Tiling a space with a repeated pattern that has no gaps or overlaps (a structure known as a tessellation) is what led mathematician [Gábor Domokos] to ponder a question: how few corners can a shape have and still fully tile a space? In a 2D the answer is two, and a 3D space can be tiled in shapes that have no corners at all, called soft cells.

These shapes can be made in a few different ways, and some are shown here. While they may have sharp edges there are no corners, or points where two or more line segments meet. Shapes capable of tiling a 2D space need a minimum of two corners, but in 3D the rules are different.

A great example of a natural soft cell is found in the chambers of a nautilus shell, but this turned out to be far from obvious. A cross-section of a nautilus shell shows a cell structure with obvious corners, but it turns out that’s just an artifact of looking at a 2D slice. When viewed in full 3D — which the team could do thanks to a micro CT scan available online — there are no visible corners in the structure. Once they knew what to look for, it was clear that soft cells are present in a variety of natural forms in our world.

[Domokos] not only seeks a better mathematical understanding of these shapes that seem common in our natural world but also wonders how they might relate to aperiodicity, or the ability of a shape to tile a space without making a repeating pattern. Penrose Tiles are probably the most common example.

As we move through the Sixth Extinction, it can be beneficial to examine what caused massive die-offs in the past. Lystrosaurus specimens from South Africa have been found that may help clarify what happened 250 million years ago. [via IFLScience]

The Permian-Triassic Extinction Event, or the Great Dying, takes the cake for the worst extinction we know about so far on our pale blue dot. The primary cause is thought to be intense volcanic activity which formed the Siberian Traps and sent global CO₂ levels soaring. In Karoo Basin of South Africa, 170 tetrapod fossils were found that lend credence to the theory. Several of the Lystrosaurus skeletons were preserved in a spread eagle position that “are interpreted as drought-stricken carcasses that collapsed and died of starvation in and alongside dried-up water sources.”

As Pangea dried from increased global temperatures, drought struck many different terrestrial ecosystems and changed them from what they were before. The scientists say this “likely had a profound and lasting influence on the evolution of tetrapods.” As we come up on the Thanksgiving holiday here in the United States, perhaps you should give thanks for the prehistoric volcanism that led to your birth?

If you want to explore more about how CO₂ can lead to life forms having a bad day, have a look at paleoclimatology and what it tells us about today. In more recent history, have a look at how we can detect volcanic eruptions from all around the world and how you can learn more about the Earth by dangling an antenna from a helicopter.

Magnetic skyrmions are an interesting example of solitons that occurs in ferromagnetic materials with conceivable solutions in electronics, assuming they can be created and moved at will. The creation and moving of such skyrmions has now been demonstrated by [Yubin Ji] et al. with a research article in Advanced Materials. This first ever achievement by these researchers of the Korea Research Institute of Standards and Science (KRISS) was more power efficient than previously demonstrated manipulation of magnetic skyrmions in thicker (3D) materials.

Magnetic skyrmions are sometimes described as ‘magnetic vortices’, forming statically stable solitons. In a broader sense skyrmions are a topologically stable field configuration in particle physics where they form a crucial part of the emerging field of spintronics. For magnetic skyrmions their stability comes from the topological stability, as changing the atomic spin of the atoms inside the skyrmion would require overcoming a significant energy barrier.

In the case of the KRISS researchers, electrical pulses together with a  magnetic field were used to create magnetic skyrmions in the ferromagnetic  (Fe₃GaTe₂, or FGaT) film, after which a brief (50 µs) electric current pulse was applied. This demonstrated that the magnetic skyrmions can be moved this way, with the solitons moving parallel to the electron flow injection, making them quite steerable.

While practical applications of magnetic skyrmions are likely to be many years off, it is this kind of fundamental research that will enable future magnetic storage and spintronics-related devices.

Featured image: Direct imaging of the magnetic skyrmions. The scale bars represent 300 nm. (Credit:Yubin Ji et al., Adv. Mat. 2024)

SpaceX’s Starship is the most powerful launch system ever built, dwarfing even the mighty Saturn V both in terms of mass and total thrust. The scale of the vehicle is such that concerns have been raised about the impact each launch of the megarocket may have on the local environment. Which is why a team from Brigham Young University measured the sound produced during Starship’s fifth test flight and compared it to other launch vehicles.

Published in JASA Express Letters, the paper explains the team’s methodology for measuring the sound of a Starship launch at distances ranging from 10 to 35 kilometers (6 to 22 miles). Interestingly, measurements were also made of the Super Heavy booster as it returned to the launch pad and was ultimately caught — which included several sonic booms as well as the sound of the engines during the landing maneuver.

The paper goes into considerable detail on how the sound produced Starship’s launch and recovery propagate, but the short version is that it’s just as incredibly loud as you’d imagine. Even at a distance of 10 km, the roar of the 33 Raptor engines at ignition came in at approximately 105 dBA — which the paper compares to a rock concert or chainsaw. Double that distance to 20 km, and the launch is still about as loud as a table saw. On the way back in, the sonic boom from the falling Super Heavy booster was enough to set off car alarms at 10 km from the launch pad, which the paper says comes out to a roughly 50% increase in loudness over the Concorde zooming by.

OK, so it’s loud. But how does it compare with other rockets? Running the numbers, the paper estimates that the noise produced during a Starship launch is at least ten times greater than that of the Falcon 9. Of course, this isn’t hugely surprising given the vastly different scales of the two vehicles. A somewhat closer comparison would be with the Space Launch System (SLS); the data indicates Starship is between four and six times as loud as NASA’s homegrown super heavy-lift rocket.

That last bit is probably the most surprising fact uncovered by this research. While Starship is the larger and more powerful  of the two launch vehicles, the SLS is still putting out around half the total energy at liftoff. So shouldn’t Starship only be twice as loud? To try and explain this dependency, the paper points to an earlier study done by two of the same authors which compared the SLS with the Saturn V. In that paper, it was theorized that the arrangement of rocket nozzles on the bottom of the booster may play a part in the measured result.

Hydrogen! It’s a highly flammable gas that seems way too cool to be easy to come by. And yet, it’s actually trivial to make it out of water if you know how. [Maciej Nowak] has shown us how to do just that with his latest build.

The project in question is a simple hydrogen generator that relies on the electrolysis of water. Long story short, run a current through water and you can split H₂O molecules up and make H₂ and O₂ molecules instead. From water, you get both hydrogen to burn and the oxygen to burn it in! Even better, when you do burn the hydrogen, it combines with the oxygen to make water again! It’s all too perfect.

This particular hydrogen generator uses a series of acrylic tanks. Each is fitted with electrodes assembled from threaded rods to pass current through water. The tops of the tanks have barbed fittings which allow the gas produced to be plumbed off to another storage vessel for later use. The video shows us the construction of the generator, but we also get to see it in action—both in terms of generating gas from the water, and that gas later being used in some fun combustion experiments.

Pedants will point out this isn’t really just a hydrogen generator, because it’s generating oxygen too. Either way, it’s still cool. We’ve featured a few similar builds before as well.

Recently China’s new CHIEF hypergravity facility came online to begin research projects after beginning construction in 2018. Standing for Centrifugal Hypergravity and Interdisciplinary Experiment Facility the name covers basically what it is about: using centrifuges immense acceleration can be generated. With gravity defined as an acceleration on Earth of 1 g, hypergravity is thus a force of gravity >1 g. This is distinct from simple pressure as in e.g. a hydraulic press, as gravitational acceleration directly affects the object and defines characteristics such as its effective mass. This is highly relevant for many disciplines, including space flight, deep ocean exploration, materials science and aeronautics.

While humans can take a g-force (g₀) of about 9 g₀ (88 m/s²) sustained in the case of trained fighter pilots, the acceleration generated by CHIEF’s two centrifuges is significantly above that, able to reach hundreds of g. For details of these centrifuges, this preprint article by [Jianyong Liu] et al. from April 2024 shows the construction of these centrifuges and the engineering that goes into their operation, especially the aerodynamic characteristics. Both air pressure (30 – 101 kPa) and arm velocity (200 – 1000 g) are considered, with the risks being overpressure and resonance, which if not designed for can obliterate such a centrifuge.

The acceleration of CHIEF is said to max out at 1,900 gravity tons (gt, weight of one ton due to gravity), which is significantly more than the 1,200 gt of the US Army Corps of Engineers’ hypergravity facility.

How do you collect a lot of data about the ionosphere? Well, you could use sounding rockets or specialized gear. Or maybe you can just conscript a huge number of cell phones. That was the approach taken by Google researchers in a recent paper in Nature.

The idea is that GPS and similar navigation satellites measure transit time of the satellite signal, but the ionosphere alters the propagation of those signals. In fact, this effect is one of the major sources of error in GPS navigation. Most receivers have an 8-parameter model of the ionosphere that reduces that error by about 50%.

However, by measuring the difference in time between signals of different frequencies, the phone can estimate the total electron current (TEC) of the ionosphere between the receiver and the satellite. This requires a dual-frequency receiver, of course.

This isn’t a new idea. There are a large number of fixed-position stations that make this measurement to contribute to a worldwide database. However, the roughly 9,000 stations can’t compete with cell phones everywhere. The paper outlines how Android smartphones can do calculations on the GPS propagation delays to report the TEC numbers.

Hams often study the ionosphere. So do sounding rockets.

Normally, you think of things casting a shadow as being opaque. However, new research shows that under certain conditions, a laser beam can cast a shadow. This may sound like nothing more than a novelty, but it may have applications in using one laser beam to control another. If you want more details, you can read the actual paper online.

Typically, light passes through light without having an effect. But using a ruby crystal and specific laser wavelengths. In particular, a green laser has a non-linear response in the crystal that causes a shadow in  a blue laser passing through the same crystal.

The green laser increases the crystal’s ability to absorb the blue laser beam. which creates a matching region in the blue beam that appears as a shadow.

If you read the article, there’s more to measuring shadows than you might think. We aren’t sure what we would do with this information, but if you figure it out, let us know.

Ruby has a long history with lasers, of course. That green laser pointer you have? It might not be all green, after all.

To tackle the growing electrification of devices, we’ll need to deploy more generation to the grid. The US Department of Energy (DOE) has unveiled a new target to triple nuclear generating capacity by 2050.

Using a combination of existing Generation III+ reactor designs, upcoming small modular and micro reactors, and “legislation like the ADVANCE Act that streamlines regulatory processes,” DOE plans to add 35 gigawatt (GW) of generating capacity by 2035 and an additional 15 GW installed per year by 2040 to hit a total capacity of 200 GW of clean, green atom power by 2050.

According to the DOE, 100 GW of nuclear power was deployed in the 1970s and 1980s, so this isn’t an entirely unprecedented scale up of nuclear, although it won’t happen overnight. One of the advantages of renewables over nuclear is the lower cost and better public perception — but a combination of technologies will create a more robust grid than an “all of your eggs in one basket” approach. Vehicle to grid storage, geothermal, solar, wind, and yes, nuclear will all have their place at the clean energy table.

If you want to know more about siting nuclear on old coal plants, we covered DOE’s report on the matter as well as some efforts to build a fusion reactor on a decommissioned coal site as well.

You don’t have to know how a car engine works to drive a car — but you can bet all the drivers in the Indy 500 have a better than average understanding of what’s going on under the hood. All of our understanding of electronics hinges on Maxwell’s equations, but not many people know them. Even fewer have an intuitive feel for the equations, and [Ali] wants to help you with that. Of course, Maxwell’s gets into some hairy math, but [Ali] covers each law in a very pragmatic way, as you can see in the video below.

While the video explains the math simply, you’ll get more out of it if you understand vectors and derivatives. But even if you don’t, the explanations provide a lot of practical understanding

Understanding the divergence and curl operators is one key to Maxwell’s equations. While this video does give a quick explanation, [3Blue1Brown] has a very detailed video on just that topic. It also touches on Maxwell’s equations if you want some reinforcement and pretty graphics.

Maxwell’s equations can be very artistic. This is one of those topics where math, science, art, and history all blend together.

The James Webb Space Telescope’s array of eighteen hexagonal mirrors went through an intricate (and lengthy) alignment and calibration process before it could begin its mission — but the process is far from being a one-and-done. Keeping the telescope aligned and performing optimally requires constant work from its own team dedicated to the purpose.

Alignment of the optical elements in JWST are so fine, and the tool is so sensitive, that even small temperature variations have an effect on results. For about twenty minutes every other day, the monitoring program uses a set of lenses that intentionally de-focus images of stars by a known amount. These distortions contain measurable features that the team uses to build a profile of changes over time. Each of the mirror segments is also checked by being imaged selfie-style every three months.

This work and maintenance plan pays off. The team has made over 25 corrections since its mission began, and JWST’s optics continue to exceed specifications. The increased performance has direct payoffs in that better data can be gathered from faint celestial objects.

JWST was fantastically ambitious and is extremely successful, and as a science instrument it is jam-packed with amazing bits, not least of which are the actuators responsible for adjusting the mirrors.

A characteristic of any thermal power plant — whether using coal, gas or spicy nuclear rocks — is that they have a closed steam loop with a condenser section in which the post-turbine steam is re-condensed into water. This water is then led back to the steam generator in the plant. There are many ways to cool the steam in the condenser, including directly drawing in cooling water from a nearby body of water. The most common and more efficient way is to use a cooling tower, with a recent video by [Practical Engineering] explaining the physics behind these.

For the demonstration, a miniature natural draft tower is constructed in the garage from sheets of acrylic. This managed to cool 50 °C water down to 20 °C by merely spraying the hot water onto a mesh that maximizes surface area. The resulting counter-flow means that no fan or the like is needed, and the hyperboloid shape of the cooling tower makes it incredibly strong despite having relatively thin walls.

The use of a natural draft tower makes mostly sense in cooler climates, while in hotter climates having a big cooling lake may make more sense. We covered the various ways to cool thermal plants before, including direct intake, spray ponds, cooling towers and water-free cooling solutions, with the latter becoming a feature of new high-temperature fission reactor designs.

Generally when assuming a chaotic (i.e. random) system like an undirected graph, we assume that if we start coloring these (i.e. assign values) with two colors no real pattern emerges. Yet it’s been proven that if you have a graph with a certain set of vertices, coloring the resulting lines in this manner will always result in a clique forming. This phenomenon has been investigated for nearly a century now after its discovery by British mathematician [Frank P. Ramsey].

The initial discovery concerned a graph with 6 vertices, providing the lowest number of vertices required. Formally this is written as R(3, 3), with subsequent cases of these Ramsey numbers discovered. They are part of Ramsey theory, which concerns itself with the question of what the underlying properties are that cause this apparent order to appear, which requires us to discover more cases.

Finding the number for a particular instance of R(m, n) can be done the traditional way, or brute-forcing it computationally. Over the decades more advanced algorithms have been developed to help with the search, and people from different fields are mingling as they are drawn to this problem. So far the pay-off of this search are these algorithms, the friendships created and perhaps one day a deep insight in the causes behind this phenomenon that may have implications for physics, chemistry and other fields.

Electrostatic motors are now common in MEMS applications, but researchers at the University of Wisconsin and spinoff C-Motive Technologies have brought macroscale electrostatic motors back. [via MSN/WSJ]

While the first real application of an electric motor was Ben Franklin’s electrostatically-driven turkey rotisserie, electromagnetic type motors largely supplanted the technology due to the types of materials available to engineers of the time. Newer dielectric fluids and power electronics now allow electrostatic motors to be better at some applications than their electromagnetic peers.

The main advantage of electrostatic motors is their reduced critical materials use. In particular, electrostatic motors don’t require copper windings or any rare earth magnets which are getting more expensive as demand grows for electrically-powered machines. C-Motive is initially targeting direct drive industrial applications, and the “voltage driven nature of an electrostatic machine” means they require less cooling than an electromagnetic motor. They also don’t use much if any power when stalled.

Would you like a refresher on how to make static electricity or a deeper dive on how these motors work?

In 2020 international shipping saw itself faced with new fuel regulations for cargo ships pertaining to low sulfur fuels (IMO2020). This reduced the emission of sulfur dioxide aerosols from these ships across the globe by about 80% practically overnight and resulting in perhaps the biggest unintentional geoengineering event since last century.

As detailed in a recent paper by [Tianle Yuan] et al. as published in Nature, by removing these aerosols from the Earth’s atmosphere, it also removed their cooling effect. Effectively this change seems to have both demonstrated the effect of solar engineering, as well as sped up the greenhouse effect through radiative forcing of around 0.2 Watt/m² of the global ocean.

The inadvertent effect of the pollution by these cargo ships appears to have been what is called marine cloud brightening (MCB), with the increased reflectivity of said clouds diminishing rapidly as these pollution controls came into effect. This was studied by the researchers using a combination of satellite observations and a chemical transport model, with the North Atlantic, the Caribbeans and South China Sea as the busiest shipping channels primarily affected.

Although the lesson one could draw from this is that we should put more ships on the oceans burning high-sulfur fuels, perhaps the better lesson is that MCB is a viable method to counteract global warming, assuming we can find a method to achieve it that doesn’t also increase acid rain and similar negative effects from pollution.

Featured image: Time series of global temperature anomaly since 1980. (Credit: Tianle Yuan et al., Nature Communications Earth Environment, 2024)

These days displays are increasingly expected to be bidirectional devices, accepting not only touch inputs, but also to integrate fingerprint sensing and even somehow combine a camera with a display without punching a hole through said display. Used primarily on smartphone displays, these attempts have been met with varying degrees of success, but a recently demonstrated version in Nature Communications which combines an OLED with photosensors in the same structure might provide a way to make such features much more effective.

The article by [Chul Kim] and colleagues of the Samsung Display Research Center in South Korea the construction of these bidirectional OLED displays is described, featuring the standard OLED pixels as well as an organic photodiode (OPD) placed side-by-side. Focusing on the OLED’s green light for its absorption characteristics with the human skin, the researchers were able to use the produced OLED/OPD hybrid display for fingerprint recognition, as well as a range of cardiovascular markers, including heart rate, blood pressure, etc.

The basic principle behind these measurements involves photoplethysmography, which is commonly used in commercially available pulse oximeters. Before these hybrid displays can make their way into commercial devices, there are still a few technical challenges to deal with, in particular electrical and optical leakage. The sample demonstrated appears to work well in this regard, but the proof is always in the transition from the lab to mass-production. We have to admit that it would be rather cool to have a display that can also handle touch, fingerprints and record PPG data without any special layers or sensor chips.