confused...

95. The instant there is a change anywhere in the cosmos, the status of the cosmos is redefined. Things in contact with the change are now being influenced by a different set of circumstances which, in turn (ad infinitum), alters their influence on thngs more distant from the impetus. The status of the cosmos changes instantly, but it takes time for the reaction to that change to propagate. Some define time in terms of the perception/propagation (relative time) and some define time in terms of the immediate status of the cosmos (absolute time).

Space exists. It is an existence. Time is a measurement of change of condition of existence(s). While the condition of space may influence the rate at which things change, it is my opinion that space-time as defined by the conventional wisdom is neither a field nor a fabric, it is a mathematical shortcut that facilitates the encoding of terms into equations.

96. i don't see the point of this thread really.
i think it's pretty well proven, that some things happened before others. or that things always happen in a certain order.
so all we did was, defining that, to a lvl everyone agrees on.
i.e a year (the time it takes to orbit the sun) is actually 365 and 1/4 days, so to simplify stuff we added feb 29th every 4 years.

we, as the observers, just needed a measurement to pinpoint different events, and did this by using what we observed.

so simple answer, time exists.

97. Originally Posted by scottaleger
Time is a separator who divide the moments in three things PAST, PERSENT and FUTURE
Yes, but whose past, present and future?

98. Time is a separator who divide the moments in three things PAST, PERSENT and FUTURE.

That,s a notion with present as a running time coordinate. Present as a word adresses this coordinate. Present on itself has no time then, no duration (just as a coordinate x cm on a ruler has not x cm length). The word present is often used though in a way where it does have time involved.

Present year, day, hour, second all have duration where a coordinate hasn,t got that.
Present day also has different coordinate for past then present year. There can be an overlap.

Present just like that has no real meaning except for this notion of time but that notion is just an aspect. Only that aspect past is not real, present is a cordinate and has no time involved and future is yet to come....so no time, just an aspect of it.

99. Originally Posted by sreeramavarmaraja
How can be time defined in the simplest way? According to my theory, time can be defined as 'change' in any form, any place in the universe. Any type of change in the real universe is called time. It can be changing of state, shape, size, color, temperature, force applied or the place etc.

So we can say that if there no change in the universe, there is no time in the universe. Because time is the 4th dimension, so if time is not there, the whole universe becomes 3 dimensional. Then the universe will stay like a paused video if there is no time. Can you prove it is not?
The most simplest definition of time I know from my studies over the years, is in terms of geometric time and fundamental time. Geometric time is the emergence of matter and fundamental time does not exist... actually, there are a number of definitions valid today in QM, keep in mind, Newtonian time does not hold; his was a vision where time flows. In GR, there is no time essentially on a global scale (the scales we attribute to the system we call the ''universe'') governed by a state vector which in principle can describe all the dynamics of the universe. In fact, I read a paper recently suggesting that it is mathematically possible to describe the state vector wave function of the universe even with an incomplete knowledge of that probability field. Anyway, this state vector when acting on the Hamiltonian Operator of the Universe amounts to a vanishing time derivative, so in this sense, one can define time as not really real.

Then of course, there is the definition of present time. Afterall, the past and future do not exist ''now'', here in our bubble of the present frame of time. The time that always ever exists is the present time

In short, I don't really think there is any easy definition of time. It's an issue itself unresolved.

100. Originally Posted by Geometrogenesis
The most simplest definition of time I know from my studies over the years, is in terms of geometric time and fundamental time.
Well, I assume that "geometric time" as a concept arises when time is treated as a coordinate function on an manifold. But I have no idea what is meant by "fundamental time"
Geometric time is the emergence of matter and fundamental time does not exist
Neither can I make any sense of this assertion.
In GR, there is no time essentially on a global scale
What does this mean?
governed by a state vector
You are using a notation for a state (or any other) vector that is highly non-standard and thus misleading at best, and wrong at second best
Anyway, this state vector when acting on the Hamiltonian Operator
WHAT?? Operators act on vectors, and NEVER the other way around

I couldn't bear to read any more

101. Originally Posted by Geometrogenesis
The most simplest definition of time I know from my studies over the years, is in terms of geometric time and fundamental time. Geometric time is the emergence of matter and fundamental time does not exist... actually, there are a number of definitions valid today in QM, keep in mind, Newtonian time does not hold; his was a vision where time flows. In GR, there is no time essentially on a global scale (the scales we attribute to the system we call the ''universe'') governed by a state vector which in principle can describe all the dynamics of the universe. In fact, I read a paper recently suggesting that it is mathematically possible to describe the state vector wave function of the universe even with an incomplete knowledge of that probability field. Anyway, this state vector when acting on the Hamiltonian Operator of the Universe amounts to a vanishing time derivative, so in this sense, one can define time as not really real.

Then of course, there is the definition of present time. Afterall, the past and future do not exist ''now'', here in our bubble of the present frame of time. The time that always ever exists is the present time

In short, I don't really think there is any easy definition of time. It's an issue itself unresolved.
Look, don't be offended, but for some reason it is very hard to figure out what you are actually saying. I think you are using math notation and terminology in a non-standard way, making it really hard to follow you. Then there are some things which are just plain wrong ( as Guitarist has pointed out ).
As for the time issue, there is such a notion as global time in GR as defined by the global FLRW metric, it just doesn't necessarily agree with local time measurements.

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