Non-Newtonian physics refers to a body of theoretical work that goes beyond Sir Isaac Newton’s three laws of motion. These laws were the foundation of Newton’s universal laws of gravitation. It was Albert Einstein in the early 20th century who introduced theories of mass and energy that provided new concepts of space, time and gravitation. Einstein’s famous theory of relativity—that gravitation is not a force but a curved field—marked a major advance over Newtonian physics and ushered in a new era of scientific research.