In many subjects you learn about what someone did rather than the people. Noether's theorem is extremely important in physics, yet I went many years without realizing Noether was a mathematician and a woman. A piece from The Guardian that links to a talk from the Perimeter Institute.
Noether was a mathematician rather than a physicist, but her theorem, which states that for every continuous symmetry in nature, there is a conservation law, is now part of the bedrock of physics.
A “continuous symmetry” of some system means a variable that can be changed to any value without affecting the system. For example the laws of physics don’t depend on where you are. There is a continuous symmetry with respect to changes of location. Noether’s theorem says that because of this, there must be a conserved quantity.
That quantity is actually momentum. So from an assumption that the laws of physics are the same wherever you are, Noether’s theorem basically allows us to prove, amongst other things, Newton’s First Law: An object will remain at rest or moving with a constant velocity unless acted on by an external force. This is a very powerful principle, with many further profound consequences, and is one of the foundation stones of the Standard Model of particle physics¹. These ideas were needed before moving on to gauge symmetries, broken symmetries and the Higgs boson.
It has been noted that the equations of Nature often seem to know much more than the people who discover them. This year marks the 150th anniversary of the publication of Maxwell's equations. Some comments on the depth of this remarkable work from The Guardian. It is also the 100th anniversary of Einstein's General Theory of Relativity..
Early knowledge of a German atom bomb project was one of the most important sparks for the Manhattan Project. Over the course of the war it became increasingly clear the German effort was too small to produce a device.
People love the myth of the lone genius. It hasn’t been true in science for a long time even though Einstein is frequently cited. Acknowledging his collaborations does nothing to detract from his brilliance. As part of their celebration of the centennial of the publication of the general relativity paper, Nature has published a quick history. Nothing new and not deep, but a nice debunking of the myth.
It is disturbing that the lone genius myth is common in engineering and technology. There are some incredibly smart people, but paraphrasing Newton, there are a lot of footprints on shoulders.
Change from dealing with tuberculosis and learning that a contagious bacteria rather than heredity was responsible. Some of the change:
Shorter Hemlines Around the turn of the century, most American women wore long dresses and skirts that reached the ground. But those skirts could be major carriers of germs found on one's floors and out in the streets. Once it became widely known that the tubercle bacilli from someone's saliva could survive for an entire day, women abandoned their long dresses, skirts, bodices, and bustles in favor of shorter hemlines that would not drag along potentially germ-ridden sidewalks.
Shaving Most men at the turn of the century featured stylish beards or mustaches, but showing off a smooth face became a new trend once public health officials maintained that men could transmit dangerous infectious particles through the scruff of their facial hair. An editorial in a 1903 Harper's Weekly stated, "Now that consumption is no longer consumption, but tuberculosis, and is not hereditary but infectious…the theory of science is that the beard is infected with the germs of tuberculosis.” Ultimately, the clean-shaven look became a symbol of the new middle-class man during the period that Harper's Weekly labeled the "the revolt against the whisker."
Robert Hooke's Micrographia is 350 years old. Lots of firsts - the first book with illustrations of plants and insects through a microscope. The first major publication of the Royal Society and probably the first scientific hit with the public. Hooke was the first to use cell to describe biological objects.