Cosmological Principle
Isotropic and Homogeneous
Location and cosmic center
Containment and edges
Cosmic edge middle
What if I threw this spear?
Atomist answer
Woodcut
Expansion of Universe
Galaxy recession
Balloon Analogy
balloon continued
The universe as a balloon
Space is expanding
The Big Bang
Redshift #1
Redshift #2 and #3
Expansion redshift
