A Portrait of reality 2nd edition.

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"outer edges" of the known universe. Not outer edges of infinity.

"The acceleration is drawn from mapping movement of younger galaxies, not by tracking changes for any one thing. The latter requires far more time than is practical." May it be impractical, but the currently used data yields inconclusive results.

That's my entire point. That unequal acceleration may happen now, but it is also possible it is not happening now but happened for a limited time in the past. The currently available data supports both theories.

I don't want to go farther with this. You, Noax, keep proving that speeds are different. I have already accepted that. You keep proving relentlessly, mercilessly and ceaselessly, that more distant something is from here, the faster it moves away from us. This I accept as well, so no need to labour the point. The only thing, the ONLY thing I am after is what tells us that the acceleration is happening now, currently, opposed to the unequal acceleration having occurred any time in the past.

All we know is speed. And that speed increases with the distance away from us -- linearly or quadratically, does not matter. It tells us unequal acceleration has occurred but it does not tell us conclusively whether the unequal acceleration occurs now or occurred in the past. Yet that is what I'm after, to know that, to nail that down.

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if the universe is expanding, wouldn't the rulers (measuring devices) expand as well?

-Imp

No, it's only the space between galaxies that's expanding. The galaxies themselves and the stuff in them is largely held together by gravity, EM forces and perhaps dark matter.

According to what I've read so far, everthing is expanding, except, of course, space. Space is a given, it can't expand or contract. I mean empty space, the three dimensional empty space.

However, what uwot was saying, as I decipher it, is that not only the outer edges are accelerating outwardly, but everything is acceleratingly separating from other stuff. And "other stuff" means literally all other stuff.

This is based on the observation that the further away things are, the faster they are separating from "other stuff".

So they extrapolate what they can observe over extreme distances and conclude that the "outwardly pushing effect" of the stuff is acting also on sizes of objects our size-- and also on smaller objects, down to protons.The only things that can't get ripped are electrons and other quarks.

This is what leads to what Noax termed "ripping apart" effect, which will mean the death of the known world as we know it. The ripping effect will occur on the same principle that sees solids rip apart as they expand. That is an unavoidable truth.

Solids rip as they expand, because -- here you need to know a bit about analytical geometry -- linear expansion is related quadratically to areal expansion, and linear expansion is related to cubical expansion cubically. And therefore no matter which way the linear expansion happens, no matter which dimensionalilty gets expanded (line, area, or volume), the other two can't increase proportionally, so they rip.

This is what the expansion theory predicts. If I understood it correctly.

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if the universe is expanding, wouldn't the rulers (measuring devices) expand as well?

-Imp

Yes, that's exactly what and how I objected.

They (whoever "they" are) use the measurements of distance increases and of speed increases in far away bodies, because magnitude of separation distance increases with magnitude of speeds between separating parts, and that is easier to observe in large, far away objects than in tiny objects like us. The separation right now is one percent every 150 million years (if I read Noax correctly). That is, any two objects in our known universe, that are 150 million light years apart, are moving at speeds with one percent difference.

The ripping-apart theory tells us that this separation is going to increase in its rate, and they suspect that by seeing that the farther away things are from each other, the faster the separation is.

[uwot]

Hi, Will. thanks for the special consideration to my criticism.

You're welcome, it was very constructive.

A. Page ten reiterated that the farther away the stuff is, it moves quicker away from the observer. That has already been accepted, I had accepted that, there was no problem with accepting it. Due to red shift.

Yeah, but I liked your point that the more distant galaxies should be redder, so I tweaked the colours.

B. Page 31 mentions the dark matter.

Dark energy. As Noax points out, they are different hypotheses to account for different phenomena.

Now, this is important:
B.1. Was dark matter B.1.a. discovered or B.1.b. hypothesized to exist BECAUSE they knew (or mistakenly believed) that the universe was accelerating outward, and therefore they needed this hypothesis to explain it?

It's the latter.

B.2. Has the acceleration been observed, in any way? I hardly think that the red shift got shifted any noticeable amount in a person's lifetime, or in two or three human generations' time.

In a nutshell, until 1999, it was generally assumed that gravity would slow down the expansion of the universe. The issue was not particularly urgent, but it implied that in several billion years gravity would halt the expansion and perhaps, over several more billion years, pull everything back together into a reverse of the Big Bang called the Big Crunch. To find out if and when this would happen, a team of scientists searched the skies looking for type 1a supernovae. These are believed to be caused by a white dwarf star hoovering up material from a companion star. In essence, there is a critical mass, beyond which a particular type of white dwarf blows up. Since this mass is the same for all such white dwarves, they always explode with the same brightness so are what are called 'standard candles'. So if you measure the apparent brightness, you can work out the distance. It was expected that supernovae in more distant galaxies would show less red shift than would be expected if the universe was expanding at a steady state, i.e. the expansion was slowing down. In fact the apparent red shift is demonstrably greater.

C. Is it possible that some ancient mind (by ancient I mean the age of the original thinker's mind who's come up with the explanation of why the red shift at the outer edge of our known universe is happening) explained the red shift as a function of current acceleration, and everyone accepted it, instead of explaining the red shift as a remnant of an acceleration at the time of the big bang? After all, the red shift we see is as old as the universe. So why suppose that the dark matter exist, if the ONLY reason we assume it exists is that we see the red shift, and we assume that it never stopped accelerating?

Well, it is the fact that the expansion appears to be accelerating that gave rise to the hypothesis. It's basic Newton, F=ma, things don't accelerate, unless there is a force acting on them.

Please tell me the answers to these questions as per the currently accepted consensus of scientific literature. Thanks.

The closest thing to a consensus is the Lambda Cold Dark Matter model (ΛCDM). Basically, Λ is whatever the acceleration of the expansion turns out to be and CDM is whatever is providing the extra gravity that prevents individual galaxies being torn apart by their rotation. You have to bear in mind that, as Richard Feynman said in the link Troll provided, "every theoretical physicist that's any good knows 6 or 7 different theoretical representations for exactly the same physics." The consensus (which in practise is the physics) is that the evidence clearly shows that there are forces we can see, but that we cannot see the causes of.

The football pitch thing is interesting... it sounds so strange to my ears. Oh, well, stranger things have been known to happen. You see, you pitch a baseball in North America... from a pitcher's mound.

Ah well, where I'm from pitch is what you use to tar and feather witches. Horses for courses.

[uwot]

if the universe is expanding, wouldn't the rulers (measuring devices) expand as well?

-Imp

Yes, that's exactly what and how I objected.

Nah. The best analogy I can think of is Catherine Wheels (a firework AKA pin wheel, apparently) In effect, a particle of matter is the body of the firework and space the sparks. The difference is that the fuel doesn't run out and the sparks don't go out, not so far at least.

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In a nutshell, until 1999, it was generally assumed that gravity would slow down the expansion of the universe. The issue was not particularly urgent, but it implied that in several billion years gravity would halt the expansion and perhaps, over several more billion years, pull everything back together into a reverse of the Big Bang called the Big Crunch. To find out if and when this would happen, a team of scientists searched the skies looking for type 1a supernovae. These are believed to be caused by a white dwarf star hoovering up material from a companion star. In essence, there is a critical mass, beyond which a particular type of white dwarf blows up. Since this mass is the same for all such white dwarves, they always explode with the same brightness so are what are called 'standard candles'. So if you measure the apparent brightness, you can work out the distance. It was expected that supernovae in more distant galaxies would show less red shift than would be expected if the universe was expanding at a steady state, i.e. the expansion was slowing down. In fact the apparent red shift is demonstrably greater.

Right. So the supernovae that are farther away, are going faster away than expected.

But what is the expected? This is a big question. Please answer it.

If the expansion was slowing down, the rate would not be steady, either. So there is a bit of sloppyiness in your text.

That the universe was expanding at a steady rate of "Speed" or "acceleration"? This is important, so please clarify.

If it's a steady rate of "speed", and I assume this is what you meant.... then you can only say that they have been accelerated, or they had been accelerated with a higher rate of acceleration, or at the same rate but for a longer time, or both. But you can't validly extrapolate that the different rates of acceleration are happening now. It could have happened a long time ago.

Let's make a diagram.

me ...............B=1.0, v=V1.................B=1-n, V=V2.............. B=1-n-m, V=V3..

Where n is a positive fraction, m is a positive fraction, and n+m <1; and V1 < V2 <V3.

I understand this is what you talked about.

B describes the brightness of the supernova, V describes the speed of the supernova, both as a function of distance away from me. (me stands for Me, first person singular, in the objective case. I should have written I, I guess.)

B simply defines the distance. It has no other function.

V is larger the farther away form me the supernova is.

Is there something I missed?

Please state what the expected V1, V2, V3 values would be and what they are now... but you don't have to if you admit that the acceleration's happening is not necessarily occurring now. According to what we know now.

If it is indeed ABSOLUTELY TRUE that it's happening now, I would like to see some explanation in terms of V1, V2, V3, and other observed factors or agents pulled in that are needed for the proof.

Please don't forget also to tell me whether the rate of expansion is meant to mean rate of speed, or rate of displacement, or rate of acceleration, and if it's one or the other, how it is measured. Just "rate of expansion" does not cut the mustard, so to speak. So changing rate of expansion is a change in speed, or a change in acceleration? And if the latter, then I need a good explanation. If the earlier "change in speed", then I stick to my guns and say that the increased acceleration could have happened a long time ago just as well as it could be happening now, and we simply don't know which is the case.

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uwot, sorry to put you through the grinder, but I do it for three reasons:
1. I can trust you for your knowledge and for being able to express yourself
2. You seem to be giving me the time of day, so to speak
3. I believe I have a very valid point which no physicist or cosmologist has thought of.

I shall cease and desist from barraging you with these arguments in one of three ways:

1. You simply ignore my questions (not very attractive for me, but I shan't have a choice but accept it)
2. You convince me that the acceleration is happening now
3. You agree with me (sincerely, not just to shut me up) that we don't know whether the acceleration happens now or has happened in the past in different rates; and perhaps sub-
and consequently undertake a joint effort to write and publish a paper on it.

[Noax]

No, it's only the space between galaxies that's expanding. The galaxies themselves and the stuff in them is largely held together by gravity, EM forces and perhaps dark matter.

According to what I've read so far, everthing is expanding, except, of course, space. Space is a given, it can't expand or contract. I mean empty space, the three dimensional empty space.

What have you read that possibly says this? Greta's comment matches everything I've read on the subject.

[Noax]

3. I believe I have a very valid point which no physicist or cosmologist has thought of.

This should ring a lot of bells if it is a scientific point, not just a philosophical one. If I think I have a valid point which no physicist or cosmologist has thought of, I have a very strong probability of which of the two is more likely to be confused.

I shall cease and desist from barraging you with these arguments in one of three ways:
2. You convince me that the acceleration is happening now

To clarify, the expansion rate (which is not a velocity) is observed to be greater now than the observed expansion rate between much older galaxies (not between us and them at the time since we cannot see our own galaxy at the time being considered). That's why they say the rate of expansion is accelerating. It is not an increase of velocity, but an increase of the rate of expansion.

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Noax, Can you tell me something? Please.

Also, uwot, I would be interested very much in our answers to these questions.

It would settle for me once and for all if the acceleration is happening now in it has happened in the past.

The velocity of a galaxy G near the outermost edge of the universe we can observe is D distance away, and moves with V velocity compared to us. It is accelerating at A acceleration rate.

Can you tell me please, if the V velocity HAD been constant (but it has not been, obviously), then where that galaxy would be now? obviously at D+d1, where d1 can be positive or negative.

If you would kindly supply the values for D, V, A, and d1.

I don't even know where to look for them. You two, Noax and uwot, seem to be extremely knowledgeable about these things. If you decline to research these values and publish them here, fine, I won't hold it against you... after all, it's as a favour that I ask you to supply these values.

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No, it's only the space between galaxies that's expanding. The galaxies themselves and the stuff in them is largely held together by gravity, EM forces and perhaps dark matter.

According to what I've read so far, everthing is expanding, except, of course, space. Space is a given, it can't expand or contract. I mean empty space, the three dimensional empty space.

What have you read that possibly says this? Greta's comment matches everything I've read on the subject.

It is a conceptual image, you either see it or you don't. I can't explain it to those who don't see it my way, and any attempt at it will be futile. I am not sure if I'm the only one in the universe who insists that three-dimensional space is a given, and it can't change its shape or stretch or contract. If it does, conceptually that's allowed, it does it against a fixed segment, a fixed area or a fixed volume, which can only be made of matter from humans' point of view. If space expands, matter, compared to it, contracts, and if space shrinks, matter, compared to it, expands. But since we are made of matter, the shrinking or expanding of space will be unnoticed by us.

If space expands and matter expands at the same rate, then you also observe no change.

Please don't touch this. It will lead to a completely futile argument in which I can't convince you and you can't convince me. I know your concept of space expansion, so you don't even have to explain it.

You asked and I repied, that's all. Please let's not go into an argument over this.

In your version of space expansion, things go farther apart from each other, but they don't change their sizes. At least quarks don't In your version, things get expanded until there is not enough EM force and gravity to hold together even the smallest particles over and above quarks. This is NOT a space expansion; because the size (if you can speak of size of a wave blimp) of a quark does not change.

So your version of space expansion applies to some aspects of the fabric of the universe, so to speak but not to other aspects, such as quarks.

This is not possible if space itself expands, and things (this is an important axiomatic assumption) don't ALL equally expand with it in proportion. Therefore it is not space (described by a three-dimensional coordinate system with infinite expanse in all six cartesian coordinate direction) that expands, but matter gets farther and farther away, pushed by (dark matter, dark energy, pick your choice, I'll never learn the difference), and the only type of thing that does not get pushed apart is quarks.

This is what the sloppy physicists' language describes as "expanding space". But it is a sloppy way of putting it.

Please, if you like, then please describe the nature of your version of "space expansion". I am sure all of us will benefit from reading your description as well.

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Dear Noax and uwot, Noax gave a value to the expansion rate. He valued it at 1% every 150 million years.

That means that if the known universe is D distance in diameter, and the universe we know is 15 billion years (inaccurate figure; I don't know the exact figure) then if that rate of expansion is constant, then 15 billion years ago the matter of the universe ought to have occupied the following volume: (

15 billion light years)/(1.01)^(15 billion years/150 million years) | divide the fraction by 15

= 15 billion light years / 1.01^(1 billion years / 10 million years) | bring the values in the denominator and numerator in the fraction to the same denominator)
= 15 billion light years / 1.01^(1000 million years / 10 million years) | (do the math)
= 15 billion light years / 1.01^100

Which yields a very, very, very, very small number. My calculator won't even come near it. I guess the proper way of doing it is taking the log of 1.01, multiply it by 100, and figure out the order of magnitude from that. My puny little Microsoft Windows 10 calculator does not give you log values.

Billion I understand to be 10^9. In European nomenclature the same number is called a milliard. A billion in European nomenclature is 10^12. I wrote this to appease uwot who speaks European English. He breathes European English. He thinks in European English. He plays soccer in European English. d-:

[Noax]

Noax, Can you tell me something? Please.

The velocity of a galaxy G near the outermost edge of the universe we can observe is D distance away, and moves with V velocity compared to us. It is accelerating at A acceleration rate.

Some things that I think are off-point: The furthest we can see is the CMB where galaxies have yet to form. That CMB that we can see wasn't very far from 'here' when the light left it, to be detected on Earth 13.7 BY later. It was only around 400000 light years away when it began that journey, although I might be wrong about that distance. The objects that were furthest away when light departed them, reaching us now, is about 5 BLY away, having been emitted 10 BY ago, and yes, galaxies had formed by then. Let's call such a galaxy 'Floyd'.

On point: That CMB stuff and that young galaxy Floyd have a distance from the stuff that would eventually form our solar system, and that distance is increasing by such and such per year, and that can be considered a velocity, which is what you're asking. It had that velocity relative to 'us' (an increase of proper distance, which is almost like an increase of local distance that a ruler measures), and that velocity is lower than it is observed today

Can you tell me please, if the V velocity HAD been constant (but it has not been, obviously), then where that galaxy would be now? obviously at D+d1, where d1 can be positive or negative.

If you would kindly supply the values for D, V, A, and d1.

Floyd was 5 BLY away, 4 BY since the big bang, and we just see it now. It happened to be increasing its proper distance from us by exactly 'c' at the time. Today we see it, it now about 15 BLY away, beyond the Hubble sphere, and moving at about 1.15c, and about to leave the part of the universes visible to us here. That means we will never ever see a picture of it that is older than we are here today. 1.15c is greater than 1.0 c, so it can be said to be accelerating.

That is one (fictional) galaxy I know about since any galaxy that distant occupies an interesting place. The ones in the dataset are not quite so young as Floyd and have those supernova that allows us to measure their distance. Floyd is either too far away or has yet to begin to show type 1a supernovas.

So more realistic numbers: Nearby galaxies 10 MLY away average a redshift showing 210 km/sec velocity. Galaxies twice as distant show 420 km/sec. But further away the law no longer holds. Galaxies 100 MLY away have an average recession velocity less than 2100 km/sec. Not a lot less, but consistently less, perhaps 2050 km/sec. The values given here are pretty accurate, using a 70 (km/sec)/Mpc value of Hubble's constant.
You need a big dataset because the average is what counts. Andromeda is only 2.5MLY away, and should be receding at about 50km/sec, but is actually moving twice that speed, and towards us, not away. Now there's a bus that's going to be hard to get out of the way of. Milky way is not stationary either. It has a velocity (relative to the mean velocity of the stuff around us) of about .02c, but our solar system is on the side of the galaxy spinning against that, so we're more like .013c relative to that mean background frame against which the velocities of all the surveyed galaxies are measured.

I don't even know where to look for them. You seem to be extremely knowledgeable about these things. If you decline to research these values and publish them here, fine, I won't hold it against you... after all, it's a favour I ask.

I don't have links to actual numbers. Those are buried in references to the data in the papers in the journals.

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Thanks Noax, for your effort, but I need the plug-in values to my predetermined variables.

Now I see it's not so easily done, as the distant objects we see in the distance are older than how they appear now at that distance.

You gave me good food for thought. Thanks.

Noax wrote: So more realistic numbers: Nearby galaxies 10 MLY away average a redshift showing 210 km/sec velocity. Galaxies twice as distant show 420 km/sec. But further away the law no longer holds. Galaxies 100 MLY away have an average recession velocity less than 2100 km/sec. Not a lot less, but consistently less, perhaps 2050 km/sec. The values given here are pretty accurate, using a 70 (km/sec)/Mpc value of Hubble's constant.

I'll have to do some number crunching here. Conceptually.

If an object is accelerated with uniform acceleration, then its average velocity is (Vnull plus Vfinal) / 2. Its displacement therefore is travelling time times average velocity.

It is assumed that the universe is accelerated (expanded) at a uniform rate.

It is assumed furthermore that the object 100 million light years away was at the same spot and same speed as we were (whoever "we" were then) 100 Million years ago.

The average velocity of a distant object, at 100 MLY away, is 1025 Km/s compared to us. It should be this far from us: 1025 Km/s times 100 MY.

If the blasted thing never accelerated compared to us, then it would be this far away: 2050 Km/s times 100 MY.

If some people would please be so kind as to calculate from the distance that this distant object (100 Million light years from us) is from us, travelling at 2050 km/s faster than us,

-- where it would be in a span of 100 million years if its average speed of travel were 1050 Km/s.

if it started out with us with the same speed and at the same spot 100 Million years ago; and

and also calculate
-- where it'd be in a span of 100 million years if it travelled at a constant speed of 2050 Km/s compared to us.

under two different assumptions:

1. A constant rate of speed change
2. no speed change.



I'm way too tired mentally to carry out the conversions and the rest of the math.

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Okay, I'm done with the calculations. It was remarkably simple.

100 000 000 years = 3.1 x e15 sec

2050 (km / sec) x 3.1 x e15 sec = 6x e18 Km = 6xe18Km/9xe12Km/ly
=5xe5 ly = half a million light years

So if the rate of displacement (velocity) was constant, the galaxy or object 100 million light years from home should have only been half a million light years away.

If the rate of displacement (velocity) was uniformly increasing, then the object 100 million light years from home should have been only two hundred and fifty thousand light years away.

Which means deceleration, instead of acceleration.

Please check my math, I'm horrible at arithmetic.