2020-02-09 08:48:15 UTC
According to GRT there is a specific amount
of energy ( energy density) in the universe that
will cause space to bend. It turns out that the
amount of energy density that was measured
in the universe is exactly the right amount
needed to cause the space not to bend at all
There isn't enough mass and energy to give
the space in the universe its curvature.
The critical mass density in the universe is
9.9 x 10^-30 g/cm^3, that keeps it flat.
Space is ''pretty flat'' to within 0,5%, according
to the WMAP 2013 measurement.
In some local places in the universe the amount
of the critical mass - energy density is higher
that causes the local space to bend.