Posted on 09/28/2008 12:26:40 PM PDT by LibWhacker
The standard model of cosmology predicts that the universe is infinite and flat. However, cosmologists in France and the US are now suggesting that space could be finite and shaped like a dodecahedron instead. They claim that a universe with the same shape as the twelve-sided polygon can explain measurements of the cosmic microwave background – the radiation left over from the big bang – that spaces with more mundane shapes cannot.
Power spectrum of the cosmic microwave background (CMB) radiation. Data from WMAP have extended the accuracy of the spectrum far beyond what was known from earlier measurements. This plot reflects the small differences in the temperature of the CMB across the sky. There are a series of peaks in the spectrum at small angular separations, but at large scales that structure disappears. Standard cosmological models cannot explain this, but Luminet and colleagues’ topological model for a finite universe can (image and text credit: Nature 425 566).
The cosmic microwave background provides a picture of the universe as it was some 400 000 years after the big bang. By this time the universe had cooled down enough for atoms to form, which meant that there were no longer any free electrons to scatter the photons produced in the early universe. Any variations or anisotropy in the temperature of the background radiation therefore reflect variations in the density of the universe at this time.
These temperature fluctuations can be expressed as a sum of spherical harmonics, and astrophysicists plot the relative strength of these harmonics as a function of angle. The height and positions of the peaks in this so-called ‘power spectrum’ are related to basic astrophysical properties of the universe.
An image showing the view in a dodecahedral space universe
Data from the first year of the WMAP satellite – unveiled in February - agreed with the predictions of the standard big bang plus inflation model of cosmology for regions of space separated by small angles. However, on larger angular scales – greater than 60° - the WMAP observations were significantly lower than this model predicted.
Jean-Pierre Luminet of the Observatoire de Paris and colleagues believe that the finite size of the universe itself is responsible for this behaviour. Moreover, they show that the predictions of a model in which space consists of 12 curved pentagons joined together in a sphere agrees with the WMAP observations. Their ‘small’, closed universe should be about 30 billion light years across.
“Our work really addresses this ancient question of whether the universe is finite or infinite,” team member Jeff Weeks, a freelance mathematician based in New York, told PhysicsWeb. “The exciting point is that this is no longer pure speculation - we now have real data.”
The team says that its result, if confirmed, will have implications for theories and models of quantum gravity, inflation and the big bang itself. However, the model needs to be tested further by studying the microwave background at larger angles using more data from WMAP and the Planck Surveyor, which is due to be launched later this decade.
David, thanks, bookmarked for later.
Cheers!
Somewhere there's a REALLY REALLY REALLY big Dungeon Master rolling our universe around to determine damage from a long spear against a frost giant.
Thanks.
Sorry I forgot you earlier... :-(
Do you have another link? That link came up “unavailable on this server.”
The standard model of cosmology has been shown to be in err some 45 years ago. While the information in this article is adds to our knowledge of the universe, it is not as much of a paradigm shift as the title and opening paragraph suggest.
See post 41.
I meant see post 43.
“Their small, closed universe should be about 30 billion light years across.”
Yet the universe estimated at 14.5 billion years old. Expansion faster then light, which they say is impossible, or a pre-existing cell being filled in by the Big Bang. Interesting choices.
“If the universe has a boundary, doesn’t that imply a frame of reference external to the universe? That would seem to violate the concept of universe.”
But not of universeS.
In fact if this theory has validity, infinite stacks of universes seem a reasonable assumption.
Interesting. Thanks for the ping!
my favorite irrational number
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