11 hours ago
- The universe has no edge; galaxies extend uniformly in all directions as far as we can detect.
- Galaxies are not arranged on a sphere; the Big Bang was not an explosion in space but an expansion of space itself everywhere.
- We cannot see the whole universe because light from distant galaxies has not had time to reach us due to the universe's evolution and expansion.
- The expansion of the universe refers to the stretching of space between galaxy clusters, not galaxies moving through space.
- Evidence for the Big Bang includes the recession of galaxies, cosmic microwave background, and abundances of hydrogen and helium.
- The Big Bang scenario describes the early universe but does not explain the origin of space, time, or energy.