An Alternative Model of Cosmology
Matter explodes outward from center point. Different velocities send matter to different distances. No galaxies yet - matter moving too fast to clump.
Matter slows down as it fights against gravity. At apex, matter stops briefly then begins falling back. During this fall, gravity finally overcomes motion and galaxies form. Milky Way forms around 20 billion years ago. Andromeda forms later around 10 billion years ago.
Galaxies fall back toward center, accelerating due to gravity. As they fall, they eat other galaxies. Black holes accumulate mass over billions of years. This accumulated mass in millions of stellar black holes IS the "dark matter."
Milky Way and Andromeda on converging paths. Andromeda is younger but ate more aggressively (twice our size). Paths will cross in 4 billion years. After merging, combined mass continues falling toward center.
All galaxies converge toward center. Everything collapses back to singularity. Then... another Big Bang? Infinite cycle?