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Re:Higher Multipoles of the Cow by Bowes-Lyon on Tuesday September 01, 2026 @05:40AM (#49519871)
Hmmm… Today is Sep 1st, not Apr 1st. That cow is a bit out of season :)
Re:Higher Multipoles of the Cow by jitl on Wednesday September 02, 2026 @10:45PM (#49545360)
> Submitted on 1 Apr 2025 (v1), last revised 1 Apr 2026 (this version, v2)
Re:Higher Multipoles of the Cow by turbostar on Wednesday September 02, 2026 @10:56PM (#49545445)
Anna Cramling, women’s international chess master, should review this paper, having popularized the Cow Opening.
Re:Higher Multipoles of the Cow by lhd1 on Wednesday September 02, 2026 @11:15PM (#49545556)
One of the cool facts about gravity is that the gravitational field of a body 'feels' spherical at a distance, even if those bodies are not spherical themselves. There are higher multipoles but they are increasingly suppressed the further you are from the body. So at least for gravity the spherical approximation turns out to be good and justified.
Re:Higher Multipoles of the Cow by DroneBetter on Wednesday September 02, 2026 @11:50PM (#49545726)
for simulating gravity in particular you can do one better, since a sphere is in turn gravitationally indistinguishable from a point mass due to the https://en.wikipedia.org/wiki/Shell_theorem#Force_on_a_point...
Re:Higher Multipoles of the Cow by lhd1 on Thursday September 03, 2026 @12:05AM (#49545806)
and you can do one better than that - Birkhoff's theorem, the relativistic analogue of the shell theorem.

https://en.wikipedia.org/wiki/Birkhoff%27s_theorem_(relativi...

Re:Higher Multipoles of the Cow by naklitechie on Thursday September 03, 2026 @01:04AM (#49546140)
This deserves a simulator
Re:Higher Multipoles of the Cow by setopt on Thursday September 03, 2026 @03:07AM (#49546825)
Ah yes, indeed, the well-known point-cow approximation!
Re:Higher Multipoles of the Cow by Sharlin on Thursday September 03, 2026 @05:27AM (#49547812)
The point-cow is simply the zero-dimensional generalization of the spherical cow.
Re:Higher Multipoles of the Cow by classified on Thursday September 03, 2026 @03:46AM (#49547081)
Hence for all practical purposes, zero-dimensional cows are spherical.
Re:Higher Multipoles of the Cow by dguest on Thursday September 03, 2026 @03:43AM (#49547062)
Beyond a "cool fact", this is the only reason that physics works, where I'm defining physics as the human study of physical laws, not the laws themselves. If we couldn't neglect higher moments systems from planetary motion to the large scale structure of the universe would be computationally intractable.

And it's not just gravity, it's also electromagnetism: charge arrangements (i.e. ions) look like point charges at a distance, meaning you can neglect the electron orbital structure. Light sources act like point sources at a distance too.

A lot of the equations you learn in introductory physics rely on the higher moments vanishing.

- The planetary motion equations (Kepler's laws) assume gravity as a point source (the three body problem can be approximated by replacing two of the bodies with 1)

- E = mgh -> assumes a homogeneous gravitational field, which is a special case of gravitational monopole near an equipotential surfaced. And of course parabolic motion and pendula only work because this holds.

Re:Higher Multipoles of the Cow by sandworm101 on Thursday September 03, 2026 @04:32AM (#49547426)
And if they were intractable, motions would be so irregular that pheneomena such as billion-year stable orbits would not be possible... leading to a lack of evolution and life generally. So it is a very good and necessary thing that cows remain mathematically spherical.
Re:Higher Multipoles of the Cow by lhd1 on Thursday September 03, 2026 @04:37AM (#49547456)
This point of view is essentially codified in effective field theory, which tells us why so much of classical physics (EM, fluids, gravity) can be seen as low order approximations of some more complete theory that we found later on. One of the great insights from 20th century physics imo.
Re:Higher Multipoles of the Cow by colechristensen on Wednesday September 02, 2026 @11:35PM (#49545635)
Submission history

From: Benjamin Lehmann [view email]

[v1] Tue, 1 Apr 2025 07:55:39 UTC (2,401 KB)

[v2] Wed, 1 Apr 2026 12:28:24 UTC (3,845 KB)

Re:Higher Multipoles of the Cow by account42 on Thursday September 03, 2026 @07:08AM (#49548508)
That's dedication.
Re:Higher Multipoles of the Cow by analog31 on Thursday September 03, 2026 @12:37AM (#49545987)
What udder nonsense.
Re:Higher Multipoles of the Cow by setopt on Thursday September 03, 2026 @03:09AM (#49546837)
Seems legitimate to me. Did you find any technical error?
Re:Higher Multipoles of the Cow by rhet0rica on Thursday September 03, 2026 @04:19AM (#49547325)
Perhaps the conclusions simply weren't mooving.
Re:Higher Multipoles of the Cow by JadeNB on Thursday September 03, 2026 @10:19AM (#49550272)
In case you missed the intentional misspelling, rather than are just going along with the joke: the word used was 'udder' (a cow's teats) rather than 'utter'.
Re:Higher Multipoles of the Cow by addag on Thursday September 03, 2026 @01:22AM (#49546235)
My physics teacher takes the spherical roast beef as an example for heat convection.
Re:Higher Multipoles of the Cow by mohamedkoubaa on Thursday September 03, 2026 @01:25AM (#49546246)
This is some bull
Re:Higher Multipoles of the Cow by DonHopkins on Thursday September 03, 2026 @02:43AM (#49546640)
Berkeley has been on the frontier of cow detection and tracking for decades.

https://www.youtube.com/watch?v=10JSPdTDFsI

Re:Higher Multipoles of the Cow by rcarmo on Thursday September 03, 2026 @03:07AM (#49546823)
We should get more of these here. My Arxiv queue is all inference stuff, this is fun!
Re:Higher Multipoles of the Cow by philipwhiuk on Thursday September 03, 2026 @05:17AM (#49547722)
I suggest reading the proceedings of SIGBOVIK: https://sigbovik.org/

Sample papers:

* The Ballmer Peak: An Empirical Search

* Selected investigations into egg logic

* Are Centaurs Actually Half Human and Half Horse?

* Unconventional Commits: An Exploration Beyond the Mundane

* Use-After-Freemoji: How Custom Emoji Replacement Retroactively Corrupts User Intent

I assume this paper will be submitted for a conference - if not it should have been.

Re:Higher Multipoles of the Cow by 220hertz on Thursday September 03, 2026 @08:33AM (#49549153)
Also "A Probabilistic Challenge-Response Algorithm for Repairing All Roads in Lebanon Via Papal Visits"
Re:Higher Multipoles of the Cow by fghorow on Thursday September 03, 2026 @05:58AM (#49548016)
Perhaps this approach should be known as "The Method of MOOments"?
Re:Higher Multipoles of the Cow by lorenzohess on Thursday September 03, 2026 @09:41AM (#49549816)
But has anyone ever analyzed the aerodynamics of a cow? Yet another point where SCA breaks down.
Re:Higher Multipoles of the Cow by quercusa on Thursday September 03, 2026 @10:50AM (#49550682)
There was a rather well-known French study.

[0] Python, Monty (1975), Monty Python and the Holy Grail

Re:Higher Multipoles of the Cow by ninju on Thursday September 03, 2026 @11:17AM (#49551376)
The Acknowledgements section, at the end of the paper, is very entertaining (as is the rest of the paper)
Re:Higher Multipoles of the Cow by ninju on Thursday September 03, 2026 @11:20AM (#49551481)
The usage of the word hexapentacontadictapole is very good
Re:Higher Multipoles of the Cow by lawlorino on Thursday September 03, 2026 @02:56PM (#49554923)
Near miss of nominative determinism; the authors name (Lehmann) is almost the same as the Finnish word for cow (Lehmän)