Short Description of the Article: Model of Scale Duality (SDM) The Model of Scale Duality (SDM) introduces a novel framework for understanding fundamental limitations in spacetime structure. The model postulates the existence of two fundamental spatial scales: The Planck scale ( m), representing the smallest possible length in nature. The cosmic scale ( m), corresponding to the maximal observable universe. These scales are connected through the fundamental equation , imposing intrinsic constraints on space and time. SDM leads to modifications in Einstein’s field equations, naturally introducing a term equivalent to dark energy, eliminating the need for exotic components. The model also predicts a modification of Heisenberg’s uncertainty principle, offering a potential explanation for galactic rotation anomalies, possibly reducing the need for dark matter. Finally, the model establishes a finite lifespan for cosmic expansion ( years), beyond which the universe may enter a stable, quantum-dominated, or oscillatory phase. This approach suggests that gravity has an intrinsic quantum nature, linked to twistor space, providing a potential bridge between general relativity and quantum mechanics.