It's About Time.

[Avatar]

Time is malleable though. Subjectively at the very least, and perhaps even objectively as we approach near C velocities.

--A

[peter]

Not being funny guys - but is this not just your minds balking at the wrench demanded by acceptance of what all you senses tell you cannot be true. There is no such thing as time. There is only space-time, and the time element is a direction as Av said, just as the up, down and side-to-side are. Ok, it's a direction on which you're fixed on a rail going in one way only......but what is before and behind is still there; relativity would not work if it weren't - and it does!

edit; Let me amplify on this to see if I can make what I'm saying clearer. If you are sitting in your chair experiencing a sucession of 'nows', at a given point your now may coencide with the now of a pigeon taking flight in St Marks square venice or alien on the far side of the universe who is riding his bike to work. Now the pigeons now at that point,because of his motion, will be infinitesimally small'y 'skewed' from yours such that at that point for him, his 'now' corresponds to a now that is fractionally different from the now point at which you were at. Over the relatively short distances of our earth these discrepancies are so small as to be unobservable [except in studies such as that of atomic clocks on planes going around the earth etc]. But from the perspective of the alien on his bike on the otherside of the universe, the situation is greatly magnified. For him, that slight discrepancy in the rate of passage of time caused by his motion, extrapolated across the huge distance he is away from you, means that his now [at the point where it equates to yours sitting in your chair] equates to one hundreds of years before or after the one you are experiencing. Your 'now slices' of the universe are skewed in respect of each others as a result of the effects of his differing motion in relation to yours.....ie his 'relative motion'. Now we have a conundrum; whose 'now slice' is the one that actually exists - and the answer of course....is both! [The video uses the analogy of slicing a loaf of bread with the ''now slices' represented by the cuts; just as the bread may be cut at different angles, your motion will determine the angle of the cut of your now-slice at that given point for you.]

Hope this has made what I'm getting at clearer. [ ]

[SoulBiter]

Actually all of those 'nows', if they are occurring at the same 'time' are the same 'now' not different 'nows' that occur differently. Your perspective doesn't change time. In other words, if I am looking at an explosion of a star through a telescope that happened 1000 years ago, the fact that I am just now seeing the light waves from that explosion, doesn't mean that I am somehow involved in that stars 'time' when that happened because I viewed that light that finally just made it here. The explosion still happened 1000 years ago. If a pigeon in Italy takes flight and I had a telescope on the bird as this happened and could see all the way to Italy from my back porch, I would actually be seeing his flight slightly after the occurrence of his flight, but only because of the amount of time it takes the light (image) to reach my retina and be decoded into his actual flight. My perspective doesn't change the actual time the bird flew.

Hashi - Mathematically, if you take an equation out to the point of infinity I don't know that anything is impossible, just highly unlikely. Mathematically there is a possibility that a pigeon will appear in my office in the next two hours. However, even though it is mathematically possible, chances are that in the next two hours a pigeon will not appear in my office.

Av - There are mathematical theories that time is malleable at approaching near C velocities, but nothing has been proven. The idea being that as we accelerate beyond a certain speed, that a time curve happens that skews time as we know it. Not travel in time per se' but somehow that because you are traveling at that speed, 7 years traveling could equal 12 years sitting on Earth. Its a fine theory but we may find that as we figure out how to travel at those speeds, that it was all poppycock.

[Hashi Lebwohl]

Hashi - Mathematically, if you take an equation out to the point of infinity I don't know that anything is impossible, just highly unlikely. Mathematically there is a possibility that a pigeon will appear in my office in the next two hours. However, even though it is mathematically possible, chances are that in the next two hours a pigeon will not appear in my office.

That is where the fun begins--almost nothing has an exactly 0 probability of happening which means that nothing is impossible. My phone is going to ring within the next hour: 99.997% likely. My boss is going to walk over to my desk in the next 10 minutes: 10% likely. I am going to buy a ticket this evening that wins the jackpot in the lottery: 1 in 100 million. A future version of myself is going to time-travel to me, give me the knowledge of how to build a time machine that will take me 20 years to build, and the first task I must accomplish when I build it is to time travel back to myself to give myself the knowledge of how it can be built: 1 in 417 octillion...but still possible.

Particles travel backwards and forward through what we perceive as "time" all the time; we just don't see it. Sometimes we do, though. "Look! A positron!" No, that is just an electron moving backwards through time.

[wayfriend]

But from the perspective of the alien on his bike on the otherside of the universe, the situation is greatly magnified. For him, that slight discrepancy in the rate of passage of time caused by his motion, extrapolated across the huge distance he is away from you, means that his now [at the point where it equates to yours sitting in your chair] equates to one hundreds of years before or after the one you are experiencing.

I don't think that this is correct. Objects in different frames of reference may experience a faster or slower time rate. But this doesn't mean that their now is different from our now. It only means that two nows that are an hour apart for us may be a day apart for someone else. Time is continuous and infinitely divisible - there's a one-to-one correspondence between every point in an hour and every point in a day.

Furthermore, it only seems like time is moving at a different rate - it's a byproduct of subjectivity, of how we measure time. Like space, time is infininitely stretchable, and, like space, we lack an absolute way to measure it which is unaffected by the stretching. We use a tailoring ruler made from elastic cloth.

[Fist and Faith]

Sure, time is another dimension. It's not the same kind of dimension. I've often heard that we live in three dimensions of space and one dimension of time. But they're entirely bound up in one another. I think I read that everything is traveling at light speed, but, for most things, most of that traveling is in the time dimension, so they go much slower in the space dimensions.

But time is no more an illusion than distance. In either case, things are truly at different points. The bowl on my desk now, the book that was there yesterday, my hand at many times, and hundreds of other things, are not all there at the same moment, separated only by my mind's illusory perception of time.

[Avatar]

Av - There are mathematical theories that time is malleable at approaching near C velocities, but nothing has been proven.

However, we know that time is subjectively malleable, and that counts too.

Psychological Time: Interval Length Judgments and Subjective Passage of Time Judgments

--A

[peter]

I think the time it takes for light to travel argument is a red-herring [no offence SoulBiter ] because we are not talking about light travel - we are talking about instances of 'now' and whether they exist in a meaningfull way to different things, performing different activities at far removed parts of the universe......and I'm struggling with it.

Let's take our two atomic clocks, one on it's journey round the earth and one stationary, by my side on the ground. We have to agree that there has to be an instant, a 'now' for me that exactly corresponds to a moment - the same moment as for me on the ground - on board the plane. But a glance at the planes clock at that moment will show a fractionally different time [slightly behind] to the clock on the ground. Now consider that moment, that 'now' [still the same moment as the one we were considering before] from the perspective of the plane [lets say a person in the seat next to the clock] - due to the slight slowing of time that 'now' corresponds to an instant, a moment slightly before the moment we thought about above, for the person on the ground. Instant A [on the ground] corresponds to instant B [on the plane]. But instant B does not correspond to instant A, but rather to instant C on the ground - an instant that occurs [from the gounds perspective] fractionally before instant A. The slowing of time as a result of the planes motion cannot but have this effect - either logic dictates it.....or acceptance of relativity demands that we abandon logic all together! [Doesn't it? ]

[wayfriend]

But a glance at the planes clock at that moment will show a fractionally different time [slightly behind] to the clock on the ground.

Peter, what happens is that time is measured differently in the two frames of reference. Now here and now there are still simultaneous -- what's really happening is that the duration from an earlier now was measured differently. Like getting two different length measurements from a rubber band.

If it worked the way you say, then when the plane comes back, the two observes would still be in different nows. Which they are not. They are in the same now. Instead, one observer took a longer [in time] path to get from the old now to the new now.

[Fist and Faith]

Yes, time passes differently in different frames of reference. But in no frame of reference does everything happen in only one moment, which is broken into illusory successive intervals by our minds.

[Fist and Faith]

If it worked the way you say, then when the plane comes back, the two observes would still be in different nows.

Thanos did that to the Avengers once. They couldn't interact with anybody because they were always a fraction of a second behind.

[peter]

Yes, I see where you are coming from. Oh well, back to the drawing board ........! (serves me right to trying to learn physics from a 10 min YouTube video I guess )

[Vraith]

Yes, I see where you are coming from. Oh well, back to the drawing board ........! (serves me right to trying to learn physics from a 10 min YouTube video I guess )

Heh...don't give up...unless you want to.
And don't believe necessarily that you are the one coming up short...
There are many [if not most, at this point] physicists...I've seen at least 3 PBS-ish shows with different leading edge folk...who say much of what you said. Even used the slicing angle thing.
One said [I think it was that guy...Greene? He's done a number of shows...] that there IS a frame of reference where everything is all-at-once.
At one point he said we feel time like a river. But from otherwhere it is a frozen river. A single, solid thing.
I'm not at all sure that solves the "but that's just your relative frame" problem...in some ways, it makes it worse.

[peter]

Hey V! (Suddenly my day seems better!) Yes, surely it's a riddle wrapped in a mystery inside an enigma, but what in this damn physics game isn't.

Read a short essay the other day where a guy said gravity isn't a thing that occurs in space - gravity is space: and if so and space is also time then a GUT has to be possible. (I'd think )

[Hashi Lebwohl]

Read a short essay the other day where a guy said gravity isn't a thing that occurs in space - gravity is space: and if so and space is also time then a GUT has to be possible. (I'd think )

Precisely. "Gravity" is the "topology" of spacetime. Matter warps spacetime towards it and the greater the amount of warping the stronger the pull of gravity. We are simply missing one or two pieces of the puzzle and this prevents us from being able to form a unified theory. Once we have those missing pieces we can put them all in place.

[Vraith]

Because I've been unhappy for a while now with the block universe---where time is a delusion/illusion and/or derivative/emergent and/or just another dimension like space [[which it obviously is NOT. Whatever it is, it is in many precise ways un-space-like]]:

I tried putting a couple cool quotes here, but the Watch won't handle certain things anymore cuz it's format brain is ossified and I didn't feel like retyping or hunting down the problem.

https://www.quantamagazine.org/a-defens ... -20170516/

[Wosbald]

+JMJ+

Because I've been unhappy for a while now with the block universe---where time is a delusion/illusion and/or derivative/emergent and/or just another dimension like space [[which it obviously is NOT. Whatever it is, it is in many precise ways un-space-like]]:

I tried putting a couple cool quotes here, but the Watch won't handle certain things anymore cuz it's format brain is ossified and I didn't feel like retyping or hunting down the problem.

https://www.quantamagazine.org/a-defens ... -20170516/

Thanx for that.

The return to Realism in philosophy has had shockwaves.

I've heard good things about this book (it's on my secondary to-read list). It might well be up yer alley.

The Singular Universe and the Reality of Time: A Proposal in Natural Philosophy

Cosmology is in crisis. The more we discover, the more puzzling the universe appears to be. How and why are the laws of nature what they are? A philosopher and a physicist, world-renowned for their radical ideas in their fields, argue for a revolution. To keep cosmology scientific, we must replace the old view in which the universe is governed by immutable laws by a new one in which laws evolve. Then we can hope to explain them. The revolution that Roberto Mangabeira Unger and Lee Smolin propose relies on three central ideas. There is only one universe at a time. Time is real: everything in the structure and regularities of nature changes sooner or later. Mathematics, which has trouble with time, is not the oracle of nature and the prophet of science; it is simply a tool with great power and immense limitations. The argument is readily accessible to non-scientists as well as to the physicists and cosmologists whom it challenges.

[peter]

Interesting link V. Don't quite get why at some points the guy talks about time as if it were split off from Einstein's space-time and at others as though it isn't: surely space-time is either an entity......... it isn't? One thing: he refers to the question of why the system started in a low entropy state and this is a point that has rumbled about in my head in a disjointed sort of way. What does this mean exactly - can I take 'low entropy' as being synonymous with 'highly ordered', because there doesn't seem to be much order in the initial big-bang universe that I can see. Lots of initially sub-atomic stuff flying about then subsequently organising itself into hydrogen - seems that entropy was decreasing at this point does it not? (I know I'm wrong here, but what am I not getting?)

Now that looks like an interesting book Wos - my library better be able to get that for me or there'll be trouble!

[Vraith]

Interesting link V. Don't quite get why at some points the guy talks about time as if it were split off from Einstein's space-time and at others as though it isn't: surely space-time is either an entity......... it isn't?

[[[[[SNIP]]]]]

can I take 'low entropy' as being synonymous with 'highly ordered',

Pre-snip:
No, it isn't "split off"---as in there is no relationship between space and time---if that's what you mean.
But neither is it just another dimension, as most of the math/models attempt to treat it. And the problems/paradoxes of time now are, at least in part, a direct result of reducing/explaining time in space/dimension terms. I'm still pondering/struggling with it...but, for instance this is one thing I think he's getting at [or is at least implied in what he says]:
Imagine you live in a one-dimensional space...a line, with no height or width, just infinite length. Given that, it makes no difference at all which direction you travel the line, the space is all the same. But if that "line" is time, it makes all the difference in the world which direction you go. One direction is utterly different from the other.
I also think it relates to something I've mentioned elsewhere---you can travel at angles to a spacial direction. [even if only abstractly, for more than 3D for us]. But not for time. There is only forward, backward. No right or left turns. No angles.

Post-snip: No, you can't take those things as synonymous. You should look into it---start with wikipedia for initial discombobulation, then keep following the trail till total confusion reigns and you're only sure of one thing: they aren't synonymous....mostly/usually except when....
Then we'll be in similar states.

[peter]

Ok V. That's as good a starting place as any! The line analogy is good - I can get my head around that.