AY 155								Spring 1989
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The Cosmological Framework:

	* The choice of (meta)physics:  physical laws and constants same 
	  everywhere and everywhen; generalized gravity the only important
	  interaction on large scales.

	* The choice of the theory of gravity:  probably the GR, more-or-less.
	  (other possibilities: PPNF, Dirac-Canuto, Milgrom-Beckenstein...)

	* The choice of topology:  simple connected at scales >>> Planck 
	  (we hope so).

	* The choice of symmetries:   (e.g., the cosmological principle)

		- Homogeneity (minimum scale = ?)
							>  FRW models
		- Isotropy (e.g., no global rotation)

NB:  The universe does not have to be simple for our brains, taste, etc.


The Friedman-Robertson-Walker models:

	Specified by the "scale" = expansion rate, age, H
		     and "form"  = curvature,    , q , 

	No. of independent parameters = 3 (usually H ,    or q ,    )

	Possible complication:  a pressure term (=zero?)

The "scale" (alias H ): still uncertain by ~ 50%.
The "form" (alias    ,    ): uncertain by ~ 100% around the critical values.