The well known (well popularized)
"There are basically three possible shapes to the Universe;
a flat Universe (Euclidean or zero curvature),
a spherical Universe (positive curvature) or
a hyperbolic Universe (negative curvature) .."
http://zebu.uoregon.edu/~js/21st_century_science/lectures/lec21.html
is true when we limit ourselves to the 'BASIC shapes'.
It is like if we would say :
Earth surface may be
1) a plain
2) valley
3) mountain
and from that, from local statistics of our surrounding,
we with try to estimate the average curvature of the planetary
surface ( ~ 2E-7 1/m) .
The 'we' in this case would be some alien ant, who was deposited on the surface
of the planet as a prank of an ID or of evolution. The we=ant may do better to
use his idle moments to attempt to organize the data relevant for her survival.
Ant should 'process the data of applied science' = ?Il faut cultiver
notre jardin,?
http://www.newyorker.com/critics/books/index.ssf?050307crbo_books
However, every culture has it'd oen Creation Myth.
http://www.magictails.com/creationlinks.html
May be it is needed as a sort of 'boundary condition' and so we ask:
What happened 'before history' and 'beyond the universe' - which really
means 'what can we know about that, which we "cannot know"?
So, after this cautionary intro, let's turn to
Search Term: complex topology universe
Monograph
Hawking, S. and Ellis, G., The Large-Scale Structure of Space and Time (Cam-
bridge Monographs on Mathematical Physics), Cambridge University Press,
Cambridge, 1983
The possibility of universe with complex topology is well known and accepted.
http://answers.google.com/answers/threadview?id=433561
What would need to be done to make this a mainstream model-
the hard part - is to connect such models to observations,
in a way which satisfies the Occam Razor requirement.
This paper reviews one such attempt, using microwave background.
Measuring the Topology of the Universe
Observations of microwave background fluctuations can yield
information not only about the geometry of the universe, but
potentially about the topology of the universe
http://www.astro.princeton.edu/~dns/nas_neg/node3.html
More specifically:
"are there observations to support expansion
from the absorption of matter thru its event horizon?"
Answer is : there are theories which postulate such 'creation of matter'
out of nowhere. They are called " steady-state theory" and it gained
many adherents in the 1950s and 1960s.
" How could the universe continue to look the same when observations
show it to be expanding, which would tend to thin out its contents?
Supporters of this cosmology balanced the ever-decreasing density that
results from the expansion by hypothesizing that matter was
continuously created out of nothing. The amount required was
undetectably small?about a few atoms for every cubic mile each year"
http://www.pbs.org/wnet/hawking/universes/html/univ_steady.html
Here is overview of the theory
http://en.wikipedia.org/wiki/Steady-state_universe
Does it agree with data?
"For most cosmologists, the refutation of the steady-state theory came
with the discovery of the cosmic background radiation in 1965, which
was predicted by the big bang theory. Steven Hawking said that the
fact that microwave radiation had been found, and that it was thought
to be left over from the big bang, was "the final nail in the coffin
of the steady-state theory."
http://en.wikipedia.org/wiki/Steady-state_universe
However, if you combine SS (Steady State) with (Universe as a Black
Hole) hypothesis, these objection fade away.
There is a specific time when our Black-Hole universe was formed, and
the matter is conserved (in combined set of universes)
So, question really: Does such theory explain current data better
that 'standard' Big Bang model.
http://www.galaxytheory.com/
I would say that question is open, particularly considering the fact
that the 'minority view' of current cosmology,
questioning the existence of the dark matter and energy is gaining momentum.
http://answers.google.com/answers/threadview?id=702444
I wanted to add to an answer you got to question you asked In a previous posting:
http://answers.google.com/answers/threadview?id=700708
question you asked:
"Is our universe a black hole and if it is where is the singularity?"
The singularity would not be in our universe, but in the 'one above us' -- where
above needs to be qualified: If we do consider universe with complex
topology paradigm
of Einstein and Riemann geometry, we really are talking about one
universe, with multiply
connected COMPONENTS. We would be in a situation similar to the times
of Edwin Hubble, who
proposed a 'wild hypothesis' that certain Nebulae (gas clouds) are
actually 'island universes'.
http://senior.billings.k12.mt.us/students/fall97/p5html1/
http://www.kidsnewsroom.org/elmer/infocentral/space/html/exploration/people/hubble.html
At that time. a new name (Galaxy) was coined and universe remain 'one'
(uni). So following
that history, we would need a new (less generic) name for a
'component' with simple topology
(with basic shape) and we would say that matter is conserved in a
universe, but matter and energy
can be exchanged between the topological components. One can imagine
whole hierarchy (a tree) of
components which have singularities, and which (on the inside side)
have more singularities (their
own black holes) forming a 'tree'. In this sense, we would have a
notion 'of up and down' in this
hierarchy, and can say that singularity is in the component which is 'above us'
Of course, that assumes that the graph of these components is indeed a
tree - that it is a poset:
http://en.wikipedia.org/wiki/Partially_ordered_set
http://en.wikipedia.org/wiki/Connectedness
Hedgie |
Clarification of Answer by
hedgie-ga
on
02 Jun 2006 11:12 PDT
bill22-ga,
first I want to apologize about the delay in answering your
RFC. The system has problems lately in notifying people aabout
requests and repsonses, and I only noticed your reguest today.
First a comment on the comment:
I agree with iang-ga on 14 Mar 2006 14:28 PST :
" Does such theory explain current data better
that 'standard' Big Bang model? In a word, no."
The standard model explains the few facts we have,
and that's main reason it is the standard model.
But I think that your question :
Is it possible?
is not the same as Ing's question (Is it the best?).
I think it is right and proper,
and even necessary to consider alternative theories.
They may turn out to 'explain best' the data not yet known.
That said, I admit I do not understand your:
" the aforementioned observations that are
consistent with that "model" but cannot be called observations just
consistent indirect phenomena?"
Can you perhaps break it into several sentences? Perhaps add some commas:
"..but cannot be called observations, just
consistent indirect phenomena?"
What do you mean by : consistent indirect phenomena???
To summarize simply: we have a few observations. Very few.
Things like
microwave background
apparent expansion of universe (based on the redshift of galaxies)
classification of stars, galaxies,
...
The intro on the beginning of my answer was attempting to convey how
little we know
(like an ant dropped in one place of a vast planet).
There are many reasonable models consistent with the few facts we do have.
Big Bang is a SIMPLE model which fits known data well.
Other models are possible. In the absence of compelling facts (some new data)
most scientist will choose the simplest (see 'Occam razor') as 'right' and Ian's
comment reflects that.
The hypothetical model (of the hierarchy of universes, embedded in
each other as black
holes) that I mentioned also explains current data. But it is much
more complex, and we
do not have enough data which would justify such a complication.
Similar example is theory according to Big Bang was preceeded by
Big Crunch and universe
is pulsating like that (from small to large) for ever. It is a
variant on Steady State
(and I do find philosophically more pretty then just one single BB
in which 'spacetime
was created') but it more complex then BB. It is possible, nevertheless.
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