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Structure of the solar system and Kepler's laws in context.
Speed at which gravity exactly provides the centripetal force.
Three laws of planetary orbits — ellipse, equal areas, T² ∝ a³.
Spectral classes (OBAFGKM) and the Hertzsprung–Russell diagram.
Main sequence to red giant to white dwarf / neutron star / black hole.
Galaxy types and structure of the Milky Way.
Recessional velocity proportional to distance; redshift.
Origin of the universe, CMB, and the age estimate.