Terminology/Isotropy
Isotropy
In physics and geometry, isotropy is uniformity in all orientations. Precise definitions depend on the subject area.
Exceptions, or inequalities, are frequently indicated by the prefix a- or an-, hence anisotropy. Anisotropy is also used to describe situations where properties vary systematically, dependent on direction. Isotropic radiation has the same intensity regardless of the direction of measurement, and an isotropic field exerts the same action regardless of how the test particle is oriented.
The cosmological principle, which underpins much of modern cosmology (including the Big Bang theory of the evolution of the observable universe), assumes that the universe is both isotropic and homogeneous, meaning that the universe has no preferred location (is the same everywhere) and has no preferred direction.
Observations made in 2006 suggest that, on distance-scales much larger than galaxies, galaxy clusters are "Great" features, but small compared to so-called multiverse scenarios.