The famous scientist who proposed the law of inertia is Sir Isaac Newton. He articulated this principle in his First Law of Motion, stating that an object at rest will remain at rest, and an object in motion will remain in motion at a constant velocity unless acted upon by a net external force. This law fundamentally changed the understanding of motion and laid the groundwork for classical mechanics. Newton's insights not only provided a framework for understanding celestial mechanics but also have applications in various fields, including engineering, physics, and everyday life, demonstrating the importance of forces and motion.