The Absence of Straight Lines: A Comparative Analysis of Gravity from Newtonian Physics to Einstein's Spacetime Curvature

This article explores the fundamental nature of gravity by comparing the classical Newtonian model with Albert Einstein's General Theory of Relativity. While Newton described gravity as a force attracting two or more objects, Einstein redefined it as a curvature of four-dimensional spacetime caused by mass. We analyze the implications of these theories through a thought experiment: a universe containing only a single massive object. The conclusion is that in such a scenario, the object would not experience any gravitational pull on itself and would move in a straight line or remain stationary, a stark contrast to the complex orbital mechanics observed in our universe filled with countless celestial bodies.