The relationship between carbon and time spans astrophysics, geology, biology, and thermodynamics. Because carbon is the foundational element of life and organic matter, its chemical transformations serve as a physical clock for the planet and the cosmos. Key Intersections of Carbon and Time 1. Radiocarbon Dating (The Biological Clock) Carbon acts as an internal clock for dead organic tissue. The Mechanism: Living organisms continuously absorb stable Carbon-12 (^{12}\text{C}) and radioactive Carbon-14 (^{14}\text{C}) from the atmosphere in a fixed ratio. The Decay: When an organism dies, it stops absorbing carbon. The trapped ^{14}\text{C} decays back into Nitrogen-14 (^{14}\text{N}) at a fixed rate, carrying a half-life of approximately 5,730 years . Time Scale: By measuring the ratio of remaining ^{14}\text{C} to ^{12}\text{C}, scientists accurately date organic materials (bones, wood, textiles) up to ~50,000–60,000 years into the past. Living Organism (Constant 14C/12C...