Redshifts and Distances
The table in the left panel gives approximate distances associated with redshifts. However,
for large redshifts the distance to an object depends on the nature and evolution of the
Universe itself. In particular, it depends on assumptions about the geometry of space and
time, and how the rate of expansion has varied with time (see Chapter 27).
Because they are related to directly measurable quantities, astronomers
tend to talk about redshifts rather than distances when
discussing very distant objects.