It was 100 years ago that Albert Einstein had a brainstorm: mass and energy are one, related by the formula E=mc2.

Just what does this formula mean? How did Einstein hit upon it? And who were the visionaries paving his way?

These questions are answered, and portrayed compellingly, in a new “NOVA” docudrama, “Einstein’s Big Idea.” It airs Tuesday on PBS.

Based on David Bodanis’ best-seller “E=mc2: A Biography of the World’s Most Famous Equation,” the program explores the lives of the men and women who helped develop concepts behind each term: E for energy; m for mass; c for the speed of light; and 2 for “squared,” the multiplication of one number by itself.

“Einstein’s Big Idea” deftly interweaves the story of Einstein, who in 1905 was a 26-year-old family man stuck in a dead-end job at a Swiss patent office, with portraits of earlier geniuses including:

¢ Michael Faraday, who rose to become one of the giants of 19th century science and laid the groundwork for the modern concept of energy.

¢ Antoine-Laurent Lavoisier, who proved that total mass is never lost, no matter what sort of physical transformation a substance undergoes.

In its extended dramatic scenes, the film not only helps explain what Einstein’s formula means, but also traces, personality by personality, the accumulating pieces of the puzzle he solved.