Notices by Robert “The Bobby Yaga” McNees (mcnees@mastodon.social)

Physicist Freeman Dyson was born #OTD in 1923.

He was known for his work in quantum electrodynamics and – among many other things – his eschatological musings about physics and the prospects for life in the far-flung future.

To the best of my knowledge, Dyson was the most prominent physicist of the modern era who never completed a PhD.

Photo: Heka Davis / AIP

Planck’s quantum hypothesis would revolutionize physics, but he initially thought it wasn’t real.

He suspected that the interaction of matter and radiation was tremendously complicated but still governed by the physics known at the time — what we now call “classical physics.”

Invoking quanta of radiation to derive the blackbody emission spectrum was, it seemed to Planck, just a mathematical trick that somehow encapsulated all that complication.

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 should be treated as it it emits and absorbs light with frequency f only in discrete chunks of energy E=hf.

Image: AIP

Many physicists remained skeptical. But Arthur Compton’s 1923 explanation of X-rays scattering off electrons was near-incontrovertible evidence that quanta were real.

If so, it was a trick that *worked*.

Previous efforts to derive the blackbody emission spectrum using classical physics gave nonsensical results at high frequencies. Replace continuous emission with discrete quanta and things work out perfectly.

Evidence for the reality of quanta began with Einstein’s explanation of the photoelectric effect in 1905. The proposal that radiation of frequency f exists only in discrete chunks of energy E=hf was the first result of Einstein’s “Miracle Year.”

Planck’s hypothesis was in fact a deep statement about the nature of Nature. Electromagnetic adiation of frequency f comes in discrete chunks of energy E=hf. It's not an artifact of a complicated interaction with matter.

Nowadays we refer to the proportionality constant h as "Planck's constant." In the SI system it takes the value h=6.626 x 10⁻³⁴ kg*m²/s, or 4.136 x 10⁻¹⁵ eV*s.

As far as we can tell, h is a fundamental constant that is hardwired into our Universe.

This sequence of events was a not uncommon narrative in the transformative years of late 19th and early 20th century physics. It would go something like this:

1. An experimental result doesn’t make sense

2. A physicist proposes a radical solution.

3. The solution seems too weird to be real. Everyone assumes it must be a convenient "trick."

4. Eventually, everyone realizes it wasn't a trick, and reality is in fact weirder than they expected.

Here's a great APS Landmarks entry where you can read more about Compton Scattering and the reality of photons.

https://physics.aps.org/story/v13/st8

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.”

The results of Planck’s December 14th lecture were submitted to Annalen der Physik a few weeks later, on January 7th, and published not long after that.

You can see the original (in German) here:
https://onlinelibrary.wiley.com/doi/epdf/10.1002/andp.19013090310

An English translation of Planck’s paper, taken from Dirk ter Haar’s “The Old Quantum Theory,” is available here:
https://web.archive.org/web/20230529024105/http://hermes.ffn.ub.es/luisnavarro/nuevo_maletin/Planck%20(1900),%20Distribution%20Law.pdf

The transition from classical to quantum physics went about as smoothly as you would expect. Happy #QuantumDay!

(Unfortunately, I have no idea who made this classic physics meme. It has been around forever. If you know, please tell me!)

That’s right, the factor of “k” that appears in the formula “S = k log W” — the formula engraved on Boltzmann’s memorial! — was actually introduced by Max Planck. Boltzmann expressed his results in terms of the ideal gas constant R.

Image: user Daderot on Wikipedia

The retraction basically says the authors relied on unpublished Monsanto studies to make key claims, that the authors weren’t independent, that Monsanto likely co-wrote the paper, and the authors received undisclosed financial compensation.

I’m not an expert, but I’ve seen this paper described as an important justification for claims about the safety of Roundup.

And now it has been retracted by the journal it appeared in over 25 years ago.

https://www.sciencedirect.com/science/article/abs/pii/S0273230099913715

“… the handling (co) Editor-in-Chief lost confidence in the results and conclusions of this article, and believes that the retraction of this article is necessary to maintain the integrity of the journal. The scientific concerns regarding the lack of carcinogenicity only derived from Monsanto studies, concerns regarding (ghost-) authorship(s) and potential conflicts of interest, none of which have been responded to, are sufficient to warrant this action.”

Yikes.

Ernst Florens Friedrich Chladni, considered a pioneer of the field of acoustics, was born #OTD in 1756.

He studied the mathematical theory of sound waves, the speed of sound in various materials, and eponymous complex patterns formed by granular materials collecting along the nodes of the vibrational modes of solid objects.

Chladni famously drew a violin bow along the edge of a thin metal plate, lightly dusted with flour, to excite the plate's vibrational modes. Here he is performing the demonstration for Napoleon.

Image: Deutsches Museum Munich, no. 527”7

This is a marketing trick that helps the Sam Altmans of the world steal Machine Learning valor to prop up a bunch of gross plagiarism machines that have all our worst biases and failings baked in.

Do not help them!

Lumping them together as “AI” gives readers the impression that a single class of tool is discerning novel protein structures, teasing subtle patterns out of mountains of LHC data, writing a student’s History 101 paper for them, and arguing that a ketamine-addled billionaire could post up Shaq in his prime. No.

Machine learning (umbrella term, I know) is a useful, sometimes transformative tool in the hands of trained researchers who understand how to deploy it and critically assess the results.

A chatbot is not useful in the same ways (though underlying technologies may be, in other contexts).