During thunderstorms, electric discharges in the air cause trees to glow with an ultraviolet aura. You can't see it with your eyes, but researchers have finally managed to measure it & recreate it in the lab.
https://news.agu.org/press-release/thunderstorms-conjure-ghostly-coronae-in-treetops-observed-outdoors-for-the-first-time/ #science #nature
The ability to make complex distinctions with high accuracy after ingesting a sufficient amount of training data is a signature feature of machine learning algorithms. But humans also have this ability, even if they are not always consciously aware of it. One of my favorite illustrations of this is the learned ability to determine (qualitatively) the temperature of water from its sound, which almost all of us have acquired purely through training data: https://www.youtube.com/watch?v=Ri_4dDvcZeM
We even have the learned ability to accurately predict the next word in a sentence, even when we do not understand the semantic content of the sentence itself. Some (rather frustrated) examples of this occur in the later stages of the classic "Who's on first?" sketch: https://www.youtube.com/watch?v=r9t097tbeT0
What Americans die from vs. what's reported in the media
Here is my presentation from today at COS on:
"The sorry state of scientific publishing and how we could move to an open and resilient infrastructure"
https://jekelylab.github.io/COS_goes_FOSS_publishing.html#/title-slide
Some geometry problems are easy to state but hard to solve! For any triangle, can an ideal point-sized billiard ball bounce around inside in a ππππππππ trajectory - a path that repeats?
The answer is "yes" for acute triangles, and this has been known since 1775. It's also "yes" for right triangles. But for obtuse triangles, nobody knows!
In 2008, Richard Schwartz showed that the answer is "yes" for triangles with angles of 100Β° or less. He broke the problem down into cases and checked each case with the help of a computer. Then progress was stuck... until 2018, when Jacob Garber, Boyan Marinov, Kenneth Moore and George Tokarsky showed the answer is "yes" for triangles with angles of 112.3Β° or less.
Beyond that we're stuck.... except for triangles with all πππ‘πππππ angles (measured in degrees). For them too the answer is "yes".
The picture here is from
George Tokarsky, Jacob Garber, Boyan Marinov, Kenneth Moore, One hundred and twelve point three degree theorem, https://arxiv.org/abs/1808.06667
and for more check out this article on Quanta:
https://www.quantamagazine.org/the-mysterious-math-of-billiards-tables-20240215/
It has been known since Fagnano in 1775 that an acute triangle always has a periodic billiard path, namely the orthic triangle. It is currently unknown whether every obtuse triangle has a periodic path. In 2006, Schwartz showed that every obtuse triangle with obtuse angle at most 100 degrees has a periodic path. The aim of this paper is to show that every obtuse triangle with obtuse angle at most 112.3 degrees has a periodic path using a computer assisted proof.
New result: you can build a universal computer using a single billiard ball on a carefully crafted table!
More precisely: you can create a computer that can run any program, using just a single point moving frictionlessly in a region of the plane and bouncing off the walls elastically.
Since the halting problem is undecidable, this means there are some yes-or-no questions about the eventual future behavior of this point that cannot be settled in a finite time by any computer program.
This is true even though the point's motion is computable to arbitrary accuracy for any given finite time. In fact, since the methodology here does *not* exploit the chaos that can occur for billiards on certain shaped tables, it's not even one of those cases where the point's motion is computable in principle but your knowledge of the initial conditions needs to be absurdly precise.
This result is not surprising to me - it would be much more surprising if you *couldn't* make a universal computer this way. Universal computation seems to be a very prevalent feature of sufficiently complex systems. But still it's very nice.
β’ Eva Miranda and Isaac Ramos, Classical billiards can compute, https://arxiv.org/abs/2512.19156.
Relative rotation speed and axial tilts of the planets.
Credit: Dr James O'Donoghue
Cognitive dissonance theory can't be considered an established theory anymore when classic papers don't stand up to scrutiny. The replication crisis continues. It is good that this work is ongoing.
1. A Multilab Replication of the Induced-Compliance Paradigm of Cognitive Dissonance https://journals.sagepub.com/doi/full/10.1177/25152459231213375
2. Debunking βWhen Prophecy Failsβ
https://onlinelibrary.wiley.com/doi/abs/10.1002/jhbs.70043
"This article shows that the authors of When Prophecy Fails misled their readersβand that scholars in psychology, sociology, and religious studies have been building theories atop a collapsed foundation."
The outer curve is a parabola.
Corey S Powell
Terence Tao
Information Is Beautiful
Gaspar Jekely
John Carlos Baez
Wonder of Science
maπpool
Mark Dominus