Heliocentric system and barrel: what they have in common
- Step 1. Heliocentric system — evolved into — Kepler’s laws. A refinement of Copernicus.
- Step 2. Kepler’s laws — evolved into — Universal gravitation. Newton derived gravitation from Kepler’s laws.
- Step 3. Universal gravitation — is used in — Gravity flow. It flows downhill under gravity.
- Step 4. Gravity flow — is used in — Aqueduct. Water flows down a gradient without pumps.
- Step 5. Aqueduct — has part — Arch. Roman aqueducts rested on arcades.
- Step 6. Arch — works like — Barrel. Staves squeezed by hoops hold their shape by the same compression as the stones of an arch.