Thorium-Metal Alloys And Radioactive Jet Engines

December 16, 2025 by Maya Posch 35 Comments

Although metal alloys is not among the most exciting topics for most people, the moment you add the word ‘radioactive’, it does tend to get their attention. So too with the once fairly common Mag-Thor alloys that combine magnesium with thorium, along with other elements, including zinc and aluminium. Its primary use is in aerospace engineering, as these alloys provide useful properties such as heat resistance, high strength and creep resistance that are very welcome in e.g. jet engines.

Most commonly found in the thorium-232 isotope form, there are no stable forms of this element. That said, Th-232 has a half-life of about 14 billion years, making it only very weakly radioactive. Like uranium-238 and uranium-235 it has the unique property of not having stable isotopes and yet still being abundantly around since the formation of the Earth. Thorium is about three times as abundant as uranium and thus rather hard to avoid contact with.

This raises the question of whether thorium alloys are such a big deal, and whether they justify removing something like historical artefacts from museums due to radiation risks, as has happened on a few occasions.

Continue reading “Thorium-Metal Alloys And Radioactive Jet Engines” →

Super-Sizing Insects And The Benefits Of Bones

December 12, 2025 by Maya Posch 24 Comments

One swol mealworm amidst its weaker brethren. (Credit: The Thought Emporium, YouTube)

Have you ever found yourself looking at the insects of the Paleozoic era, including the dragonfly Meganeuropsis permiana with its 71 cm wingspan and wondered what it would be like to have one as a pet? If so, you’re in luck because the mad lads over at [The Thought Emporium] have done a lot of the legwork already to grow your own raven-sized moths and more. As it turns out, all it takes is hijacking the chemical signals that control the development phases, to grow positively humongous mealworms and friends.

The growth process of the juveniles, such as mealworms – the larval form of the yellow mealworm beetle – goes through a number of molting stages (instars), with the insect juvenile hormone levels staying high until it is time for the final molt and transformation into a pupa from which the adult form emerges. The pyriproxyfen insecticide is a juvenile hormone analog that prevents this event. Although at high doses larvae perish, the video demonstrates that lower doses work to merely inhibit the final molt.

Continue reading “Super-Sizing Insects And The Benefits Of Bones” →

Step Into My Particle Accelerator

December 11, 2025 by Al Williams 16 Comments

If you get a chance to visit a computer history museum and see some of the very old computers, you’ll think they took up a full room. But if you ask, you’ll often find that the power supply was in another room and the cooling system was in yet another. So when you get a computer that fit on, say, a large desk and maybe have a few tape drives all together in a normal-sized office, people thought of it as “small.” We’re seeing a similar evolution in particle accelerators, which, a new startup company says, can be room-sized according to a post by [Charles Q. Choi] over at IEEE Spectrum.

Usually, when you think of a particle accelerator, you think of a giant housing like the 3.2-kilometer-long SLAC accelerator. That’s because these machines use magnets to accelerate the particles, and just like a car needs a certain distance to get to a particular speed, you have to have room for the particle to accelerate to the desired velocity.

A relatively new technique, though, doesn’t use magnets. Instead, very powerful (but very short) laser pulses create plasma from gas. The plasma oscillates in the wake of the laser, accelerating electrons to relativistic speeds. These so-called wakefield accelerators can, in theory, produce very high-energy electrons and don’t need much space to do it.

Continue reading “Step Into My Particle Accelerator” →

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.

Continue reading “MagQuest: Measuring Earth’s Magnetic Field With Space-Based Quantum Sensors” →

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.