Natura - nature actualia - actual entities Mundus Plinius - physical world Astra Plinius - celestial bodies Universe (Supercluster) Virgo-Hydra-Centaurus Supercluster (Supercluster) Virgo Supercluster (Cluster) Local Group (Galaxy) Milky Way Galaxy veter. (Spiral arm) Orion Arm (Region) Local Bubble Local Interstellar Cloud (Planetary system) Solar System (Planet-satellite system) Earth System (Planet) Earth veter. "spheres" (Earth) (Sphere) Lithosphere (Earth) - layer of rock "strata" "chronostratigraphic units" "global chronostratigraphic units" (Eonothem) Phanerozoic Eonothem (541.0 Ma - present) (Erathem) †Paleozoic Erathem (541.0 - 251.902 Ma) (System) †Silurian System (443.8 - 419.2 Ma) (Series) †Llandovery Series (443.8 - 433.4 Ma) 1 (Stage) †Rhuddanian Stage (443.8 - 440.8 Ma) 2 (Stage) †Aeronian Stage (440.8 - 438.5 Ma) 3 (Stage) †Telychian Stage (438.5 - 433.4 Ma)