Posts Tagged physics
Water might spontaneously explode!
Posted by mark in Basic stats & math, physics on September 11, 2026
My chemical engineering curriculum at the University of Minnesota included a course on fluid mechanics. All I remember about this tool was that it involved very intense math, including a prominent role for imaginary numbers—stemming from taking the square root of negative 1. I thought that was very cool. The class discussed the equations of Navier-Stokes, but they featured too many partial derivatives for my taste. However, I learned enough to know their value to understanding fluid dynamics. Thus, I can appreciate the achievement by OpenAI to solve the Navier-Stokes problem of the equations breaking down. If you haven’t been tracking this news, I recommend you read this Science briefing on OpenAI’s breakthrough, why it’s important, and how it ignited a controversy .
But there’s one thing about OpenAI’s solution to the Navier-Stokes problem that greatly worries me. It allows for the laws of physics breaking down under certain extreme conditions, enabling water to spontaneously explode.
“There seems to be nothing in those equations that prevents a wayward eddy from suddenly turning in on itself, tightening into an angry gyre, until the density of the energy at its core becomes infinite: a catastrophic ‘‘singularity.’’ Someone tossing a penny into the fountain by the faculty center or skipping a stone at the Santa Monica beach could apparently set off a chain reaction that would take out Southern California.”
– University of California mathematics professor Terence Tao quoted in an article about him by New York Times Magazine, 7/24/25
Oh, oh!
Experiment creates a reversal in time
When your boss applies maximum time-pressure by saying “I want your results yesterday,” consider lining up a couple of lasers to get the job done. Next, as demonstrated by scientists at the University of Toronto, gather up rubidium atoms and chill them to near absolute zero. Then take some shots with your lasers and take your time from the subsequent reversal. It’s all laid out by experimental evidence that a photon can spend a negative amount of time in an atom cloud.
“It took a positive amount of time, but our experiment observing that photons can make atoms seem to spend a *negative* amount of time in the excited state is up!”
– Aephraim Steinberg, a physicist at the University of Toronto
For an easier 5-minute readout from Scientific American, see this 9/30/24 post: Evidence of ‘Negative Time’ Found in Quantum Physics Experiment.
Next on the agenda for making your work easier is to capture some negative energy. Soon, thanks to advancements in physics, you will be getting jobs done yesterday with no effort whatsoever!
Chance discovery on random walk in Utrecht
Posted by mark in science, Uncategorized on December 11, 2023
Last week I taught a class on design of experiments to a biotech company in Leiden, Netherlands. Afterwards I spent a few days in Utrecht with some friends from Germany. Imagine my excitement (nerd alert!) when on my first walk from our hotel to the city center just a few hundred feet down the sidewalk I encountered this mural featuring a differential equation.
Not being a physicist, I did not immediately grasp the formula’s importance, nor the clue provided by the fellow high-stepping down a street. It turns out this fellow is a drunk whose walk has become random. The mural, as explained by Utrecht University, pays homage to their famous professor Leonard Ornstein who, in the early 1900s along with another physicist—George Uhlenbeck—developed an important variant of the “random walk”—a term introduced by pioneering statistician Karl Pearson. The Ornstein-Uhlenbeck process is used to derive models from “big” financial data, including inflation rates, commodity prices and stock values.
I did not expect to gain an education on a vacation expedition.
Very cool!
PS: I thought about asking my colleague Martin Bezener, a PhD statistician, for his opinion on the chances of coming across something so relevant to our mission at Stat-Ease while on a random walk. But I will not bother, because I already know what he would say: “One-hundred percent: It already happened”.
Butterfly effect debunked (but, even so, best you not step on them)
It’s peak butterfly season—a beautiful time of the year to watch for these wonderfully winged insects, such as the Tiger Swallowtail caught on camera this week by my son-in-law Ryan Bretzel.
Coincidentally, physicists from the Los Alamos National Laboratory just announced* that we need not worry about butterflies in Minnesota setting off hurricanes in Florida, as speculated by chaoticians (such as Dr. Ian Malcolm in the movie Jurassic Park).
“For those interested in the technical details, a number of entangled qubits were run through a set of logic gates before being returned to their initial setup.”
– Mike McRae, Science Alert, 7/31/20, Time Travel Simulation Shows Quantum ‘Butterfly Effect’ Doesn’t Exist
That’s one less thing to worry about for Floridians! They need all the help they can get, being at the peak of pandemic and hurricane season.
* Recovery of Damaged Information and the Out-of-Time-Ordered Correlators, Bin Yan and Nikolai A. Sinitsyn, Physical Review Letters, 125, 040605 – Published 24 July 2020.