Hi Reader, astronomers found a star that tells two contradictory stories. Its chemistry says it's 10 billion years old. But vibrations rippling through its interior reveal it's only 5 billion years old. The paradox? Stellar violence. The red giant orbits Gaia BH2, a dormant black hole that likely contaminated it during a past merger, artificially aging its chemical signature while keeping its interior young. Speaking of black holes and contradictions: our first story this week shows how physicists resolved a long-standing paradox.

Coming up this week:
🪐 Black holes finally pass physics' most basic test
🪡 A safer way to tie surgical stitches
🇲🇽 How Mexico plans to 7x Latin America's computing power

PHYSICS

Black Holes Finally Pass Physics' Most Basic Test

Cool a black hole toward absolute zero and its entropy (the measure of disorder in the universe) goes negative. According to the third law of thermodynamics, this shouldn’t be possible: entropy must be non-negative and vanish as temperature approaches absolute zero. Every quantum system in the universe obeys this rule. Coffee cooling on your desk. Electrons in semiconductors. Atoms locked in crystal lattices. But black holes seemed to break physics’ most fundamental rules.

A team of physicists has discovered why. Published in Physical Review Letters, physicists show that black holes do obey the third law - when you calculate their entropy correctly. “Suppose you are given an assortment of quantum systems and tasked to calculate the average entropy,” the researchers explain. “Ideally, you would calculate the entropy of each system and then average over these entropies. This is called the quenched entropy. Instead, it is often easier for physicists to calculate the annealed entropy, which takes averages first and then calculates entropy - a wrong order of operations.”

At high temperatures, the order doesn't matter. Both methods agree. But at low temperatures, they split: quenched entropy (the right answer) approaches zero, while annealed entropy (the easier calculation) plunges negative.

But there’s a catch. Quenched entropy is notoriously difficult to compute for black holes. So the team introduced a new quantity called semiquenched entropy. Working in a simplified model called Jackiw-Teitelboim gravity - a two-dimensional toy universe where quantum effects are easier to track - they calculated semiquenched entropy using two approaches. The first summed contributions from wormholes, hypothetical tunnels connecting different regions of spacetime. The second used techniques from random matrix theory.

The result: Semiquenched entropy stays positive and vanishes smoothly at zero temperature. “If we were to instead sum over a finite number of wormhole corrections, we would not see that the semiquenched entropy is positive,” the team noted. “This means that accounting for all wormholes is critical to understand the quantum nature of black holes.”

This work is purely theoretical, calculated in simplified models rather than observed directly. But it closes a troubling loophole where the math seemed to say black holes violate quantum rules. The result proves black holes have isolated ground states - unique lowest-energy configurations - just like every other quantum system.

TL;DR: Physicists proved that black holes obey the third law of thermodynamics when entropy is calculated correctly. The fix required a new calculation method and summing infinite wormhole contributions, confirming black holes behave like ordinary quantum systems with well-defined ground states.

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BIOMEDICAL ENGINEERING

A Safer Way to Tie Surgical Stitches

A surgeon's fingertips are trained instruments. Pull a stitch too tight and tissue strangles, choking off blood flow. Too loose and wounds gape open. Every year, millions of patients bet their recovery on that tactile judgment. But what if the thread itself could do the judging?

Researchers at Zhejiang University have engineered surgical sutures with built-in mechanical fuses: slipknots calibrated to release at an exact force, with results published in Nature. The knots transmit force with 95.4% consistency without the need for batteries or sensors.

The team tested their “sliputures” on surgeons with varying experience. Junior surgeons using the smart knots improved their force precision by 121%, performing as well as veterans. In rat experiments, wounds closed at 1.3 newtons, half the force an unguided robot would apply, sealed without choking blood flow and healed two days faster than controls.

"When a slipknot opens, the thread bends, twists, slides and rubs against itself, and the geometry of the knot changes very quickly," lead researcher Tiefeng Li explains. That complexity, precisely controlled through pre-tightening forces and knot design, becomes surgical intelligence. “If a slipknot is tandem-linked to a dead knot on the same suture, they can share the tensile load,” Li continues, meaning the slipknot releases exactly when the surgical knot reaches ideal tension.

The team tested their “sliputures” with surgical robots, systems where surgeons control robotic arms from a console. They added cameras that watch for the knot to unfurl, then automatically stop the robotic arm from pulling further. The team also built machines that can manufacture these knotted sutures automatically at factory scale, making them practical for commercial production. If adopted clinically, sliputures could make precise suturing accessible in resource-limited hospitals and operating rooms where electronic force sensors are impractical or in remote facilities without reliable electricity.

TL;DR: Researchers created “sliputures”: surgical threads with slipknots engineered to release at precise forces. The knots improved novice surgeons' precision by 121%, accelerated wound healing in animal models, and integrated successfully into robotic surgery systems.

ARTIFICIAL INTELLIGENCE

How Mexico Plans to 7x Latin America's Computing Power

The global scramble for computing power has a new contender. Mexico announced plans to build Coatlicue, a 314-petaflop supercomputer named after the Mexican earth mother goddess. President Claudia Sheinbaum, who has a background in physics and energy engineering , unveiled the project: “We're very excited. It is going to allow Mexico to fully get in on the use of artificial intelligence and the processing of data that today we don't have the capacity to do.”

The numbers tell the story of Mexico's ambition. Coatlicue would be seven times more powerful than Pegaso in Brazil, currently Latin America's fastest at 42 petaflops. Mexico's current top system runs at just 2.3 petaflops, making Coatlicue a 136-fold leap. Built over 24 months at a cost of six billion pesos (about $327 million), the machine will use around 14,480 GPUs housed in roughly 200 cabinets with water-based cooling and high-speed connectivity.

The applications are sweeping: processing over 2 million satellite images for monitoring soil, drought, and irrigation patterns; refining extreme weather forecasting; analyzing genomic registries and epidemiological data; training AI language models for federal institutions; and optimizing Mexico's customs inspection systems.

While construction begins in January 2026, Mexico has arranged interim access to Barcelona Supercomputing Center's MareNostrum 5 starting next month, bridging the gap until Coatlicue comes online in 2027.

Coatlicue won't rival America's 1.8-exaflop El Capitan or Europe's Jupiter. But it puts Mexico on the global high-performance computing map and gives the country its own hardware foundation for training and deploying advanced AI rather than renting foreign cloud capacity.

TL;DR: Mexico is building Coatlicue, a 314-petaflop public supercomputer - seven times faster than Latin America's current leader and 136 times Mexico's existing top machine. The $327 million, 24-month project targets AI research, climate modeling, agriculture optimization, and data sovereignty, with interim access starting January 2026 via Barcelona's facilities.

In Other News

Meet ICARUS 2.0, the internet of animals. A satellite the size of a shoebox just became Earth's surveillance system for 100,000 animals. ICARUS 2.0 launched its first CubeSat receiver. 5-gram tags on birds, bats, and turtles worldwide now beam GPS coordinates, body temperature, and environmental data to space. The goal: turn animal movements into an early-warning system for biodiversity loss, emerging diseases, and environmental disasters.

After 100 years, have we seen dark matter? University of Tokyo astronomer found a 20 GeV gamma-ray excess in 15 years of Fermi data matching ~0.5 TeV WIMP annihilation. The energy spectrum and spatial pattern align with predictions, but Galactic foregrounds complicate interpretation.

NASA finds lightning on Mars. Perseverance's SuperCam microphone detected 55 millimeter-scale electrical sparks during Martian dust storms - the first direct evidence of atmospheric electricity on Mars. They analyzed 28 hours of recordings, finding discharges during the strongest winds and dust devils. The tiny “mini-lightning” could affect future mission electronics and influence Martian chemistry.

The hybrid waves that might power 6G. German physicists created a chip where sound waves and magnetic spin waves merge into hybrid "magnon-polarons" with exceptionally low energy loss. The breakthrough could enable 6G phones to use agile filters that retune themselves in real-time, replacing today's fixed radio components.

The sharpest look yet at a solar flare. Just 30 minutes before a powerful X1.2 solar flare, astronomers captured the sharpest-ever view of the blast's birthplace. Germany's GREGOR telescope revealed twisted 100-km magnetic filaments where the explosion would begin, offering the clearest glimpse yet into how the Sun's most violent eruptions ignite.

Your brain isn’t “adult” until age 32. Cambridge scientists identified five phases of neural development across 4000 people: childhood (0–9), adolescence (9–32), adulthood (32–66), early aging (66–83), and late aging (83+). Each phase shows distinct wiring patterns, redefining when adolescence actually ends.

How JUNO Beat 50 Years of Neutrino Experiments. China's JUNO detector just beat 50 years of neutrino physics in 59 days. Using reactor antineutrinos, it measured two key oscillation parameters with 1.6× better precision than all past experiments, confirming the detector's design and setting the stage to crack the neutrino mass ordering puzzle.

This Week in History

December 2, 1942. 49 scientists led by Enrico Fermi flipped the switch on Chicago Pile‑1 (a crude stack of uranium and graphite under a squash court at the University of Chicago’s Stagg Field) and for the first time ever, achieved a self-sustaining nuclear chain reaction. That event quietly ignited the Atomic Age and turned nuclear energy from theory into reality.

November 28, 1954. Enrico Fermi died in Chicago at age 53. By then, he’d transformed physics: he quantified beta-decay, championed the neutrino, formulated what we now call Fermi-Dirac statistics, and led the world’s first controlled nuclear chain reaction.

December 1, 2020. The 900-ton instrument platform of Arecibo Observatory collapsed onto its 305-metre radio dish after support cables failed, destroying the world’s most iconic radio telescope and ending nearly six decades of pioneering astronomy.

This Week’s Puzzle

🧩

Who killed Wittgenstein?

Wittgenstein has been murdered.

The police narrow it down to four suspects:

• Friedrich Nietzsche
• Lou Andreas-Salomé
• Karl Marx
• Ludwig Feuerbach

They also know two things:

1. Exactly one of them is guilty.
2. The guilty person always lies; everyone else always tells the truth.

In their interviews, each suspect makes a single statement:

• Nietzsche: “Salomé is the culprit.”
• Salomé: “Marx is innocent.”
• Feuerbach: “Salomé’s statement is true.”
• Marx: “Nietzsche’s statement is false.”

Who killed Wittgenstein?

Until next time,

The Ve Team 👋

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Solution

Let’s test each suspect as the culprit and see who fits.

1. Suppose Nietzsche is guilty. Then Nietzsche is lying, so his claim “Salomé is the culprit” is false.
Everyone else must be telling the truth:

• Salomé says “Marx is innocent” → Marx really is innocent.
• Feuerbach says “Salomé’s statement is true” → Salomé is indeed telling the truth.
• Marx says “Nietzsche’s statement is false” → Nietzsche’s accusation really is false.

No contradictions. So Nietzsche could be the culprit.

Now we check the others to see if any of them also work.

2. Suppose Salomé is guilty.​
Then Salomé is lying: “Marx is innocent” would be false, so Marx is actually guilty.
That gives us two culprits (Salomé and Marx), which is not allowed.
So Salomé cannot be the culprit.

3. Suppose Marx is guilty.​
Then Marx is lying, so “Nietzsche’s statement is false” is itself false. That means Nietzsche’s statement is actually true, Salomé is the culprit. Again we end up with two culprits (Marx and Salomé), so this is impossible.

4. Suppose Feuerbach is guilty.
​Then Feuerbach lies: “Salomé’s statement is true” must be false, so Salomé’s statement is actually false. If Salomé’s “Marx is innocent” is false, Marx is guilty. That gives us two culprits (Feuerbach and Marx). Also not possible.

The only scenario that doesn’t lead to a contradiction is the first one. So Nietzsche is the killer.