Higher multipoles of the cow

View PDF HTML (experimental) Abstract:The spherical cow approximation is widely used in the literature, but is rarely justified. Here, I propose several schemes for extending the spherical cow approximation to a full multipole expansion, in which the spherical cow is simply the first term. This allows for the computation of bovine potentials and interactions beyond spherical symmetry, and also provides a scheme for defining the geometry of the cow itself at higher multipole moments. This is especially important for the treatment of physical processes that are suppressed by spherical symmetry, such as the spindown of a rotating cow due to the emission of gravitational waves. I demonstrate the computation of multipole coefficients for a benchmark cow, and illustrate the applicability of the multipolar cow to several important problems. Comments: April Fools' paper that got a little out of hand. No cows were harmed. Matches published version Subjects: High Energy Astrophysical Phenomena (astro-ph.HE); Popular Physics (physics.pop-ph) Cite as: arXiv:2504.00506 [astro-ph.HE] (or arXiv:2504.00506v2 [astro-ph.HE] for this version) https://doi.org/10.48550/arXiv.2504.00506 arXiv-issued DOI via DataCite Journal reference: Am. J. Phys. 94, 264-271 (2026) Related DOI: https://doi.org/10.1119/5.0287411 DOI(s) linking to related resources 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)