The Cosmic Lavoisier Principle: Conservation of Matter-Energy Across All Scales — From Stellar Cycles to Galactic Black Holes

Lavoisier's principle — nothing is lost, nothing is created, everything is transformed — was established at the chemical scale in 1789. We propose that this principle extends unchanged across all physical scales, from atomic transformations to galactic dynamics. The central black hole of a galaxy is its ultimate expression: a reservoir of matter-energy accumulated over billions of years, not destroyed but waiting in extreme transformation. We argue that the black hole functions as the structural organ of the galaxy — not a passive object but the gravitational anchor of the entire galactic system. Piercing it would catastrophically destabilise the galactic structure. A final conjecture addresses the Fermi paradox: advanced civilisations may disappear not because they fail to advance, but because they succeed — reaching the level where the energy they need requires destroying the system that produced them. This is the Complexity Trap. All claims are speculative and clearly marked.