How is Einstein's energy equation true

Einstein's thought leader

Having grown up in the best of circumstances, she was a very unusual woman - both then and now. At a time when this was completely unusual for women, she acquired such detailed knowledge of physics that she was able to correct Newton: Emilie du Chatelet, born December 17, 1706. She never lacked self-confidence; in a letter to Frederick II she wrote:

"If I add up my gifts, I can say that I am not inferior to anyone."

That wasn't even an exaggeration. Voltaire, France's literary star, was happy with her for a long time:

"Truly: Emilie is the divine lover - endowed with beauty, wit, compassion and all other feminine virtues."

When she and Voltaire met, she was already married to Monsieur du Chatelet, a professional soldier who had little objection to his wife's liaison with the poet and who allowed the two of them to turn his dilapidated castle near Cirey in Champagne into a refuge where they could indulge in science, among other things. When trying to explore the nature of fire - following a call for tenders from the French Academy of Sciences - Emilie Voltaire was way ahead. While Voltaire experimented clumsily and not very systematically, the marquise limited herself to theoretically spinning well-known phenomena further - with astonishing success. If light hits the earth at its known high speed and has a mass, the consequences would be devastating. But that was nowhere to be seen. So light had to be massless. That is close to the interpretation that we take to be true today.

After all, Emilie du Chatelet and Voltaire were tired of each other:

"For 20 years I was happy with the man who had tied my soul. I have lost this happiness. And nothing brings back a lost love."

But Emilie's interest in science was unbroken. She remembered curious experiments in which brass cylinders fell from different heights into soft clay. From the depths of penetration one could conclude that the energy of moving bodies increases with the square of their speed. Newton, on the other hand, had adopted the simple speed. What if she translated Newton's main work, the "Principia Mathematica", into French and revised it in the process? Emilie had found her purpose in life. She corrected Newton's energy formula and is therefore considered to be the pioneer of Einstein's famous formula "E equals m times c square".

When she was 42, Emilie du Chatelet became pregnant again. She must have suspected that the end was imminent, because she was now driving the Newton translation with all her energy towards its conclusion. Contrary to expectations, the birth went off without any problems. The chroniclers smugly noted that the newborn was placed on a geometry book and Madame went to sleep afterwards. For a few days the marquise was fine. Then she got a fever. Doctors were consulted and she appeared to be recovering. Then, on September 10, 1749, she was dead.

This is the end of the career of what is possibly the most capable European physicist and mathematician of the 18th century. The encyclopedias have certainly honored Emilie du Chatelet, but mostly attributed her fame to the men around her. That was not due to Voltaire, who had always recognized Emilie's superiority in scientific matters.