Time...

[studiot]

1 hour ago, michel123456 said:

Right. But if you describe fusion or fission time-reversed things will not look that much awkward as an omelette getting back to an egg.

Yes and getting free energy by time reversal will get you a perpetual motion machine.

But I don't think that happens in Physics either.

 

However I do see your point about continuous v fragmented reversals.

I just don't accept it is confined to living systems and offered the first non living example that came into my head.

As a matter of interest, how does being born and living and dying backwards work?
(I saw the film - did you)

That gives interesting pause for thought.

[jajrussel]

3 hours ago, michel123456 said:

I have repeatedly thoughts about this. All the examples we use are direct products of Life (an egg) or by-products (a broken glass). But when you take examples from simple physics, you see water getting into vapor & vapor getting back into droplets. So I am still wondering about the validity of the argument.

 

Is time effected by our choices? Can we get it to pace back and forth? Can we assign time the properties of our samples? Wouldn’t time then become sample dependent? I suspect the reasoning behind assigning time, properties that only present in certain samples with or without regard to the samples size is to effect an outcome. Any result might only apply to what is sampled. I can’t very well say that water freezes at a certain temperature in a specific amount of time then declare that all things will freeze at that temperature in the same amount of time.

I suspect that the validity of the argument was simple reasoning.

 I love eggs, it would become uncomfortable should they go back into the shell.

[michel123456]

4 hours ago, studiot said:

Yes and getting free energy by time reversal will get you a perpetual motion machine.

But I don't think that happens in Physics either.

 

However I do see your point about continuous v fragmented reversals.

I just don't accept it is confined to living systems and offered the first non living example that came into my head.

As a matter of interest, how does being born and living and dying backwards work?
(I saw the film - did you)

That gives interesting pause for thought.

Yes, time for thought.

Generally speaking I find that one cannot use any living system as an example of physical process. Life is totally weird. If you examine physical systems (out of Life), you may come to the conclusion that birth & death never happen. Once you introduce living elements yes birth & death do occur. As about time, one must admit that most (if not all) physical laws are time-symmetric.

5 hours ago, jajrussel said:

Is time effected by our choices? Can we get it to pace back and forth? Can we assign time the properties of our samples? Wouldn’t time then become sample dependent? I suspect the reasoning behind assigning time, properties that only present in certain samples with or without regard to the samples size is to effect an outcome. Any result might only apply to what is sampled. I can’t very well say that water freezes at a certain temperature in a specific amount of time then declare that all things will freeze at that temperature in the same amount of time.

I suspect that the validity of the argument was simple reasoning.

 I love eggs, it would become uncomfortable should they go back into the shell.

To me, Time is not an external thing. It is not a kind of wind that flows around us.

Time is the impression we get while moving through. We are the ones moving. We are the ones who get old. The bizarre thing is that even when you don't move an inch, you still get older. You still "move" though time.

[swansont]

8 hours ago, michel123456 said:

Right. But if you describe fusion or fission time-reversed things will not look that much awkward as an omelette getting back to an egg.

And there’s a reason for that. Simple systems do not have as many states available to them, so the entropy is lower, and can’t change as much. A one-dimensional elastic collision looks perfectly fine in time reversal, but there is only one possible final state. 

The more “moving parts” the system has, the more awkward the entropy violation looks.

[MigL]

Exactly.
Simple systems at the quantum level don't seem to have a preferred time direction, and are reversible.
Some are even required to be ( think of virtual particles ).
Statistical systems, however, quickly gain an 'arrow' of time.

[michel123456]

11 hours ago, swansont said:

And there’s a reason for that. Simple systems do not have as many states available to them, so the entropy is lower, and can’t change as much. A one-dimensional elastic collision looks perfectly fine in time reversal, but there is only one possible final state. 

The more “moving parts” the system has, the more awkward the entropy violation looks.

Like laminar flow reversal. Mesmerizing.

 

[Martyred Goat]

My personal belief is that each instant is a static state, Like a frame rate. This means that movement does not occur

[Strange]

1 hour ago, Martyred Goat said:

This means that movement does not occur

Eppur si muove.

[Martyred Goat]

5 minutes ago, Strange said:

Eppur si muove.

Nah, Space would have to be infinitely divisible. Jump jump jump jump jump, Looks like movement. Me thinks :p

[Strange]

1 minute ago, Martyred Goat said:

Space would have to be infinitely divisible.

As far as we know, it is.

[swansont]

13 hours ago, Martyred Goat said:

My personal belief is that each instant is a static state, Like a frame rate. This means that movement does not occur

As this is science it's not what you believe that matters. It's what evidence you have. Pretty strong evidence that movement occurs.