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Lucis
Nutritional Yeast

Registered: 03/28/15
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Our universe: An expanding bubble in an extra dimension 2
#25713508 - 12/31/18 10:10 AM (5 years, 4 months ago) |
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Our universe: An expanding bubble in an extra dimension
Source:
Uppsala University researchers have devised a new model for the Universe - one that may solve the enigma of dark energy. Their new article, published in Physical Review Letters, proposes a new structural concept, including dark energy, for a universe that rides on an expanding bubble in an additional dimension.
We have known for the past 20 years that the Universe is expanding at an ever accelerating rate. The explanation is the "dark energy" that permeates it throughout, pushing it to expand. Understanding the nature of this dark energy is one of the paramount enigmas of fundamental physics.
It has long been hoped that string theory will provide the answer. According to string theory, all matter consists of tiny, vibrating "stringlike" entities. The theory also requires there to be more spatial dimensions than the three that are already part of everyday knowledge. For 15 years, there have been models in string theory that have been thought to give rise to dark energy. However, these have come in for increasingly harsh criticism, and several researchers are now asserting that none of the models proposed to date are workable.
In their article, the scientists propose a new model with dark energy and our Universe riding on an expanding bubble in an extra dimension. The whole Universe is accommodated on the edge of this expanding bubble. All existing matter in the Universe corresponds to the ends of strings that extend out into the extra dimension. The researchers also show that expanding bubbles of this kind can come into existence within the framework of string theory. It is conceivable that there are more bubbles than ours, corresponding to other universes.
The Uppsala scientists' model provides a new, different picture of the creation and future fate of the Universe, while it may also pave the way for methods of testing string theory.
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DividedQuantum
Outer Head


Registered: 12/06/13
Posts: 9,886
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Re: Our universe: An expanding bubble in an extra dimension [Re: Lucis] 1
#25713643 - 12/31/18 11:15 AM (5 years, 4 months ago) |
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This is highly reminiscent of the "inflationary multiverse" hypothesis, which has come under fire recently in the astrophysics community. This looks like a refinement of it, of sorts. Thanks for sharing.
-------------------- Vi Veri Universum Vivus Vici
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LogicaL Chaos
Ascension Energy & Alien UFOs




Registered: 05/12/07
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Re: Our universe: An expanding bubble in an extra dimension [Re: Lucis]
#25726590 - 01/06/19 06:48 AM (5 years, 4 months ago) |
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Holy SHIT.
Makes a lot of sense. Hyperdimensional gravity maybe?
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chibiabos
Cosmic Pond Scum



Registered: 03/16/17
Posts: 4,180
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Re: Our universe: An expanding bubble in an extra dimension [Re: LogicaL Chaos]
#25729361 - 01/07/19 03:29 PM (5 years, 4 months ago) |
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There's practically no details about anything that the Swedish group did (probably because the article was just supposed to report the fact that the paper had been published or accepted for review). It would be nice if they at least gave the name of the PI though...
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chibiabos
Cosmic Pond Scum



Registered: 03/16/17
Posts: 4,180
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Re: Our universe: An expanding bubble in an extra dimension [Re: DividedQuantum]
#25729371 - 01/07/19 03:31 PM (5 years, 4 months ago) |
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Quote:
DividedQuantum said: This is highly reminiscent of the "inflationary multiverse" hypothesis, which has come under fire recently in the astrophysics community.
Why are the astrophysicists taking issue with it? That's not really their field. It's cosmology.
edit: Found the abstract, at least. If you don't know what some of the weird, unreadable names mean then look them up. That's not a snide remark, they just all refer to specific theorems that these people are trying to use in order to solve what amounts to a big-ass geometry problem and it would take me at least a few months to write anything that even resembled a useful primer.
Quote:
Recent developments in string compactifications demonstrate obstructions to the simplest constructions of low energy cosmologies with positive vacuum energy. The existence of obstacles to creating scale-separated de Sitter solutions indicates a UV/IR puzzle for embedding cosmological vacua in a unitary theory of quantum gravity. Motivated by this puzzle, we propose an embedding of positive energy Friedmann-Lemaître-Robertson-Walker cosmology within string theory. Our proposal involves confining 4D gravity on a brane which mediates the decay from a nonsupersymmetric five-dimensional anti–de Sitter false vacuum to a true vacuum. In this way, it is natural for a 4D observer to experience an effective positive cosmological constant coupled to matter and radiation, avoiding the need for scale separation or a fundamental de Sitter vacuum.
Edited by chibiabos (01/07/19 03:42 PM)
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