Concept
Cosmic Expansion
Space itself stretching, carrying galaxies apart.
The universe is expanding so that distances between distant galaxies grow over time, described by the Hubble–Lemaître law.
Overview
The universe is expanding so that distances between distant galaxies grow over time, described by the Hubble–Lemaître law.
See also
Black Holes
Regions where gravity stops light itself.
Dark Matter
The invisible mass holding galaxies together.
Heliopause
The edge of the Sun's bubble in space.
Photon Sphere
Where light itself can orbit a black hole.
Reionization Epoch
When the first stars and galaxies relit the universe.
Cosmological Constant
A constant energy density of empty space.