Physics

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When placed in water, their long flagella—tails that propel them forward—create a so-called active bath. This dynamic environment helps form gel-like aggregates by acting like a small fire and raising the "temperature" to an equivalent of 2,000°C, similar to one a blacksmith needs to craft metals. It even manages to spin tiny micro disks.

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The scientists, therefore, needed to take a step back and come up with an experiment to clarify what was happening. To do so, Grober used a 3D nanoprinter to create smooth, symmetrical micro disks similar to hockey pucks. After introducing these "pucks" into the active baths filled with E. coli, they were surprised to see them spin clockwise, which negated the earlier hypothesis that symmetrical shapes do not turn.

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"It is a well-known result in our field that the counter-rotation of the body and flagella (tail) of an E. coli cause it to swim in clockwise circles near a solid surface," Grober explains.

"We realized that we could flip these dynamics upside down by confining the E. coli in a microscopic channel beneath the puck. These experiments utilize the exact same hydrodynamic effect to create, essentially, a microscopic and contactless engine, which drives the persistent rotation of the puck."

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I recently came across a theory from Japan that tries to explain physical phenomena based on the structure of the observer.

It attempts to connect relativity and quantum mechanics through the concept of the observer, which I found quite interesting.

I found a video explaining the idea, so I’m sharing it here: 👉 https://notebooklm.google.com/notebook/c714dc8c-eb93-4317-b369-8e57fac880fc?artifac

Curious to hear what people think.

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submitted 3 weeks ago* (last edited 2 weeks ago) by supersquirrel@sopuli.xyz to c/physics@mander.xyz
 
 

In 2018, Smorra and his team realised that they would need to move antimatter away from the factory to somewhere quieter – and hatched an escape plan. “We had seen the impact of the magnetic field fluctuations, so it was clear that we would eventually need to continue our precision measurements [elsewhere],” says Smorra.

This wasn’t an easy task. Containing antimatter typically requires powerful magnetic fields produced by superconducting magnets, which need to be kept at near-absolute zero, requiring huge amounts of power. Smorra and his team designed STEP to use just a 30-litre tank of liquid helium to keep the magnets cool, so the electronics can instead run on a simple diesel generator. For the upcoming test run, though, it will use only battery power.

The magnet also has to be engineered to cope with the stop-start accelerations that occur while driving, as well as a bespoke vacuum system to ensure that the absence of problematic regular matter can be maintained while the antiprotons are loaded into and unloaded from the trap.

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When the electric field is applied, phonons moving in the direction of the field last longer and travel farther than those moving in other directions. As a result, heat can move through the material almost three times more efficiently along the direction of the electric field, offering a powerful way to manage thermal energy in advanced technologies.

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The key innovation in this motor lies in the use of amorphous steel, a material that differs from conventional electrical steels commonly used in motor cores. Unlike traditional steel, which has a crystalline atomic structure, amorphous steel has a disordered atomic arrangement.

This unique structure gives it superior magnetic characteristics, including higher magnetic permeability and much lower core losses. In electric motors, magnetic losses such as eddy current losses and hysteresis losses occur when the magnetic field in the stator repeatedly changes during operation.

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In 1980 a 3M factory accidentally built a force field. Nobody ever studied it.

An engineer walked into a production corridor and couldn't get through. Not a locked door, not a blocked aisle — the air itself stopped him.

His name was David Swenson. He was carrying an electrometer to measure electric field strength. It slammed to its maximum reading before he even reached the machinery. He leaned his full body weight forward. He could not advance. He had to walk backwards to escape.

The production manager came to look. His short curly hair stood completely straight the moment he entered the area. He reportedly said he didn't know whether to fix it or sell tickets.

3M fixed it.


What was actually happening

The machine was simple enough — a wide roll of polypropylene film (the stuff inside adhesive tape) being unwound at 1,000 feet per minute, fed up 20 feet to overhead rollers, across the ceiling, and back down to a slitting machine. The whole path formed an enclosed three-sided tent of moving film, open at the floor.

21 feet wide. 20 feet tall. Moving at speed.

When surfaces separate, they swap electrical charge — the same effect as rubbing a balloon on a jumper. It scales with area and speed. A wide reel of film at 1,000 ft/min generates charge fast.

Normally that charge bleeds off into the air. But the enclosed tent geometry changed everything. The two parallel moving film walls acted like the plates of a giant capacitor. Charge built up with nowhere to go — faster than the air could drain it — until the field inside exceeded the threshold where air normally just arcs and discharges.

Except it didn't arc and discharge. It held. Fed continuously by the moving film, sustained in a dynamic equilibrium.

The result was a bounded region of electrostatic field so intense it physically resisted a human body passing through it.

Key measurements and facts

Detail Value
Date August 1980
Location 3M plant, South Carolina
Film material Biaxially oriented polypropylene
Film width 21 feet (6.4 m)
Film height 20 feet (6.1 m)
Line speed 1,000 ft/min (~5 m/s)
Measured field ≥ 200,000 V/ft — instrument ceiling, actual value unknown
Observed effects Engineer physically stopped; flies held suspended inside field; hair standing on people nearby
Primary source D. Swenson, ANTEC '97, Society of Plastics Engineers


Why nobody studied it

This is the part that's hard to explain.

Swenson wrote it up. In 1995 — fifteen years later — he presented it at an ESD (electrostatic discharge) symposium. Two years after that it appeared in conference proceedings. And then essentially nothing happened.

  • No research group tried to reproduce it
  • No physicist published a theoretical model of the geometry
  • No materials scientist asked what would happen with better materials
  • The DoD apparently expressed interest and then never followed up
  • 3M reorganised the production line and the conditions that caused it were eliminated

The entire documented record is: one engineer, one event, two conference papers. Every secondhand account online — and there are many — traces back to those same two documents.

Three reasons it probably died:

1. Wrong incentives. 3M had a manufacturing problem, not a research opportunity. Fix it and ship product. Nobody gets paid to wonder.

2. Bad instrumentation. Swenson's electrometer maxed out before he reached the machine. The actual peak field was never measured — only bounded from below. "At least this strong" is a hard foundation to build on.

3. The literature went small. Triboelectric research since 2012 has almost entirely focused on nanogenerators — tiny devices harvesting microwatts from wearable sensors. Hundreds of papers per year, all asking how to go smaller. Nobody is asking what happens when you run the same physics at industrial scale in a closed geometry with modern materials.


The detail that proves it wasn't a fluke

Workers at the plant noticed the wall appeared preferentially in the early morning, when humidity was low. By afternoon it weakened or vanished.

Humid air conducts. It bleeds charge off surfaces before it accumulates. Dry morning air raises the ceiling — charge generation outpaces dissipation.

The workers had identified the control variable without knowing it. They knew when to expect it. They just never told a physicist.

A one-off freak accident doesn't have a predictable schedule. This one did.


The gap that still exists

Modern triboelectric materials like PTFE hold charge roughly 35× more effectively than the polypropylene 3M was using. The geometry is documented. The physics is well understood at small scale. Computational tools exist that didn't in 1980.

The forward/backward model closes: working from known charge densities and the documented geometry predicts surface fields in the multi-megavolt-per-metre range — consistent with Swenson's minimum measurement. The numbers meet in the middle.

Nobody has built a COMSOL simulation of the 3M geometry. Nobody has run a parametric sweep to find the threshold conditions. Nobody has asked what a deliberately engineered version of this would produce with modern materials.

That's a graduate thesis sitting completely unclaimed, 45 years later.


Primary source: D. Swenson, "Wide Polypropylene Web Static Charge, A Phenomenon Worthy of Star Trek" — ANTEC '97, Society of Plastics Engineers, 1997

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In the fast moving field of two dimensional materials, even a slight rotational shift between layers can dramatically change how a material behaves. Scientists previously discovered that when atom thin crystals are stacked with a small angular mismatch, their electronic properties can transform. This approach, known as moiré engineering, has become a key strategy for designing new forms of quantum matter.

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