The property of being uniform throughout space. The assumption of homogeneity is part of the cosmological principle. The Universe is clearly not homogeneous on the scale of planets, stars, or galaxies. However, astronomers assume that on a large enough scale the Universe is homogeneous: that is, a large enough box placed anywhere in the Universe would contain roughly the same numbers of galaxies and clusters of galaxies as any other.
Subjects: Astronomy and Astrophysics.