What equation is known as "Einstein's Big Idea"? A - MC = e + m²
B - B/4AC - 2a = C²
C - A² + B² = C²
D - E = mc²
Answer: D - E = mc² Often called "Einstein's Big Idea," E = mc² stands for energy = mass times the speed of light squared. Derived from Einstein’s Special Theory of Relativity, the equation shows that energy and mass (i.e. all matter) are different forms of the same thing — a new concept at the time, and one that would have an enormous impact on the world.