If you’re looking to add a pop of glowing whimsy to your workspace, check out this vibrant jiggly desk toy by [thzinc], who couldn’t resist the allure of Adafruit’s NOODS LED strands. [thzinc]’s fascination with both glowing LEDs and levitating tensegrity designs led to an innovative attempt to defy gravity once again.
The construction’s genius is all about the balance of tension across the flexible LED strands, with three red ‘arms’ and a blue ‘hanger’ arm supporting the central hub. [thzinc]’s early designs faced print failures, but by cleverly reorienting print angles and refining channel designs, he achieved a modular, sturdy structure. Assembly involved careful soldering, tension adjustments, and even a bit of temporary tape magic to perfect the wobbling equilibrium.
But, the result is one to applaud. A delightful, wobbly desk toy with a kind of a Jell-O vibe that dances to your desk’s vibrations while glowing like a mini neon sign. We’ve covered tensegrity constructions in the past, so with a little digging through our archives you’ll be able to find some unique variations to build your own. Be sure to read [thzinc]’s build story before you start. Feel free to combine the best out there, and see what you can bring to the table!
The schematic diagram of the experimental centrifuge. (Credit: Jianyong Liu et al., 2024)
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.
Of course, [Gauthier] didn’t arrive at this solution immediately. Their first thoughts went to RFID or perhaps a pressure sensor to detect the cats, coupled with something motorized to open and shut the window, like a belt or maybe a linear actuator. But ultimately, the system has to be robust, so that’s when [Gauthier] got the idea to employ gravity by using pulleys and weights.
Although we take a lot of scientific knowledge for granted today, each of the basics – whether it be about light, gravity, mass or the shape of the Earth – had to be theorized and experimentally verified. In the case of gravity, as far back as around 500 BCE the Ionian Greek philosopher Heraclitus theorized on the balance created by what we came to call ‘gravity’. Later, the Greek philosopher Aristotle coined his own postulations and Greek physicist Archimedes did research that led him to discover the center of mass. Centuries later, the Roman engineer and architect Vitruvius argued for the concept of specific gravity rather than mass alone.
Da Vinci’s sketch and the Caltech experiment replicating it.
Although scientific pursuits in this area ground to a halt in Europe during medieval times, the Renaissance saw a renewed interest in the topic, with newly published research performed on Leonardo da Vinci‘s notes showing that he appears to – unsurprisingly – have also created a number of experiments aimed at determining the properties of gravity. One of the major limitations of the 15th century was that many of the basic scientific tools we have come to rely on since the 19th century such as accurate clocks, along with many other products of advanced alloys and metallurgy simply did not exist. Da Vinci’s experiment in this context is nothing if not ingenious in its simplicity.
By the time of the European Renaissance, the Aristotelian concept of gravity as solely a factor of an object’s mass was dismissed by many in favor of a model that saw the motion of an object affected by its velocity and mass, also influenced by works published by Persian scholars. When Da Vinci set up his experiment, he focused specifically on the acceleration of the falling objects by pouring a large number of granules or possibly water droplets from a pitcher which was being pulled along a straight path. He theorized that if the pitcher was being accelerated at the same rate as the objects are accelerating due to gravity, it’d create a isosceles right triangle.
When the researchers ran his experiment and compared Da Vinci’s notes on the results, they realized that although he had made a mistake in his model, at the small scale this would not have affected the results, making it valid and an early precursor to what later be published by Isaac Newton in the 17th century.
[Fearless Night]’s slick dual hourglass doesn’t just simulate sand with LEDs, it also emulates the effects of gravity on those simulated particles and offers a few different mode options.
The unit uses an Arduino (with ATMEGA328P) and an MPU-6050 accelerometer breakout board to sense orientation and movement, and the rest is just a matter of software. Both the Arduino and the MPU-6050 board are readily available and not particularly expensive, and the LED matrix displays are just 8×8 arrays of red/green LEDs, each driven by a HT16K33 LED controller IC.
The enclosure and stand are both 3D-printed, and a PCB not only mounts the components but also serves as a top cover, with the silkscreen layer of the PCB making for some handy labels. It’s a clever way to make the PCB pull double-duty, which is a technique [Fearless Night] also used on their earlier optical theremin design.
Those looking to make one of their own will find all the design files and source code handily available from the project page. It might not be able to tell time in the classical sense, but seeing the hourglass displays react to the device’s orientation is a really neat effect.
The International Space Station is humanity’s most expensive gym membership.
Since the earliest days of human spaceflight, it’s been understood that longer trips away from Earth’s gravity can have a detrimental effect on an astronaut’s body. Floating weightless invariably leads to significantly reduced muscle mass in the same way that a patient’s muscles can atrophy if they spend too much time laying in bed. With no gravity to constantly fight against, an astronauts legs, back, and neck muscles will weaken from disuse in as little as a week. While this may not pose an immediate problem during spaceflight, astronauts landing back on Earth in this physically diminished state are at a higher risk of injury.
Luckily this problem can be largely mitigated with rigorous exercise, and any orbiting vessel spacious enough to hold human occupants for weeks or months will by necessity have enough internal volume to outfit it with basic exercise equipment such as a treadmill or a resistance machine. In practice, every space station since the Soviet Union’s Salyut 1 in 1971 has featured some way for its occupants to workout while in orbit. It’s no replacement for being on Earth, as astronauts still return home weaker than when they left, but it’s proven to be the most practical approach to combating the debilitating aspects of long duration spaceflight.
Early NASA concept for creating artificial gravity.
Of course, there’s an obvious problem with this: every hour spent exercising in space is an hour that could be better spent doing research or performing maintenance on the spacecraft. Given the incredible cost of not just putting a human into orbit, but keeping them there long-term, time is very literally money. Which brings us back to my original point: astronauts spending two or more hours each day on the International Space Station’s various pieces of exercise equipment just to stave off muscle loss make it the world’s most expensive gym membership.
The ideal solution, it’s been argued, is to design future spacecraft with the ability to impart some degree of artificial gravity on its passengers through centripetal force. The technique is simple enough: just rotate the craft along its axis and the crew will “stick” to the inside of the hull. Unfortunately, simulating Earth-like gravity in this way would require the vessel to either be far larger than anything humanity has ever launched into space, or rotate at a dangerously high speed. That’s a lot of risk to take on for what’s ultimately just a theory.
But a recent paper from the University of Tsukuba in Japan may represent the first real steps towards the development of practical artificial gravity systems aboard crewed spacecraft. While their study focused on mice rather than humans, the results should go a long way to codifying what until now was largely the stuff of science fiction.
Gravity is one of the more obvious forces in the universe, generally regarded as easily noticeable by the way apples fall from trees. However, the underlying mechanisms behind gravity are inordinately complex, and the subject of much study to this day.
A major component of this study is around the concept of gravitational waves. First posited by Henri Poincaré in 1905, and later a major component of Einstein’s general theory of relativity, they’re a phenomena hunted for by generations of physicists ever since. For the team at the Laser Interferometer Gravitational-wave Observatory, or LIGO, finding direct evidence of gravitational waves is all in a day’s work.
