The cosmological principle in astronomy
A) is only an assumption, for which we don't have any real evidence yet
B) applies only to the Milky Way Galaxy, not to anything outside it
C) is confirmed by many observations done by Hubble and many other astronomers since
D) is contradicted by the existence of quasars
E) is an old Greek idea, now completely discredited by modern observations

Question

Quizplus · Accepted Answer

The cosmological principle is the assumption that the universe is homogeneous (looks the same in all directions) and isotropic (has the same physical properties in all directions) on large scales. This principle has been confirmed by many observations, including the cosmic microwave background radiation, the large-scale distribution of galaxy clusters, and the Hubble expansion of the universe. Quasars are not necessarily contradicting the cosmological principle as they are found throughout the universe and do not have any effect on the large-scale physical properties of the universe.

The Cosmological Principle in Astronomy