Defining Time: Our Everyday Mystery

[jeebs]

I recently realized that we use this concept constantly but I have absolutely no idea how I would answer this. Never in any school physics lesson or university lecture I've attended has anyone even mentioned this. It's just sort of taken for granted because we all have experience of it passing. This a pretty open ended question, just thought I'd throw it out there. So, how would you define this quantity we call time?

 

[Edi]

Tim is change/ movement. If there is no movement/ change in a system (and I mean at the deepest possible level), then practically, there is no time flowing. And it works backwards - no time= no change/ movement.
Jap.. this is the best I have :P

And yes - this is a very good and fundamental question that is bugging me for some time now..

 

[pallidin]

I would agree. "Time" is just a concept that involves "change"
Without change there can be no time.

However, one has to be a little careful with this.
That is, just because something may not change internally does not mean that it doesn't change with respect to its external environment.
Movement of an internally, non-changing object through space is an example.

In short, "time" is a measurement of change, specific on perspective frame.

 

[jeebs]

that's kind of unsatisfying I think. I mean, we could be sat in an enclosed room with no windows just staring at a wall, and be unable to detect any movement of anything, but we'd have no reason to suppose that time had stopped just because we couldn't see any of its effects. we could assume the world outside was still going about its business. am I missing the point here?

 

[khemist]

You see the effect of time because you are still living. The fact your heart is beating is an indicator of time.

Time is obviously relative, however, and people might not agree on the simultaneity of a specific event.

 

[bp_psy]

My favorite textbook definition for time is :"If the internal state of a particle or a localized object is changing, its successive states define a continuum,which we call the time of that particle"
Classical Mechanics, Volume 1 A. Desloge

Whether that is enough for you is another issue.

 

[Arsenic&Lace]

"Time is what happens when nothing else does." --Feynman Lectures

 

[James A. Putnam]

The difficulty with time, I think, has to do with perception. We receive data from photons that consist of changes of velocity with respect to time. Moving down theoretically, it means that changes of distance with respect to time are not constant, they vary. I know that you know this. My point is that if we return to considering the data, and, recognize that we use it to form a visualization of what may be happening in the outside world, then visualizing distance and not visualizing time is a matter of interpretation. Time is not less real than is distance. Distance does not gain credibility leaving time to be an effect just because one is visualized and the other is not. (Gravity is not visualized either).

The cause of changes in distance are not known. The cause of time is not known. That is because, we do not know what cause is. Theoretical physics is necessary in order to substitute imagined causes for that which we cannot know. We can imagine something that we choose to generically call force to account for changes of position of an object; but, we cannot imagine something that causes time to move on. Force causes acceleration; but, that same imagined cause cannot cause time to accelerate. It is rather inferred from theory. Inferring is not satisfactory for explaing what time is. So, without an obvious clear answer, it is sometimes put forward that the motion of objects causes time. In other words, time is an effect.

Relativity theory seems to support this idea, so, it continues to be put forward. My point to this is that everything we observe is an effect. We never observe cause. Therefore, that which we observe objects to do may relate to time, but, cannot be shown to be the cause of time. The 't' in physics equations is always about a non-constant standard of cyclic activity. When that 't' varies it does not tell us what time is doing, it tells us what that cyclic activity is doing. If we discovered a measure of duration in time that was constant everywhere, at all time, in the universe, then we would know that time is not an effect of motion. However, that discovery would also necessitate doing away with Relativity Theory alltogether. Perhaps the most interesting possibility of an existing natural constant standard of time is that as a universal constant it should already appear in today's theories. Its interpretation may be incorrect; but, it should be already recognized by us under a different name.

Everything we learn comes from observing patterns in changes of velocity. There are two clearly fundamental properties that we cannot put into containers. We cannot isolate them in order to experiment on them. Neither one experiences changes of velocity. Those two properties are space and time. Since we cannot push or pull either of them, we cannot make measurements of rates of change for either. We only experiment on objects. We only know what it is that objects do. Objects are always things that exist in space and during time. Objects cause other objects to change that which they were doing. Objects causing effects that we observe to occur to other objects do not tell us about either space or time.

James

 

[PhysDrew]

The simplest of question yet one of the most elusive!
Wasn't the question of time's uni-directionality one of the causes for physicist's to attempt to formulate a theory of everything? For in order to examine the nature of time, one must go back to the beginning. And once physicists mathematically examined the beginning with the two main theories of the time, the maths turned out to be nonsense.
And i don't think that the implication that if an entity is living, time is passing. A virus is considered 'dead' outside of a host. Surely time doesn't stop for the virus? How would it's metabolism kick in once it found its way into a host? How would it know, if time ceased for the virus?

 

[71STARS]

Time is a measure of our Planet's 24 hour segment. Other planets and star system will naturally differ. We have even calculated light-years based on our conception of the Speed of Light, but it may differ within other systems. Bottom Line: Time is a measure.

 

[Oldfart]

I think of time as a sort of ether which is repelleded by mass, energy. and by objects moving through space. Thus it might be a particle, and maybe is represented by what we call dark energy. Figuring this out is way outside my pay grade...

OF

 

[Pilot7]

The question is the deepest (physical) question I know. I spend several years on this one (basically as the guiding question of a masters and then PhD thesis in philosophy and the philosophy of physics).

Here is my favourite answer:

Time is God's way of keeping everything from happening at once...

Okay, and a little more explicative:

Time in physics actually has somewhere on the order of 14 flavours. For example in quantum physics, there are at least 10 different and even inconsistent definitions of time. Relativity theory, Quantum Gravity, etc. all do weird things with time. Coming back to classical physics, even here it has several variants. There is time the measure used in a laboratory and time the theoretical metric used to describe the evolution of classical systems. And there are some ways it has been used to talk about entropy and even be defined in terms of entropy (thinking to Prigagine for example).

On thing in all of this to keep in mind. All notions of “flow” are strictly non-physical. In fact, this sort of “time” has been traditionally called “psychological time”. Now what I will add is that if you think this through, you will see that there is still a pretty serious mystery behind all this: What is flow? This was the question I was addressing in the context of my graduate work—very subtle stuff. There is not theory in physics that even hints at what this could conceivably be, with the possible exception of certain variations of quantum gravity that treat the wave collapse as a genuinely “real” or ontological phenomenon. Even then, it requires something of a conceptual dance to tease out the semantic features that would make flow flow (pun intended).

If anyone is interested, write me and I will forward a copy of one of my papers that has a fair amount of background of all this stuff in it. (In other words, even if you don't like my approach to the problem, you get a taste of who else has said what about the issue).

 

[GoliathX]

I have a theory which can explain time, dark matter, dark energy and the expansion of space easily.

First, I do not have a background in mathematics or physics. I was pursuing a pre-engineering degree before I got derailed by life stuff and will not be going back anytime soon.

Second, how can I go about getting taken seriously? Where is a place that I could honestly begin?

This is an honest inquiry and no I will not share this information publicly.

Thank you.

 

[Athletico]

I have a theory which can explain time, dark matter, dark energy and the expansion of space easily.

First, I do not have a background in mathematics or physics. I was pursuing a pre-engineering degree before I got derailed by life stuff and will not be going back anytime soon.

Second, how can I go about getting taken seriously? Where is a place that I could honestly begin?

This is an honest inquiry and no I will not share this information publicly.

Thank you.

I'd post your thoughts here. People on PF are pretty open-minded for the most part. Just be prepared for criticism - especially if your views are highly speculative and go against the grain of accepted theories.

 

[DrGreg]

I have a theory which can explain time, dark matter, dark energy and the expansion of space easily.

First, I do not have a background in mathematics or physics. I was pursuing a pre-engineering degree before I got derailed by life stuff and will not be going back anytime soon.

Second, how can I go about getting taken seriously? Where is a place that I could honestly begin?

This is an honest inquiry and no I will not share this information publicly.

Thank you.

I'd post your thoughts here. People on PF are pretty open-minded for the most part. Just be prepared for criticism - especially if your views are highly speculative and go against the grain of accepted theories.

No, if your views are highly speculative and go against the grain of accepted theories, then it's against the rules of this forum to post your thoughts here:

Overly Speculative Posts:
One of the main goals of PF is to help students learn the current status of physics as practiced by the scientific community; accordingly, Physicsforums.com strives to maintain high standards of academic integrity. There are many open questions in physics, and we welcome discussion on those subjects provided the discussion remains intellectually sound. It is against our Posting Guidelines to discuss, in most of the PF forums or in blogs, new or non-mainstream theories or ideas that have not been published in professional peer-reviewed journals or are not part of current professional mainstream scientific discussion. Personal theories/Independent Research may be submitted to our Independent Research Forum, provided they meet our https://www.physicsforums.com/showthread.php?t=82301; Personal theories posted elsewhere will be deleted. Poorly formulated personal theories, unfounded challenges of mainstream science, and overt crackpottery will not be tolerated anywhere on the site. Linking to obviously "crank" or "crackpot" sites is prohibited.

Unfortunately, without a background in mathematics or physics you will have great difficulty in being taken seriously anywhere else. For people to take your theory seriously, they will expect you to have a good understanding of existing theories. (E.g. see the Independent Research Guidelines referred to above.)

 

[GoliathX]

No, if your views are highly speculative and go against the grain of accepted theories, then it's against the rules of this forum to post your thoughts here:



Unfortunately, without a background in mathematics or physics you will have great difficulty in being taken seriously anywhere else. For people to take your theory seriously, they will expect you to have a good understanding of existing theories. (E.g. see the Independent Research Guidelines referred to above.)

It is not really that highly speculative, all it really is is a change in perspective of how the current theories are currently viewed. It is just one thing or idea that can explain a bunch of these things we scratch our heads at, more than just specified above.

I have a good understanding of existing theories, I just do not have the schooling to go with it. Well read, just can't do the math, by myself that is. I would love to work with somebody that does possesses those qualities, but I have no idea how to go about finding somebody willing to come down to my level (little math).

I don't just want to throw the idea out there however, especially on a message board. It is not because I am worried about criticism, that is expected.

 

[pallidin]

Second, how can I go about getting taken seriously?

Well, that must be "earned"
That is, you must prove yourself right(or reasonably so) WITHOUT any DEMAND that others MUST prove you wrong.

In other words, try not to have an attitude like "well, you can't prove me wrong so I must be right"
That just goes nowhere really fast, and makes one look like a babbling idiot.

So, with a speculative theory, I would approach it by first asking reasonable, specific questions. Allow yourself to be educated by the responses.

 

[GoliathX]

Well, that must be "earned"
That is, you must prove yourself right(or reasonably so) WITHOUT any DEMAND that others MUST prove you wrong.

In other words, try not to have an attitude like "well, you can't prove me wrong so I must be right"
That just goes nowhere really fast, and makes one look like a babbling idiot.

So, with a speculative theory, I would approach it by first asking reasonable, specific questions. Allow yourself to be educated by the responses.

That is not an issue. I am trying to bring this information humbly, I know where I stand. I am at the bottom rung of the ladder pretty much when it comes to credentials.

I have seen plenty of people raise their hands triumphantly saying THEY HAVE THE ANSWER only later to be seen with their tail between their legs. I do not have THE ANSWER. What I have may possibly be an answer, but I don't have the means or the methods to verify this by myself.

 

[pallidin]

... but I don't have the means or the methods to verify this by myself.

OK, well, that's perfectly fine, so what are your questions or statements regarding your theory? Let's start with that.

 

[GoliathX]

I am not quite sure where to begin, honestly. Like I stated earlier, I don't wish to put everything out on a message board.

I guess the expansion of space is as good as any.

Space isn't expanding, all of the material within 'space' is getting smaller. The more mass and volume something has the quicker this takes place. This is why everything around us is redshifting.

Go ahead and ask your questions, I will do my best to answer them.

 

[PhysDrew]

Space isn't expanding, all of the material within 'space' is getting smaller. The more mass and volume something has the quicker this takes place. This is why everything around us is redshifting.

So are you saying that all of the mass in the universe is getting smaller? Or is the volume of the mass getting smaller (in which case the density would increase)? Seems to me that either of these would lead to violations in the theories of relativity and the effects of gravity (please correct me if I'm wrong).

 

[pallidin]

So, you are under the impression that the "space" is contracting as opposed to expanding. Do I have that right?

 

[pallidin]

A little heavy, but a good treatment on "redshift":

http://en.wikipedia.org/wiki/Redshift

 

[GoliathX]

No, I am not saying space is contracting, nor am I saying objects are becoming more dense.

I am saying that all objects are decreasing their size in space. This is where I know that I don't have enough of an education in math or physics to explain myself but I will do my best.

Think of it like a tesseract, but in time. In one moment the outer cube exists, but as what we call 'time' passes, 'time' being change, the same cube exists but each point in the 3rd dimension has decreased its volume in physical space. This happens continuously.

It is a fractal in that in the very next moment, which never ends, it can only be self-similar. It cannot be the same thing twice. We know that all of the atoms in the cube move, but the space between all things increases as well (but is an illusion).

This would be why everything is 99.9% space, in, through and around atoms. Not because space is expanding, but these things, by nature of the 4th dimension and what it is, are getting smaller.

Time passing is a fractal. All movements and change are self-similar to what it previously was. Things change because nothing can be the 'exact' same thing it was before.

Hopefully this makes some sense.

 

[bp_psy]

What I have may possibly be an answer, but I don't have the means or the methods to verify this by myself.

I am sorry but you do not have any "possible answers". You only have a illogical sequence of ideas that sound cool to you but do not really mean anything.
You should learn what a scientific theory is ,how it is developed and what is its purpose before you even try to think of coming with one of your own.

 

[PhysDrew]

No, I am not saying space is contracting, nor am I saying objects are becoming more dense.

I am saying that all objects are decreasing their size in space. This is where I know that I don't have enough of an education in math or physics to explain myself but I will do my best.

Think of it like a tesseract, but in time. In one moment the outer cube exists, but as what we call 'time' passes, 'time' being change, the same cube exists but each point in the 3rd dimension has decreased its volume in physical space. This happens continuously.

It is a fractal in that in the very next moment, which never ends, it can only be self-similar. It cannot be the same thing twice. We know that all of the atoms in the cube move, but the space between all things increases as well (but is an illusion).

This would be why everything is 99.9% space, in, through and around atoms. Not because space is expanding, but these things, by nature of the 4th dimension and what it is, are getting smaller.

Time passing is a fractal. All movements and change are self-similar to what it previously was. Things change because nothing can be the 'exact' same thing it was before.

Hopefully this makes some sense.

Hmmm doesn't really sound plausible. Sounds unnecessarilly complex as well (Occam's razor would do wonders with this). So are you implying that the universe is finite?

 

[GoliathX]

Hmmm doesn't really sound plausible. Sounds unnecessarilly complex as well (Occam's razor would do wonders with this). So are you implying that the universe is finite?

Not sure how it would be more complex. 4th dimension being both 'time' and volume (volume being a point tangent off of every 3 dimensional surface point, not sure if I am explaining dimension correctly here) explains the redshift of all solar objects away from us as well as the movement of local bodies away from us (sun and moon).

Right now, they explain the expansion of space as 'possibly' being Dark Energy since they really don't have a good grasp as what is really causing it, as well as why those objects further from us are moving more rapidly. The sun (15cm per year) and moon (4cm per year) moving away from us is currently believed to be because of tidal forces.

Which would be more complex to explain the expansion? A 4th dimensional change over time that occurs to all objects (micro and macro), or a bunch of other options that we aren't even sure of?

 

[PhysDrew]

Which would be more complex to explain the expansion? A 4th dimensional change over time that occurs to all objects (micro and macro), or a bunch of other options that we aren't even sure of?

I see you point, however the bunch of other options are based on the well known, experimentally proven (as well as rigorous mathematical proofs) theories.

And also, when you say the 4th dimension is both time and volume, are you implying that both time and volume are changing linearly? Sounds like it, as you say volume being a point tangent off of every 3D surface. I can think of at least one specific example where volume change isn't linear.

 

[GoliathX]

I know that the math works for those other options, I am not saying they don't and I am also not saying they are not right. I don't see why it would have to be either/or and not both/and. With a 4th dimensional change there is certainly room for other causes for expansion as well.

I do mean linearly. Tangent off of every point of a surface, yes, meaning a sphere within a sphere at the Planck scale. And another, and another and so on over what we call 'time'.

What is your example? Just want to make sure we are seeing it the same.

 

[PhysDrew]

Well I have to say it certainly sounds interesting to me. But yes not sure if I'm understanding your view of linear volume change. The example relates to a simple thermodynamic process in the freezing of water. From 0 to 4 degrees celsius the volume of water decreases, whereas from 4 degrees celsius on, the volume increases. This is why only the top layer of a lake freezes (as water has its greatest density at 4 degrees celsius, thus the temperature of water below the ice is set at 4 degrees, as the more dense water 'sinks'), and has important consequences for life on Earth overall. Variations like this seem to make volume an intrinsic property of matter, rather than an extrinsic, emergent phenomenon.