Solving The Mystery Of The Mayan Calendar’s 819-Count Cycle

April 27, 2023 by Maya Posch 51 Comments

Mayan Calendar Round. (Source: Chichen Itza)

Despite the mysticism that often clouds the Mayan calendar in popular culture, fact remains that the calendar system in use by the Mayans was based on a system used throughout the pre-Columbian Mesoamerican societies, dating back to at least the 5th century BCE. Characteristic of this system is the cyclical nature, with the Mayan calendar featuring three common cycles: the Long Count, Tzolk’in (260-day) and the 365-day, solar-based Haab’. Combined, these three cycles formed what is known as the Calendar Round and which lasts for 52 haab’ (years).

What was less obvious here was the somewhat obscure 819-day count that was found in certain locations in Mayan constructions. Now researchers John H. Linden and Victoria R. Bricker figure that they have discovered how this new cycle matches up with the previously known Calendar Round. In previous reports by e.g. Barbara McLeod and Hutch Kinsman in 2012, they noted the ongoing debate on this 819-day count and its potential purpose. The new insight by Linden and Bricker is that by increasing the calendar length to 20 periods of 819 days, it matches up with all synodic periods of the visible planets, explaining it as a planetary astronomical cycle.

What is interesting here is that the Mayan counting system is base-20 (vigesimal). Whether coincidence or not when it comes to this part of the Mayan calendar, it is good to see that more secrets of the Classical Mayan society are being recovered. With modern day Maya still living where their ancestors once did, these discoveries help them to recover and reconnect to the parts of their history that were so brutally destroyed by the invading Europeans.

(Heading image: El Caracol observatory at Chichen Itza, Mexico)

The Modern WWW, Or: Where Do We Want To Go From Here?

April 27, 2023 by Maya Posch 52 Comments

From the early days of ARPANET until the dawn of the World Wide Web (WWW), the internet was primarily the domain of researchers, teachers and students, with hobbyists running their own BBS servers you could dial into, yet not connected to the internet. Pitched in 1989 by Tim Berners-Lee while working at CERN, the WWW was intended as an information management system that’d provide standardized access to information using HTTP as the transfer protocol and HTML and later CSS to create formatted documents inspired by the SGML standard. Even better, it allowed for WWW forums and personal websites to begin to pop up, enabling the eternal joy of web rings, animated GIFs and forums on any conceivable topic.

During the early 90s, as the newly opened WWW began to gain traction with the public, the Mosaic browser formed the backbone of the WWW browsers (‘web browsers’) of the time, including Internet Explorer – which licensed the Mosaic code – and the Mosaic-based Netscape Navigator. With the WWW standards set by the – Berners-Lee-founded – World Wide Web Consortium (W3C), the stage appeared to be set for an open and fair playing field for all. What we got instead was the brawl referred to as the ‘browser wars‘, which – although changed – continues to this day.

Today it isn’t Microsoft’s Internet Explorer that’s ruling the WWW while setting the course for new web standards, but instead we have Google’s Chrome browser partying like it’s the early 2000s and it’s wearing an IE mask. With former competitors like Opera and Microsoft having switched to the Chromium browser engine that underlies Chrome, what does this tell us about the chances for alternative browsers and the future of the WWW?

Continue reading “The Modern WWW, Or: Where Do We Want To Go From Here?” →

Leonardo Da Vinci’s Visualization Of Gravity As A Form Of Acceleration

April 26, 2023 by Maya Posch 20 Comments

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.

Ambrosianus L 99 sup., p. 190, ll. 14–23, UV fluorescence image by Lumière Technology. Upside-down Latin overtext in dark brown and Greek undertext in light brown.

Reading Ptolemy’s Treatise On The Meteoroscope On Palimpsests After Centuries Of Recovery Attempts

April 25, 2023 by Maya Posch 12 Comments

During the Middle Ages much of Ancient Greek and Roman scientific, legal and similarly significant texts written on parchment were commonly erased, mostly because of the high cost of new parchment and the little regard given to these secular texts. Although recovery attempts of the remaining faint outlines of the old text has been attempted since at least the 19th century, these often involved aggressive chemical means. Now researchers have managed to recover the text written by Ptolemy on a parchment that suffered such a previous recovery attempt.

The term for a parchment and similar on which the existing text was washed or scraped off is a palimpsest, via Latin from Ancient Greek παλίμψηστος (palímpsēstos, from παλίν + ψαω = ‘again’ + ‘scrape’). In the case of this particular treatise, it is part of L 99 sup which is kept at the Biblioteca Ambrosiana in Milan, Italy. This collection contains fifteen palimpsest parchment leaves previously used for three Greek scientific texts: a text of unknown authorship on mathematical mechanics and catoptrics, known as the Fragmentum Mathematicum Bobiense (three leaves), Ptolemy’s Analemma (six leaves), and a so far unidentified astronomical text on six leaves.

Outermost six rings of the meteoroscope, not to scale. Nh, Sh, Eh, and Wh are cardinal points of the horizon; Ne and Se are the north and south celestial poles; Nz and Sz are the north and south poles of the ecliptic; and Z is the zenith. (Gysembergh et al., 2023)

It is this last text that has now been identified, courtesy of work by Victor Gysembergh and colleagues. Whereas 19th century palimpsest recovery attempts by Angelo Mai involved reagents, during the 20th century ultraviolet illumination became the preferred method, followed by similar non-destructive analysis methods. For this study UV fluorescence and multispectral reflectance imaging was employed, which allowed for significant more of the original Greek text to be uncovered. Most notable, this revealed Ptolemy’s treatise on the Meteoroscope, which is an instrument for measuring the position, length, and direction of the apparent path of a shooting star.

This new recovery builds upon text previously recovered by other researchers since Mai’s attempts, and fills in more details, although it must be noted that not all of the text has been recovered. It’s hoped that in future imaging sessions more can be recovered of this irreplaceable text, that like so many of its kind nearly got destroyed during Europe’s darkest era.

(Top image: Ambrosianus L 99 sup., p. 190, ll. 14–23, UV fluorescence image by Lumière Technology. Upside-down Latin overtext in dark brown and Greek undertext in light brown.)

Generating Entangled Qubits And Qudits With Fully On-Chip Photonic Quantum Source

April 23, 2023 by Maya Posch 8 Comments

As the world of computing and communication draws ever closer to a quantum future, researchers are faced with many of the similar challenges encountered with classical computing and the associated semiconductor hurdles. For the use of entangled photon pairs, for example, it was already possible to perform the entanglement using miniaturized photonic structures, but these still required a bulky external laser source. In a recently demonstrated first, a team of researchers have created a fully on-chip integrated laser source with photonic circuitry that can perform all of these tasks without external modules.

In their paper published in Nature Photonics, Hatam Mahmudlu and colleagues cover the process in detail. Key to this achievement was finding a way to integrate the laser and photonics side into a single, hybric chip while overcoming the (refractive) mismatch between the InP optical amplifier and Si₃N₄ waveguide feedback circuit. The appeal of photon-based quantum entanglement should be obvious when one considers the relatively stable nature of these pairs and their compatibility with existing optical (fiber) infrastructure. What was missing previously was an economical and compact way to create these pairs outside of a laboratory setup. Assuming that the described approach can be scaled up for mass-production, it may just make quantum communications a realistic option outside of government organizations.

Soft Robotic System For In Situ 3D Bioprinting And Endoscopic Surgery

April 20, 2023 by Maya Posch 8 Comments

The progress of medical science has meant increasingly more sophisticated ways to inspect and repair the body, with a shift towards ever less invasive and more effective technologies. An exciting new field is that of in situ tissue replacement in a patient, which can be singular cells or even 3D printed tissues. This in vitro approach of culturing replacement tissues comes however with its share of issues, such as the need for a bioreactor. A more straightforward approach is printing the cells in vivo, meaning directly inside the patient’s body, as demonstrated by a team at the University of New South Wales Sydney with a soft robot that can print layers of living cells inside for example a GI tract.

In their paper, the team — led by [Dr Thanh Nho Do] and PhD student [Mai Thanh Thai] — describe the soft robot that is akin to a standard endoscope, but with a special head that has four soft microtubule artificial muscles (SMAM) for three degrees of freedom and fabric bellow actuators (FBA) that provide the motion desired by the remote controller. The system is configured in such a way that the operator inputs the rough intended motions, which are then smoothed by the software before the hydraulics actuate the head.

In a test on a simulated GI tract, the researchers were able to manipulate a prototype, and deposit a range of materials from the installed syringes. They envision that a system like this could be used as with endoscopes and laparoscopy to not only accurately deposit replacement cells inside the patient’s body, but also to perform a range of other surgical interventions, whereby the surgeon is supported by the system’s software, rather than manipulating the instruments directly.

NASA’s Ingenuity Mars Helicopter Completes 50th Flight

April 18, 2023 by Maya Posch 20 Comments

While NASA’s Perseverance rover brought an array of impressive scientific equipment to the surface of Mars, certainly its most famous payload is the stowaway helicopter Ingenuity. Despite being little more than a restricted-budget experiment using essentially only off-the-shelf components that you can find in your smartphone and e-waste drawer, the tenacious drone managed to complete its fiftieth flight on April 13 — just days before the two year anniversary of its first flight, which took place on April 19th of 2021.

Engineers hoped that Ingenuity would be able to show that a solar-powered drone could function in the extremely thin atmosphere of Mars, but the experiment ended up wildly exceeding expectations. No longer a simple technology demonstrator, the helicopter has become an integral part of Perseverance’s operations. Through its exploratory flights Ingenuity can scout ahead, picking the best spots for the much slower rover, with rough terrain only becoming a concern when it’s time to land.

Since leaving the relatively flat Jezero Crater floor on January 19th of 2023, Ingenuity has had to contend with significantly harsher terrain. Thanks to upgraded navigation firmware the drone is better to determine safe landing locations, but each flight remains a white-knuckle event. This is also true for each morning’s wake-up call. Although the rover is powered and heated continuously due to its nuclear power source, Ingenuity goes into standby mode overnight, after which it must re-establish its communication with the rover.

Though there’s no telling what the future may hold for Ingenuity, one thing is certain — its incredible success will shape upcoming missions. NASA is already looking at larger, more capable drones to be sent on future missions, which stand to help us explore the Red Planet planet faster than ever. Not a bad for a flying smartphone.

Continue reading “NASA’s Ingenuity Mars Helicopter Completes 50th Flight” →