#electrodynamics
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mcnees.bsky.social
Freeman Dyson submitted a lovely little two-page paper to Physical Review #OTD in 1951. It showed that perturbation theory in quantum electrodynamics produces a divergent series. It's one of my favorites, an absolute classic of the field. 🧪 ⚛️

journals.aps.org/pr/abstract/...
The beginning of the paper reads: Divergence of Perturbation Theory in Quantum Electrodynamics F. J. DYSON Laboratory of Nuclear Studies, Cornell University, Ithaca, New York (Received November 5, 1951) An argument is presented which leads tentatively to the conclusion that all the power-series expansions…
November 5, 2025 at 7:24 PM
jjgass.bsky.social
Few people know that Trump's undergrad degree from Wharton was in quantum electrodynamics. Which was VERY cutting-edge when he graduated in the mid-60s.

(No, I can't explain what magnets are)
comraderobot.bsky.social Notorious RBMK @comraderobot.bsky.social · 1d
everyone dunking here has homework due in 30 minutes explaining to me what magnets are
atrupar.com Aaron Rupar @atrupar.com · 1d
Trump: "Nobody knows what magnets are."
November 10, 2025 at 9:37 PM
forth-ite.bsky.social
✨The 7th Annual Nick Kylafis Distinguished Lecture was successfully held today (29/10), featuring the renowned astrophysicist Prof. Roger Blandford. The lecture, was entitled “New Horizons in Extreme Electrodynamics of Black Holes and Neutron Stars.”
October 29, 2025 at 2:46 PM
rhettallain.bsky.social
New #physics video - finding the magnetic field due to a loop of current. No tricks in this derivation - but I do it again with #python (you probably knew that). #electrodynamics

youtu.be/D5xrtFD3uYM
Electrodynamics: Magnetic Field due to a Loop of Current
YouTube video by Dot Physics
youtu.be
October 27, 2025 at 8:37 PM
dsng480.bsky.social
This guy is not known for his work in quantum electrodynamics, but that's one more who will at least stay home.
October 27, 2025 at 7:27 PM
rmeddy.bsky.social
QED- Quod Erat Demonstratum or Quantum Electrodynamics
October 25, 2025 at 10:39 PM
rycparke.bsky.social
tvtropes.org/pmwiki/pmwik...

en.wikipedia.org/wiki/Quantum...

(Comic Book Premise: Magneto from X-Men discovers Quantum Electrodynamics)
October 20, 2025 at 7:30 PM
knautwuff.bsky.social
Explaining quantum electrodynamics with a soft palate lisp, past a sippy cup.
October 16, 2025 at 10:00 PM
buckrawheat.bsky.social
Gotta add it to the list
Xkcd comic with crazy phenomena and an explanation of the obvious uses corporations would put them to use for if they existed Remote viewing and dowsing - oil prospecting Auras, homeopathy, remote prayer - healthcare cost reduction Astrology, tarot - financial/business planning Crystal energy - regular energy Curses, hexes - the military The last 2 work: Relativity - GPS devices Quantum electrodynamics - semiconductor circuit design "Eventually, arguing that these things work means arguing that modern capitalism isn't *that* ruthlessly profit-focused"
October 15, 2025 at 2:23 AM
konsyse.com
Renowned theoretical physicist Albert Einstein first introduced the Special Relativity Theory in the paper “On The Electrodynamics of Moving Parties” he published in 1905. In 1915, he also introduced another theory called the General Relativity Theory.
Special Relativity vs General Relativity: The Difference — Konsyse
Albert Einstein first introduced the Special Relativity Theory in in 1905 and in 1915, he also introduced the General Relativity Theory.
www.konsyse.com
October 11, 2025 at 6:00 AM
gilmorejon.bsky.social
reading this made me realize that the hard problem of consciousness is roughly equivalent to stopping a physicist who's describing electrodynamics to say 'wait. until you tell me *why* electrons are attracted to protons, I won't accept your descriptive claims'
October 8, 2025 at 3:33 AM
anthropic42.bsky.social
Flight Dynamics Officer, computational fluid dynamics, quantum electrodynamics: These are among the perfectly legitimate uses of the word “dynamic” in science, mathematics, and engineering.

In contrast, I have utterly no clue what a “dynamic” opinion page would even be.
October 8, 2025 at 3:58 AM
rhettallain.bsky.social
New #physics #electrodynamics video - using #python to display the electric field due to dipole water molecule.

youtu.be/BmvTOyyZQpo
Electrodynamics: Calculating the Electric Dipole Moment For Water
YouTube video by Dot Physics
youtu.be
October 6, 2025 at 11:06 PM
toffat.bsky.social
I messed up in some places but I think I did okay on my midterm today!

Praise be to Introductions to Electrodynamics Fourth Edition by David J. Griffiths 🙏🙏🙏

Gotta be my favorite textbook so far
October 6, 2025 at 4:43 PM
rhettallain.bsky.social
This #physics #electrodynamics video is for future-Rhett because he's going to forget how to make a quiver plot and contour plot due to an electric dipole. #python #iteachphysics

youtu.be/cP3l6-2Z9rs
Electrodynamics: Plotting the Potential and Electric Field for a Dipole with Python
YouTube video by Dot Physics
youtu.be
October 2, 2025 at 3:28 PM
photophart.com
Magical raindrops. Sometimes light plays tricks more marvelous than quantum electrodynamics would lead you to believe are possible.

#photography #bnwmacro #macrophotography #grayscale #raindrops
Black and white sparkling raindrops on leaves.
September 28, 2025 at 1:24 PM
mcnees.bsky.social
Let's go through some of his arguments.

At the beginning of the paper, Einstein presents two reasons why our understanding of electrodynamics (the rules governing charges, currents, and electromagnetic fields) must be incomplete. (2/n)
September 26, 2025 at 6:18 PM
mcnees.bsky.social
That is *not* what happens.

Neither one of us is accelerating, so we both agree that Newton's laws describe mechanical phenomena. That's what is meant by "inertial observer" or "inertial frame of reference."

Einstein says we must therefore also agree on the laws of electrodynamics. (17/n)
September 26, 2025 at 8:49 PM
mcnees.bsky.social
Happy 120th birthday, special relativity!

Albert Einstein introduced special relativity in the paper "On The Electrodynamics Of Moving Bodies," published in Annalen der Physik #OTD in 1905. 🧪 ⚛️ 🔭

Manuscript: onlinelibrary.wiley.com/doi/abs/10.1...
English: www.fourmilab.ch/etexts/einst...
A black and white photo of Albert Einstein, around age 25, sitting at a desk. He is a wearing a flannel suit and resting his right arm on the desk. Einstein is looking to the left of the photographer in this posed photo. The first paragraph of the paper, in German. Translated to English is reads: It is known that Maxwell's electrodynamics—as usually understood at the present time—when applied to moving bodies, leads to asymmetries which do not appear to be inherent in the phenomena. Take, for example, the reciprocal electrodynamic action of a magnet and a conductor. The observable phenomenon here depends only on the relative motion of the conductor and the magnet, whereas the customary view draws a sharp distinction between the two cases in which either the one or the other of these bodies is in motion. For if the magnet is in motion and the conductor at rest, there arises in the neighbourhood of the magnet an electric field with a certain definite energy, producing a current at the places where parts of the conductor are situated. But if the magnet is stationary and the conductor in motion, no electric field arises in the neighbourhood of the magnet...
September 26, 2025 at 6:17 PM
mcnees.bsky.social
But Einstein's conjecture does more than obviate the ether.

Once we assume that the laws of electrodynamics hold in all "inertial" reference frames, we reach some confusing conclusions that force us to revise our most basic ideas about space (where things happen) and time (when they happen). (10/n)
September 26, 2025 at 6:31 PM
mcnees.bsky.social
Einstein addresses these issues (and revolutionizes physics) with a simple conjecture that has radical consequences.

He postulates:

“...the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good." (6/n)
September 26, 2025 at 6:26 PM
mcnees.bsky.social
Having fixed kinematics so that it reflects Nature rather than an intuition trained on cars and baseballs, Einstein moves on to electrodynamics.

He works out the transformation of Maxwell’s laws, and derives (among other results) the special relativistic form of the Doppler shift. (29/n)
The passage of Einstein’s paper, in the original German, showing the Doppler shift of light due to relative motion between observer and source.
September 26, 2025 at 9:22 PM
mcnees.bsky.social
Second, Einstein reminds the reader that all attempts to detect the motion of Earth through the “luminiferous ether“ — a hypothetical medium that most scientists assumed was necessary for the propagation of electromagnetic waves — had failed. (5/n)
Examples of this sort, together with the unsuccessful attempts to discover any motion of the earth relatively to the “light medium,” suggest that the phenomena of electrodynamics as well as of mechanics possess no properties corresponding to the idea of absolute rest. They suggest rather that, as has already been shown to the first order of small quantities, the same laws of electrodynamics and optics will be valid for all frames of reference for which the equations of mechanics hold good.1 We will raise this conjecture (the purport of which will hereafter be called the “Principle of Relativity”) to the status of a postulate, and also introduce another postulate, which is only apparently irreconcilable with the former, namely, that light is always propagated in empty space with a definite velocity c which is independent of the state of motion of the emitting body.
September 26, 2025 at 6:25 PM
mcnees.bsky.social
First, Einstein points out odd asymmetries in the way scientists explained electrodynamic phenomena associated with relative motion between two objects.

Those explanations were often very different depending on the point of view: Object A at rest and Object B moving, or vice-versa. (3/n)
It is known that Maxwell's electrodynamics -as usually understood at the present time- when applied to moving bodies, leads to asymmetries which do not appear to be inherent in the phenomena. Take, for example, the reciprocal electrodynamic action of a magnet and a conductor. The observable phenomenon here depends only on the relative motion of the conductor and the magnet, whereas the customary view draws a sharp distinction between the two cases in which either the one or the other of these bodies is in motion.For if the magnet is in motion and the conductor at rest, there arises in the neighborhood of the magnet an electric field with a certain definite energy, producing a current at the places where parts of the conductor are situated. But if the magnet is stationary and the conductor in motion, no electric field arises in the neighborhood of the magnet. In the conductor, however, we find an electromotive force, to which in itself there is no corresponding energy, but which...
September 26, 2025 at 6:21 PM
2001dalmatians.bsky.social
But wait, there's more. He didn't know it, but his E&M equations were relativistically valid. There is a reason Einstein's Special Relativity paper had a title like "On the Electrodynamics of Moving Bodies".
September 23, 2025 at 1:36 AM