Physics is full of beautiful bits of terminology that sit at the intersection of mathematics and poetry. DeWitt gave one of my favorite examples.

It can he found in his book "Supermanifolds,” where he had to introduce some terminology for a concept he calls "supernumbers.”

Supernumbers are elements of something called a Grassmann algebra. The algebras Dewitt had in mind are infinite-dimensional. One typically needs an infinite set of complex numbers to describe just one of these supernumbers.

Bryce DeWitt, a major figure of 20th century theoretical physics who made substantial contributions to field theory, especially the field theoretic approach to quantum gravity, was born #OTD in 1923.

Image: UT Physics History

@j_bertolotti co-sined

☝️A long thread I wrote last year, on Stephen Hawking’s life and work. Everything from the laws of black hole mechanics to being a guest on The Simpsons.

Me trying to give my dog his pill.

Winter birds.

@OranMagal In my defense I was calling a landline

Someone answered??

@bradk I should be so lucky

Welp, I just typed a phone number into my calculator app.

@Birk_lab “So uhhh... what am I looking at here?”

German astronomer Martin Brendel took the first known photograph of an aurora #OTD in 1892, at Alta fjord in northern Norway.

@thomasfuchs lollll

@jpshoer That is correct. Short and hunch-backed. It was a deliberately mean dig at him.

Finally, Isaac Newton supposedly told a friend that his dog Diamond helped him uncover two theorems. Also, there’s a story about Diamond being responsible for a fire that destroyed some of Newton’s papers.

I believe the bit about the theorems, but as far as the fire is concerned, I think the dog was framed.

Anyway, Isaac Newton died in 1727. Here's a copy of his death mask. It was made in 1892 from the plaster originals. I think he sort of looked like Colin Firth?

Image: Newton Institute, on loan from the Whipple Museum of Science

The law was repealed after lobbying by Robert Boyle, whose work at the time was laying the groundwork for modern chemistry.

Newton, who was obsessed with alchemy, hypothesized that the campaign to repeal the law meant that Boyle must have found an alchemical method for producing gold!

(This was not the case. You cannot chemically transmute an element. All the gold on Earth was likely formed in supernovae or a collision between neutron stars. Boyle did not have access to either of those.)

Here is a little story about Newton which may or may not be related to his interest in the responsibilities of the Royal Mint.

In 1688 the British Parliament repealed the "Act Against Multipliers."

This was a law that had been passed in 1404. It forbid alchemists from transmuting base metals into something more precious, like gold or silver. Makes sense – you don't want alchemists devaluing your currency!

He had himself made a Justice of the Peace, and would go undercover –– sometimes in disguise! –– to collect evidence. Then, after the counterfeiters had been arrested, Sir Isaac Newton would often question them himself.

This is not exactly in keeping with the image of Sir Isaac Newton that most of us probably have. Apparently he liked to get his hands dirty!

More on this from the Royal Mint Museum:
https://www.royalmintmuseum.org.uk/journal/people/isaac-newton/

Anyway, we all know about Newton's scientific accomplishments. What is lesser known is the fact that he served first as Warden and then Master of the Royal Mint for the last 30 years of his life, from 1696 to around 1727.

He took this position very seriously. During the Great Recoinage of 1696 he estimated that as much as 20% of the reclaimed currency was counterfeit. Newton took it upon himself to deal with the problem.