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Sunday, June 5, 2022

Burl & Burr

Burl (pronounced burl)

(1) A small knot or lump in wool, thread, or cloth.

(2) A dome-shaped growth on the trunk of a tree; a wart-like structure which can be 1 m (39 inches) or more across and .5 m (19 inches) or more in height; typically harvested and sliced to make the intricately patterned veneers used in furniture or car interiors.

(3) To remove burls from (cloth) in finishing (which technically means the same as to de-burl).

(4) In Scottish, Australian and NZ slang (1) an attempt; to try (especially in the phrases “give it a burl” & (2) “going for a burl” (going for a drive in a car) (both largely archaic and the latter restricted to the antipodes).

1400–1450: From the late Middle English burle (a small knot or flaw in cloth), from the Old French bouril & bourril (flocks or ends of threads which disfigure cloth), from the Old French bourre & burle (tuft of wool) and akin to the Medieval Latin burla (bunch, sheaf), from the Vulgar Latin burrula (small flock of wool), from the Medieval Latin burra (flock of wool, fluff, coarse hair; shaggy cloth).  The source of the Latin forms is unknown.  The slang forms are probably from the Scottish birl (a twist or turn) but use in this sense seems now to be restricted to Scotland and the South Island of New Zealand.  The large, rounded outgrowth on the trunk or branch of a tree can be highly prized if on a species (most famously walnut) where the timber of a burl develops the swirling, intricate patterns which are used as thinly sliced veneers in the production of furniture and other fine products, notably in car interiors.  Burls develop from one or more twig buds, the cells of which continue to multiply but never differentiate so the twig can elongate into a limb.  In American English, burl has been used to describe "a knot or excrescence on a walnut or other tree" since 1868 but burr is now often used interchangeably.  Burls rarely cause harm to trees but careless (often unlawful) harvesting can cause damage.  The related noun is burler; the noun plural is burls.  The present participle is burling, the simple past and past participle burled.

Burl was productive in English although some forms have a tangled history.  The adjective burly is derived from the circa 1300 borlich (excellent, noble; handsome, beautiful), probably from the Old English borlice (noble, stately (literally "bowerly", ie fit to frequent a lady's apartment)).  The sense evolved by circa 1400 to mean "stout, sturdy" and later "heavily built".  Some etymologists also suggest a connection between the Old English and the Old High German burlih (lofty, exalted) which was related to burjan (to raise, lift).  In Middle English, it was applied also to objects (even transitory things like cloud formations) but has long been restricted to people. 

The noun burlesque (piece composed in burlesque style, derisive imitation, grotesque parody) had been in use since the 1660s, the earlier adjective (odd, grotesque), from the 1650s, from the sixteenth century French burlesque, from the Italian burlesco (ludicrous), from burla (joke, fun, mockery), presumably from the Medieval Latin burra (trifle, nonsense (literally "flock of wool" and thing something light and trivial)).  The more precise adjectival meaning "tending to excite laughter by ludicrous contrast between the subject and the manner of treating it" is attested in English by 1700.  Comedy and burlesque represent the two great traditions of representational ridicule, the former draws characters in conventional form, the latter by using a construct quite unlike themselves.  As long ago a 1711, one critic described burlesque as existing in two forms, the first represents mean persons in accoutrements of heroes, the other describes great persons acting and speaking like the basest among the people.  By the late nineteenth century, it typically meant "travesties on the classics and satires on accepted ideas" and vulgar comic opera while the modern sense of something risqué ("a variety show featuring striptease) is an invention of American English which co-evolved during the same era and became predominant by the 1920s..

The noun burlap (coarse, heavy material made of hemp, jute, etc., used for bagging) dates from the 1690s, the first element probably from the Middle English borel (coarse cloth), from the burel or the Dutch boeren (coarse), although there may have been some confusion with boer (peasant).  The second element, -lap, meant "piece of cloth".  There has been debate about the noun hurly-burly (originally hurlyburly) (commotion, tumult) which in the 1530s was apparently an alteration of the phrase hurling and burling, a reduplication of the fourteenth century hurling (commotion, tumult), from the verbal noun of hurl.  Shakespeare had hurly (tumult, uproar) and the early fifteenth century hurling time was the name applied by chroniclers to the period of tumult and commotion around Wat Tyler's (circa 1341–1381; a leader of the 1381 Peasants' Revolt in England) rebellion.   In the early nineteenth century a hurly-house was said to be a "large house in a state of advanced disrepair" and there is presumably some connection with the dialectal Swedish hurra (whirl round) but it’s all quite murky and whether burly in this context is related to burl in the sense of something rough or merely coincidental a rhyme is uncertain.

Burr (pronounced bur)

(1) A rough or irregular protuberance on any object, as on a tree (spelled also as burl).

(2) A small, handheld, power-driven milling cutter, used by machinists and die makers for deepening, widening, or undercutting small recesses (technically called burr grinders which, with a revolving disk or cone with abrasive surfaces are used to smooth burr holes).

(3) In metal fabrication, a protruding, ragged edge raised on the surface of metal during drilling, shearing, punching, or engraving (spelled also as buhr); a blank punched out of a piece of sheet metal.

(4) A washer placed at the head of a rivet.

(5) In ceramics, a fragment of brick fused or warped in firing.

(6) In any form of engineering, to form a rough point or edge on.

(7) In structural phonetics, (1) a pronunciation of the r-sound as a uvular fricative trill, as in certain Northern English dialects (of which the Northumberland is an exemplar) or the retroflex r of the West of England, (2) a pronunciation of the r-sound as an alveolar flap or trill, as in Scottish English or (3) any pronunciation popularly considered rough or nonurban.

(8) To speak with a burr (to speak roughly, indistinctly, or inarticulately) (can be applied neutrally or as a (usually class-loaded disparagement).

(9) A whirring sound or rough, humming sound.

(10) In the sense of a broad ring on a spear or tilting lance (placed below the grip to prevent the hand from slipping), a variant of burrow (in obsolete sense: borough) (dating from the sixteenth century and now rare except in historic reference).

(11) In geology, a mass of hard siliceous rock surrounded by softer rock.

(12) A sharp, pointy object, such as a sliver or splinter (regionally specific).

(13) As bur; a seed pod with sharp features that stick in fur or clothing.

(13) In anatomy, the ear lobe (archaic).

(14) In zoology, the knot at the bottom of an antler (analogous with the burrs (or burls) on trees.

1375–1425: From the late Middle English burre (possibly related to the Old English byrst (bristle)), burrewez (plural) & buruhe (circle), a variant of brough (round tower), an evolutionary fork of which became the Modern English broch.  It was cognate with the Danish burre & borre (burdock, burr) and the Swedish borre (sea-urchin).

The spelling burr was a variant of the original bur, the addition probably a tribute by the written to the spoken long R sound, the use in phonetics noted from the 1750s, presumably both imitative and associative, the sound being thought of as rough like a bur; the onomatopoeic form may be compared with the French bruire.  The original idea of "rough sound of the letter -R" (especially that common in Northumberland) was later extended to "northern accented speech" in general and was soon integrated into the English class system as one of many class identifiers.  It may be the sound of the word is imitative of the speech peculiarity itself, or it was adapted from one of the senses of bur (the late fourteenth century phrase “to have a bur in (one's) throat” was a figure of speech suggesting the choking sensation or huskiness associated with having something rough caught in the windpipe) but the authoritative Oxford English Dictionary (OED) notes that despite the similarity, the Scottish -r- is a lingual trill, not a true burr.

The circa 1300 bur (prickly seed vessel of some plants) from the Middle English burre was from a Scandinavian source, either the Danish borre, the Swedish hard-borre or the Old Norse burst (bristle), from the primitive Indo-European bhars.  In the 1610s, it was transferred to refer to a "rough edge on metal" which led ultimately to the use in phonetics and the name give to various tools and appliances.  The noun burstone dates from the late thirteenth century and was an adaptation from the Middle English burre, the stone so-named presumably because of its roughness.  Aaron Burr (1756–1836, US vice-president (1800–1804)) fled after killing a political rival in a duel and plotted to create an independent empire in the western US.  In 1807 he was acquitted on a charge of treason.  To remove a burr (typically in engineering or carpentry) is to deburr (or debur).  The noun plural is burrs, the present participle burring and the simple past & past participle burred.  The homophones are Bur & brr.

The noun rhotacism dates from 1830 in the sense of “an extensive or particular use of 'r'”, from the Modern Latin rhotacismus, from the Ancient Greek rhotakizein, from rho (the letter -r-), from the Hebrew or Phoenician roth.  A technical adaptation from 1844 was the use to describe the conversion of another sound, usually "s" to "r" (as in Aeolian Greek, which at the end of words changed -s to –r, the related forms being rhotacize & rhotacization.

European burr (or burl) walnut with extensive “bud eyes”.

Regarding timber veneers, the conventional wisdom is that burl is American English while burr is used in the rest of the English-speaking world.  That’s not accurate although burl in this sense is an American innovation from 1868 and probably a useful one.  In the specialized arboreal branch of botany, the words cancer and canker were also once used to describe the growths on trees but these uses seem never to have extended beyond the profession.

Burr (or burl) walnut interior detailing on 1967 Mercedes-Benz 600 (W100) Landaulet (top) and 1963 & 1965 Jaguar Mark Xs (bottom).

In another specialized field, those in carpentry concerned with fine veneers, there are further distinctions, some defining a burr as an English word meaning a type of growth on a side of a tree which is full of “bud eyes” (the most distinctive pattern associated with expensive veneers) while burl is of US origin and refers to any type of growth on the side of a tree, including burrs.   That would seem to suggest burl would thus include the healing growth over surface damage or broken branches.  Others, notably timber merchants seem most often to regard burls as any highly figured wood with twisted and contorted grain regardless of whether it comes from a growth on the side of a tree, root, stump, or has grown all the way up the trunk, and whether it contains bud eyes or not.  In commerce, this is doubtlessly useful because people buy timber for veneering on the basis of appearance rather than where it happened to grow.  It would of course be useful if one word could be accepted to mean the growth on a tree and the other the harvested timbers from these growths but, being English, such things never happen.

Burrs (or burls) on a tree.  Burls should not be confused with galls which are small and form along twigs and leaves.  Burls are much larger and form on trunks and branches as an integral part of the tree.  Galls grow outside and are independent of the tree.

Thursday, June 8, 2023

Superleggera

Superleggera (pronounced soo-per-lee-ghera)

(1) In automotive coach-building, a method of construction which combined a framework of thin steel tubes with aluminum outer panels, producing a lightweight structure.

(2) In recent years, a designation used as a model name to refer to a “lightweight” vehicle even if not a classic superleggera structure.

1935 (a patent for the technique issued in 1936):  From the Italian superleggera (super light) (feminine singular of superleggero), the construct being super- + leggero.  Super was from the Latin super-, from the Proto-Italic super, from the primitive Indo-European upér (over, above) which was cognate with the Ancient Greek πέρ (hupér) (above) and the Proto-Germanic uber (now familiar in English and translated as “over” although this doesn’t wholly convey the sense in Modern German).  Leggero (light in weight, slight, thin) was from the Old French legier, from the Vulgar Latin leviārius, from the Latin levis, from the Proto-Italic leɣis, from the primitive Indo-European hlengwih-, from hléngus, from hleng (lightweight). The cognates included the Sanskrit लघु (laghú), the Ancient Greek λφρός & λχ́ς (elaphrós & elakhús) and the Old English lēoht (the ultimate source of the English light).  Superleggera is a noun & adjective; the noun plural is superleggeras (or in the Italian the masculine plural is superleggeri, the feminine plural superleggere).

Carrozzeria Touring and superleggera

It was in 1926 that two Milanese lawyers discussed how bored they were with mundane, if lucrative, legal work and much preferred the exciting world of the automobile, the industry then something like that of IT in the early twenty-first century in that a critical mass of users had been established, growth was consistent and new ventures were coming and going amid a milieu of M&A (mergers & acquisitions).  The lawyers negotiated a controlling interest in Milan-based coachbuilder Carrozzeria Falco, changing the company’s name to Carrozzeria Touring.  Contracts to provide bodywork soon followed including from some of the industry’s major manufacturers including Citroën, Isotta Fraschini & Alfa Romeo and for some time they continued to adopt Falco’s methods which was an adaptation of the “Weymann” system which involved laying fabric over lightweight frames supported by a traditional separate chassis.  Touring produced elegant coachwork of a high quality and attracted the patronage of both Benito Mussolini (1883-1945; Duce (leader) & prime-minister of Italy 1922-1943) and Victor Emmanuel III (1869–1947; King of Italy 1900-1946) although perhaps more influential was the Queen who was often photographed alighting from one of Touring’s large cars, a more imposing sight than the exit of her diminutive husband.

1938 Alfa Romeo 8C-2900B LeMans with Touring Superleggera (left), a wrought-iron artwork installation based on the idea using the Volkswagen Beetle as a model (centre) and Lindsay Lohan with conventional (body-on-chassis) Beetle (Herbie: Fully Loaded (2005)).

Touring proved innovative in its use of strong, lightweight alloys to support the fabric skins and they enjoyed much success also in applying the technique to aircraft components such as wings and fuselages but during the 1930s with both the military and civilian airlines wanting to fly higher, faster, for longer and in all weather, the shift was beginning towards all-metal construction.  This was an organic evolution of the Weymann technique but the weight and other characteristics of sheet aluminum differed greatly from stretched-fabric and the system needed substantially to be re-engineered and it was the lessons learned from fabricating fuselages which led to Touring developing superleggera, the design patented in 1936.  The essence of superleggera was a skeleton of small diameter tubes which formed a body’s core shape, to which were attached thin aluminum-alloy panels which provided both aerodynamic form and strength.  Compared with earlier methods, as well as being inherently light, the method afforded great flexibility in fashioning shape and Touring took advantage of the properties of the metal to create both complex and flowing curves.  Some of their cars of the era did have lovely lines and in addition to the collaboration with Alfa Romeo which yielded sports cars, gran turismo machines and racing cars, the house attracted business from Lancia, Bianchi and others.

1938 Lancia Astura IV series coupé by Touring (left), 1949 Ferrari 166mm barchetta by Touring (centre), and 2014 Ducati 1199 Superleggera (right).

In the post war years, an era in which demand was high and regulations rare, the number of cars built according to the superleggera system increased as Touring licensed the use of its patent to others including Hundon in the US, Pegaso in Spain and Bristol, Aston Martin & Lagonda in England.  Bristol particularly took to the idea because of their long experience with airframes but perhaps the most influential stylistically was the 1948 Ferrari 166 MM Touring barchetta, a charismatic shape which provided a template which would remain recognizable in Ferraris for a quarter-century, the motif of the egg-crate grill still in use today.  While superleggera was unsuited to volume production, for the exclusive ranges at the upper end of the market it was ideal and both Lamborghini and Maseratis emerged built with the technique.  Although the two are sometimes confused because there are visual similarities under the skin, the space-frame method differs in that it can support the whole structural load whereas a superleggera is attached to an existing chassis.

1960 Aston Martin DB4 GT Zagato (left), 1961 Aston Martin DB4 Convertible (centre; the Volante designation wasn't then in use) and 1965 Aston Martin DB5 Saloon.

In the public mind, the most enduring connection was with Aston Martin which was granted a license to use the design and the Superleggera construction method at its Newport Pagnell plant for a fee of £9 for each of the first 500 bodies and £5 for each subsequent unit and the DB4 & DB5 (the latter made famous in the early James Bond films) were both built thus.  However, they represented something of the end of the era because governments were starting to pass laws which demanded road cars attain a certain degree of crash-worthiness, something the superleggera technique couldn’t be adapted conform to without sacrificing the very lightness which was its raison d'etre.  Additionally, the manufacturers were moving swiftly to replace body-on-frame with unit-construction.  Touring attempted to adapt to the changing environment by offering its services as a coach-builder for small, exclusive production runs and made the necessary capital investment but it had become crowded field, the supply of coach-builders exceeding the demand for their skills.  Touring ceased operations in 1966 but four decades on, there was an unexpected revival of the name, the company re-established as Carrozzeria Touring Superleggera, offering automotive design, engineering, coach-building, homologation services, non-automotive industrial design, and the restoration of historic vehicles.  A number of very expensive one-off and limited-production ventures for Maserati, Alfa Romeo and Bentley followed but what attracted most comment was the Sciàdipersia, shown in coupé form at the Geneva Motor Show in 2018, the cabriolet introduced the flowing year.  Based on the underpinnings of the Maserati Grantourismo, although owing no visual debt, it was very much in the tradition of the three Maserati 5000 GTs Touring built in 1959-1960, the first of which had been ordered by the Shah of Iran.  Superleggera however is now just a name with an illustrious history, the method of construction no longer in use and when used as a model designation, it now simply denotes what a literal translation of the Italian suggests: lightweight.

The original Maserati 5000 GT "Shah of Iran" by Touring (left; chassis #103-002) and Touring's Maserati Sciàdipersia in coupé form (centre; 2018) and roadster (right; 2019).

Vickers Wellingtons (B-series, Mark 1) during production, the geodesic structure visible, Brooklands, England, 1939.

There are obvious visual similarities between the classic superleggera method and the geodesic structure used in airframes and some buildings, most famously the “geodesic dome”.  The imperatives of both were strength both aim to create strong and lightweight structures, but they differ in their specific design and application.  As used in airframes, the geodesic structure consisted of a network of intersecting diagonal braces, creating a lattice framework which distributed loads as evenly as possible while providing a high strength-to-weight ratio.  This was of great significance in military airplanes used in combat because it enhanced their ability better to withstand damage better, the stresses distributed across the structure rather than being restricted to a limited area which could create a point-of-failure.  The geodesic framework was based on geometric principles which had been developed over centuries and typically employed hexagons & triangles to render a structure which was both rigid & light.  Superleggera construction differed in that it involves the creation of a lightweight tubular frame, covered with aluminum body panels of a thinness which wouldn’t have been possible with conventional engineering.  The attraction of the superleggera technique was the (relatively) minimalistic framework supported the skin, optimizing weight reduction without compromising strength.  So, structurally, the difference was the geodesic design used a network of intersecting braces to form a lattice, while the superleggera construction used a tubular frame covered with panels.

Tuesday, November 21, 2023

Assimilate

Assimilate (pronounced uh-sim-uh-leyt (verb) or uh-sim-uh-lit (noun))

(1) To take in and incorporate as one's own; absorb.

(2) To bring into conformity with the customs, attitudes, etc., of a group, nation, or the like; adapt or adjust.

(3) In physiology, to convert (food) to substances suitable for incorporation into the body and its tissues; to transform food into living tissue by the process of anabolism.

(4) To cause to resemble (usually followed by to or with).

(5) To compare; liken (usually followed by to or with).

(6) In phonetics, to modify by assimilation (usually followed by “to”); to change a sound into another under the influence of one adjacent to it.

Early 1400s: From the Middle English verb assimilate (first used in early fifteenth century physiology in the sense of "absorb into and make part of the body), from the Latin assimulātus, from the Classical Latin assimulātus (likened to, made similar; imitated), past participle of assimilāre & assimulāre (to make like, copy, imitate, assume the form of; feign, pretend) and perfect passive participle of assimulō), from the assimilated construct ad (to) + simulare (make similar), from similis (like, resembling, of the same kind).  The meaning "make alike, cause to resemble" and intransitive sense "become incorporated into" date from the 1620s.   In linguistics, the technical meaning "bring into accordance or agreement in speech" was adopted in 1854 and the related forms are assimilated & assimilating.  The very common adjective unassimilated, a creation of the biological sciences also used in chemistry, was first noted in 1748.  The adjective assimilative is from the 1520s, the alternative assimilatory not formed until 1775.  The adjective assimilable was from the Latin assimilabilis, from assimilāre & assimulāre (to make like; assume the form of) and the related form is assimilability.  The noun assimilation, from the Old French assimilacion, from the Latin assimilationem (nominative assimulō) (likeness, similarity) a noun of action from the past-participle stem of assimilāre e (to make like), was an early fifteenth century creation meaning "act of assimilating" and used in the medical field in reference to the body's use of nutrition,   The meaning "process of becoming alike or identical, conversion into a similar substance" is from the 1620s. It came into figurative use from circa 1790 and became part of the jargon of psychology in 1855.  It was in the mid-late twentieth century that as "cultural assimilation" it became controversial.  Assimilate is a noun & verb, assimilation & assimilator are nouns, assimilation, assimilable, assimilatory & assimilative are adjectives, assimilationist is a noun & adjective, assimilated is a verb and assimilating is a verb & adjective; the most common noun plural is assimilations.

Assimilation in speech elements

Phonetic assimilation describes a sound-change where some phonemes (more typically consonants) shift to become more similar to other nearby sounds.  A common phonological process across languages, assimilation can occur within a word or between words.  Although often heard in normal speech, the frequency increases as delivery becomes more rapid.  Interestingly, assimilation can cause the spoken sound to differ from the accepted correct pronunciation or, to become the accepted form (usually because it makes pronunciation smoother and more "natural"), the latter often making the list of canonical or received speech.  There are various classes of the phenomenon:

Frequently, the word "handbag" is phonetically assimilated.  Lindsay Lohan with Gucci Mini Trapuntata Zumi Dome Bag (left) with Hermes Tote Bag (with assimilated hair color) (centre) and with Chanel Flab Bag in black (right). 

Place assimilation happens typically in rapid speech but in many cases the influence becomes the default for all but the most fastidious.  The classic example is "handbag" where the "n" sound assimilates to the place of articulation of the following "b" sound rendering it more like "m" (nasal assimilation) or the frequently heard "han-bag" (phonetic assimilation).

Progressive Assimilation describes instances when, followed by a bilabial sound A speech sound articulated with both lips, such as in "impossible" or "incredible," the "n", assimilating to the following sound.  It's sometimes cited as an "consonant harmony": is the prefix "in-" becoming assimilated to the following consonant: In "impossible", the "n" sound becomes a bilabial "m" to match the following bilabial "p" sound.  This differs from "vowel harmony" which is less common.  In vowel harmony, the vowel sound in a prefix can assimilate to the following vowel: In words such as "react" or "rearrange," the "i" sound in the prefix "re-" becomes more like the following "i"/ sound in the root.

Phonetic AssimilationMr Abbott (Tony Abbott (b 1957, Prime Minister of Australia 2013-2015)) phonetically assimilates as Mr Rabbit (left), Land-Rover (1950 Series I, SWB (80")) phonetically assimilates as lan-drover (centre) and Eric Abetz (b 1958, Liberal Party senator for Tasmania, Australia 1994-2022) phonetically assimilates as Erica Betts (right).  In the case of Mr Abbott, phoneticians call this "linking": the final "r" sound assimilating to the following vowel sound.

Voicing assimilation is probably one of the most frequently heard (and criticized) forms of assimilation and it's associated not only with certain dialects or working class speech.  In a world like "have", the "v" sound will often assimilate to the voiceless "f" sound when followed by a voiceless sound ("I have to go" gets pronounced as "I haf to go").  Elocution teachers note that the habit is now so widespread that "haf" is the standard form among entire classes.

Saturday, May 13, 2023

Geodesic

Geodesic (pronounced jee-uh-des-ik or jee-uh-dee-sik)

(1) In spherical geometry, a segment of a great circle.

(2) In mathematics, a course allowing the parallel-transport of vectors along a course that causes tangent vectors to remain tangent vectors throughout that course (a straight curve, a line that is straight; the shortest line between two points on a specific surface).

1821: A back-formation from geodesy (a branch of science dealing with the measurement and representation of Earth, its gravitational field and geodynamic phenomena (polar motion, Earth tides, and crustal motion) in three-dimensional, time-varying space and with great (and "down-to-earth" as it were) practical application in surveying.  The adjectives geodesical & geodetic had first appeared in 1818 & 1819 respectively, both from geodetical which had been in use since the early seventeenth century.  All the forms are derive ultimately from the Ancient Greek γεωδαισία (geodaisía) from γῆ (geo) (earth) + δαιεῖν (daiesthai) ("to divide" or "to apportion") and the use in English was most influenced by the French géodésique, dating from 1815.  In general use, the word entered general use after 1953 when it was used of the "geodesic dome" (a structure built according to geodesic principles); despite the earlier use in wartime aircraft construction, the use there was only ever "engineer's slang".    Geodesic is a noun & adjective, geodesicity is a noun, geodesical is an adjective and geodesically is an adverb; the noun plural is geodesics.    The alternative adjectival form geodetic appeared in 1834 but fell from use by mid-century.  

Four-dimensional space-time.

Geodesic describes the curve that locally minimizes the distance between two points on any mathematically defined space, such as a curved manifold; essentially the path is the one of the most minimal curvature so, in non-curved three-dimensional space, the geodesic is a straight line.  Under Albert Einstein's (1879-1955) theory of general relativity (1915), the trajectory of a body with negligible mass on which only gravitational forces are acting (ie a free falling body), defines the geodesic in curved, four-dimensional spacetime.  Dictionaries and style guides seem to prefer “space-time” but scientists (and space nerds) like “spacetime” and because it was one of them who “invented it”, it seems polite to ignore the hyphen.  The term, a calque of the German Raumzeit (the construct in English being (obviously) space + time) first appeared in a paper by German mathematician Hermann Minkowski (1864–1909), published in the Philosophical Review.  The existence of the noun plural "spacetimes" does not imply something to do with the so-called multiverse (in cosmology, a hypothetical model in which simultaneously more than one universe exists) but rather that there are different space-times created in different places at different times.

General relativity fan girl Lindsay Lohan in optical illusion dress from the Autumn-Winter collection of interior designer Matthew Williamson (b 1971), illustrating an object causing the curvature of spacetime, Gift Global Gala, Four Seasons hotel, London, November 2014.  An “optical illusion dress” is one which uses a fabric print or other device to create the effect and differs from an “illusion dress” which is made with skin-tone fabrics placed to emulate the wearer’s own flesh.

In Einstein's theory of general relativity, gravity is treated not as a force as had been the historic understanding explained in the writings of Sir Isaac Newton (1642–1727) but rather as a curvature of spacetime caused by the presence of mass and (thus) energy.  The Sun, being a massive object, causes a (relatively) significant curvature in the surrounding spacetime and the Earth, as it moves through this curved spacetime, follows a path (a geodesic) which manifests as what appears to be an “orbit” around the Sun.  It is this curvature of spacetime that is perceived as the “gravitational pull” of the Sun on the Earth, keeping it in a (relatively) stable and predictable orbit.  Einsteinian physics supplanted Newtonian physics as the structural model of the universe and nothing has since been the same. 

Hull of Vickers R.100 Airship.

Sir Barnes Wallis (1887-1979) was an English engineer, best remembered as the inventor of the bouncing bomb used by the Royal Air Force in Operation Chastise (dubbed the "Dambusters" raid) to attack the Ruhr Valley dams during World War II and the big Tallboy (6 tonnes) and Grand Slam (10 tonnes) deep-penetration "earthquake" bombs.  Wallis had been working on the Admiralty’s R.100 airship when he visited the Blackburn aircraft factory and was surprised to find the primitive wood-and-canvas methods of the Great War era still in use, a notable contrast to the elegant and lightweight aluminum structure of airships.  He was soon recruited by Vickers to apply his knowledge to the new generation of fixed-wing aircraft which would use light alloy construction for the internal structure.  His early experience wasn’t encouraging, the first prototype torpedo bomber, which used light alloy wing spars inspired by the girder structure of R.100, breaking up mid-air during a test-flight.  Returning to the drawing board, Wallis designed a revolutionary structural system; instead of using beams supporting an external aerodynamic skin, he made the structural members form the aerodynamic shape itself.

The geodesic structure in an airframe.

The principle was that the members followed geodesic curves in the surface, the shortest distance between two points in the curved surface although he only ever referred to it in passing as geodetic; it wouldn’t be until later the label came generally to be applied to the concept.  As a piece of engineering, it worked superbly well, having the curves form two helices at right angles to one another, the geodetic members became mutually supporting, rendering the overall framework immensely strong as well as comparatively light.  Revolutionary too was the space efficiency; because the geodetic structure was all in the outer part of the airframe meant that the centre was a large empty space, ready to take payload or fuel and the inherent strength was soon proven.  While conducting the usual wing-loading stress tests to determine the breakage point, the test routine was abandoned because the wings couldn’t be broken by the test rig.

Vickers Wellseley.

The benefits inherent in the concept were soon demonstrated.  Vickers’ first geodesic aircraft, the Wellesley, entered service in 1937 and in 1938, three of them, making use of the massive fuel capacity the structure made possible, flew non-stop from Ismailia in Egypt to Darwin in Australia, setting a new world record distance of 7,158 miles (11,265 km), an absolute record which stood until broken in 1946 by a Boeing B-29 Superfortress; it remains to this day the record for a single-engined aircraft with a piston engine, and also for aircraft flying in formation.  While the Wellesleys were under construction, Wallis designed a larger twin-engined geodetic bomber which became the Vickers Wellington, the mainstay of the RAF’s Bomber Command until 1943 when the new generation of four-engined heavy bombers began to be supplied in in the volume needed to form a strategic force.  Despite that, the Wellington was still used in many roles and remained in production until after the end of hostilities.  Over eleven-thousand were built and it was the only British bomber to be in continuous production throughout the war.

Vickers Wellington fuselage internal detail.

The final aircraft of the type, with a more complex geodetic structure was a four-engined heavy bomber called the Windsor but testing established it didn’t offer significantly better performance than the heavies already in service, and the difficulties which would be caused by trying to replicate the servicing and repair infrastructure was thought too onerous so it never entered production.  Post-war, higher speeds and operating altitudes with the consequent need for pressurised cabins rendered the fabric-covered geodetics obsolete.

Aston Martin DB4 GT Zagato (one of 19 in the "Continuation Series", production of which began in 2019) during construction, an aluminium panel being attached to the superleggera frame, Aston Martin Works, Newport Pagnell, Buckinghamshire, England.

There are obvious visual similarities between the classic superleggera method and the geodesic structure used in airframes and some buildings, most famously the “geodesic dome”.  The imperatives of both were strength both aim to create strong and lightweight structures, but they differ in their specific design and application.  As used in airframes, the geodesic structure consisted of a network of intersecting diagonal braces, creating a lattice framework which distributed loads as evenly as possible while providing a high strength-to-weight ratio.  This was of great significance in military airplanes used in combat because it enhanced their ability better to withstand damage better, the stresses distributed across the structure rather than being restricted to a limited area which could create a point-of-failure.  The geodesic framework was based on geometric principles which had been developed over centuries and typically employed hexagons & triangles to render a structure which was both rigid & light.  Superleggera construction differed in that it involves the creation of a lightweight tubular frame, covered with aluminum body panels of a thinness which wouldn’t have been possible with conventional engineering.  The attraction of the superleggera technique was the (relatively) minimalistic framework supported the skin, optimizing weight reduction without compromising strength.  So, structurally, the difference was the geodesic design used a network of intersecting braces to form a lattice, while the superleggera construction used a tubular frame covered with panels.

Thursday, February 3, 2022

Planet

Planet (pronounced plan-it)

(1) In astronomy (now also as “major planet), any of the eight large spherical bodies revolving about the sun in elliptical orbits and shining by reflected light: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, or Neptune, in the order of their proximity to the sun.

(2) A similar body revolving about a star other than the sun.

(3) A celestial body moving in the sky, as distinguished from (the apparently fixed) stars, applied also to the sun and moon (obsolete except in historic reference).

(4) In astrology, the sun, moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, or Pluto: regarded as sources of energy or consciousness in the interpretation of horoscopes.

1250-1300: From the Middle English planete, from the late Old English planete, from the Old French planete (which endures in Modern French as planète), from the Latin planeta & planetes (found only in plural planētae), from the Ancient Greek πλανήτης (plantēs) (wanderer), (ellipsis of πλάνητες στέρες (plánētes astéres (literally “wandering stars”)), from the Ancient Greek πλανάω (planáō) (to wander about, to stray), from planasthai (to wander), of uncertain etymology.  It was cognate with the Latin pālor (to wander about, to stray), the Old Norse flana (to rush about), and the Norwegian flanta (“to wander about”); from here English ultimately gained flaunt.  The source may have been a nasalized form of the primitive Indo-European root pele- (flat; to spread) on the notion of "spread out" but it’s speculative, etymologists noting a similarity of meaning in the Greek plazein (to make devious, repel, dissuade from the right path, bewilder) the evidence simply doesn’t exist to permit a conclusion to be drawn.  Planets were originally so-called because, viewed by the astronomers from Antiquity, they display apparent motion, unlike the stars which seemed “fixed” in space, the word derived from the Ancient Greek phrase plánētes astéres (literally “wandering stars”), ultimately from planasthai (to wander).  Thus the earliest definitions of planets encompassed both the Moon and Sun but not the Earth.  The sense define by modern science of a “world which orbits a star" was first noted in English in the 1630s.  It wasn’t until the Copernican revolution that the Earth was recognized as a planet, and the Sun was seen to be fundamentally different.

The noun planetoid (one of the asteroids, or minor planets, revolving about the sun between the orbits of Mars and Jupiter) is from 1803, the adjectival form planetoidal adopted in 1809.  Strangely, there’s never been an accepted definition of planetoid.  Within astronomical circles, it was initially a synonym for asteroid, "asteroid" referring to the star-like image seen through a telescope while "planetoid" described the object’s planet-like orbit.  In the literature, by the early twentieth century “planetoid” and “asteroid” were both widely used but the latter had prevailed almost wholly by the late 1970s.  This decline in use as a synonym is because it had instead become handy as a word to describe a subset of the larger members of the asteroid community, used to mean “planet-like in form or geology”.  Improvements in observational capacity in the early twenty-first century saw a surge in use as so many more planetary bodies were discovered in the Kuiper belt and beyond.  Within the astronomical community, there was a consensus most were hardly asteroids and concomitant with doubts as to the appropriate definition of "planet", planetoid was the label of choice.

The noun protoplanet (a large, diffuse cloud of matter in the orbit of a young star, regarded as the preliminary state of a planet) dates from 1949, the construct being proto- + planet.  The proto- prefix was a learned borrowing from the Ancient Greek πρωτο- (prōto-), a combination form of πρτος (prôtos) (first), superlative of πρό (pró) (before).  The adjective planetary (of or pertaining to a planet) was from the 1590s, probably influenced by the Late Latin planetarius (pertaining to a planet or planets) although the Oxford English Dictionary (OED) notes the only attested meaning as a noun was "an astrologer".  The planetary nebula, so-called because of the shape as seen through a telescope, is from 1785.  1690s The adjective interplanetary (existing between planets) was used in the sense of "travel between planets” as early as 1897 although the English philosopher and physician John Locke (1632–1704) used intermundane in the same sense, the Roman Epicureans having had intermundia (neuter plural) for "spaces between the worlds", translating from the Ancient Greek metakosmia.  Mundane was from the Middle English mondeyne, from the Old French mondain, from the Late Latin mundanus, from the Classical Latin mundus (world).  The noun planetarium (orrery, astronomical machine which by the movements of its parts represents the motions and orbits of the planets) dates from 1734 and was a creation of Modern Latin, the construct being the Late Latin planeta + Latin -arium (a place for).  The modern meaning "device for projecting the night sky onto the interior of a dome" describe the device developed by the optical engineering company Zeiss in Germany; it was first demonstrated in Munich in 1923, the word planetarium adopted in English in 1929.

#plutoisaplanet: Pluto photographed on 14 July 2015 by the New Horizons interplanetary space probe, launched by NASA in 2006.

The Galileian satellites of Jupiter were initially called satellite planets but were later reclassified along with the Moon.  The first observed asteroids were also considered planets, but were reclassified when became apparent how many there were, crossing each other's orbits, in a zone where only a single planet had been expected.   Pluto was found where an outer planet had been expected, but doubts were soon raised about its status because (1) it was found to cross Neptune's orbit and (2) was much smaller than the expectation had suggested.  The debate about the status of Pluto went on for decades after its discovery in 1930.  The pro-planet faction may have become complacent, thinking that because Pluto had always been a planet, it would forever be thus but, after seventy-six years in the textbooks as a planet, the International Astronomical Union (IAU) in 2006 voted to re-classify Pluto as a dwarf planet on the basis that the icy orb failed to meet a set of criteria which the IAU claimed had been accepted for decades.

To be a planet, the IAU noted, the body must (1) orbit a sun, (2) be sufficiently massive to it pull itself into a sphere under its own gravity and (3), "clear its neighborhood" of debris and other celestial bodies, proving it has gravitational dominance in its corner of the solar system.  Pluto fails the third test.  Because it orbits in the Kuiper Belt (a massive ring of asteroids and planetoids that stretches beyond the orbit of Neptune), Pluto is surrounded by thousands of other celestial bodies and chunks of debris, each exerting its own gravity.  Pluto is thus not the gravitationally dominant object in its neighborhood and therefore, not a planet and but a dwarf, a sort of better class of asteroid.  The IAU’s action had been prompted by the discovery in the Kuiper Belt of a body larger than Pluto yet still not meeting the criteria for planethood.  Feeling the need to draw a line in the cosmos, the IAU dumped Pluto.

Lindsay Lohan in Planet Fitness commercial played during Super Bowl 2022.

However #plutoisaplanet is a thing and Pluto’s supporters have a website, arguing that while it’s universally accepted a planet should be spherical and orbit the Sun, the "clearing the neighborhood" rule is arbitrary, having appears only in a single paper published in 1801.  The history is certainly muddied, Galileo having described the moons of Jupiter as planets and there are plenty of other more recent precedents to suggest the definitional consensus has bounced around a bit and there are even extremists really to accept the implications of loosening the rules such as the moons of Earth, Jupiter and Saturn becoming planets.  Most however just want Pluto restored.

The most compelling argument however is probably just that the IAU are a bunch of humorless cosmic clerks, something like the Vogons ("...not actually evil, but bad-tempered, bureaucratic, officious and callous.") in Douglas Adams’ (1952–2001) Hitchhiker's Guide to the Galaxy and that Pluto should be restored to planethood because of the romance.  Although lacking the lovely rings of Saturn (a feature shared on a smaller scale by Jupiter, Uranus & Neptune), Pluto is the most charming of all because it’s so far away; desolate, lonely and cold, it's the solar system’s emo.  If for no other reason, it should be a planet in tribute to the scientists who, for decades during the late nineteenth and early twentieth centuries, calculated possible positions and hunted for the elusive orb.  In an example of Donald Rumsfeld's (1932–2021; US secretary of defense 1975-1977 & 2001-2006) “unknown knowns”, the proof was actually obtained as early as 1915 but it wasn’t until 1930 that was realized.  In an indication of just how far away Pluto lies, since the 1840s when equations based on Newtonian mechanics were first used to predict the position of the then “undiscovered” planet, it has yet to complete even one orbit of the Sun, one Plutonian year being 247.68 years long.

The name Pluto is from the Roman god of the underworld, from the Classical Latin Pluto & Pluton, from the Ancient Greek Πλούτων (Ploútōn) (god of wealth) from ploutos (wealth; riches (probably originally "overflowing" from the primitive Indo-European pleu- (to flow).  It was the alternative Greek name or epithet of Hades in his function as the god of wealth (precious metals and gems, coming from beneath the earth, form part of his realm).