MagQuest: Measuring Earth’s Magnetic Field With Space-Based Quantum Sensors

December 9, 2025 by Maya Posch 8 Comments

Recently the MagQuest competition on improving the measuring of the Earth’s magnetic field announced that the contestants in the final phase have now moved on to launching their satellites within the near future. The goal here is to create a much improved World Magnetic Model (WMM), which is used by the World Geodetic System (WGS). The WGS is an integral part of cartography, geodesy and satellite-based navigation, which includes every sat nav, smartphone and similar with built-in GNSS capabilities.

Although in this age of sat navs and similar it can seem quaint to see anyone bother with using the Earth’s magnetic field with a compass, there is a very good reason why e.g. your Android smartphone has an API for estimating the Earth’s magnetic field at the current location. After your sat nav or smartphone uses its magnetometer, the measurements are then corrected so that ‘north’ really is ‘north’. Since this uses the WMM, it’s pertinent that this model is kept as up to date as possible, with serious shifts in 2019 necessitating an early update outside of the usual five-year cycle.

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A mirrorless camera is mounted on a stand, facing downwards toward a rotating microscope stage made of wood. A pair of wires come down from the stage, and a man's hand is pointing to the stage.

Building A Microscope Without Lenses

December 4, 2025 by Aaron Beckendorf 7 Comments

It’s relatively easy to understand how optical microscopes work at low magnifications: one lens magnifies an image, the next magnifies the already-magnified image, and so on until it reaches the eye or sensor. At high magnifications, however, that model starts to fail when the feature size of the specimen nears the optical system’s diffraction limit. In a recent video, [xoreaxeax] built a simple microscope, then designed another microscope to overcome the diffraction limit without lenses or mirrors (the video is in German, but with automatic English subtitles).

The first part of the video goes over how lenses work and how they can be combined to magnify images. The first microscope was made out of camera lenses, and could resolve onion cells. The shorter the focal length of the objective lens, the stronger the magnification is, and a spherical lens gives the shortest focal length. [xoreaxeax] therefore made one by melting a bit of soda-lime glass with a torch. The picture it gave was indistinct, but highly magnified. Continue reading “Building A Microscope Without Lenses” →

Ore Formation: A Surface Level Look

December 4, 2025 by Tyler August 9 Comments

The past few months, we’ve been giving you a quick rundown of the various ways ores form underground; now the time has come to bring that surface-level understanding to surface-level processes.

Strictly speaking, we’ve already seen one: sulfide melt deposits are associated with flood basalts and meteorite impacts, which absolutely are happening on-surface. They’re totally an igneous process, though, and so were presented in the article on magmatic ore processes.

For the most part, you can think of the various hydrothermal ore formation processes as being metamorphic in nature. That is, the fluids are causing alteration to existing rock formations; this is especially true of skarns.

There’s a third leg to that rock tripod, though: igneous, metamorphic, and sedimentary. Are there sedimentary rocks that happen to be ores? You betcha! In fact, one sedimentary process holds the most valuable ores on Earth– and as usual, it’s not likely to be restricted to this planet alone. Continue reading “Ore Formation: A Surface Level Look” →

Sensor Package Aims To Predict Acid Rain

December 1, 2025 by Lewin Day 6 Comments

Acid rain sucks, particularly if you run a fancy university with lots of lovely statues outside. If you’d like to try and predict when it’s going to occur, you might like this project from [Mohammad Nihal].

When rain is particularly acidic, it’s usually because of the combination of sulfur dioxide or nitrogen dioxide and moisture in the atmosphere. This combination ends up making sulfuric acid or nitric acid that then falls to the ground as precipitation. The low-pH rain that results can harm ecosystems, melt statues, and just generally give everyone a hard time.

[Mohammed] decided to try and predict acid rain by building a simple device based on an Arduino Nano. It records SO2 levels with an MQ-136 gas sensor, and NO2 levels with an unspecified MEMS-based sensor. There’s also a DHT11 temperature & humidity sensor in the mix, which is important since moisture content plays a role. The Arduino reads these sensors and uses a simple predictive algorithm to create an “Acid Rain Risk Score” that is displayed on a 16×2 character LCD. It’s all wrapped up in a fun 3D printed enclosure that looks like a cloud.

There are some limitations to the device. Namely, it doesn’t necessarily have a great read on atmospheric SO2 and NO2 levels in the atmosphere, particularly at altitudes where rain is formed, because the sensor sits inside the device indoors. However, the basic concept is there, and improvements could certainly be made with some upgrades and further research.

The Eleven-Faced Die That Emulates Two Six-sided Dice

November 28, 2025 by Donald Papp 28 Comments

Rolling two six-sided dice (2d6) gives results from 2 to 12 with a bell curve distribution. Seven being the most common result, two and twelve being the least common. But what if one could do this with a single die?

This eleven-sided die has a distribution matching the results of 2d6.

As part of research Putting Rigid Bodies to Rest, researchers show that a single eleven-sided asymmetric shape can deliver the same results. That is to say, it rolls numbers 2 to 12 in the same distribution as 2d6. It’s actually just one of the oddball dice [Hossein Baktash] and his group designed so if you find yourself intrigued, be sure to check out the 3D models and maybe print your own!

The research behind this is a novel method of figuring out what stable resting states exist for a given rigid body, without resorting to simulations. The method is differentiable, meaning it can be used not just to analyze shapes, but also to design shapes with specific properties.

For example, with a typical three-sided die each die face has an equal chance of coming up. But [Hossein] shows (at 8:05 in the video, embedded below) that it’s possible to design a three-sided die where the faces instead have a 25%-50%-25% distribution.

How well do they perform in practice? [Hossein] has done some physical testing showing results seem to match theory, at least when rolled on a hard surface. But we don’t think anyone has loaded these into an automated dice tester, yet.

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Boosting Antihydrogen Production Using Beryllium Ions

November 25, 2025 by Maya Posch 27 Comments

Antihydrogen forms an ideal study subject for deciphering the secrets of fundamental physics due to it being the most simple anti-matter atom. However, keeping it from casually annihilating itself along with some matter hasn’t gotten much easier since it was first produced in 1995. Recently ALPHA researchers at CERN’s Antimatter Factory announced that they managed to produce and trap no fewer than 15,000 antihydrogen atoms in less than seven hours using a new beryllium-enhanced trap. This is an eight-fold increase compared to previous methods.

To produce an antihydrogen atom from a positron and an antiproton, the components and resulting atoms can not simply be trapped in an electromagnetic field, but requires that they are cooled to the point where they’re effectively stationary. This also makes adding more than one of such atom to a trap into a tedious process since the first successful capture in 2017.

In the open access paper in Nature Communications by [R. Akbari] et al. the process is described, starting with the merging of anti-protons from the CERN Antiproton Decelerator with positrons sourced from the radioactive decay of sodium-22 (β⁺ decay). The typical Penning-Malmberg trap is used, but laser-cooled beryllium ions (Be⁺) are added to provide sympathetic cooling during the synthesis step.

Together with an increased availability of positrons, the eight-fold increase in antihydrogen production was thus achieved. The researchers speculate that the sympathetic cooling is more efficient at keeping a constant temperature than alternative cooling methods, which allows for the increased rate of production.

Water On Mars? Maybe Not

November 24, 2025 by Al Williams 9 Comments

We were as excited as anyone when MARSIS (the Mars Advanced Radar for Subsurface and Ionosphere Sounding) experiment announced there was possibly liquid water under the southern polar ice cap. If there is liquid water on Mars, it would make future exploration and colonization much more feasible. Unfortunately, SHARAD (the Shallow Radar) has a new trick that suggests the data may not indicate liquid water after all.

While the news is a bummer, the way scientists used SHARAD to confirm — or, in this case, deny — the water hypothesis was a worthy hack. The SHARAD antenna is on the Mars Reconnaissance Orbiter, but in a position that makes it difficult to obtain direct surface readings from Mars. To compensate, operators typically roll the spacecraft to give the omnidirectional antenna a clearer view of the ground. However, those rolls have been under 30 degrees.

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