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2023
8 articles on this page- Zero Angular Momentum: The Falling Cat and the Geometry of Shape Space A cat dropped upside-down rotates 180° and lands on its feet, despite having zero angular momentum throughout. This is not a trick and not a violation of physics. The explanation took physicists from 1894 to 1993 to fully work out, and the answer — a geometric phase arising from the holonomy of a fiber bundle — is the same mathematics that governs the Berry phase in quantum mechanics and the Aharonov-Bohm effect in electrodynamics. We adopted two strays this year. They fall beautifully.
- Can a Planet Have a Moon? Teaching Exomoon Detection with a Disco Ball Motor Every classroom treatment of exoplanet detection focuses on the transit method. What gets omitted is that moons of exoplanets could also host life — and that with a small motor and a slight modification to the standard transit experiment, you can show students what an exomoon signature looks like in a light curve. Published in MNU Journal in 2023.
- How Low Can You Go? Measuring Latency for Networked Music Performance Across Europe We measured end-to-end audio and video latency for LoLa and MVTP across six European research-network links. One-way audio latency ranged from 7.5 to 22.5 ms in these deployments. Route topology and endpoint processing made air distance alone a poor predictor; one firewall comparison found higher loss and buffer instability.
- The Milky Way Is a Gravitational Wave Detector LIGO uses 4-kilometre laser arms to detect gravitational waves at hundreds of hertz. Pulsar timing arrays use millisecond pulsars scattered across the Milky Way — arms measured in light-years — to detect gravitational waves at nanohertz frequencies, ten orders of magnitude lower. In June 2023, four collaboration papers reported evidence for a stochastic gravitational wave background. The Milky Way itself was the detector.
- Fremde Welten: Teaching Exoplanet Detection in the Secondary School Classroom A unit for lower secondary physics classes (grades 8–10) on detecting exoplanets with analogy experiments. Published in Unterricht Physik in 2023, it starts where students’ misconceptions are — with the (wrong) assumption that you can just look at exoplanets through a telescope — and works forward from there.
- How to Actually Film a Classroom: An Open-Access Manual on Classroom Videography Three years after writing about why classroom video works, Charlotte Kramer, Kai Kaspar, and I wrote a manual on how to actually do it. The gap between interpreting study-specific evidence for video-based learning and producing usable footage turns out to be substantial. The manual is open access. Here is what is in it and why some of it surprised me to write.
- The Charm of Impossibilities: Group Theory and Messiaen’s Modes of Limited Transposition Messiaen’s seven modes of limited transposition cannot be fully transposed through all twelve keys — not by convention, but because of group theory. The modes are pitch-class sets whose stabiliser subgroups in ℤ₁₂ are non-trivial. The orbit–stabiliser theorem gives the exact count of distinct transpositions for each mode. The subgroup lattice constrains the possible symmetry types; it does not select Messiaen’s seven scales.
- Nobody Is Normal: A Roast I Had to Retract I wanted to roast the psychiatric slogan “Up close, nobody is normal” for trivialising severe illness. The evidence does not support that verdict. Continuum beliefs are generally associated with less stigma, although a slogan alone is not a tested intervention and clinical thresholds still matter.
2022
2 articles on this page- Spiral Out: Tool’s Lateralus, the Fibonacci Sequence, and the Mathematics of Musical Structure Alongside physics and astronomy, two other things have occupied an unreasonable share of my attention since adolescence: mathematics and music. Lateralus by Tool — released 2001, still in rotation — is the piece that most conspicuously occupies the intersection. The song is frequently analysed through Fibonacci numbers, including reported lyric counts and a 9/8–8/8–7/8 metre grouping. This post separates checked arithmetic from listening analysis and authorial interpretation.
- What Black Hole Images Actually Show (and Why a Wormhole Would Look Different) The EHT images of M87* and Sgr A* are remarkable not because they surprised us, but because they confirmed a century-old prediction at microarcsecond precision. The more interesting question: what would a wormhole look like? Completely different — and we have never seen that.