Mach's Principle

Mach's principle is the idea that the inertia of an object—its resistance to changes in motion—depends on the presence and distribution of mass in the universe. Essentially, it suggests that local physical laws are influenced by the overall gravitational effects of distant masses, meaning that the behavior of an isolated object can't be fully understood without considering the entire cosmos. This concept influenced Albert Einstein when developing his theory of General Relativity, highlighting the interconnectedness of mass, motion, and gravity in the fabric of space-time.