[extropy-chat] mathscapes

[scerir]

Scientific American issued something special on the 100th 
anniversary of "Electrodynamics of moving bodies".
http://www.sciamdigital.com/index.cfm?sc=top_nav

[Below a short comment, by a good methematician, stolen from
another forum]

Much of interest, but the most interesting is the piece 
on the "Landscape" model of superstring theory.  Basically, 
the idea is that the "local universe" has a geometry which 
dictates both its "space-time" structure and the 
behavior of its elementary particles.  

Specifically, in topological terms, one has a fiber bundle 
whose "base" is a 4-manifold space-time and whose fiber is 
a 6 manifold.  There are, of course, additional geometric 
structures, viz., a Lorentz structure on the base - classical 
GR - and a geometry on the fiber which governs the behavior 
of strings, as well as dictating the local cosmological constant.  

Thus, the laws of GR emerge from the 4-dim geometry and "particle 
theory" from the 6-dim "hidden" geometry whose diameter is on 
the Planck scale.  

On this view, the only realizable local universes, represent 
local minima of a certain potential function. The not-so-Big Bang, 
in this model, is triggered by the transition of a single fiber 
to a new topology and geometry, which explosively ramifies, a 
la hyperinflation, into a new, largely stable mini-universe, 
such as ours.  

Mathematically and philosophically, this is a very attractive 
model, and neatly answers the theological version of the strong 
anthropic principle, as well as rendering rather pointless the 
perrenial question "What came before the Big Bang?"

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Something a little bit more physical, or less epiontic,
can be found in this paper by Tegmark et al.
http://www.arxiv.org/abs/hep-th/0409072