>It is easier to imagine a "Euclidian space", i.e., a space where Euclid's axioms are valid. But it is now generally accepted that this applies to real space, only as a first approximation.
I'd need an update here.
Some 25 years ago, when I was at college, it was stated that the geometry of the universe is hyperbolic, i.e. has a negative curvature. IOW, it's a Lobachevsky space - which Lobachevsky himself proved in mid-nineteenth century by measuring a defect in a triangle (total of its angles being less than 180 degrees) between some stars when seen in the summer and in the winter.
Other than that, I haven't heard anything new on the subject - was this proven more strongly since, or is this a part of a larger picture, or what's the latest anyway? What's the geometry of our space?