Notices tagged with otd, page 3

My favorite serendipitous alignment of author names and paper topic occurred #OTD in 1992, when Dr. D'Eath and Dr. Payne submitted 3 papers to Physical Review exploring the physics of black holes smashing into each other at relativistic speeds.

Dr. D’Eath and Dr. Payne getting together to work on something as catastrophic as ultra-relativistic black hole collisions is A+ branding.

https://link.aps.org/doi/10.1103/PhysRevD.46.658

Paul Dirac's paper on quantum emission and absorption of radiation was submitted to the Royal Society #OTD in 1927. It advanced the first quantum mechanical theory of electrodynamics and is considered by many to mark the birth of ✨Quantum Field Theory✨

This thread is for the quantum gravity folks, and it does not lead where you expect.

https://royalsocietypublishing.org/doi/abs/10.1098/rspa.1927.0039

Physicist Rudolph Mössbauer was born #OTD in 1929. He is best known for his eponymous scattering phenomenon in which gamma rays are absorbed without recoil by nuclei in a crystal lattice. This allows frequency measurements precise enough for tests of general relativity.

Let's just get this out of the way: Yes, he was a handsome. Was he setting unrealistic standards for future physicists? Also yes. Please don’t let this prejudice your opinion of his scientific contributions.

Isaac Newton was made aware of Jean Bernoulli's "brachistochrone" problem #OTD in 1697. He solved it later that evening, showing that the curve of fastest descent between two points was given by a portion of a cycloid.

Newton published his solution anonymously in the Philosophical Transactions of the Royal Society of London. Bernoulli would later say that the identity of the author was obvious; he recognized "the lion by his claw."

Swedish mathematician Niels Fabian Helge von Koch was born #OTD in 1870.

He established results in number theory, including one that relates the Riemann hypothesis to the asymptotic distribution of prime numbers. But he is probably best known for what we call the "Koch Curve" – one of the first examples of a fractal.

Mathematician Alfred Tarski was born #OTD in 1901.

The Banach-Tarski paradox asserts that a ball in three dimensions can be decomposed into a finite number of pieces which, after translation and rotation, can be reassembled into *two* distinct copies of the original ball.

The paradox also works in more than three dimensions, but not in one or two without significant technical modifications.

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

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

Physicist and mathematician Isaac Newton was born #OTD in 1643.

Newton revolutionized our understanding of mathematics, mechanics, gravity, and optics. Later in life he served as warden of the Royal Mint, reforming currency and foiling counterfeiters.

Portrait: Barrington Bramley, after Godfrey Kneller

Today, 15 years ago #OTD the person or group with the fictive name of “Satoshi Nakamoto” created the first cryptocurrency named Bitcoin with the thought of it becoming a secure and fast alternative to fiat currency.

Now it's known as the most wasteful use of electricity, inefficient and limiting capability/functionality, as well as being among the most insecure and de-anonymizing ways to transfer money.

However, what Satoshi Nakamoto probably hasn't expected is how many scam-currencies would come after theirs, and how their invention would create a new breed of the most annoying people known to our species: crypto-bros.

Lynn Conway, electricial engineer and computer scientist, co-architect of the VLSI design revolution, and transgender activist, was born #OTD in 1938.

She invented Dynamic Instruction Scheduling at IBM, but IBM fired her when they learned she was transitioning.

Photo: Lynn Conway

Edwin Hubble announced #OTD in 1925 that Andromeda and other spiral nebulae were in fact separate galaxies outside the Milky Way, in a paper read to an AAS meeting by H.N. Russell.

The Universe was far larger than what many astronomers had allowed themselves to imagine. It was more than just our little island of stars.

Hubble built on observations by Vesto Slipher, collaborated with Milton Humason, and relied on Henrietta Swan Leavitt’s Cepheid variable work to reach this conclusion.

Mathematician, physicist, and computer scientist, the great omnimath John von Neumann was born #OTD in 1903.

He considered his quantum mechanics contributions to be most important. To get a sense of the breadth of his work, look at his Wikipedia “known for” list.

Mary Somerville was born #OTD in 1780. She was a scientist, writer, and artist; the first woman (along with Caroline Herschel) to belong to the Royal Astronomical Society; and the first signature on Mill’s 1868 Women’s Suffrage petition.

Image: self portrait (Somerville College, Oxford)

The Apollo 8 astronauts performed lunar orbit insertion #OTD in 1968.

Frank Borman, Jim Lovell, and Bill Anders became the first humans to orbit the moon, the first to see an earthrise, fifty three years ago today.

Anders spotted the Earth coming up over the Moon’s horizon:

"Oh my God, look at that picture over there! It's the Earth coming up. Wow, is that pretty!"

Image: NASA

Physicist David Bohm, who developed a non-local formulation of quantum mechanics that he hoped would evade some of the conceptually thorny aspects of the Copenhagen Interpretation, and would later inspire the work of John Bell, was born #OTD in 1917.

The International Symposium on Gravitational Collapse and Other Topics in Relativistic Astrophysics met #OTD in 1963 to discuss recently discovered "quasi-stellar radio sources." But the meeting is best known for a surprising announcement about black holes.

Image: Physics Today

Something that isn’t as widely known is that “h” is not the only fundamental constant that was introduced during Planck’s presentation to the German Physical Society #OTD in 1900!

Planck was investigating emission and absorption by blackbodies, so he needed a way to relate energies and temperatures. Thus, he had to introduce what we now refer to as “Boltzmann’s constant.”

Happy #QuantumDay to all who celebrate!

Max Planck presented work on blackbody radiation to the German Physical Society #OTD in 1900. His novel “quantum hypothesis” suggested that matter emits and absorbs light with frequency f only in discrete chunks of energy E=hf.

Image: AIP

☝️Grace Hopper – “Amazing Grace” was born #OTD in 1906.