Cosmological Redshift in FRW Metrics with Constant Spacetime Curvature
  Cosmological redshift z grows as the Universe expands and is conventionally
viewed as a third form of redshift, beyond the more traditional Doppler and
gravitational effects seen in other applications of general relativity. In this
paper, we examine the origin of redshift in the Friedmann-Robertson-Walker
metrics with constant spacetime curvature, and show that---at least for the
static spacetimes---the interpretation of z as due to the "stretching" of space
is coordinate dependent. Namely, we prove that redshift may also be calculated
solely from the effects of kinematics and gravitational acceleration. This
suggests that its dependence on the expansion factor is simply a manifestation
of the high degree of symmetry in FRW, and ought not be viewed as evidence in
support of the idea that space itself is expanding.
