Block universe vs two senses of now.

[tar]

There is, in my estimation a requirement that one holds reality in an imaginary model of it, that one then compares against the input of the senses to judge change.

 

In this internalization process the model is judged against the model and an analogous version of the universe is judged against an analogous version of the universe. The space in the brain, and the time it takes signals to reach from one area to another, allow for the a priori understanding of space and time. Comparisons and analogies are built up from these already understood concepts, and from the synthesis of various thusly built up understandings, one can visualize and comprehend the table of judgments and the categories of Kant. And one can "say something" about the universe, without actually knowing the thing, as it is.

 

Addressing david345's questions to me, on the matter.

 

"1.Have you fully observed the nerves connecting your eyeballs to your brain. Do you have a complete explanation of your eyes and brain? How can you claim you can observe things if you have no proof you even know what observation is?"

 

No, but scientist have dissected mammals and done autopsies and found there are nerves connecting my eyeballs to my brain. I assume the arrangement in my head is similar to the arrangement in other mammals and other humans. I have what I consider observation, and I have what you consider observation and since we both have similar systems of observation and recording, when we stand together and look at the stars and I observe a shooting star, and you say "did you see that", I say yes.

 

"2.One can move in space because of time. How does one move in time? How does time flow?

 

Time "moves" at the speed of light. It is the pace at which the rest of the universe arrives at any single point of view, or at any single particular observer.

"3.Do you actually have something that disproves or contradicts the block universe?"

 

Yes. The human being cannot "see" faster than the speed of light. Therefore EVERYTHING that is not within a moment's view (say 2 to 3 seconds), is not happening currently, but has already happened in the past. The "flip flop" has to happen here, as one needs to imagine something happening now, at a distance, in order to see it as a present signal, later. And the signals from distant objects that are present now, must have been sent out, or have "happened" earlier.

"4.Yes or no. Have you took a god's eye veiw and seen the past disappeared."

 

There was a time when I was 13. That time, does not exist, here and now. From a god's eye view, there where an infinite amount of ages that I have been, but there is only one of them that is currently true, here and now, where I am. Nobody else in the universe has witnessed this particularly aged TAR, until they read this, at which point, I am actually a bit older, doing something else. You can imagine me doing something else, and know I must be doing something else, without seeing me do it. The particular arrangement of my neighborhood, the state, the country, the world, the Milky Way, and the local cluster has no doubt changed since I was 13. We all have seen it disappear, from our local, here and now perspective, AND from a god's eye view, that 13 year old, and the arrangement of the universe at that point in time, no longer exists. The images from that 13 year old exist, but only in a half shell 48 lyrs from where the Earth was when I was 13. Places in the Milky Way, like Proxima Centauri saw that 13 year old TAR 45 years ago, and are currently witnessing a 58 year old TAR and what the Earth was doing 3 years ago, in 2012.

"5. Yes or no. Does something not exist because you can't observe it at the present moment?"

 

It absolutely MUST exist, if it is at tremendous distance, so you can see it later.

"6. How do you explain the experimental eveidence showing time dilation? How does this agree with your universal now?"

 

I am not 100 percent convinced that time dilation is not what I am talking about. The "flip-flop" is between the local here and now, and the imaginary there and now. When two locations are separated by space, which is the definition of two locations, there are two observers required, to each take a place. There cannot be then a God's eye view, which establishes a third now, which sees them both happening at the same time. Einstein's definition of simultaneity is that light takes the same time to get from A to your eye as it takes light to get from B to your eye. If they arrive at your eye in the same instant, the two events, A and B were simultaneous. It is trivial to show that if I position myself so, I can see A before B or B before A, so the events are not universally simultaneous. But similarly it can be shown in a trivial manner, that to our first observer, both A and B happened before she saw the events. That is, that the events "happened" at a particular time, a universal time, that everyone that ever sees them, can calculate back, according to the distance they are from each event, and tell you what they were doing, or what time it was, when the distant event happened.

"7. You still have avoided answering weather the universe had a beginning or has been around forever."

 

I am thinking that the universe started 13.8 billion years ago, but most likely required some initial conditions from which to start.

"8. Yes or no. Do you believe in universal simultaneity?"

 

No. I believe there is here and now for every observer, and a universally true "present" moment that is what is occurring for the first and only time, everywhere, now.

"9. Is time the fourth dimension?"

 

Yes.

"10. How fast does time flow?"

 

Speed of light.

"11. If your theory is LET then why do you keep talking about what can't be observed when LET is based off the additional assumption of an unobservable ether?"

 

I think of the ether as an imaginary construct. One can always put themselves in the shoes of another, in an imaginary fashion, but cannot actually be the other. The "flip-flop" is important to control. You can experience the guy standing on your right and imagine you are standing to his left, but that is not a paradox. Both conditions are true, as long as you carry everything over to the other perspective, and realize there is a "true" direction the Earth is rotating in, whether you look at it from the top or the bottom. It is just going one way and that is neither clockwise, nor counter-clockwise, but that singular direction that it would have to be going in, for someone to see it turning counterclockwise when imagined from above, and clockwise, when imagined from below.

"12. If the present doesn't exist then does the light you see come from things which did not exist?"

 

The present absolutely exists. Twice. Once from here and now. Once from everywhere at once. Each item that currently exists, from the universal now perspective only exists once, and is currently doing what it is doing, for the first and only time it will do it. When we see light coming from a distant object, it is representative of what that object was doing previously, but is reaching us currently and is the only way we will ever witness that object from here and now. But, let's say we would go to that distant object, very quickly. We would never be able to get there now, and see what it is doing currently, because it would age, during the trip. But when we got there, both us and it would be exactly the age of the universe, and looking back at the Earth, the Earth would look like it was doing something after we left, but it would be a not up to date image, and what the Earth was currently doing would not get to us until light traveled the distance between.

 

"13. How does one detect this universal reference frame which represents the universal now?"

 

One imagines it having to be the case. One detects the universe, exactly as we detect it. One photon at a time.

Regards, TAR

Edited August 3, 2015 by tar

[Strange]

Time "moves" at the speed of light.

 

That doesn't make sense. Speed (of light, or anything else) is measured in metres per second (or equivalent). How can you define time in m/s?

 

I suppose you could define the "speed of time" as 1 second per second but that is pretty meaningless.

 

Einstein's definition of simultaneity is that light takes the same time to get from A to your eye as it takes light to get from B to your eye. If they arrive at your eye in the same instant, the two events, A and B were simultaneous.

 

That is not the definition of simultaneous. If A is closer but you see it at the same time as B, then A obviously happened first.

 

But similarly it can be shown in a trivial manner, that to our first observer, both A and B happened before she saw the events. That is, that the events "happened" at a particular time, a universal time

 

I don't see how that follows.

[tar]

Strange,

 

Well, considering that one second per second means nothing, at least time moving at the speed of light, means something.

 

Perhaps it means nothing unless you consider that when two things are separated by a distance, the two things also are separated by a certain time. Like the Mars rover, doing something now, and us seeing it 14 minutes later. If we would see it approaching a hole, and tell it to turn left, we would have to give it the instructions planning that it will keep going toward the hole for 28 minutes. It's here and now, and our here and now are separated by a distance. That distance is a time like distance, when you consider that it takes a message 14 minutes to link the two here and nows.

 

If you claim two events were similtaneous, and they were not the same distance from you, and you saw them at the same time, you would be wrong.

Consider you see Alpha Centauri shining at the same time you see Andromeda shining, and the two events are not simultaneous.

 

Regards, TAR

[MigL]

Don't follow any of this or see what it has to do with the 'block universe'.

 

The block universe is an off-shoot of Einstein's GR, which basically states that every event, past, present and future, is embedded in the 'block' of space-time, and as such, is deterministic, by definition.

Current science does not consider the universe deterministic ( one of the short-falls of GR ).

 

Laplace's demon was one early attempt at demonstrating the absurd results of determinism ( look it up ).

Chaos theory and QM's Uncertainty Principle nailed the coffin shut on determinism.

[david345]

3. How does this contradict the block universe? The block universe is in full agreement with relativity. In the block universe light moves at the speed of light. It takes time for light to reach your eyes. Nothing in the block universe requires you to see anything instantly. Light acts the way you describe it.

 

Your argument of two senses of now can apply to anything.

There are two senses of red apples. When I look at the apple it is the red I see. When I'm not looking it is the red I imagine it to be.

There are two types of the leaning tower of Pisa. When I'm looking it is the leaning tower I see. When I'm not looking it is the leaning tower I imagine it to be.

 

I don't understand why you are so obsessed with the speed of light. You act as though it is some sort of magic wand capable of disproving anything I say.

David: The Warriors won the NBA championship.

Tar: Only in your imagination. The light hadn't reached your eyes yet...

 

If you are claiming something doesn't exist because you can't see it instantly then you are claiming nothing exists.

 

4. "We all have seen it disappear, from our local, here and now perspective, AND from a god's eye view"

 

13. This reference frame can never be detected. Not now, not in the past, not in the future. No one has ever detected it and no one ever will. Your theory is based off that which is completely undetectable.

 

Tar: "It's here and now, and our here and now are separated by a distance. That distance is a time like distance".

No, actually that would be considered a space like interval. It's past and our present would be considered a time like interval if sufficient time has elapsed for a signal traveling light speed or slower to reach us.

 

Migl,

The block universe mainly applied to realtivity although it does apply to certain interpretations of quantum mechanics such as many worlds theory.

 

The subject of chaos is a difficult one. I am currently finishing up "differential equations, dynamical systems, and an introduction to chaos." The chapters on chaos are not easy. Chaos is not inconsistent with determinism. They are sensitive to initial conditions. There is what is called a sensitivity constant. Often chaotic systems are studied by reducing the study of flow to the study of the Poincare map. One may also analyze systems using symbolic dynamics. We are a long way off from understanding chaotic systems such as the Lorenz system. Simpler systems of differential equations have equilibrium points such as saddles or sinks. Others have limit cycles. Solutions may approach a circle from the outside and inside. 2 × 2 autonomous linear systems can largely be understood using only the trace-determinant plane. Chaotic systems are not so easy. The Lorenz system is a famous chaotic system. With certain perimeters it has an attractor. An attractor for the flow is an invariant set which attracts all nearby solutions. In two dimensions an attractor can be just equilibrium points, limit cycles, and the solutions which connect them. In higher dimensions you can have stranger attractors. You could think of these as strange shapes or sets which attract nearby solutions.

Here are some examples of chaos:

 

Theorem. (Dynamics of the Lorenz Model) The Poincaré map P restricted to the attractor A for the Lorenz model has the following properties:

1. P has sensitive dependence on initial conditions;

2. Periodic points of P are dense in A;

3. P is transitive on A.

We say that a mapping with the above properties is chaotic. We caution the reader that, just as in the definition of an attractor, there are many definitions of chaos around. Some involve exponential separation of orbits, others involve positive Liapunov exponents, and others do not require density of periodic points.

 

Like I said. These chapters were not easy. Take my statements however you like.

Edited August 4, 2015 by david345

[Strange]

Well, considering that one second per second means nothing, at least time moving at the speed of light, means something.

 

You seem to be confusing the time it takes light to reach you with the rate at which your clock ticks. Does your clock tick at the speed of light?

 

 

If you claim two events were similtaneous, and they were not the same distance from you, and you saw them at the same time, you would be wrong.

 

So you admit you were wrong about that, at least. Good.

Chaos theory and QM's Uncertainty Principle nailed the coffin shut on determinism.

 

Chaos theory certainly didn't. The whole point of chaotic systems is that they are completely deterministic. But unpredictable.

[MigL]

Consider a pool table with balls scattered on it.

You would think that with Newton's laws you could completely determine the future evolution of the system, and if the system was linear in response you'd be right. That is if a small adjustment made in the motion of one ball resulted in a small adjustment to the evolution of the system.

In chaotic, or non linear systems, that is not the case. A trivial adjustment in the angle of the trajectory of one ball may allow it to completely miss its intended target, resulting in a totally different ( non linear ) future evolution.

Now Heisenberg's principle doesn't allow us to know the exact states of quantum particles, but these effects 'average out' in the macroscopic world we live in.

So neither, by itself will get rid of determinism. But when the two are combined, even a quantum fluctuation, combined with a non linear response will make any future system evolution unpredictable, ie. non deterministic.

[tar]

Strange,

 

I might be confusing things from time to time, but It is because I might be thinking of things from the "universal now" point of view, as well as from the "here and now" point of view, and when I think things make sense to me, and seem to be true from both points of view, I might make a statement that seems contradictory from a "one now" point of view, or a block universe point of view, but I present the notion as a solution to the contradiction, not as a creator of paradox.

 

If here and now is true for us, it must also be true for the Mars rover. Since there is only one instance of the Mars rover, it must be doing only one thing currently. When we see it doing it, in its here and now 14 minutes have already passed, and it has done 14 minutes of things in its here and now. We imagine it has done 14 minutes worth of stuff when we see it doing the thing it did 14 minutes ago. If "right now" in the universal now sense, there is an observer halfway between us and the Mars rover, she will see what the rover was doing 7 minutes ago. If there is an observer on Mars, they will see what the Rover is doing now (in the universal now sense.)

 

The thing the rover is doing right now in the universal now sense, is the same thing it is doing when we see it 14 minutes, when the middle observer sees it in 7 minutes and when the Mars observer looks at it now. I have the clock ticking equally fast at every location in the universe. I have every location in the universe exactly as old, as the universe, with 13.8 billion years of history of events in that location, behind it.

 

Where the requirement for both nows to exist come in, is in the fact that we "see" what happened at certain locations, in all directions, 13.8 billion years ago. Those photons are "really" hitting our equipment NOW. But, that location, whose photons we are currently receiving has had 13.8 billion years to do other stuff, in the same sense that the Mars rover has had 14 minutes to do other stuff. The hydrogen in that location has probably evolved into quasars and galaxies, and 2 or three generations of stars and associated planets have occurred, there, in that here and now. That here and now exists as surely as the CMB. So that location exists, is real, is true, in two senses. One, according to its own here and now, and one, according to some distant observer's here and now. Since there are an infinite amount of locations in the universe, each a different distance, or at least a set of locations at every ly distance between 1 ly and 45 billion lys distance from that location, there are at least 45 billion different ages that observers could see that location as being, from their here and now. So if you want to assume the consciousness of each and every possible observer, you could say that everything that ever happened in the universe is happening right now, in somebody's here and now, but that is only half of the block universe claim. The block universe claims as well that all future events exist. Where? They have not happened yet. Anywhere. They remain undetermined, until they happen.

 

Regards, TAR

First they happen in the universal now, and then later they happen here, when the photons get here and now, from there and then. Where ever the here and now you are analyzing happens to be, it is currently 13.8 billion years old, and sees a universe that "looks" just like it looks from here, with old stuff close by and young stuff far away.

The most recent moment that the universe has ever experienced just happen right in front of you, in your own house. And that goes equally for every observer in the universe. What happens next, will happen for the first time, everywhere.

Edited August 4, 2015 by tar

[Strange]

This is just the same old nonsense about "two nows" and a "universal now". It is hard to imagine how that can make sense to anybody.

 

You seem to think that something happens again just because some light from it happening reaches you. Presumably that means that it happens an infinite number of times as the light passes every point in space.

 

 

I have the clock ticking equally fast at every location in the universe. I have every location in the universe exactly as old, as the universe, with 13.8 billion years of history of events in that location, behind it.

 

And that is why you are proven to be wrong. Again. Neither of those statements are true; neither can be true in the universe we inhabit.

But when the two are combined, even a quantum fluctuation, combined with a non linear response will make any future system evolution unpredictable, ie. non deterministic.

 

Unpredictable and non-deterministic are separate concepts.

 

Quantum effects are non-deterministic but predictable (at least in terms of probability).

Simple classical systems are deterministic and predictable.

Chaotic systems are deterministic but not predictable.

[MigL]

And when you combine quantum effects with chaotic systems, what do you get ?

[Strange]

And when you combine quantum effects with chaotic systems, what do you get ?

 

Something which is neither deterministic nor predictable.

 

In other words, real life.

[david345]

According to the block universe the past, present, and future are all there. This does not necessarily require the future to be determined by the past.

With a chaotic system a small change in initial conditions can lead to big changes later on. They aren't necessarily completely unpredictable. A small error can grow to a large error over time. Typically Lyapunov time is used. You would probably need infinite precision to predict their behavior for all future times. There are still ways to understand chaotic systems even if your initial conditions are off. Some systems have a chaotic attractor. If two initial conditions start far apart both will move towards the attractor. Once they are at the attractor they will move away from each other while remaining on the attractor. The solutions will move away from each other as you would expect from a chaotic system. The interesting thing is that they will remain on the attractor even though they are moving apart from each other.

Consider the example from Differential equations, dynamical systems, and an introduction to chaos:

In Figure 14.1, we have displayed the solution curves through two different initial conditions P1 =

(0, 2, 0) and P2 = (0,−2, 0) Note how both solutions start out very differently, but eventually have more or less

the same fate: They both seem to wind around a pair of points, alternating at

times which point they encircle. This is the first important fact about the Lorenz

system: All nonequilibrium solutions tend eventually to the same complicated

set, the so-called Lorenz attractor.

There is another important ingredient lurking in the background here. In

Figure 14.1, we started with two relatively far apart initial conditions. Had we

started with two very close initial conditions, we would not have observed the

“transient behavior” apparent in Figure 14.1. Rather, more or less the same

picture would have resulted for each solution. This, however, is misleading.

When we plot the actual coordinates of the solutions, we see that these two

solutions actually move quite far apart during their journey around the Lorenz

attractor. This is illustrated in Figure 14.2, where we have graphed the x

coordinates of two solutions that start out nearby, one at (0, 2, 0), the other (in

gray) at (0, 2. 01, 0). These graphs are nearly identical for a certain time period,

but then they differ considerably as one solution travels around one of the lobes

of the attractor while the other solution travels around the other. No matter

how close two solutions start, they always move apart in this manner when

they are close to the attractor. This is sensitive dependence on initial conditions,

one of the main features of a chaotic system.

Another good explanation of chaos and the attractor.

http://theconversation.com/explainer-what-is-chaos-theory-10620

Edited August 5, 2015 by david345

[MigL]

Interesting stuff.

 

I remember when first studying statistical mechanics, thinking " how is it possible to model the behavior of a billion, billion particles ?"

I was young and naïve.

Now we're building mathematical models to predict the 'unpredictable'.

[tar]

david345,

 

Interesting article on chaos.

 

I did not know about the Feigenbaum constant. Still don't, as I don't fully comprehend what is happening there, but it still leaves a question, whether the future is determined or not, as to where this "there" is that you claim that the future is.

 

Is there an observer somewhere that is experiencing this future...now? Can we/will we ever have any contact with this observer? That is, what is the connection with our universe, our reality, that this future, that exists, and is real, according to block universe existence? Where and when is it happening, and when will people on Earth know about it?

 

Regards, TAR

Thread,

 

It is said that the universe is "currently expanding" at an accelerated pace. Is this sensible? Does it concur with a block universe approach? If a block universe approach is sensible, how does one pick a current condition for the entire universe, past present and future, to be in?

 

Regards. TAR

Strange,

 

"You seem to think that something happens again just because some light from it happening reaches you. Presumably that means that it happens an infinite number of times as the light passes every point in space."

 

Well yes. That about sums up what I think must be the case, for us to see something in the sky tonight, happening, that actually happened 3 years ago, or 50 thousand years ago. It requires that a location in space 16billion miles closer to the events, saw the both things happen yesterday, and an observer 16 billlion miles in the opposite direction will see both events tomorrow.

 

Regards, TAR

[Strange]

It is said that the universe is "currently expanding" at an accelerated pace. Is this sensible? Does it concur with a block universe approach?

 

Of course it does. The expanding universe ("big bang") model is based on GR which is, as you now know, treats space-time as a static 4-dimensional manifold (the "block universe").

 

You may be able to visualise this by an analogy: as you move away from the north pole, the lines of latitude get longer (expand). Similarly, at increasing coordinates along the time dimension, the spatial dimensions of the universe get larger.

 

If a block universe approach is sensible, how does one pick a current condition for the entire universe, past present and future, to be in?

 

This makes no sense. What does "current" condition mean when you are talking about past, present and future?

 

"You seem to think that something happens again just because some light from it happening reaches you. Presumably that means that it happens an infinite number of times as the light passes every point in space."

 

Well yes. That about sums up what I think must be the case, for us to see something in the sky tonight, happening, that actually happened 3 years ago, or 50 thousand years ago.

 

I intended that as a slightly satirical comment because I couldn't believe anyone would really think that.

 

A supernova is an event - something that happens at some specific point in space and time (x₁,y₁,z₁,t₁). Your perception of it is another, separate, event that happens at a different point in space-time (x₂,y₂,z₂,t₂). There is no concept of "now" in any of that. You might choose to label the event where you perceive it as "now" but by the time you say that it is already in the past (and therefore not "now").

[tar]

Strange,

 

I understand it was sarcasm, from your point of view, but I do actually understand the way I am looking at it, and it is not so much for me a matter of thinking that such is the way I am thinking about it, as much as I think that the simple requirements I am describing, are the way it must be, to add up and make sense.

 

david345 asked me 13 questions, which I answered

 

Let me ask you and anyone else that wants to respond these two questions and a follow up.

 

Is it true that the Sun is here now, burning in our sky, and providing life giving energy to the life forms on this planet?

Is it true that the photons from the Sun that strike the Earth this moment, here and now, left the Sun 7 minutes ago?

 

Is there any other way to understand this, but that the Sun is currently, now, sending out photons, that we will experience, in 7 minutes?

 

Regards, TAR

[MigL]

And you don't seem to understand that a 'local now' does not apply to something that is 7 ( more like 8 ) light-minutes away.

The only information and effects you can possibly get from the Sun are 8 minutes removed.

 

It makes no sense to say " I am seeing the Sun as it was 8 minutes ago; What is it actually doing 'now' ? "

[Strange]

I understand it was sarcasm, from your point of view, but I do actually understand the way I am looking at it, and it is not so much for me a matter of thinking that such is the way I am thinking about it, as much as I think that the simple requirements I am describing, are the way it must be, to add up and make sense.

 

I don't think that something which only makes sense to you is useful as a description of "the way it must be".

 

Is it true that the Sun is here now, burning in our sky, and providing life giving energy to the life forms on this planet?

 

What do you mean by "here" (but no, it is about 150 million km away, not here). And what do you mean by "now"? Do you mean we can see it now? Or that it is 150 million km away now?

 

Is it true that the photons from the Sun that strike the Earth this moment, here and now, left the Sun 7 minutes ago?

 

Just over 8, actually.

 

Is there any other way to understand this, but that the Sun is currently, now, sending out photons, that we will experience, in 7 minutes?

 

Correct.

I think the problem is that you are trying to apply the vague and subjective concept of "now" to a rigorous model. It won't work.

 

Events are defined by their space-time coordinates (x,y,z,t). Relativity tells us how different events are related. There is no such thing as "now" in relativity.

Edited August 5, 2015 by Strange

[lulugaga]

Interesting stuff.

 

I remember when first studying statistical mechanics, thinking " how is it possible to model the behavior of a billion, billion particles ?"

I was young and naïve.

Now we're building mathematical models to predict the 'unpredictable'.

what's interesting there, just curious.

 

Time is a distraction from seeing things sharp. The break of light is the key, watch nature.

Numbers mean nothing so does maths, just leading to the illusion of ever being able to be faster than light can carry on information.

This is phil here right?

[tar]

Strange,

 

Well you are right. Just because I think it "must be" a certain way, does not mean it must be that way. The universe will be exactly as it is and do exactly what it does, whether I "get it" or not. But that goes the same for the people that model the universe as a block. What works in their head, does not have to be the way it is. Particularly when we speak of time, and immense distances. You can't wrap your head around such things...that is, the model is going to be insufficient to account for all the actual relationships involved. The reality is too immense and longlived, for a model to do it justice. And you have the boundary condition problem, of not being able to take a stand somewhere where you can see the whole thing at once. In the block universe model you have spacetime coordinates that allow for each time and place to have its own existence, with no place and time for that existence to take place. It makes no sense to me. The universe itself has laid out a particular way of being, of existing that I believe has to be exactly the way we see it, the way we "get it". We are in and of the universe, our way of sensing it, and remembering it, and affecting it, and being affected by it, has to be the actual way it is done. I reject the consideration that the universe is "weird" and impossible things are possible, like a broken glass coming back together, because its condition as a whole glass is just as real as its condition as a bunch of shards. Its not sensible to think such. You cannot assume a godlike position where you can make up the rules, and see things from an other than human perspective, when the human perspective is the one that you see the universe from, in the first place.

 

Subjectivity and objectivity are real states that a human can have, but only in the sense that I can put myself in someone else's shoes. I cannot put myself in God's shoes, and neither can you.

You cannot see the Sun both as it currently is, and as it currently is. You have to understand that the objective observer is just as bound to the realities of the universe as the subjective observer is. When you talk about a rigorous model, you forget that there is nothing more rigorous already than the reality itself. It already fits together flawlessly, the Sun is already connected to the Earth by streams of photons that have been going on for millions of years. It already fits, the Sun is already "here" and in addition, it takes light 7-8 minutes to get from the Sun to the Earth, so the Sun MUST currently be sending out some photons, for us to see when we look at the Sun in 8 minutes.

 

The flip-flop, between model and reality, between subjective view and objective view, has to be made completely and each time, the shift in perspective is made.

 

david345 suggested in the "is the universe created alone" thread that relativity was a block universe

 

This turn of phrase indicated to me, that he had his rigorous model and his objective universe, all fouled up. The universe is going to be what it is, no matter what we say about it, or think about it, here, today. And for that matter, what the brightest Cosmologist on the planet has to say about it, does not make a bit a difference as to what the universe has done, up to now, and what its going to do next, except in the very local universe, as in our planet and solar system and maybe 100 lyrs out. Beyond that, we don't have much knowledge or control. Things happening NOW just on the other side of the Milky Way, will not "get here" informationwise, for 100,000 years. Being a pen pal with somebody on the other side of the Milky Way is not a possible thing in this universe. Not the way its laid out. You are dead before your message makes it a fraction of the way there, and you have not decided whether you are talking to someone you just saw on that planet (who has been dead for 100,000 years) or whether you are imagining someone living there Now, who will have been dead for 100,000 years, by the time your message gets to them.

 

Either way. You have to shift you sight from your eyes, to you mind's eye, appropriately inorder to understand what is possible in this universe, according to the way it is laid out. The way our measurement, and imagination understand it HAS TO BE laid out, for us to see what we see, and for us to imagine what we imagine.

 

If the Sun is 8 light minutes away. It must not be burning now, as it could have just blown up. We only know it was burning 8 minutes ago. But its been burning rather consistently for millions of years, so we can expect, that in 8 minutes it will still be burning in our skies and warming our skin. So we can imagine, that it MUST be burning now, for us to see it burn in 8 minutes.

 

Regards, TAR

Same thing for "the universe is currently expanding".

 

All our information is old. The further away, the more uncurrent, it is. It could have slowed its expansion to a stop and we would not see it doing that immediately. What we see the universe doing is not what it is currently doing. Heck, what we see the Sun doing, is not what it is currently doing. We won't even know that, for 8 minutes.

Edited August 6, 2015 by tar

[Strange]

Strange,

 

Well you are right. Just because I think it "must be" a certain way, does not mean it must be that way. The universe will be exactly as it is and do exactly what it does, whether I "get it" or not. But that goes the same for the people that model the universe as a block.

 

Nope. Because that is a mathematical model based on evidence and confirmed by large numbers of experiments.

 

 

You can't wrap your head around such things...that is, the model is going to be insufficient to account for all the actual relationships involved.

 

Irrelevant. The model works, even if you can't visualise four-dimensional pseudo-Riemannian manifolds.

 

 

It makes no sense to me

 

<shrug>

 

If the Sun is 8 light minutes away. It must not be burning now, as it could have just blown up. We only know it was burning 8 minutes ago. But its been burning rather consistently for millions of years, so we can expect, that in 8 minutes it will still be burning in our skies and warming our skin. So we can imagine, that it MUST be burning now, for us to see it burn in 8 minutes.

 

For one thing, we know a lot about the way stars work so it is more than an assumption that the sun is still burning now.

 

On the other hand, Betelgeuse might have already gone supernova. We might see that tomorrow or in 600 years. Or it might not happen for another million years.

 

But so what? There are things we cannot know. Big deal.

[MigL]

 

And you still don't grasp that " what its currently doing " is meaningless.

 

The Sun could have stopped burning, or even vanished, but nothing would change for 8 min.

Its image, heat, gravity, etc., would be exactly the same. We would see it in the sky, feel its warmth and continue orbiting it for 8 min, as no information can travel any faster.

 

You can imagine what the Sun is 'currently' doing, but that's all it is until information reaches us, IMAGINATION.

Edited August 7, 2015 by MigL

[tar]

Strange,

 

"For one thing, we know a lot about the way stars work so it is more than an assumption that the sun is still burning now."

 

Well...that is my point. It seems simple and required and evident to me. I don't understand why you are arguing that my view is nonsense.

 

There is something that the Sun MUST be doing NOW, for us to receive the released photons in 8 minutes.

There must be some photons half way here 3/4 of the way here, and 186,000 miles away, right now in order for us to see the Sun burning in 4 minutes, 2 minutes and one second from now.

How could it be otherwise?

 

Regards, TAR

[Strange]

There is something that the Sun MUST be doing NOW, for us to receive the released photons in 8 minutes.

There must be some photons half way here 3/4 of the way here, and 186,000 miles away, right now in order for us to see the Sun burning in 4 minutes, 2 minutes and one second from now.

How could it be otherwise?

 

I don't see why anyone would disagree with that (well, maybe, if it is stated in terms of photons; but if you use classical light waves then it is obviously true).

 

What possible connection does that have with your idea?

[tar]

MigL,

 

What is difficult about the shift between what is being sensed and what is being imagined, in this regard (that of the two senses of now) is that the one is the flip side of the other. That is, while you hold the one as real, the other is imaginary. It is a matter of convention, or of definition, to decide if you are going to call the one real and the other imaginary, or the one knowable and the other unknowable, or the one subjective and the other objective...or, accept that both are true, at the same time, in their own sense. When I started "thinking" this way, I thought I was actually understanding what relativity means. That things are true from one's reference frame AND they are true in a fitting way from another as well. Giving all reference frames, all "current" positions in the universe, the age of the universe, and an imaginary (in the sense that we have to visualize it existing outside our view, but within our comprehension) existence, which turns out to be the actual existence, that later shows itself to be the case, as the photons arrive...all adds back and makes sense, and connects the whole universe to the other parts, in exactly the way they are connected. By the speed of light.

 

Regards, TAR

Strange,

 

That is my idea. What part of my idea are you calling nonsense, when that is the basis of my idea, that there are two nows. The one that is actual, that we don't see, and the one we see that is actually an image of the distant event. (which is the way all observers in the universe, must see it, so it IS reality. The two senses of now.)

 

Regards, TAR

Edited August 7, 2015 by tar