Translated and wrote commentary on Sir Isaac Newton’s work, Principia Mathematica. Her translation, published posthumously in 1759, is still considered the French standard by which all others are measured. She also published several papers throughout her lifetime, including one describing her research on fire, in which she correctly predicted what would later be described as infrared radiation. And some modern biographers report having seen in her notebooks a derivative of the equation made famous by Einstein: E = MC2. A crater on Venus was named in her honor. Her longtime lover, the philosopher and poet Voltaire, wrote to the King of Prussia that she “was a great man whose only fault was being a woman.” (Èmilie du Châtelet)
Now, I love Emilie du Chatelet. I read all about her after I went to see the play Legacy of Light in Boston last year. (Really enjoyable play, btw.) But let’s not get carried away. What Ms. du Chatelet did was discover that kinetic energy goes as velocity squared (K = mv2). The common thought at the time was that kinetic energy is linear with velocity (K = mv), so her discovery and well-thought out experiments were significant - but that does not mean that she discovered relativity!
The confusion here comes about because the equation that everyone knows, E = mc2, is not the full equation. There’s actually a second term that deals with momentum, the energy of a moving object. It’s not surprising that a moving object has energy, right? If I throw a ball at a window, it’ll transfer some of its energy and break the window. But what if an object is at rest? If the ball rolls to a stop at your feet, does it still have energy? It turns out it does! (Although only a very small amount.) That “rest energy” is given by E = mc2. That idea, among many others, is what made Einstein famous.
So let’s give Ms. du Chatelet credit where credit is due without making up anything extra - she did some amazing work. She studied the nature of fire, light, and color, as well as magnetism, elasticity, and resistance, making significant insights with ingenious experiments. Her name ought to be the next mentioned after Newton’s in intro. physics classes. Given the resources she had available to her, I find it amazing that she refused to simply be one of the wealthy society, with nice dresses, fabulous hairdos, and empty conversation, and instead bucked the societal norm to pursue science.
Thanks for this! I love that this is getting people talking and sharing their knowledge!