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Chitons are back in international headlines again! Or, to be more technically accurate, the overlooked armored mollusks at least made it into the news (perhaps for the first or second time in their 400-500 million year history). These remarkable miniature tanks consist of a muscular mollusk which lives encased in 8 interlocking pieces of hard aragonite armor. The armor is not only a shell–it contains integral parts of the chiton such as aragonite eyes and other sensory cells. Thanks to this robust design, chitons are extremely successful and they can be found living in intertidal zones worldwide. Although they lack the pizzazz of their flamboyant mollusk cousins such as bobtail squid or giant clams, chitons are of enormous interest to a new generation of materials scientists who have been studying the natural world to get fresh ideas for molecular engineering. This weekend’s news story comes from such scientists who discovered that a brown rectangular chiton, Cryptochiton stelleri, (aka the “gumboot chiton”, or “the wandering meatloaf”) contains an esoteric mineral named santabarbaraite never before found in a living creature. Santabarbaraite is an extremely hard and tough mineral (itself only discovered by scientists in the year 2000) which contains a surprising amount of water. In the parlance of chemists, it is an amorphous ferric hydroxy phosphate mineral hydrate. The gumboot chitons manufacture this material as part of their long rows of rock-hard teeth (with which they scrape algae from marine rocks). Coincidentally, gumboot chitons are the largest chitons out there, with a maximum possible length of 36 centimeters (14 inches).
This is undoubtedly fascinating to people with advanced understanding of the chemical structures and properties of matter, but it is somewhat abstruse. The study’s lead author, scientist Derk Joester of Northwestern helps contextualize the importance of the finding by noting that “mechanical structures are only as good as their weakest link, so it’s interesting to learn how the chiton solves the engineering problem of how to connect its ultrahard tooth to a soft underlying structure.” The researchers are already planning how to use the secrets they have gleaned from the chiton to print hard santabarbaraite structures onto soft papers.
While we sort things out here on Earth, let’s take a little break and check out how everything is going at a place which is so far away and yet so close–the dark side of the moon. Back at the very end of 2018 the Chinese Space Agency successfully landed a lunar probe on the far side of the moon (the first “soft” landing in that hemisphere ever). China has been diligently working on lunar exploration and, prior to this landing they had already launched a relay satellite named “Queqiao” into operational orbit about 65,000 kilometers (40,000 miles) beyond the moon so that their far-side probe would be able to communicate with Earth. Since the beginning of 2019, Chinese scientists have been exploring the moon’s dark side (which isn’t actually dark per se, but which is largely unknown to Earth’s inhabitants since the moon is tidally locked).
As the Chinese Yutu-2 rover was exploring terrain near the Von Kármán crater (a large impact site with a diameter of around 180 kilometers (110 miles)), the radio controlled vehicle found something interesting. The ground was covered in strange glistening green blobs which looked like something from H.G. Wells’ moon or from moon mission comic books of the 40s.
I couldn’t find a good photo, so I will use this fantasy illustration instead. Keen eyed viewers will spot salient geopolitical trends in the drawing.
Geologists and astrophysicists have been speculating as to the nature of these amorphous lumps (which stand out dramatically on the monochrome surface of the moon–not that that is evident in any of the photos I could find) and they now believe they have an explanation. The glossy lumps are probably a mixture of of pagioclase, iron-magnesium silicate, olivine and pyroxene. These minerals are known to be found on the moon thanks to NASA’s manned missions 5 decades ago. Speculation is that an intense impact melted them together into glass-like amorphous nodules of thesort which are foundin high energy events here on Earth (apologies to everyone who was hoping it was alien eggs or lunar bio-slime). There is still a mystery though: the regolith of the Von Kármán crater is not composed of these materials, so lunar scientists are still trying to understand where the glossy green rocks came from.
magnificent adult Peltogyne purpurea tree (photo by Reinaldo Aguilar)
Imagine a huge tropical tree with a heart of deep purple. OK—you don’t have to imagine it. Such trees exist: they are the Peltogyne genus of flowering trees. The Peltogyne are native to Central and South America. They are part of the larger Fabaceae family–the bean family–a vast family of plants which are extremely important to humankind. The beans and legumes make up subsistence food for much of the world’s population and are instantly familiar…but it is hard to see the family resemblance between a little bean runner and a purpleheart tree. The latter grows to heights of up to 30–50m (120–150 ft) tall and can have trunk diameters of up to 1.5 meters (5 feet). Only in the pod-like seed is there a ready family resemblance (at least to laypeople like me).
Agerminating purpleheart bean…er seed (Reinaldo Aguilar)
Purpleheart is one of the hardest and stiffest woods in the world. The heartwood cures into a rich purple hue of great beauty. The trees are coveted by woodworkers (even though craftsmen need razor sharp implements of hardened steel or carborundum to work the obdurate wood). As you can imagine this has put great pressure on the wild trees and some species are now endangered.
Here are some pieces made from purpleheart wood. The wood is ideal for bows, gears, gun handles, tools, and any other application which requires hard wood which does not deteriorate, however because of its rarity and prohibitive price it is generally only seen in small accents and art pieces. If you are lucky enough to have an item made of purpleheart you should treat it carefully. Exposure to ultraviolet light causes the purple to deepen to an opaque medium brown (although it is still pretty and just as hard).
Purpleheart recurve bow (by bowyer for “Lumberjocks”)
It has been a long time since I blogged about anything gothic! I was going to make up for this by writing about some high gothic ladies’ fashion from the era of darted hoods, three-foot-long sleeves and wimples. Unfortunately when I looked up “gothic ladies” on Google image search all sorts of crazy pictures came up. The things which I have seen have left me baffled, scared, and riled up. I am abandoning gothic ladies fashion until some indeterminate point in the ambiguous future and seeking something safer. Chastened, I present you with a small gallery of gothic benches and church pews.
Carved American Gothic style oak bench circa 1910
Medieval-style pine bench
French Gothic Church Bench Solid Oak Turn of the Century
Gothic Settle
Antique French Gothic Hall Bench
ferrebeekeeper 