Questions about time

[Reivax]

The concept of time.

I'm thoroughly confused by it. I don't claim to know much about it at all, and it's a concept I cannot get my head around. I've read about time dilation, different dimensions, and other physics related topics and while I can sort of grasp them, there comes a point where I realize how just being human can limit my ability to understand some things and it leads me into a spiral of doubt and uncertainty.

Questions like:

• Is time as we view it an illusion?
• Are we conditioned to see time in a linear way?
• Does time even exist?
• Has everything already happened but we are just viewing one moment at a time?

*Some are more philosophical than scientific and some may be unfalsifiable concepts.

If we live a life with the view that time is linear, we'll be born, see events as leading to other events until finally, we die. But if time is just an illusion is there room in there for us to be eternal beings that don't really have chronology etc?

I know these ideas may sound wooish, and some are, but i'm just trying to get a discussion going about time in general and how it really works and relates to daily phenomenon.

Go nuts!

Thanks

 

[Cylinder]

Is time as we view it an illusion?

Since at the level of human perception time manifests as a constant yet it has been shown not to be a constant, then you could say yes, I suppose

Are we conditioned to see time in a linear way?

Yes.

Does time even exist?

Yes. Though there are no real candidate theories that I'm aware of (and what I'm not aware of could fill a library), time is well-modeled, measurable and can be manipulated. It's as real as gravity in that regard.

Has everything already happened but we are just viewing one moment at a time?

That's unfalsifiable, since we're only allowed to draw empirical conclusions from what we can actually view or model.

I have a high-school understanding of physics, so take it with a grain of salt.

 

[Farsight]

Is time as we view it an illusion?

That depends on how you view it! What is an illusion, is the notion of "travelling forwards through time". We don't travel through time at all. You can travel through space, no problem. You can jump forward a metre. You can't jump forward a second. Some people say "we're all travelling forwards through time at one second per second", but we aren't actually travelling through it at all. Others will say "clocks measure the flow of time", but they don't. All they do is accumulate some kind of regular motion and show you a reading that you then call "the time".

Are we conditioned to see time in a linear way?

Yes, I'd say so. But I don't think there's much of a problem with that. Time is linear like this is linear: 1 2 3 4 5 6 7 8 9. The problem comes when people start thinking we can move along this linear thing and then start talking about time travel. We don't even travel forwards in time, so travelling backwards in time is totally out of the question.

Does time even exist?

Yes, but it doesn't exist the way people say. It's something like heat in this respect. You know that heat is real, it will burn you. Heat exists. And yet when you go down to the subatomic level, there's no such thing as heat. A "hot" particle is merely one that's moving fast. The temperature of gas is actually a measure of average kinetic energy, or an "average measure of motion". Time is similarly an emergent property, but is a "cumulative measure of motion". And time will make your hair turn white. Time will kill you too.

Has everything already happened but we are just viewing one moment at a time?

If it hasn't happened yet it hasn't happened. And we're just viewing what's happening. As for we are viewing, it's worth thinking about. Hold your hands up a foot apart. You can see a gap between them. That's space. You can't see it in itself, but you can see that the space between your hands is there. Now waggle your hands. You can see them moving. You can see motion. Now try to see time. You can't. That's because it's something derived from space and motion through it. People will tell you that you can't have motion without time, but in truth it's the other way round. If you stop the clock you stop it moving. In some science fiction movie when they "stop time", what they're really doing is stopping motion. Once you get used to focussing on the motion the "mystery" of time just melts away.

 

[epepke]

The concept of time.

I'm thoroughly confused by it. I don't claim to know much about it at all, and it's a concept I cannot get my head around. I've read about time dilation, different dimensions, and other physics related topics and while I can sort of grasp them, there comes a point where I realize how just being human can limit my ability to understand some things and it leads me into a spiral of doubt and uncertainty.

Questions like:

Is time as we view it an illusion?

Not really, at least any more than space is an illusion.

Are we conditioned to see time in a linear way?

Define "linear." Define "conditioned." Are you talking about the so-called arrow of time? Fairly different from talking about time in general and probably useful to keep it clear what you are talking about.

Does time even exist?

As much as space does.

Has everything already happened but we are just viewing one moment at a time?

Again, confusing. Sounds like you might be talking about the arrow of time as opposed to space-time as a manifold. There are a lot of potentially interesting things to say about this, but it really helps to keep clear what you are talking about.

 

[sol invictus]

Is time as we view it an illusion?
Are we conditioned to see time in a linear way?

Yes and yes. At least according to our best understanding, time is a dimension much like the other three (but with one crucial mathematical difference). It can be "rotated" into the other three - that corresponds to a velocity.

Instead, we tend to see time as something that "passes", and passes at the same rate for everyone. But we know from direct experiment that is wrong - clocks tick at different rates when they move, or when they are in gravitational fields.

Does time even exist?

Yes, of course.

Has everything already happened but we are just viewing one moment at a time?

Yes, in a way. Think of all times and places laid out in front of you as a grid. A human life is a long, thin ribbon stretching through time, with some wiggles because the person traveled. At each point on that ribbon, the person remembers their past, but not their future, and that point defines their present.

 

[dafydd]

Does time even exist?

Yes. Try watching a Barry Manilow concert and you will discover that one hour can seem like a week.

 

[C_Felix]

If we weren't around to quantify time, would it exist?
This goes to the whole arrow of time and entropy.

How else could one view time as opposed to linear? Circular?

 

[Skepticemea]

I'd answer but I'm in a hurry.

 

[Mark6]

It's about time somebody asked them!

 

[Loss Leader]

Is time as we view it an illusion?

Yes. But, everything we view is an illusion. We don't experience reality so much as imagine it. That's just the way the brain works.

Are we conditioned to see time in a linear way?

Yes. We're conditioned by evolution. If we didn't view time as linear, we wouldn't observe cause and effect and then we'd die every time we tried to cross at an intersection.

Does time even exist?

Yes.

Has everything already happened but we are just viewing one moment at a time?

No.

But if time is just an illusion is there room in there for us to be eternal beings that don't really have chronology etc?

Oh, I doubt it.

 

[Reivax]

Thanks for the replies so far.

Thanks epepke, I think I am referring the arrow of time, but more specifically 'the perceptual arrow of time', which ultimately follows the 'thermodynamic arrow of time'. I just found these terms here, but they correspond with the ideas I had in my mind.

I think I had a different idea of what I meant by 'linear', than what the term 'linear time' actually means. I basically meant how time flows chronologically (past, present, future) and this more closely corresponds to the 'arrow of time' instead.

For 'conditioned', I mean evolved to see time in an illusive way, or perhaps in one of many ways.

Sorry for the confusion, I hope this clears things up.

 

[Farsight]

You're conditioned to think that time flows when there's no actual evidence for that. You can see space and things moving, but you can't see time flowing. Clocks are said to "measure the flow of time" but actually, they don't. Open up a mechanical clock and you see cogs moving, not time flowing. They just clock up some kind of regular motion. The "arrow of time" is a bit like "the direction of entropy". Think of that as a generalised varion of say "the direction of a chemical reaction" and you appreciate that it's nothing like a spatial direction.

 

[Merton]

Forward time travel?

Farsight, I recall hearing about an experiment where physicists sent a particle forward in time, but cannot locate the source at the moment. I believe it happened 5-10 years ago, but I heard it from a friend and don't really know the specifics of the experiment. Have you heard of this? If so, and assuming the experiment was accurate, wouldn't this qualify as traveling through time?

After Googling for it a while, I'm starting to wonder if my friend misrepresented the experiment or relayed some sensationalized journalism about it. I just can't find it anywhere!

 

[ctamblyn]

Farsight, I recall hearing about an experiment where physicists sent a particle forward in time, but cannot locate the source at the moment. I believe it happened 5-10 years ago, but I heard it from a friend and don't really know the specifics of the experiment. Have you heard of this? If so, and assuming the experiment was accurate, wouldn't this qualify as traveling through time?

After Googling for it a while, I'm starting to wonder if my friend misrepresented the experiment or relayed some sensationalized journalism about it. I just can't find it anywhere!

Perhaps your friend was thinking of relativistic time dilation, which is a very well-established phenomenon. For example, muons (at rest relative to the measurer) have a lifetime of about 2 microseconds, and so even at almost the speed of light would only travel about 600 m (on average) before decaying. However, due to time dilation as judged by observers standing on the ground, high-energy muons produced by cosmic rays in the upper atmosphere can reach the Earth's surface and be detected. From a journalist's point of view, perhaps that would count as time travel into the future.

More here:
http://en.wikipedia.org/wiki/Time_dilation#Experimental_confirmation

 

[Merton]

Very possible. I'm a little ashamed that I didn't follow the military credo "trust but verify" on this one; a lesson for next time, I guess.

 

[Kid Eager]

There was a series of articles in New Scientist in an issue a few months ago that dealt with the question of time.

Ah, found the issue:
http://www.newscientist.com/article/mg21128330.400-about-time-what-is-it.html
http://www.newscientist.com/article/mg21128330.500-about-time-why-does-times-arrow-fly-only-one-way.html

 

[Dr.Sid]

Is time as we view it an illusion?

I'd say yes. Time does not exist by itself .. we can't also perceive time itself. We can perceive events - changes in state of the world .. and we only can measure time by comparing how many events of type A does it toke to event to happen. Any system which has more states which transform from one into another, will have time.

Are we conditioned to see time in a linear way?

What do you mean by linear ? Like non-branching ? Only moving at constant speed ? As for the second, on psychological level it is not true, and on physical level it's not true either (because of relativity).

Does time even exist?

That's kind of problem of what 'exist' means .. if it means 'it can be perceived' then yes.

Has everything already happened but we are just viewing one moment at a time?

So far physics cannot predict quantum states. So from our point of view, the future is not determined. And we don't have any other point of view .. so no, it did not already happened.
On the other hand, what human perceive, indeed all already happened, just few moments ago.

 

[Perpetual Student]

• Is time as we view it an illusion?

Why should time be any more an illusion than space, matter or any other aspect of our experience? It is something that we use to judge relationships between objects and events and is no more illusory than anything else we experience.

• Are we conditioned to see time in a linear way?

I think we have every reason to believe that within a frame of reference, time is linear. If we stay within one frame, all clocks will move along at the same pace, giving us no evidence that time is non-linear in any way. When moving about from frame to frame, time is non-linear.

• Does time even exist?

If it doesn't exist how could the universe evolve and how we say anything about the age of the universe?

• Has everything already happened but we are just viewing one moment at a time?

The equation: [latex] t^* = \gamma( t - \dfrac{vx}{c^2})[/latex] by varying x by large positive and negative amounts tells us that what we think has happened has not yet happened for someone else and what someone else thinks has happened has not yet happened for us.

 

[Farsight]

Farsight, I recall hearing about an experiment where physicists sent a particle forward in time, but cannot locate the source at the moment. I believe it happened 5-10 years ago, but I heard it from a friend and don't really know the specifics of the experiment. Have you heard of this?

No I'm afraid not.

If so, and assuming the experiment was accurate, wouldn't this qualify as traveling through time?

No. You just can't "travel" through time. It's just a figure of speech.

After Googling for it a while, I'm starting to wonder if my friend misrepresented the experiment or relayed some sensationalized journalism about it. I just can't find it anywhere!

It's probably something to do with making a particle go very fast, so that time dilation occurs. This is something like you and me synchronising our watches, then I go off on a round trip in a gedenken spaceship. When we meet up again ten years later I haven't got any wrinkles and grey hairs, whilst you have. But we meet up at the same time. I don't start living in your past, and you don't start living in my future. It's just that I've experienced less "local motion" on account of my macroscopic motion through space, that's all.

 

[Merton]

Farsight, yeah, that was my bad. I don't know what my friend was talking about, but it seems clear that he didn't understand or remember the experiment well.