average density of matter

hyperbolic space

Big Bang

isotropic

closed universe

lookback time

combined average mass density

mass density of radiation

compression

matter density parameter

cosmic background radiation

matter-dominated universe

cosmic light horizon

negative curvature

cosmic microwave background (CMB)

observable universe

cosmological constant

Olbers’s paradox

cosmological principle

open universe

cosmological redshift

Planck time

cosmology

plasma

critical density

positive curvature

dark energy

primordial fireball

dark energy density parameter

radiation-dominated universe

dark-energy−dominated universe

rarefaction

density parameter

relativistic cosmology

era of recombination

spherical space

flat space

virtual particle pairs

homogeneous

zero curvature

Hubble time