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RickArcher
Post  Post subject: Big Bang System Expansion Accelerating?  |  Posted: Sat Jan 14, 2017 1:45 pm

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This thread is about the idea that the speed of expansion of the observable universe is apparently increasing. The closest I could find of a similar thread was one called Does Space Move?. This is what seemed to be stated in my other thread More than One Everything. For instance:-
Zinjanthropos wrote:
Krauss is a pretty smart dude:
Quote:
“In 5 billion years, the expansion of the universe will have progressed to the point where all other galaxies will have receded beyond detection. Indeed, they will be receding faster than the speed of light, so detection will be impossible.

In order to reach a speed greater than the speed of light they must be accelerating. Does that not go against Newton's Laws of motion? An object will travel at the speed of the initial force, it will not accelerate or slow down unless acted upon by another force. Also … what's happened to Einstein's Theory about the speed of light and its limit on everything?


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geordief
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Sat Jan 14, 2017 3:19 pm

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RickArcher wrote:
This thread is about the idea that the speed of expansion of the observable universe is apparently increasing. The closest I could find of a similar thread was one called Does Space Move?. This is what seemed to be stated in my other thread More than One Everything. For instance:-
Zinjanthropos wrote:
Krauss is a pretty smart dude:
Quote:
“In 5 billion years, the expansion of the universe will have progressed to the point where all other galaxies will have receded beyond detection. Indeed, they will be receding faster than the speed of light, so detection will be impossible.

In order to reach a speed greater than the speed of light they must be accelerating. Does that not go against Newton's Laws of motion? An object will travel at the speed of the initial force, it will not accelerate or slow down unless acted upon by another force. Also … what's happened to Einstein's Theory about the speed of light and its limit on everything?

I have heard that expansion is a scaling effect and that is why it is possible for faraway objects to recede from each other at speeds that are faster than light.

I don't understand this scaling mechanism but I think it is wrong to be thinking of this speed in terms of what you would understand as "acceleration".


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Chrispen Evan
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Sat Jan 14, 2017 10:09 pm
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Quote:
In order to reach a speed greater than the speed of light they must be accelerating. Does that not go against Newton's Laws of motion? An object will travel at the speed of the initial force, it will not accelerate or slow down unless acted upon by another force. Also … what's happened to Einstein's Theory about the speed of light and its limit on everything?


It is the expansion of space, driven by Dark Energy we believe, and as such is not a material object. So relativity doesn't apply as that is concerned with massive objects. And Newtons Law is obeyed because of DE.


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RickArcher
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Mon Jan 16, 2017 9:21 am

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geordief wrote:
I don't understand this scaling mechanism ….

Never heard of the scaling mechanism before. I get the impression it is another word for the expansion of space itself.
Chrispen Evan wrote:
It is the expansion of space, driven by Dark Energy we believe, and as such is not a material object. So relativity doesn't apply as that is concerned with massive objects. And Newtons Law is obeyed because of DE.

This is a heck of a thing to get your head around. I don't think the lay person can get anywhere at all with the idea that space itself can expand. I mean, isn't that basically saying that 'nothing' can expand?

Does anyone actually understand it, or is it like the idea that the universe must have something to do with a circle, and if you keep on going in a straight line you will eventually end up back where you started? It's a theory, but no one can get anywhere with actually understanding it?

And while I'm at it, what is the connection between time and the Big Bang? Why do they say that time started at the Big Bang? Is it the same confusion as with the use of the word 'universe'? Just as they really mean the 'observable universe' do they really mean that our measure of time starts at the Big Bang?


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geordief
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Mon Jan 16, 2017 11:58 am

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RickArcher wrote:
geordief wrote:
I don't understand this scaling mechanism ….

Never heard of the scaling mechanism before. I get the impression it is another word for the expansion of space itself.
Chrispen Evan wrote:
It is the expansion of space, driven by Dark Energy we believe, and as such is not a material object. So relativity doesn't apply as that is concerned with massive objects. And Newtons Law is obeyed because of DE.

This is a heck of a thing to get your head around. I don't think the lay person can get anywhere at all with the idea that space itself can expand. I mean, isn't that basically saying that 'nothing' can expand?

Does anyone actually understand it, or is it like the idea that the universe must have something to do with a circle, and if you keep on going in a straight line you will eventually end up back where you started? It's a theory, but no one can get anywhere with actually understanding it?

And while I'm at it, what is the connection between time and the Big Bang? Why do they say that time started at the Big Bang? Is it the same confusion as with the use of the word 'universe'? Just as they really mean the 'observable universe' do they really mean that our measure of time starts at the Big Bang?

I think it is a way of explaining the apparent observation that the distances between all large objects (galaxies etc) are increasing all the time-and doing so in a way that the is no "centre" that can be identified as being the source of this phenomenon.

So they say "space is expanding". That doesn't have to mean that anything is happening to the "space" since ,as you say space is another word for "nothing" but "space is expanding" expresses the idea that distances are increasing evenly in all directions (a scaling effect)

I hope I have not misunderstood this and stand to be corrected..

By the way this expansion only occurs when gravity does not come into the equation ,a in here on Earth , the Solar system etc etc......

"Time starting at the Big Bang" is ,again as I have picked, up loose talk and not to be taken literally -or even as correctlThe Big Bang is uncharted territory


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geordief
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Mon Jan 16, 2017 12:06 pm

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RickArcher wrote:
geordief wrote:
Does anyone actually understand it, or is it like the idea that the universe must have something to do with a circle, and if you keep on going in a straight line you will eventually end up back where you started? It's a theory, but no one can get anywhere with actually understanding it?


Well ,of course ,how can you travel in a "straight" line when every movement (including the passage of light) is affected by gravity?

So long as gravity is taken into consideration ,any object will have this tendency to "come home" eventually (as a thought experiment only)


Again I stand to be corrected if I have expressed this poorly or wrongly.


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RickArcher
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Wed Jan 18, 2017 9:07 am

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geordief wrote:
I think it is a way of explaining the apparent observation that the distances between all large objects (galaxies etc) are increasing all the time-and doing so in a way that the is no "centre" that can be identified as being the source of this phenomenon.

So they say "space is expanding". That doesn't have to mean that anything is happening to the "space" since ,as you say space is another word for "nothing" but "space is expanding" expresses the idea that distances are increasing evenly in all directions (a scaling effect)
Mmmm, don't see how saying that it is 'space' that is expanding makes the 'no centre' bit easier to understand. Even if it is space that is expanding there still has to be a 'centre' doesn't there? I think the example they give is the balloon expanding, but that has a centre from which everything is expanding … doesn' it?

geordief wrote:
By the way this expansion only occurs when gravity does not come into the equation ,a in here on Earth , the Solar system etc etc......
Crumbs, that makes it even more confusing.


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geordief
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Wed Jan 18, 2017 11:19 am

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RickArcher wrote:
Mmmm, don't see how saying that it is 'space' that is expanding makes the 'no centre' bit easier to understand. Even if it is space that is expanding there still has to be a 'centre' doesn't there? I think the example they give is the balloon expanding, but that has a centre from which everything is expanding … doesn' it?

geordief wrote:
By the way this expansion only occurs when gravity does not come into the equation ,a in here on Earth , the Solar system etc etc......
Crumbs, that makes it even more confusing.

Forget about "space". This expansion is (I believe) a verified observation and not a theory . Describe it as a "space" expanding if it suits you but first accept the expansion in all directions since this is an observed fact that we have to accept as "part of the furniture".

Measured distances
between the galaxies are increasing all the time -in all directions,at the same rate and without "preference" (so no "centre").

The reason (again my understanding) for the expansion not to apply in solar systems and here on Earth is that gravity is the dominant force .

As usual ,I very much stand to be corrected but that is my fairly settled understanding.


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Lynx_Fox
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Wed Jan 18, 2017 5:56 pm

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geordief wrote:
This expansion is (I believe) a verified observation and not a theory .
Huh? It's not a theory UNTIL it is verified--this is a science forum after all :-)


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geordief
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Wed Jan 18, 2017 7:36 pm

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Lynx_Fox wrote:
geordief wrote:
This expansion is (I believe) a verified observation and not a theory .
Huh? It's not a theory UNTIL it is verified--this is a science forum after all :-)


oops. :oops: Could I have said "This expansion is (I believe) a verified observation and not a hypothesis ."?

I hope the rest of my post contained no other clangers.


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RickArcher
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Mon Jan 23, 2017 8:14 am

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geordief wrote:
Measured distances between the galaxies are increasing all the time -in all directions,at the same rate and without "preference" (so no "centre").
I have discovered that the balloon analogy refers to 4D. The surface of the balloon represents our 3D Big Bang system, and that is where our brains cannot comprehend.

I can understand the distances increasing in all directions bit because that is what happens in an explosion, but what about the 'no centre' bit? They are saying that the reason we can't find the centre point is because it is in the 4D part. The centre in the balloon analogy is inside the balloon.

What would happen if you opened out the balloon like they open out the Earth to show a flat view? Would there be a centre point then I wonder?


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geordief
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Mon Jan 23, 2017 10:55 am

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RickArcher wrote:
geordief wrote:
Measured distances between the galaxies are increasing all the time -in all directions,at the same rate and without "preference" (so no "centre").
I have discovered that the balloon analogy refers to 4D. The surface of the balloon represents our 3D Big Bang system, and that is where our brains cannot comprehend.

I can understand the distances increasing in all directions bit because that is what happens in an explosion, but what about the 'no centre' bit? They are saying that the reason we can't find the centre point is because it is in the 4D part. The centre in the balloon analogy is inside the balloon.

What would happen if you opened out the balloon like they open out the Earth to show a flat view? Would there be a centre point then I wonder?

With the same caveats* as above ,what no one can do is to turn these mathematical models into "sensible" pictures in their head.

On the other hand we can all open our eyes and observe events as they actually unfold around us and (very) far away.

That is a true picture and(mediated through our senses) how thing actually work

The models "we" make are extremely hard to learn and understand (even harder to improve on). Unless we are in a position to understand these models then we cannot (I am not saying you are) criticize them and be unhappy that they are so hard to get one's head around.

We do have the experts who ,hopefully can understand the models and we also have popularizers who , Moses like try to pass the message on to laymen.

Feynman is a very good example of someone who could do both but we have to be content with a limited understanding of the models if, like me we lack the ability to learn them "first hand"

To respond directly to your post, it is a very good start to appreciate that all analogies are only aids to understanding and all are flawed and fail at some stage,

Perhaps there is encouragement in the idea that if a layman was to think he /she understood these ideas fully then he would probably be mistaken (the same may also apply to the experts)

* my status as lacking any real authority and welcoming my "ideas" being corrected


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Northerner
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Mon Jan 23, 2017 12:18 pm

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geordief wrote:
I think it is a way of explaining the apparent observation that the distances between all large objects (galaxies etc) are increasing all the time-and doing so in a way that the is no "centre" that can be identified as being the source of this phenomenon.

So they say "space is expanding". That doesn't have to mean that anything is happening to the "space" since ,as you say space is another word for "nothing" but "space is expanding" expresses the idea that distances are increasing evenly in all directions (a scaling effect)

Maybe I have this wrong, but I have never thought of space as being "another word for nothing".


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geordief
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Mon Jan 23, 2017 12:27 pm

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Northerner wrote:
geordief wrote:
I think it is a way of explaining the apparent observation that the distances between all large objects (galaxies etc) are increasing all the time-and doing so in a way that the is no "centre" that can be identified as being the source of this phenomenon.

So they say "space is expanding". That doesn't have to mean that anything is happening to the "space" since ,as you say space is another word for "nothing" but "space is expanding" expresses the idea that distances are increasing evenly in all directions (a scaling effect)

Maybe I have this wrong, but I have never thought of space as being "another word for nothing".

And I may be wrong also, but since (I feel )we cannot put our finger on or define what space is ,I prefer to think of it in terms of things we can actually observe and measure.

So "space to me is just "measured distances". Maybe "nothing" is an unhelpful way of trying to describe it (the measurements are certainly something)


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RickArcher
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Wed Jan 25, 2017 9:04 am

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geordief wrote:
To respond directly to your post, it is a very good start to appreciate that all analogies are only aids to understanding and all are flawed and fail at some stage,
Oh I know, I've tried to make up analogies myself (on other subjects) and never found a perfect one yet.

geordief wrote:
Perhaps there is encouragement in the idea that if a layman was to think he /she understood these ideas fully then he would probably be mistaken (the same may also apply to the experts)
Crumbs :)

Northerner wrote:
Maybe I have this wrong, but I have never thought of space as being "another word for nothing".
Ah no, you can't be allowed to say that without also stating how you do think of space :)

I know space is not totally empty, there are the odd atoms floating about apparently, there's debris, there's comets, there are also the odd stars and planets dotted about within it …… but what are they all actually … IN?


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Northerner
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Wed Jan 25, 2017 12:18 pm

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For me "nothing" means the absence of matter, time and space.
I have always understood space, also time and matter, came into existence with the Big Bang.
In other words the BB did not occur in an already existing space.
One can speculate as to what, if anything, existed "before" the BB but, at present, we have no way of knowing or even if a "before" required the existence of "space" as we understand the concept.
Also it has been suggested, altho' not proven so far, space is not continuous in that it breaks down into what is called quantum foam at the level of the Planck Length.
If this is true it would certainly mean space could never be defined as being equivalent to "nothing".


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janus
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Wed Jan 25, 2017 4:42 pm

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RickArcher wrote:
What would happen if you opened out the balloon like they open out the Earth to show a flat view? Would there be a centre point then I wonder?


Since there are an infinite number of ways to "open out" the balloon, the "center" would just be a arbitrary choice and have no special meaning. (you can open the Earth up so that the North pole is at the "center", or the South pole, the Mediterranean sea, , Rugby ND, or any other point on the surface of the Earth. None of them is any better than the other.)


Last edited by iNow on Wed Jan 25, 2017 5:03 pm, edited 1 time in total.
fixed broken quote


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RickArcher
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Mon Jan 30, 2017 8:49 am

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Northerner wrote:
For me "nothing" means the absence of matter, time and space.
I have always understood space, also time and matter, came into existence with the Big Bang.
I have always never understood that concept. It is the time and space bit I do not understand. I cannot see what they have got to do with it, or even how they can have anything to do with it. I don't dissmiss it, it's a fascinating theory and one that should be explored, I just can't get anywhere at all with understanding it.

Northerner wrote:
In other words the BB did not occur in an already existing space.
This is the crux of the problem. To our minds at present that sentence makes absolutley no sense because our brains cannot actually picture such a thing. It is where both science and religions come to a full stop.

I always remember when I was about sixteen having a big revelation about nothing, so to speak :) ..... I suppose we've all had it at some time in our lives. I used to think 'Oh well, the stars just go on and on and at some point they stop. Then there's nothing' … but then it dawned on me … 'Wait a minute, even nothing has to have an edge to it, a boundary'. Then I remember thinking 'Cripes, the whole darn universe is impossible', and somehow that took the pressure off my O Levels.

Northerner wrote:
Also it has been suggested, altho' not proven so far, space is not continuous in that it breaks down into what is called quantum foam at the level of the Planck Length.
If this is true it would certainly mean space could never be defined as being equivalent to "nothing".
I've never heard of this theory before. Don't understand it but that's interesting. Quantum foam? Planck length? Mmmm, I will Google.

janus wrote:
Since there are an infinite number of ways to "open out" the balloon, the "center" would just be a arbitrary choice and have no special meaning. (you can open the Earth up so that the North pole is at the "center", or the South pole, the Mediterranean sea, , Rugby ND, or any other point on the surface of the Earth. None of them is any better than the other.)
Ah, I see. Thanks Janus.


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wireless
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Sat Feb 18, 2017 7:27 pm

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Check out the sticky by DrRocket.


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Chrispen Evan
Post  Post subject: Re: Big Bang System Expansion Accelerating?  |  Posted: Sat Feb 18, 2017 10:27 pm
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space is just like a blank sheet of paper on which you can impose a coordinate system. it is different to what we colloquially term "space".


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