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PostPosted: Tue Jan 25, 2011 4:46 pm 
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I've heard it said that the Universe came about through a "Planck fluctuation", whatever that is.
In the beginning there was Max Planck. :lol:

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PostPosted: Tue Jan 25, 2011 7:35 pm 
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spoon wrote:
ATM we all agree to,
-the age of the universe : 13.7 Bn. years.
Do we also agree on the shape of the universe as an expanding sphere ?
If yes, -then it must have a center, and a radius of 13.7 Bn. light years, or more. If we still agree, I will make it tricky...
The GRB 090423... It detonated just 630 million years after the big bang.


The Universe only appears spherical to us because we are looking back 13.7 billion light years in all directions. However, our Observable Universe is most likely only a small part of a much larger Universe - we can't see the part 13.8 billion light years distant because the light from it hasn't reached us yet.

From the viewpoint of an observer currently at the location that produced the GRB 630 million years after the Big Bang, our location in the Universe is 13 billion light years distant, near the edge of the observable universe, and appears to be receding at a speed close to the speed of light. If the observer looked in the opposite direction however, they would see a part of the Universe that is too distant for us to see.

We need to remember that the Big Bang explosion didn't expand into a previously empty volume of space - the tiny volume in which the Big Bang occurred was the whole universe - there is no empty volume of space for a shock front to expand into or to provide a boundary to the Universe.


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PostPosted: Tue Jan 25, 2011 8:53 pm 
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Does that mean in that scenario that the whole Universe is very old perhaps infinitely old?
But I presume nobody is claiming that they actually know the answer to this question in a factual sense.

David

Does that also mean that in this scenario the whole universe is infinite in extent?


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PostPosted: Tue Jan 25, 2011 10:21 pm 
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hi Joe,
Let me explain my addition.
The very early Univers was much much smaller than today, maybe the size of an apple, and shortly after, the size of the sun, then galaxie-sized... This increase in volume (expansion in all directions), must take place in a spherical-shape, (please let me know, if you have a better suggestion). In other words, we can create a mathematical centre within the sphere, and (here it comes) - not contradicting the way it expands in all directions,- The Border !! The front, not occupied seconds ago, now time and distances exist here..In front of the front, infinite room for expansion, ready to be formatted with the fabric of existence. I know that I have taken the "outside looking at the expanding lightball" view.. -and maybe that´s not good, but it helps in the search of The Earths position in The Universe...
Please find more wrongs in my scribble.
Yours curiously,
Spoon

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PostPosted: Tue Jan 25, 2011 10:22 pm 
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David Frydman wrote:
Does that mean in that scenario that the whole Universe is very old perhaps infinitely old?
But I presume nobody is claiming that they actually know the answer to this question in a factual sense.


I know the answer and it is NO !

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Does that also mean that in this scenario the whole universe is infinite in extent?


Ditto NO !

You can't have infinities because if you do then everything is possible and has already happened an infinite number of times in an infinite number of locations.


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PostPosted: Tue Jan 25, 2011 10:44 pm 
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I am not sure if that logic is mathematically correct.

David


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PostPosted: Tue Jan 25, 2011 11:01 pm 
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@ tony
Hi, I hear you say that the Universe is much older than 13,7 Bn. years.!
I will not argue against that ! I would even say much-much older. It makes a lot of sense if you believe in the age of GRB 090423. So, the team calculating this 13,7 Bn. age, should start doing their stuff again...Someting so basic, is essential for further good results...!
Tony, do you see the start, (right after BB), as spheric, with a content of energy/mass expanding in all directions, like the overyeasted bread-dough, or do you have another suggestion ?
Yours,
Spoon

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PostPosted: Tue Jan 25, 2011 11:21 pm 
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Having been watching this thread I think the difficulty is with the mental model those trying to understand are using. For me it just does not work trying to think of things in our traditional 3D framework. When I start thinking e.g. as a sphere expanding you have to start asking "expanding into what ?" and the problems just get worse.

I find the ballon analogy/model very useful provided one appreciates that it is a 2D model. But I cannot then use the same model in 3D because (as others have tried) you start thinking about the inside of the ballon and it is expanding (being inflated) and inflated into where and where is the centre and the analogy just falls apart. I guess if there was a useful 3D analogy/model people would use it rather than the ballon - so I guess there is not one.

But I do find it easy to accept "as ballon but in 3D". And I don't seem to keep trying to thing of a ball getting bigger or anything - just ballon in 3D.

Ian


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PostPosted: Wed Jan 26, 2011 12:37 am 
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Deimos, try imagine some raisin-bread dough, with lots of yeast in. As it grows, all the raisins gets further apart, and its in real 3-D, no need to switch your brain into 2-D mode.. BTW, did you check the expansion link ?

http://www.exploratorium.edu/hubble/tools/center.html

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PostPosted: Wed Jan 26, 2011 8:21 am 
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spoon wrote:
hi Joe,
Let me explain my addition.
The very early Univers was much much smaller than today, maybe the size of an apple, and shortly after, the size of the sun, then galaxie-sized... This increase in volume (expansion in all directions), must take place in a spherical-shape, (please let me know, if you have a better suggestion).

Spoon, this has only limited use, in my opinion. It still gives the impression of a boundary that is growing into an already existing space. Taking the analogy to absurd lengths - consider a spaceman located near the "skin" of the apple-sized universe; he is facing away from the core of the apple in the direction - supposedly - of the expansion (please forgive my primitive diagrams).

Image


He will not see an edge, or boundary, he will see objects receding from him - all objects are moving away from all other objects. Clearly then, the universe cannot be considered spherical or likened to a raisin-filled dough ball. Expansion happens everywhere in every direction, not from a centre out.

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PostPosted: Wed Jan 26, 2011 10:02 am 
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spoon wrote:
Deimos, try imagine some raisin-bread dough, with lots of yeast in. As it grows, all the raisins gets further apart, and its in real 3-D, no need to switch your brain into 2-D mode.. BTW, did you check the expansion link ?

http://www.exploratorium.edu/hubble/tools/center.html


I have considered such models and they just don't work. If they did then people would be saying "Imagine raisin bread in 3D ..." but they don't they say "Imagine a ballon surface ...".

When I was studying my Cosmology course I found the mental image you use has a massive impact on your understanding the concepts. Adopt a bad model and you (I) just don't understand the concept. Get a good model in your head and it immediately becomes clear - and I think this thread is an excellent example of that.

Several found that I'd spend ages struggling to get to grips with an idea and then suddenly, read something else and change one's mental picture and it is immediately clear as day. I can appreciate it can be difficult to give up an idea (e.g. that a football has a centre and thus so must the Universe).

The link gives nothing to suggest a "centre" or "raisin dough" (looks targeted at junior school teaching thing, very simplistic). It again has to apply a 2D model to our Universe to explain the concept - a model that does not work it you just then extrapolate to a football.

Ian


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PostPosted: Wed Jan 26, 2011 10:08 am 
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Kev said that we can't have infinities because everything would have already happened and an infinite number of times.
But what if the Universe is infinitely varied? In this case, we would have a continuum of infinite change that need not repeat itself. The Universe could just as well be infinitely diverse, not infinitely repetitive.
If our Universe had an absolute "Big Bang" beginning ( instead of always existing in unknown pre-existing states ), on the basis of Kev's position, everything would eventually repeat itself anyway, given enough time to do it in.

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PostPosted: Wed Jan 26, 2011 11:47 am 
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@joe,
Okay, Do we agree that,
-the Universe have been smaller in the past,
and therefore have increased(still are) its Volume..?
-there was NO single-explosion, driving all content in one direction(like on your drawing) namely away from the mathematical(theoretical) center ? Ok, then :
The front i consider consists of the fastest moving particles/energy we can think of (lightspeed at the moment), and if you want to observe the event from here, you will see nothing looking out, and nothing looking inwards, -no problems for me here. The only problem, is that you have to use an infinite amount of energy to obtain and keep this fast moving position in the skin (Einstein says no !). I hope that we agree in, that there are NO major (or minor) objects even close to this fast moving front (objects have mass, therefore no speed of light here !).
The oldest object GRB 090423 is dated 13.1 Bn. years old, please se post above. This giant selfcontradiction, of a gamma-flash emitted before the assembly of Earth, and now suddenly the "light" bends back to hit our telescopes, can only be made right by admitting that the Universe have to be much-much older (and bigger) than NASA states. But we can only see objects up to a distance of 13.1 Bn. light years, surely this fact does not exclude the theory of a much-much older(larger) Universe.
Therefore no matter at which direction we observe today , we see the same picture, from the inside of a "little" spheric cutout with a radius of 13.1 Bn light years, appearing very uniform in density (the same all around). If we agree that the Universe is much-much bigger (read older), than the 13.7 Bn. years, ( quote Nasa WMAP 07 19 2010 ".. we can estimate the age of the universe to about 1%: 13.7 ± 0.13 billion years!
"), -lots of paradoxes will disappear, and some contradictions wil be fixed, like the age of GRB 090423, that could be correct !
I know that NASA is a heavyweight opponent, but they have been wrong many times before.
I am also thinking about a model with 2 different fronts... one from the inflation-event(field-preparation-front), and a slower one from the expansion-event(photons etc.). Will return with more about this later.
Yours, spoon

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PostPosted: Wed Jan 26, 2011 12:13 pm 
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Demios,
You say : "I have considered such models and they just don't work. If they did then people would be saying "Imagine raisin bread in 3D ..." but they don't they say "Imagine a ballon surface ...".
I really don't see the point here..! the growing dough model is in 3D already, dont imagine, just watch it grow, and BTW I don't think the dough-model is flawless, just better and simpler. Don't get stuck with the balloon-model, just because it's in many books for students, and has been for many years...Move forward and start thinking new thoughts.. and maybe we will find some new theories/facts, that will help us understand everything...
BTW, the link is perfectly correlated to the dough-model, if you can imagine the dots in 3 dimensions, and yes it's for kids, but not wrong or bad, just a funny optical-illusion game(model) of what expansion in all directions can make a starwatcher believe/conclude...
Yours, spoon

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PostPosted: Wed Jan 26, 2011 1:31 pm 
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spoon wrote:
The front i consider consists of the fastest moving particles/energy we can think of (lightspeed at the moment), and if you want to observe the event from here, you will see nothing looking out, and nothing looking inwards, -no problems for me here. The only problem, is that you have to use an infinite amount of energy to obtain and keep this fast moving position in the skin (Einstein says no !).

Unless I'm interpreting you incorrectly you seem to be making a classic mistake here. Objects that are very distant, at the edge of the observable universe for example, appear to be moving close to the speed of light but they are not physically moving at that speed. Einstein is correct.

Space is expanding all around us at approximately 77 km/s/Mpc. At the edge of the observable universe the rate of expansion is the same - 77 km/s/Mpc. It is nowhere near the speed of light.

If you drive away from a car at 30m/h, the car appears to be receding at 30m/h. If the car starts up and drives in the opposite direction at the same speed of 30m/h it will appear to be receding at 60m/h. It is still only moving at 30m/h.

Quote:
if you want to observe the event from here, you will see nothing looking out, and nothing looking inwards,

Wrong. The universe is homogenous and isotropic. No place is "special" and if you were at the edge of the observable universe you would see almost exactly what we see from here.

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