 Natural Environment How Human History has been impacted by the environment, science, nature, geography, weather, and natural phenomena 
November 28th, 2012, 12:06 PM

#251  Knighterrant
Joined: Oct 2011 From: Lago Maggiore, Italy Posts: 17,771  Quote:
Originally Posted by sylla1 Hawking on a finite universe.
Having no boundary (as a sphere) is not the same as having no limits (as the same sphere).
Hawking's model is finite; it proposed limits.
That said, the critical point here is that Dr Hawking was talking here about one or several finite " universes" like our observable one Observable universe  Wikipedia, the free encyclopedia .
By definition, all those " universes" would be contained within the whole Universe as regularly defined, i.e. ( MerriamWebster)
Or like the equivalent definition of Wikipedia from a composite of at least four major encyclopedias & dictionaries Universe  Wikipedia, the free encyclopedia
AFAIK (I may be wrong, and I would love to be corrected here ) Hawking's model states nothing about the finiteness (or lack of it) of any such whole Universe as regularly defined above, i.e. the OP.
Just for the sake of clarity, IMHO there is currently simply no major scholar disagreement on the finite nature of the observable universe, as described by the Big Bang theory and supported by a plethora of empirical data.
If the OP is about the Universe as a whole, the whole existence under this later regular definition, my position must still remain the same; it is currently impossible to know if the Universe is infinite or finite.
This is the OP:
After 250 posts? As simple as possible;
The observable universe is clearly finite.
The whole Universe, who knows ?
(Yup, people and even scholars are using the same word for different concepts)  Let's evaluate the intrinsic value of such a discussion ... if conclusions were certain we will read about a certainly finite or infinite universe on school books ... [with or without limits].
A part this, I said too that Hawking consider the universe finite [like Einstein], but without limits.
A scientist is a free thinker ... Quote:
“So long as the universe had a beginning, we could suppose it had a creator. But if the universe is really completely selfcontained, having no boundary or edge, it would have neither beginning nor end: it would simply be. What place, then, for a creator?”
― Stephen Hawking  Free minds for free confrontations of opinions and ideas [also changing them].
 
 
November 28th, 2012, 12:43 PM

#252  Suspended indefinitely
Joined: Dec 2009 Posts: 19,933  Quote:
Originally Posted by AlpinLuke Let's evaluate the intrinsic value of such a discussion ... if conclusions were certain we will read about a certainly finite or infinite universe on school books ... [with or without limits].
A part this, I said too that Hawking consider the universe finite [like Einstein], but without limits.
A scientist is a free thinker ...
Free minds for free confrontations of opinions and ideas [also changing them].  Nope; a finite observable universe without boundaries, but naturally still with limits (hence finite); exactly as the sphere analogy.
Such conception of finiteness is not dependent of quantum mechanics, but of astronomical observations (naturally "newtonian") and especially of the Big Bang theory.
 
 
November 28th, 2012, 01:24 PM

#253  Knighterrant
Joined: Oct 2011 From: Lago Maggiore, Italy Posts: 17,771  Quote:
Originally Posted by sylla1 Nope; a finite observable universe without boundaries, but naturally still with limits (hence finite); exactly as the sphere analogy.
Such conception of finiteness is not dependent of quantum mechanics, but of astronomical observations (naturally "newtonian") and especially of the Big Bang theory.  First of all this part of the OP at this point has entered the legend ! Quote:
Simple answers would be appreciated
 Now, I see that probably there is something to explain about the conceptualization of something "finite without limits" .
Unfortunately we would have to leave again the field of cosmology to dive into philosophy. Anyway I can make a try [still in the field of physics].
To look well, we live on the surface of a sphere [actually Earth is not a perfect sphere, anyway is a good "sample"], so that we should be able to prove [or disprove] the conceptualization of the surface of a sphere being finite but without limits [even if reasoning about a 3D object, a sphere is a 3D object ...].
Let's try this:
if I invite a friend of mine to meet me "on the limit of the surface of Earth" [or on a limit / an edge of the surface of Earth, if we prefer] ... where would you expect me to wait for him?
[I mean in which physical point/s of the terrestrial surface].
More simple [in honor of the OP]
Where does the surface of Earth begin?
Where does the surface of Earth end?

Last edited by AlpinLuke; November 28th, 2012 at 01:31 PM.

 
November 29th, 2012, 09:25 AM

#254  Spiritual Ronin
Joined: Aug 2009 From: Minnesnowta Posts: 21,071  Quote:
Where does the surface of Earth begin?
Where does the surface of Earth end?
 Begin: 4.54 billion years ago
End: 4 to 5 billion years from now
 
 
November 29th, 2012, 09:41 AM

#255  Suspended indefinitely
Joined: Dec 2009 Posts: 19,933 
Some elementary English: Quote: fi·nite adjective
having definite or definable limits
 ( MerriamWebster)
AFAIK the concept is equally valid in Italian or any other language I'm aware of.
Just check out any sphere.
(Because no infinite sphere is known)
This (or any other) sphere naturally has no boundaries, but equally naturally it has limits: in geometrical terms, its surface.
 
 
November 29th, 2012, 11:31 AM

#256  Knighterrant
Joined: Oct 2011 From: Lago Maggiore, Italy Posts: 17,771  Quote:
Originally Posted by Rasta Begin: 4.54 billion years ago
End: 4 to 5 billion years from now  Well, not when [temporally], but where [geometrically]. Temporally, you're absolutely right ...
 
 
November 29th, 2012, 11:35 AM

#257  Knighterrant
Joined: Oct 2011 From: Lago Maggiore, Italy Posts: 17,771 
You haven't understood the point. Quote:
Originally Posted by sylla1 Some elementary English: ( MerriamWebster)
AFAIK the concept is equally valid in Italian or any other language I'm aware of.
Just check out any sphere.
(Because no infinite sphere is known)
This (or any other) sphere naturally has no boundaries, but equally naturally it has limits: in geometrical terms, its surface.  Ok, but this comment is out of context. Probably it's again my fault I'm not able to explain well ... I'm not asking about the limits of the sphere [it's obvious that the surface of a sphere is its limit ...]. I'm wondering about the limits of the surface of the sphere [the 2D membrane limiting its volume].
The universe is a spacetime curved in an hyperdimension like the surface of the sphere [a 2D membrane] is curved in the third dimension.
 
 
November 29th, 2012, 11:36 AM

#258  Suspended indefinitely
Joined: Dec 2009 Posts: 19,933  Quote:
Originally Posted by AlpinLuke Well, not when [temporally], but where [geometrically]. Temporally, you're absolutely right ...  And geometrically too.
 
 
November 29th, 2012, 11:38 AM

#259  Suspended indefinitely
Joined: Dec 2009 Posts: 19,933  Quote:
Originally Posted by AlpinLuke You haven't understood the point.
Ok, but this comment is out of context. Probably it's again my fault I'm not able to explain well ... I'm not asking about the limits of the sphere [it's obvious that the surface of a sphere is its limit ...]. I'm wondering about the limits of the surface of the sphere [the 2D membrane limiting its volume].
The universe is a spacetime curved in an hyperdimension like the surface of the sphere [a 2D membrane] is curved in the third dimension.  " Out of context" just in your educated opinion now, ostensibly not so just some posts ago, and certainly not according to Dr. Hawking and so many other authors using this illustrative analogy.
Hint: you are simply making a semantic confusion between " boundary" & " limit", definitely not any synonymous terms within this context.
 
 
November 29th, 2012, 11:40 AM

#260  Knighterrant
Joined: Oct 2011 From: Lago Maggiore, Italy Posts: 17,771 
In other words ... always honoring the simplicity of the OP ...
walking along the surface of a sphere ... will I meet an edge or a boundary or a limit of any kind ... or will I be able to walk and walk and walk ... passing may times from the same points [of course], but will I meet a stop?
 
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