The Nature of Time

[studiot]

7 minutes ago, swansont said:

It's also impossible to have a system where nothing changes (at the quantum level), so isn't this all moot?

I hadn't looked before but I see this is posted in quantum theory, so is this comment conditioned by that ?

I find the discussion itself interesting (even if it might be in the wrong place).

But I don't think change is the right word.

Time is an independent variable that we use to measure difference, congruence and similarity.
There does not have to be a change for these to occur.

 

2 minutes ago, Strange said:

On the other hand, in GR time is not a thing that “passes”; there is no change, it represents the universe as a static 4D manifold. 

So, as so often, it largely comes down to what one means by “time” (and “change” and “real” ...)

Edit this also fits with Strange's cross posting.

 

Edited January 15, 2020 by studiot

[Strange]

I would suggest this might be better placed in Philosophy

[swansont]

11 minutes ago, Strange said:

I would suggest this might be better placed in Philosophy

My thought is that if the OP placed it in physics, then they get a physics answer. If they want a philosophy answer, they should be the one to post in philosophy.

29 minutes ago, studiot said:

I hadn't looked before but I see this is posted in quantum theory, so is this comment conditioned by that ?

To some extent, yes. It makes the argument about change even worse. 

[Eise]

1 hour ago, swansont said:

It's also impossible to have a system where nothing changes (at the quantum level), so isn't this all moot?

That is a good point. Of course a system where nothing happens is impossible, but I think my example shows that one can only speak of time when there are changes; and also the other way round. However, we cannot observe time, but we can observe changes (especially hands of a clock), which for me makes 'change' the more primitive concept. As in a thread a long time ago (i.e. many changes happened since then...), about the same topic, you said 'time' is an abstraction, to which I only added "yes, to be specific, an abstraction of change". 

1 hour ago, Strange said:

On the other hand, in GR time is not a thing that “passes”; there is no change, it represents the universe as a static 4D manifold. 

I find this an unfair comparison. Take such a 4D manifold, and compare it for T = 0 and T = 1. If everything else is the same, then there was no change; if not there was. 

I do think that time exists, but it exists in another way than physical objects, that exist in time (and space, of course).

It is similar to the question if the laws of nature exist. There I also say they exist, but again in a different way than physical objects. When one does not account for this different ontological status of physical objects, time and space, and laws of nature, it can lead to all kind of stupid philosophical questions (as we had here several times) like 'how do the laws of nature govern the universe'.

Edited January 15, 2020 by Eise

[studiot]

Hello Eise, you seem to have missed my response(s) in our conversation.

[scuddyx]

19 hours ago, Huckleberry of Yore said:

Based on just my 50+ years of observation I've decided that most likely Time is real and not an illusion, but Now most certainly is.  I've pondered how to state this mathematically and what it really means.  Others will probably just say it's gibberish but I've seen a lot of that recently here. 

Hi, Thanks for your reply. 

If the 'Now' is the only thing we experience - is it not the only thing we can be sure of that it is not an illusion?

The past and future may be constructs of the mind and consequently illusions.

[swansont]

50 minutes ago, Eise said:

That is a good point. Of course a system where nothing happens is impossible, but I think my example shows that one can only speak of time when there are changes; and also the other way round. However, we cannot observe time, but we can observe changes (especially hands of a clock), which for me makes 'change' the more primitive concept. As in a thread a long time ago (i.e. many changes happened since then...), about the same topic, you said 'time' is an abstraction, to which I only added "yes, to be specific, an abstraction of change". 

Where the OP's argument breaks down is that if I have an unchanging system at point A, and at point B I have a clock which is measuring the passage of time, the argument must become that time only exists near point B but not point A. And I would like to hear a defense of that claim.

Otherwise, time is passing where the unchanging system is.

[iNow]

3 minutes ago, scuddyx said:

Hi, Thanks for your reply. 

If the 'Now' is the only thing we experience - is it not the only thing we can be sure of that it is not an illusion?

The past and future may be constructs of the mind and consequently illusions.

If anything, “now” is a construct of the mind and a bit of an illusion since our personal version of it is stitched together based on various inputs arriving at different rates from the past.

Further, your now and my now are not the same, even though it may feel intuitive for there to be a universal now or universal present. There is not.

Edited January 15, 2020 by iNow

[swansont]

1 minute ago, scuddyx said:

Hi, Thanks for your reply. 

If the 'Now' is the only thing we experience - is it not the only thing we can be sure of that it is not an illusion?

The past and future may be constructs of the mind and consequently illusions.

"Now" is not well defined in physics. We quantify things. We tag them with a value of t.

And constructs of he mind have no relevance to the physics discussion. Time can be measured. It's not an illusion.

[scuddyx]

21 hours ago, scuddyx said:

Time only exists if there is change.  The tick of a clock.  The beating of your heart.  A photon of light from the sun enters your eye instantaneously (zero time) in its frame of reference.  This is because it has experienced no change.  Its wave function has evolved as described by Schrodinger’s Equation – but it is only when the wave function collapses or decoheres does it experience time.   Quantum Decoherence is the key to understanding time. 

What do you think?

.

19 hours ago, iNow said:

Photons don't have a valid reference frame since (by definition) they're never at rest

 

I think you're putting the cart before the horse here. What is change if there is no time? Without time, change itself is not possible.

 

"[Time] is one of those concepts that is profoundly resistant to a simple definition." ~C. Sagan

https://www.pbs.org/wgbh/nova/time/sagan.html

Thanks for your comments.  In reply:

If a spacecraft was travelling from the neighbourhood of the sun to earth at 10% of the speed of light the occupants and onboard clock would experience/measure about 8 minutes.  If it travelled faster at 99% of the speed of light, due to time dilation, the clock would measure show about 1 minute of elapsed time.  If it travelled even faster at 99.9999% of the speed of light, the clock would show the journey taking only 1 second. Consequently photons, that travel at the speed of light, would be expected to ‘experience’ zero time and instantaneous travel time.  

Physicists and philosophers have been unable to define time, other than to observe it represents the change of something – tick of a clock, heart beats etc.  Some physicists start their theories by assuming that we live in an arena of space and time.  Special and general relativity show there is no absolute time.  IMHO Time is an emergent phenomenon from quantum mechanics. What changes is the decoherence of the wavefunction.  This is consistent with the photon travelling instantaneously until it hits something, is measured or otherwise decoheres.  Decoherence is the key to understanding time.  This applies to all massless particles that travel at the speed of light.  Other particles couple or interfere with the Higgs Field.  The more they couple, the more decoherence happens, and more time they experience.  This slows them down from the speed of light.  The particles that experience the most decoherence slow down the most.  This appears has if they have more inertia.  This ones with most inertia appear to us as having the greatest mass.  This is how mass arises and varies between particles.

2 hours ago, Strange said:

I would suggest this might be better placed in Philosophy

I believe this real physics, hopefully leading to a better understanding of space and time, gravity, mass etc.

I am hoping for some constructive replies.  Thanks

54 minutes ago, iNow said:

If anything, “now” is a construct of the mind and a bit of an illusion since our personal version of it is stitched together based on various inputs arriving at different rates from the past.

Further, your now and my now are not the same, even though it may feel intuitive for there to be a universal now or universal present. There is not.

Physics aside do you agree with the philosophy of Now as described by Mindfulness, Buddhism or Eckhart Tolle's Power of Now?  Thanks 

53 minutes ago, swansont said:

"Now" is not well defined in physics. We quantify things. We tag them with a value of t.

And constructs of he mind have no relevance to the physics discussion. Time can be measured. It's not an illusion.

Time is not an illusion but an emergent phenomenon than appeared shortly after the Big Bang.

Edited January 15, 2020 by scuddyx
Repeated text removed. Thanks

[studiot]

33 minutes ago, scuddyx said:

I believe this real physics,

 

Then you will be able to domonstrate your claims mathematically please.

 

34 minutes ago, scuddyx said:

 

I am hoping for some constructive replies.  Thanks

 

Why do you bother to ask when you don't reply to them?

[scuddyx]

3 minutes ago, studiot said:

 

Then you will be able to demonstrate your claims mathematically please.

 

 

Why do you bother to ask when you don't reply to them?

The concepts are very simple unlike the maths which is waiting to be published. 

Sorry I haven't replied to your diagram.  I am waiting until your conversation with others has concluded.  Thanks 

[iNow]

1 hour ago, scuddyx said:

If a spacecraft was travelling from the neighbourhood of the sun to earth at 10% of the speed of light the occupants and onboard clock would experience/measure about 8 minutes.

Actually, light itself takes 8+ minutes to get from the sun to the earth. At only 10% light speed, the elapsed time would be longer.

1 hour ago, scuddyx said:

Physics aside do you agree with the philosophy of Now as described by Mindfulness, Buddhism or Eckhart Tolle's Power of Now? 

Can't say I'm familiar with their core thesis, so unable to comment.

[swansont]

1 hour ago, scuddyx said:

 IMHO Time is an emergent phenomenon from quantum mechanics. What changes is the decoherence of the wavefunction.  This is consistent with the photon travelling instantaneously until it hits something, is measured or otherwise decoheres.  Decoherence is the key to understanding time. 

Decoherence of what? Can we not discuss time using classical physics? 

Quote

This applies to all massless particles that travel at the speed of light.  Other particles couple or interfere with the Higgs Field.  The more they couple, the more decoherence happens, and more time they experience.  This slows them down from the speed of light.  The particles that experience the most decoherence slow down the most.  This appears has if they have more inertia.  This ones with most inertia appear to us as having the greatest mass.  This is how mass arises and varies between particles.

You seem to be using decoherence as a magic wand. What is decohering, and how does decoherence manifest itself as time?

What is your model of how particles that couple with the Higgs experience time in proportion to how strongly they couple, and thus is depends on mass? Does this mean time passes differently for an electron vs a proton? Or a hydrogen atom vs a cesium atom? That is in direct conflict with the equivalence principle, and has been experimentally excluded at a pretty high level of precision.

For reference, I have randomly chosen a paper that shows confirmation of local position invariance

https://arxiv.org/abs/1301.6145

 

 

[studiot]

1 hour ago, scuddyx said:

The concepts are very simple unlike the maths which is waiting to be published. 

Sorry I haven't replied to your diagram.  I am waiting until your conversation with others has concluded.  Thanks 

 

But the maths in my diagrams is very simple.

Further you should be able to explain stationary waves, which do not change with time, but are simple but essential parts of quantisation.

[scuddyx]

1 hour ago, iNow said:

Actually, light itself takes 8+ minutes to get from the sun to the earth. At only 10% light speed, the elapsed time would be longer.

Can't say I'm familiar with their core thesis, so unable to comment.

It is true that light takes 8.32 seconds to get from the sun to the earth. Clocks on a spacecraft travelling at 10% light speed would slow down by 0.5%.  At 99.9999% light speed the clocks will slow down by 99.86% compared to clocks on earth. I will modify my posting to clarify this. Thanks. Taking this towards the limit - the photons of light 'experience' zero time in their journey to earth.  There is no absolute time frame of reference.

Edited January 15, 2020 by scuddyx

[MigL]

Just like every other time this topic has come up, some of us are confusing the measuring mechanism with time.
The only measuring mechanism we have are clocks, which are based on cyclical change between two states, so we tend to assume 'time' is based on that change. We have NO other way of gauging time; that doesn't make time a result of that change.

And as has been pointed out many times, in previous discussions, this is equivalent to confusing a ruler with distance.

[Prometheus]

2 hours ago, scuddyx said:

Physics aside do you agree with the philosophy of Now as described by Mindfulness, Buddhism or Eckhart Tolle's Power of Now?  Thanks 

I'm Buddhist. I've not heard of the philosophy/power of Now. Is it perhaps a Western interpretation of some Buddhist principle?

It's interesting that the Buddha refused to answer questions regarding the nature of the universe. We don't need to know much about nature of time to strive towards a more wholesome life.

Edited January 15, 2020 by Prometheus

[swansont]

1 hour ago, scuddyx said:

It is true that light takes 8.32 seconds to get from the sun to the earth. Clocks on a spacecraft travelling at 10% light speed would slow down by 0.5%.  At 99.9999% light speed the clocks will slow down by 99.86% compared to clocks on earth. I will modify my posting to clarify this. Thanks. Taking this towards the limit - the photons of light 'experience' zero time in their journey to earth.  There is no absolute time frame of reference.

[emphasis added]

Minutes, not seconds.

At 0.1c, as you show, the time dilation effect is small. So it will take ~80 minutes to make the trip at that speed.

You can't really say that the photons experience zero time. There are no equations that we have that work in the photon's frame of reference which would allow you to definitively conclude that. The equations we have work in inertial reference frames. 

[scuddyx]

32 minutes ago, Prometheus said:

 

I'm Buddhist. I've not heard of the philosophy/power of Now. Is it perhaps a Western interpretation of some Buddhist principle?

It's interesting that the Buddha refused to answer questions regarding the nature of the universe. We don't need to know much about nature of time to strive towards a more wholesome life.

Eckhart Tolle’s book ‘The Power of Now’ has sold over 2 million copies.  In 2011, he was listed by Watkins Review as the most spiritually influential person in the world.  Tolle is not identified with any particular religion, but he has been influenced by a wide range of spiritual works including Buddhism (Wiki).  Tolle's philosophy is based on the nature of time. 

[iNow]

4 minutes ago, scuddyx said:

Tolle's philosophy is based on the nature of time. 

I’m familiar with a quote from him that I like. He’s says, “We are the universe expressing itself as a human being for a little while.”

As you seem to acknowledge, though, this is philosophy, not physics. 

Philosophy is what helps us wonder about the moon and why we should care about it. Physics is what allows us to actually land on it and do something with those dreams. 

[scuddyx]

1 minute ago, swansont said:

[emphasis added]

Minutes, not seconds.

At 0.1c, as you show, the time dilation effect is small. So it will take ~80 minutes to make the trip at that speed.

You can't really say that the photons experience zero time. There are no equations that we have that work in the photon's frame of reference which would allow you to definitively conclude that. The equations we have work in inertial reference frames. 

The time dilation equations suggest that particles moving infinitely close to the speed of light would slow down almost entirely.  As mass-less particles travel at the speed of light I make the assertion that they would experience zero time.  Is there an error with this logic?

16 minutes ago, iNow said:

I’m familiar with a quote from him that I like. He’s says, “We are the universe expressing itself as a human being for a little while.”

As you seem to acknowledge, though, this is philosophy, not physics. 

Philosophy is what helps us wonder about the moon and why we should care about it. Physics is what allows us to actually land on it and do something with those dreams. 

It's philosophy, not physics as there are no equations in order to make and confirm predictions.  His work provides pointers and food for thought.  The idea that there is a oneness or a consciousness that underpins all life and non-life is similar to the claim by some quantum physicists that the universe is represented by a single waveform. 

[Huckleberry of Yore]

4 hours ago, scuddyx said:

If the 'Now' is the only thing we experience - is it not the only thing we can be sure of that it is not an illusion?

Do we?  Given the latency between neurons firing and keypresses maybe now is best defined as "in the very recent past".  This is obviously philosophical, and whimsical.  But I was alluding to something more fundamental, not just word play.  Again, probably gibberish.

It's relevant to ask, is time quantized?  If so then one could identify a point in time (a now) as distinct from any other.  So for any given time t1 in T (all of time) there exists a time t2 for which t2>t1 AND there is no t* for which t1<t*<t2.  Also, can we say that in a universe, don't all time lines intersect eventually, with varying degrees of latency?  But in a "multiverse" that would not be the case?

[Endy0816]

1 hour ago, scuddyx said:

The time dilation equations suggest that particles moving infinitely close to the speed of light would slow down almost entirely.  As mass-less particles travel at the speed of light I make the assertion that they would experience zero time.  Is there an error with this logic?

You get division by zero at c for time taken, though the distance(based on the equations) does become zero.

 

[MigL]

2 hours ago, scuddyx said:

Is there an error with this logic?

Yes there is.
Division by zero is undefined.
Which means the equations are asymptotically valid, but fail, or are not applicable, at v=c .