Changes

'''Curvature of spacetime''' of our universe is none since [[spacetime]] has to be flat on the [[Noether theorem]] that requires flat (or [[Minkowski]], which means the same thing) spacetime for the [[conservation of energy]] to hold.  

'''Curvature of spacetime''' of stationay universe is none since [[spacetime]] has to be flat on the [[Noether theorem]] that requires flat (or [[Minkowski]], which means the same thing) spacetime for the [[conservation of energy]] to hold.  

The flat '''curvature of spacetime''' does not reqire all of [[curvatures of spacetime]] to disappear since they, being non zero, may combine together in flat [[spacetime]] as it may happen in our universe where [[curvature of space]] together with other [[curvatures of spacetime]] may produce a flat [[spacetime]].

The flat '''curvature of spacetime''' does not reqire all of [[curvatures of spacetime]] to disappear since they, being non zero, may combine together in flat [[spacetime]] as it may happen in stationary universe where [[curvatures of space]] together with other [[curvatures of spacetime]] may produce a flat [[spacetime]].