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Author Topic:   Size of the Universe
fallacycop
Member (Idle past 3780 days)
Posts: 692
From: Fortaleza-CE Brazil
Joined: 02-18-2006


Message 16 of 22 (493640)
01-10-2009 3:10 AM
Reply to: Message 7 by cavediver
01-09-2009 5:58 AM


No, for several reasons. Hoof Hearted's 156 billion is not correct, nor is your article, which doesn't help...

Do you have any idea where the 156 billion figure came from? did they just pull that one out of their asses?


This message is a reply to:
 Message 7 by cavediver, posted 01-09-2009 5:58 AM cavediver has responded

Replies to this message:
 Message 17 by Rrhain, posted 01-10-2009 4:10 AM fallacycop has not yet responded
 Message 19 by cavediver, posted 01-10-2009 5:42 AM fallacycop has not yet responded
 Message 20 by cavediver, posted 01-10-2009 8:27 AM fallacycop has not yet responded

  
Rrhain
Member (Idle past 132 days)
Posts: 6349
From: San Diego, CA, USA
Joined: 05-03-2003


Message 17 of 22 (493644)
01-10-2009 4:10 AM
Reply to: Message 16 by fallacycop
01-10-2009 3:10 AM


fallacycop writes:

quote:
Do you have any idea where the 156 billion figure came from? did they just pull that one out of their asses?

No. They actually did calculations and reached the conclusion that the edge of the universe is 78 billion light years away. Well, since we're just as far away from one edge as the other, that gives a figure of 156 billion lights years across.

Neil Cornish is an astrophysicst as Montana State University:

the starting point of a photon reaching us today after travelling for 13.7 billion years is now 78 billion light-years away

While I certainly respect cavediver's opinion, he is confusing the results of the study for his own ideas of what they were studying. That is, he is confusing the size of the universe with the size of the observable universe.

Indeed, the edge of the observable universe is about 46 billion light years away. The results of this study are not about the edge of the visible universe but rather the edge of the universe. The two are not the same.

The finding by Neil J. Cornish, David N. Spergel, Glenn D. Starkman, and Eiichiro Komatsu as published in Physical Review Letters, "Constraining the Topology of the Universe" is that the universe has a lower bound of 24 gigaparsecs distance in every direction:

The first year data from the Wilkinson Microwave Anisotropy Probe are used to place stringent constraints on the topology of the Universe. We search for pairs of circles on the sky with similar temperature patterns along each circle. We restrict the search to back-to-back circle pairs, and to nearly back-to-back circle pairs, as this covers the majority of the topologies that one might hope to detect in a nearly flat universe. We do not find any matched circles with radius greater than 25°. For a wide class of models, the nondetection rules out the possibility that we live in a universe with topology scale smaller than 24 Gpc.

They think that if we get a better map of the anisotropy, they could extend it out to about 28 Gpc.

And more importantly, note that the discovery is not technically the size of the universe. Instead, it is a lower bound on the size of the universe. The universe could easily be larger...it just can't be smaller than 24 Gpc.


Rrhain

Thank you for your submission to Science. Your paper was reviewed by a jury of seventh graders so that they could look for balance and to allow them to make up their own minds. We are sorry to say that they found your paper "bogus," specifically describing the section on the laboratory work "boring." We regret that we will be unable to publish your work at this time.
This message is a reply to:
 Message 16 by fallacycop, posted 01-10-2009 3:10 AM fallacycop has not yet responded

Replies to this message:
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cavediver
Member (Idle past 1903 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 18 of 22 (493646)
01-10-2009 5:16 AM
Reply to: Message 17 by Rrhain
01-10-2009 4:10 AM


While I certainly respect cavediver's opinion, he is confusing the results of the study for his own ideas of what they were studying

:laugh:

quote:
we live in a universe with topology scale smaller than 24 Gpc.

You have to understand what this means. In my case, I was working on this particular area two decades ago, years before Neil started looking into it and talking to me about it :D

Edited by cavediver, : No reason given.


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 Message 17 by Rrhain, posted 01-10-2009 4:10 AM Rrhain has not yet responded

  
cavediver
Member (Idle past 1903 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 19 of 22 (493649)
01-10-2009 5:42 AM
Reply to: Message 16 by fallacycop
01-10-2009 3:10 AM


Do you have any idea where the 156 billion figure came from? did they just pull that one out of their asses?

Typical popular science screw-up. Neil is looking at potential topological compactifcation of the Univese (my first major research area), where the actual Universe is smaller than it appears and what we see in deep field images are possible multiple loops around the Universe. So we may actually be seeing ouselves at earlier and earlier times as we look deep into the Universe.

Neil is continuing the work I was performing which is analysing our furthest data for signs of this repetition. When I was working on this, we only had the deep galaxy and quasar catalogues to work with - this was before COBE. Neil has COBE and WMAP observations of the CMBR is study. His results, like mine, do not show any sign of repetition but he can put a lower confidence bound on the size of the smallest repetition cell. This bound is the 24 Gpc quoted, which is the 78 billion light years quoted. This is not a radius. But confusion leads to thinking it is, so it is doubled to 156 billion light years!! It is also smaller (for obvious reasons!) than the observable Universe. If the size of the smallest cell is 78 billion light years, then the identified sides of the cell lie 39 billion light years away from us in opposite directions. The edge of the observable Universe *NOW* is 46 billion light years away. So the edge of any possible repeating cell is only just smaller than the observable Universe itself. So we are getting closer and closer to ruling out an observable multiply connected universe. Which is a shame.

Pictures to follow...

Edited by cavediver, : No reason given.


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 Message 16 by fallacycop, posted 01-10-2009 3:10 AM fallacycop has not yet responded

  
cavediver
Member (Idle past 1903 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 20 of 22 (493683)
01-10-2009 8:27 AM
Reply to: Message 16 by fallacycop
01-10-2009 3:10 AM


Sorry about the ascii pics but I hate uploading pictures and then have them vanish after a short while...

Ok, our Observable Universe looks like this:


? ? ? ? ? ? ?

*********
*** ***
** **
* *
* *
* *
? * * ?
? * O * ?
? * * ?
* *
* *
* *
** **
*** ***
*********
<---------------------->
92 billion light years

The O is us :)

Now, what I was looking for is evidence that the Universe is actually much smaller than this, and our sight wraps around the Universe multiple times, giving rise to this:


| | | | | |
| | | | | |
| | ********* | |
---+-----+-***-+-----+-***-+-----+---
| ** | | ** |
| *| O | O | O |* |
| * | | | | * |
---+--*--+-----+-----+-----+-*---+---
| * | | | | * |
| * | O | O | O | * |
| * | | | | * |
---+--*--+-----+-----+-----+--*--+---
| * | | | | * |
| *| O | O | O | * |
| ** | | ** |
---+-----+-***-+-----+-***-+-----+---
| | ********* | |
| | | | | |
| | | | | |

<----->
Smallish

What we could see is multiple images of our own cluster of galaxies (and maybe the Milky Way istelf!) repeated in the night sky. This idea that the Universe could be wrapped around on itself is not that strange. In all of our higher dimensional theories, we consider the extra dimensions compactifed on some scale, such that they wrap up tightly. Thus, it is entirely reasonable to consider the possibility that our larg-scale dimensions are also compactified, just on a larger scale.

I carried out statistical tests, looking for possible correlations in the coordinates of the farthest galaxies and quasars. To discover this would be fanatstic as it would enable us to *see* the evolution of galaxies and clusters, as we could see the same galaxy at different times. Sadly, we do not see any eidence of this in our deep field images of the Universe.

Neil et al have examined the Cosmic Microwave Backgorund Radiation (CMBR) for possible correlations. It too is suggesting that there is no repetition, or at least, the size of the repeating cell is almost the size of the Observable Universe itself - depicted here:


| |
| |
| ********* |
| *** *** |
---------**---------------**---------
*| |*
* | | *
* | | *
* | | *
* | O | *
* | | *
* | | *
* | | *
*| |*
---------**---------------**---------
| *** *** |
| ********* |
| |
| |
<----------------->
24Giga Parsecs
or
78 biliion light years

Hope this clears it up :)

Edited by cavediver, : No reason given.


This message is a reply to:
 Message 16 by fallacycop, posted 01-10-2009 3:10 AM fallacycop has not yet responded

Replies to this message:
 Message 21 by Annafan, posted 01-10-2009 10:47 AM cavediver has responded

  
Annafan
Member (Idle past 2838 days)
Posts: 418
From: Belgium
Joined: 08-08-2005


Message 21 of 22 (493706)
01-10-2009 10:47 AM
Reply to: Message 20 by cavediver
01-10-2009 8:27 AM


Cavediver writes:

What we could see is multiple images of our own cluster of galaxies (and maybe the Milky Way istelf!) repeated in the night sky. This idea that the Universe could be wrapped around on itself is not that strange. In all of our higher dimensional theories, we consider the extra dimensions compactifed on some scale, such that they wrap up tightly. Thus, it is entirely reasonable to consider the possibility that our larg-scale dimensions are also compactified, just on a larger scale.

Very interesting.. I had heard of this before, but always considered it one of those "far out" ideas.

But there's something I'm confused with... And here it is.

So the idea would be:

- we see ourselves now, in this time
- we use a powerful telescope that can look back, say 5 billion (light)years, and maybe what we see is actually our OWN galaxy 5 billion years ago
- we use an EVEN more powerful telescope that can look back, say 10 billion (light)years, and maybe what we see is our own galaxy TEN billion years ago

Ok, sounds in some way thinkable.

But why would this be "discrete"? Where are the intermediate "past stages"?

Think about making a painting in paint software, with the "brush" tool, where you can configure the spacing between brushstrokes when you move the mouse. THe example with the telescopes of different power, would be like painting with a brush that leaves, say 100 pixels (5 billion years) between brush impressions on the canvas. But why wouldn't it be like a brush with NO intervals (resulting in a solid line on the canvas), all past stages still visible.

I hope you understand what I mean. :)


This message is a reply to:
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cavediver
Member (Idle past 1903 days)
Posts: 4129
From: UK
Joined: 06-16-2005


Message 22 of 22 (493725)
01-10-2009 11:45 AM
Reply to: Message 21 by Annafan
01-10-2009 10:47 AM


But there's something I'm confused with...

The discrete nature of the images is a function of the diameter of the basic "cell"-size of the Universe. The multiple images are created by light wrapping around the cell multiple times. So, light from the Sun comes straight to us in 8 minutes. Some of the light goes straight past us across the entire Universe to the cell edge*, wraps around the Universe and comes back towards us from the opposite far edge of the Universe and we see a second image of the Sun, only this time aged by the time it took the light ray to traverse the entire Universe. There will be another image where the light wraps around two times, three times, etc. But you need an integer number of wrappings around the Universe for each image.

*there is no defined edge of course. If you think of us in the centre of the Universe, this is simply the point where you are equidistant from home in either direction.


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