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Can anyone tell me about the early theories? or direct me to where I can find information on them?

Thank you

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Can anyone tell me about the early theories? or direct me to where I can find information on them?

Thank you

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marcus

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Can anyone tell me about the early theories? or direct me to where I can find information on them?

Thank you

random off top of head,

Steven Weinberg "prediction" of positive Lambda needs to be deflated.

An astronomer at Harvard Observatory named Loeb has shown that Weinberg "anthropic" prediction doesnt actually work---if you follow the reasoning it can predict a Lambda that is an order of magnitude larger than what Weinberg said. It was probably just a lucky guess. I don't know the details because not interested in anthropic stuff---but would be skeptical.

You can find Loeb's paper just by plugging Loeb into the arxiv search engine. or Abraham Loeb

Early theories? what about Willem De Sitter in 1917?

Two years after Einstein comes out with Gen Rel in 1915, De Sitter finds a solution with positive Lambda-----accelerating expansion.

it is the empty or blank universe with positive Lambda, just like

Minkowskispace is the flat unexpanding empty blank universe.

So De Sitter space is a kind of paradigm-----the vanilla version not only of expanding universe but of accelerating expanding

============

there is plenty more.

In the early 1990s Rafael Sorkin a quantum gravitist predicted positive Lambda

I have tried to understand how he arrived at it and I read his paper

"Forks in the Road to Quantum Gravity"

http://www.citebase.org/abstract?id=oai:arXiv.org:gr-qc/9706002 [Broken]

this describes the earlier (circa 1992 IIRC) prediction and gives source where it is on the record

but can't say I follow his reasoning

=============

I'm sure other folks can come up with plenty more.

But for starters here is something on De Sitter and De Sitter space

http://en.wikipedia.org/wiki/Willem_de_Sitter

http://en.wikipedia.org/wiki/De_Sitter_universe

http://en.wikipedia.org/wiki/De_Sitter_space

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Wallace

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I can't think of the name right now but I will try and search around but there was a cosmologist in the 70's that wrote a bunch of papers including a Nature letter about a Lambda universe. They predicted it based on chemical evolution data but it was generally thought that not enough was known about the modeling of the evolution to believe the prediction.

I will try and chase the reference down...

Edit: I found it, it was Beatrice Tinsley that was plugging this idea in the late 70's.http://www.nature.com/nature/journa...;jsessionid=FA994C36ABBF80657BA78438C627556C" is a link to the nature article.

I will try and chase the reference down...

Edit: I found it, it was Beatrice Tinsley that was plugging this idea in the late 70's.http://www.nature.com/nature/journa...;jsessionid=FA994C36ABBF80657BA78438C627556C" is a link to the nature article.

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Kim

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marcus

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It's neat that Wallace knew of something that was just the ticket.

Kim

Just for the sake of my own curiosity, I find the topic

so I would like to hear a little more---if you would be willing to show your hand a bit.

What sorts of social implications could there be?

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Wallace

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As far as I know people just didn't trust the modeling that the method used required since there was no way to verify the implications by some other measure. I think the reason the accelerating universe is more accepted now is that it is seen in multiple independent data sets, although the SN results are probably the keys set of observations.

I studied a fair bit of the history, philosophy and sociology of science back in my undergrad days. Like marcus I would be interested in some more details of your study.

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Big Bang did not and never expect `an accelerating expansion` while the model of flat and infinite universe (astro-ph/0605213) must have the `accelerating expansion`.

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Social Implications might no longer be the best term. While looking at Tinsley, I found that she staunchly supported the accelerating universe idea while others waffled. Right now, I think that hunting some social influence that allowed her to believe so firmly in the idea is my best bet.

(The Einstein/De Sitter debates also look very interesting but I think they have been studied. Tinsley's work look unexplored and it's recent enough to find most of it.)

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Chronos

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Perhaps this will be useful:

http://www.shpltd.co.uk/eisberg-tinsley.pdf [Broken]

http://www.shpltd.co.uk/eisberg-tinsley.pdf [Broken]

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Garth

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Thank you __Chronos__, that was an interesting and moving read.

Tinsley's Nature paper argued for a [itex]\Lambda[/itex], accelerating, universe based on the value of Hubble's constant, "of the order of 100 km s^{-1} Mpc^{-1}" and the age of Globular clusters "of the order of 16,000 Myr".

It is interesting to speculate that now DE and acceleration are firmly part of the standard model the present age of the universe at 13.8 Gyrs is still short of Tinsley's age of the globular clusters, but their present estimated age is younger. I wonder if she had that new age to work with, and hence also possible adjustment to both that age and H_{0}, whether her case for [itex]\Lambda[/itex] would have been so strong?

We might also note that back in 1978 a value for H_{0} often used was midway between 50 and 100 km s^{-1} Mpc^{-1} i.e. 70 km s^{-1} Mpc^{-1}, (e.g. see Weinberg), almost the present value.

Garth

Tinsley's Nature paper argued for a [itex]\Lambda[/itex], accelerating, universe based on the value of Hubble's constant, "of the order of 100 km s

It is interesting to speculate that now DE and acceleration are firmly part of the standard model the present age of the universe at 13.8 Gyrs is still short of Tinsley's age of the globular clusters, but their present estimated age is younger. I wonder if she had that new age to work with, and hence also possible adjustment to both that age and H

We might also note that back in 1978 a value for H

Garth

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