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De Sitter & Accelerating Expansion?



 
 
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  #1  
Old August 20th 03, 10:13 PM
pragmatist
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Default De Sitter & Accelerating Expansion?

De Sitter and accelerated expansion

DeSitters model: a spherical three dimensional universe with time
everywhere perpendicular to the three locally perpendicular, large,
circular 'space` axes so that events viewed at a distance are subject
to an 'angular` red shift due to distance from the observer without
any 'real` expansion. ( Time 'stops` at 1/4 circumference, reverses at
the antipode.)

Has any observational evidence firmly ruled out this model?

If such a universe were expanding, would not an observer perceive an
acceleration in expansion measured by red shift velocities such as has
lately been observed?

Just an idle thought, besides, its such a pretty model.
Pragmatist
  #2  
Old August 21st 03, 12:48 AM
Old Man
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Default De Sitter & Accelerating Expansion?

pragmatist wrote in message
om...
De Sitter and accelerated expansion

DeSitters model: a spherical three dimensional universe with time
everywhere perpendicular to the three locally perpendicular, large,
circular 'space` axes so that events viewed at a distance are subject
to an 'angular` red shift due to distance from the observer without
any 'real` expansion. ( Time 'stops` at 1/4 circumference, reverses at
the antipode.)

Has any observational evidence firmly ruled out this model?

If such a universe were expanding, would not an observer perceive an
acceleration in expansion measured by red shift velocities such as has
lately been observed?

Just an idle thought, besides, its such a pretty model.
Pragmatist


Within the last three months, Old Man has read most of the sections
(a few without comprehension) in PJE Peebles' book, "Principles of
Physical Cosmology", and although some the work of de Sitter is
covered therein, Old Man does not recall any mention of this
particular model. It sounds preposterous to Old Man, and since he
doesn't put any emphasis on it, maybe Peebles feels the same way.
[Old Man]



  #3  
Old August 21st 03, 10:22 PM
pragmatist
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Default De Sitter & Accelerating Expansion?

"Old Man" wrote in message news:3f42b680_1@newsfeed...

Within the last three months, Old Man has read most of the sections
(a few without comprehension) in PJE Peebles' book, "Principles of
Physical Cosmology", and although some the work of de Sitter is
covered therein, Old Man does not recall any mention of this
particular model. It sounds preposterous to Old Man, and since he
doesn't put any emphasis on it, maybe Peebles feels the same way.
[Old Man]


I haven't read Peebles, if that was a recommendation, I will look him
up.
The descripton I offered is my interpretation of a description I read
in 'Space, Time, and Gravitation` - Sir Arthur Eddington - 1920,
(Harper Ed. 1959)
de Sitter is not completely ignored today, as a matter of fact he is
refered to in a recent lecture by Hawking, (of which I understood
little but enjoyed for what crumbs I could gather, and of course, for
the language. You've got to hand it to them, the Brits can still
write.)
Pragmatist
  #4  
Old August 22nd 03, 12:54 AM
Old Man
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Posts: n/a
Default De Sitter & Accelerating Expansion?

pragmatist wrote in message
om...
"Old Man" wrote in message

news:3f42b680_1@newsfeed...

Within the last three months, Old Man has read most of the sections
(a few without comprehension) in PJE Peebles' book, "Principles of
Physical Cosmology", and although some the work of de Sitter is
covered therein, Old Man does not recall any mention of this
particular model. It sounds preposterous to Old Man, and since he
doesn't put any emphasis on it, maybe Peebles feels the same way.
[Old Man]


I haven't read Peebles, if that was a recommendation, I will look him
up.
The descripton I offered is my interpretation of a description I read
in 'Space, Time, and Gravitation` - Sir Arthur Eddington - 1920,
(Harper Ed. 1959)
de Sitter is not completely ignored today, as a matter of fact he is
refered to in a recent lecture by Hawking, (of which I understood
little but enjoyed for what crumbs I could gather, and of course, for
the language. You've got to hand it to them, the Brits can still
write.)
Pragmatist


Peebles' book is comprehensive, but the organization leaves something
to be desired. Old Man had to put it down for awhile and do some
background reading at the introductory level before starting over again
from the beginning. It made a lot more sense the second time through.
It was still a tough grind, and being retired and more or less carefree,
that's not necessarily what Old Man is after. [Old Man]



  #5  
Old August 22nd 03, 06:23 AM
pragmatist
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Posts: n/a
Default De Sitter & Accelerating Expansion?

"Old Man" wrote in message news:3f440970_2@newsfeed...


Peebles' book is comprehensive, but the organization leaves something
to be desired. Old Man had to put it down for awhile and do some
background reading at the introductory level before starting over again
from the beginning. It made a lot more sense the second time through.
It was still a tough grind, and being retired and more or less carefree,
that's not necessarily what Old Man is after. [Old Man]


Pragmatist is also retired, didn't plan it this way, but it happened
anyhow.
A good grind is valuable sometimes in that it keeps the dust and
cobwebs from collecting.
(That third person stuff is catching.)
Cheers - Pragmatist
  #6  
Old August 23rd 03, 02:08 AM
Old Man
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Posts: n/a
Default De Sitter & Accelerating Expansion?


pragmatist wrote in message
om...
"Old Man" wrote in message

news:3f440970_2@newsfeed...


Peebles' book is comprehensive, but the organization leaves something
to be desired. Old Man had to put it down for awhile and do some
background reading at the introductory level before starting over again
from the beginning. It made a lot more sense the second time through.
It was still a tough grind, and being retired and more or less carefree,
that's not necessarily what Old Man is after. [Old Man]


Pragmatist is also retired, didn't plan it this way, but it happened
anyhow.
A good grind is valuable sometimes in that it keeps the dust and
cobwebs from collecting.
(That third person stuff is catching.)
Cheers - Pragmatist


A hard grind can be fun for that with illumination at the end of the
tunnel, but there is little reward when, in the end, comprehension
fails. Nothing ventured, nothing gained, but greed and vanity are
poor masters. Frivolous time wasters that they are, they can make
one old before his time. [Old Man]
[Old Man]


  #7  
Old August 25th 03, 04:18 AM
pragmatist
external usenet poster
 
Posts: n/a
Default De Sitter & Accelerating Expansion?

"Old Man" wrote in message news:3f456c5f_1@newsfeed...


A hard grind can be fun for that with illumination at the end of the
tunnel, but there is little reward when, in the end, comprehension
fails. Nothing ventured, nothing gained, but greed and vanity are
poor masters. Frivolous time wasters that they are, they can make
one old before his time. [Old Man]
[Old Man]


So look for easier pickings. There must be a lot of things of which
you thought 'someday I've got to look into that`. Today is someday,
and the learning curve for a new subject is so much easier. At
entry/intermediate level in a new area, there are interesting things
to learn just for the reading.
Age broadens one, so while we sit here broadening our asses we might
as well broaden our interests.
Hang in there - Pragmatist
 




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