Somehow, neutrinos went from just another random particle to becoming tiny monsters that require multi-billion-dollar facilities to understand. And there’s just enough mystery surrounding them that we feel compelled to build those facilities since neutrinos might just tear apart the entire particle physics community at the seams.

It started out innocently enough. Nobody asked for or predicted the existence of neutrinos, but there they were in our early particle experiments. Occasionally, heavy atomic nuclei spontaneously—and for no good reason—transform themselves, with either a neutron converting into a proton or vice-versa. As a result of this process, known as beta decay, the nucleus also emits an electron or its antimatter partner, the positron.

There was just one small problem: Nothing added up. The electrons never came out of the nucleus with the same energy; it was a little different every time. Some physicists argued that our conceptions of the conservation of energy only held on average, but that didn’t feel so good to say out loud, so others argued that perhaps there was another, hidden particle participating in the transformations. Something, they argued, had to sap energy away from the electron in a random way to explain this.

source: ars

GPS is perhaps one of the most audacious geo-engineering feats ever undertaken, and its traces can be felt with just an antenna and a motive.

All that said, it’s not as though there’s a cacophony of navigation data swarming around you, deafening if you could just hear it. In reality, the GPS signals surrounding you are astoundingly weak. To take an analogy: imagine a normal light bulb, like the one that might be above you now. Pull it twenty thousand kilometers away from the room you’re in, and have it flash, on, off, on, off, a million times a second. Imagine straining your eye to watch the shimmer of the bulb, two Earths away, and listen to what it’s telling you.

source: trivium

In the world of modern portable devices, it may be hard to believe that merely a few decades ago the most convenient way to keep track of time was a mechanical watch. Unlike their quartz and smart siblings, mechanical watches can run without using any batteries or other electronic components.

Over the course of this article I’ll explain the workings of the mechanism seen in the demonstration below. You can drag the device around to change your viewing angle, and you can use the slider to peek at what’s going on inside:

Determining the airspeed and altitude of a fighter plane is harder than you’d expect. At slower speeds, pressure measurements can give the altitude, air speed, and other “air data”. But as planes approach the speed of sound, complicated equations are needed to accurately compute these values. The Bendix Central Air Data Computer (CADC) solved this problem for military planes such as the F-101 and the F-111 fighters, and the B-58 bomber. This electromechanical marvel was crammed full of 1955 technology: gears, cams, synchros, and magnetic amplifiers. In this blog post I look inside the CADC, describe the calculations it performed, and explain how it performed these calculations mechanically.

The world’s strongest magnet is a million times stronger than Earth’s magnetic field.

A tour of the National High Magnetic Field Laboratory and its 45 Tesla magnet.

Twenty years ago, physicists set out to investigate a mysterious asymmetry in the proton’s interior. Their results, published today, show how antimatter helps stabilize every atom’s core.

We learn in school that a proton is a bundle of three elementary particles called quarks — two “up” quarks and a “down” quark, whose electric charges (+2/3 and −1/3, respectively) combine to give the proton its charge of +1. But that simplistic picture glosses over a far stranger, as-yet-unresolved story.

In reality, the proton’s interior swirls with a fluctuating number of six kinds of quarks, their oppositely charged antimatter counterparts (antiquarks), and “gluon” particles that bind the others together, morph into them and readily multiply. Somehow, the roiling maelstrom winds up perfectly stable and superficially simple — mimicking, in certain respects, a trio of quarks.

paper: https://www.nature.com/articles/s41586-021-03282-z

source: HN

This article is a comprehensive guide to the Roland Juno’s digitally-controlled analog oscillators (DCOs). I fell in love with the Juno early in my synthesizer journey and I’ve spent the last year or so doing research on its design so that I could create my own Juno-inspired DCO, Winterbloom’s Castor & Pollux.

source: trivium

Cameras and the lenses inside them may seem a little mystifying. In this blog post I’d like to explain not only how they work, but also how adjusting a few tunable parameters can produce fairly different results:

This is amazing work.

source: HN

It’s more than 120V. It’s even more than the other 120V! It is the sum of the two (and sometimes a different two!) that makes us who we are. Learn about the US electrical system in this not-at-all snarky video!

The ETHW is not a “how-does-technology-work” site. The scope of the ETHW is historical; instead of focusing on the inner workings of technology, it aims to explain how the technology was developed, who were the major players involved, and what long term significance the technologies have. The ETHW is not only an encyclopedia of the history of technology, but it also contains a full range of materials that relate to the legacy of engineering, including personal accounts, documents, and multimedia objects. In that sense, it is a combination reference guide, blog, virtual archive, and on-line community.

In this blog post I’d like to look at these simple machines up close. I’ll explain how gears affect the properties of rotational motion and how the shape of their teeth is way more sophisticated than it may initially seem.

Movement is important in this article so most of the visualizations are animated – you can play and pause them by tapping on the button in their bottom left corner. By default the animations are enabled, but if you find them distracting, or you want to save power, you can globally pause all animations, just make sure to unpause them as needed.

This is very neat.

source: HN

It was the first proof of concept test for Project Silica, a Microsoft Research project that uses recent discoveries in ultrafast laser optics and artificial intelligence to store data in quartz glass. A laser encodes data in glass by creating layers of three-dimensional nanoscale gratings and deformations at various depths and angles. Machine learning algorithms read the data back by decoding images and patterns that are created as polarized light shines through the glass.

source: HN

Solar power is all very well, but it is available only during daylight hours. If something similarly environmentally friendly could be drawn on during the hours of darkness, that would be a great convenience. Colin Price, an atmospheric scientist at Tel Aviv University, in Israel, wonders if he might have stumbled across such a thing. As he told a meeting of the International Union of Geodesy and Geophysics, held in Montreal in July, it may be possible to extract electricity directly from damp air—specifically, from air of the sort of dampness (above 60% relative humidity) found after sundown, as the atmosphere cools and its ability to hold water vapour diminishes.

source: HN

The purpose of this article is to collect and consolidate a list of these alternative methods of working with displays, light and optics. This will by no means be an exhaustive list of the possibilities available — depending on how you categorize, there could be dozens or hundreds of ways. There are historical mainstays, oddball one-offs, expensive failures and techniques that are only beginning to come into their own.

There’s more to life than the LCD.

source: L

The basic idea of a nuclear reactor is really simple. In fact, you could make a toy to explain it to kids.

So, where will these be used? I’ve no idea at this point, and I don’t really care—I just love the physics. More seriously, it takes a very bright light to turn a laser on like this (think ~1TW/cm2), so the applications will certainly be niche.

Nano Letters, 2019, DOI: 10.1021/acs.nanolett.9b00510

source: ars

Turner found that the assumptions of Pearce and others that the mounds’ complex tunnel systems serve to circulate air and remove heat to regulate interior temperatures isn’t accurate. The air mixing isn’t the result of the colony’s internal heat but air pressure from outside the mound. The termites build the mounds so tall to catch the wind, and their porous outer surface is what allows the air to move into and through the colony. Turner likens the effect to the alveoli in human lungs: the mound almost “breathes.”

Just going to link to the whole blog.

source: L

Vision is an essential sensory modality for humans. Our visual system detects light between 400 and 700 nm (Dubois, 2009, Wyszecki and Stiles, 1982, Schnapf et al., 1988), so called visible light. In mammalian photoreceptor cells, light absorbing pigments, consisting of opsins and their covalently linked retinals, are known as intrinsic photon detectors. However, the detection of longer wavelength light, such as near-infrared (NIR) light, though a desirable ability, is a formidable challenge for mammals. This is because detecting longer wavelength light, with lower energy photons, requires opsins (e.g., human red cone opsins) to have much lower energy barriers. Consequently, this results in unendurable high thermal noise, thus making NIR visual pigments impractical (Ala-Laurila et al., 2003, Baylor et al., 1980, Luo et al., 2011, St George, 1952). This physical limitation means that no mammalian photoreceptor can effectively detect NIR light that exceeds 700 nm, and mammals are unable to see NIR light and to project a NIR image to the brain.

To this end, the successful integration of nanoparticles with biological systems has accelerated basic scientific discoveries and their translation into biomedical applications (Desai, 2012, Mitragotri et al., 2015). To develop abilities that do not exist naturally, miniature nanoscale devices and sensors designed to intimately interface with mammals including humans are of growing interest. Here, we report on an ocular injectable, self-powered, built-in NIR light nanoantenna that can extend the mammalian visual spectrum to the NIR range. These retinal photoreceptor-binding upconversion nanoparticles (pbUCNPs) act as miniature energy transducers that can transform mammalian invisible NIR light in vivo into short wavelength visible emissions (Liu et al., 2017, Wu et al., 2009). As sub-retinal injections are a commonly used ophthalmological practice in animals and humans (Hauswirth et al., 2008, Peng et al., 2017), our pbUCNPs were dissolved in PBS and then injected into the sub-retinal space in the eyes of mice. These nanoparticles were then anchored and bound to the photoreceptors in the mouse retina.

source: MR

The bizarre illumination was sparked by an “electric arc flash” tied to faulty equipment at a Con Edison substation, a spokesman for the utility, Bob McGee, said early Friday. The equipment, located about 20 feet above the ground, contained cables that transmit 138,000 volts of electricity — a staggering amount compared with the 120 volts supplied to American households.