Oort cloud

17 April 2023

Diagram of solar system distances showing the Oort cloud. The scale is in astronomical units (AU) and is logarithmic.

The Oort cloud is a mulititude of icy celestial bodies that is postulated to exist beyond the Kuiper belt and that is the source of long-period comets (i.e., those that have orbital periods greater than two-hundred years). The cloud is named after astrophysicist Jan Oort (1900–1992) who postulated its existence in 1950. But Oort was not the first to do so. He was preceded by Ernst Öpik (1893–1985), who had postulated its existence in 1932. As a result, the cloud is sometimes referred to as the Öpik-Oort Cloud. In his description, Öpik used the word cloud:

If, however, among our observable objects there is a sensible proportion of meteors with R exceeding 10000 a.u., it may be only the result of a very peculiar distribution of meteoric matter at the outskirts of the solar system—a kind of a meteoric cloud, or shell, of a density much higher than may be anticipated from the observed frequency of solar meteors caught on the surface of the terrestrial atmosphere.

(In this paper, Öpik used meteors as a general category that included comets “for the sake of simplicity.”)

While Oort also used the word cloud in his 1950 paper, like Öpik he did not append his own name to it:

From a score of well-observed original orbits it is shown that the “new” long-period comets generally come from regions between about 50 000 and 150 000 A.U. distance. The sun must be surrounded by a general cloud of comets with a radius of this order, containing about 1011 comets of observable size; the total mass of the cloud is estimated to be of the order of 1/10 to 1/100 of that of the earth. Through the action of the stars fresh comets are continually being carried from this cloud into the vicinity of the sun.

The term Oort cloud is in place by 1961, when it appears in an article in the Bulletin of the Astronomical Institute of Czechoslovakia. Given the casual use of the term without explanation in an article that is only tangentially related to the cloud, it would appear that Oort cloud was already in common use among astronomers by this date:

Comets with [cube root of] p < 0.1, not included in Fig. 5, are members of the Oort cloud.

In early use, one also finds the form Oort’s comet cloud or the Oort cometary cloud, as in this article, a 1964 translation of a 1963 Soviet journal article:

On the basis of the analogy between the Lorentz force and the Coriolis force in an inertial system, the equations of hydrodynamics are formulated here for an ensemble of noncolliding particles in such a system. The equations derived are similar to the equations of collisionless magnetohydrodynamics. The evolution of rotating objects (the Galaxy, galactic clusters, meteor streams, the Oort cometary cloud, etc.) can be discussed on the basis of these equations.

The term starts appearing in the popular press in 1973 in articles discussing the comet Kohoutek of that year. This one is from the Christian Science Monitor of 20 November 1973:

Experts speculate that comets originate somewhere beyond the orbit of Pluto in Oort’s cloud, named after Jan Oort. The Dutch astrophysicist theorized that there exists a ring of comet-like snowballs in the outer reaches of the solar system. On rare occasions one is nudged out of place and begins falling toward the sun.

The Oort cloud has never been directly observed. Its existence is merely theorized based on the behavior of long-period comets.

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Sources:

Grass, Stephen. “…Astronomers Await This Burning Sphere from Beyond Pluto.” Christian Science Monitor, 20 November 1973, B8. ProQuest Historical Newspapers.

Marochnik, L.S. “Collisionless Hydrodynamics in Inertial Frames of Reference” (translation). In Soviet Astronomy, 8.2, September–October 1964, 202–09 at 202. Original in Astronomicheskii Zhurnal, 41.2, 22 November 1963, 264–73. NASA Astrophysics Data System.

Oort, J.H. “The Structure of the Cloud of Comets Surrounding the Solar System, and a Hypothesis Concerning Its Origin.” Bulletin of the Astronomical Institute of the Netherlands, 11.408, 13 January 1950, 91–110. NASA Astrophysics Data System.

Öpik, E. “Note on Stellar Perturbations of Nearly Parabolic Orbits.” Proceedings of the American Academy of Arts and Sciences, 67.6, October 1932, 169–83 at 181. JSTOR

Oxford English Dictionary, third edition, June 2004, s.v. Oort, n.

Sekanina, Z. “Collisions of Comets with Dust Particles in Interplanetary Space” (30 August 1961). Bulletin of the Astronomical Institute of Czechoslovakia, 13, 1962, 155–163 at 162. NASA Astrophysics Data System.

Image credit: NASA/JPL-Caltech, 2013. Wikimedia Commons. Public domain image.

cæsium / cesium

Caesium-133 crystal stored in an ampule of argon

14 April 2023

Caesium, also spelled cesium, is a soft, silvery-gold alkali metal. Its atomic number is 55, and its symbol is Cs. It is the first element discovered through spectrography, when in 1860 Gustav Kirchhoff and Robert Bunsen identified it through its two distinct lines in the blue portion of the visible spectrum. The following year, when they published their research, they named the element after the Latin caesius or bluish-gray:

Die Leichtigkeit, mit welcher der nur einige Tausendstel eines Milligramins betragende, noch dazu mit Lithion-, Kali- und Natron-Verbindungen gemischte Stoff an dem blauen Lichte seines glühenden Dampfes als ein neuer und einfacher erkannt werden konnte, wird es wohl gerechtigt erscheinen lassen, wenn wir für denselben den Namen Caesium mit dem Symbol Cs vorschlagen, von caesius, welches bei den Alten vom Blau des heiteren Himmels gebraucht wird.

(The ease with which the substance, which amounts to only a few thousandths of a milligram and is also mixed with lithium, potassium and sodium hydroxide compounds, could be recognized as a new and simpler substance from the blue light of its glowing vapor, will make it appear justifiable that if we propose for it the name caesium, with the symbol Cs, from caesius, which is used by the ancients from the blue of the clear sky.)

Kirchhoff and Bunsen did not isolate the metal, however. That was first done by Carl Setterberg in 1882.

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Sources:

Kirchhoff, Gustav and Robert Bunsen. “Chemische Analyse durch Spectralbeobachtungen.” Annalen der Physik und Chemie. 189.7 (1861), 337–381 at 338. HathiTrust Digital Archive.

Miśkowiec, Pawel. “Name Game: The Naming History of the Chemical Elements: Part 2—Turbulent Nineteenth Century.” Foundations of Chemistry, 8 December 2022 (online).

Oxford English Dictionary, second edition, 1989, s.v. caesium, n.

Setterberg, Carl. “Über die Darstellung von Rubidium- und Cäsiumverbindungen und Über die Gewinnung der Metalle Selbst.” Annalen der Chemie. 211.1 (1882), 100–116. HathiTrust Digital Archive.

Image credit: Dennis “S.K.”, 2008. Wikimedia Commons. Licensed under a Creative Commons Attribution 3.0 Unported license.

brothel

Brothel, by Joachim Beuckelaer, 1562

12 April 2023

A brothel is, of course, a place where prostitutes ply their trade. It is a word that developed within English, tracing back to an Old English root but with semantic and morphological changes over the centuries. The current meaning doesn’t appear until the Early Modern period.

Brothel can be traced back to the Old English root broþ-, meaning to degenerate, contemptible. The root is more commonly found in the verb abreoþan, meaning to fail. That latter verb appears in the poem The Battle of Maldon, which was probably written shortly after 991 C.E. The passage in question depicts the thane Offa attempting to rally the English troops after the death of their lord, Byrhtnoth:

                                    Us Godric hæfð,
earh Oddan bearn,         ealle beswicene.
Wende þæs formoni man,         þa he on meare rad,
on wlancan þam wicge,         þæt wære hit ure hlaford;
forþan wearð her on felda         folc totwæmed,
scyldburh tobrocen.         Abreoðe his angin,
þæt he her swa manigne         man aflymde!

(Godric, the cowardly son of Odda, has betrayed us all. Many a man thought that when he rode away on his horse, on that stately steed, that it was our lord; therefore, the army on the field became scattered, the shield wall broken. May his attempt fail that he put to flight so many men!)

And by the Middle English period we see the noun brethel, meaning a contemptible person, a wretch. And a brethel could be either male or female. It appears by c.1275 in the form breþeling in a poem bearing the modern title of Ten Abuses:

Hwan þu sixst on leode.
King þat is wilful.
And domesmon niminde.
Proest þat is wilde.
Bischop slou.
Old mon lechur.
Ȝunch mon lieȝer.
Wimmon schomeles.
Child un-þeaud.
Þral vn-buxsum.
Aþeling briþeling.
Lond wið-ute laȝe.
Al so seide bede;
Wo þere þeode.

(When you see in a people
A king that is willful;
A judge a bribe-taker;
A priest is wanton;
A bishop a sloth;
A old man a lecher;
A young man a liar;
A woman shameless;
A child unmannerly;
A thrall rebellious;
A prince a bretheling;
A land without law;
Thus said the prayer:
Woe to the nation.)

The modern form brothel appears by c.1470 when William Langland uses it in the A-text of his poem Piers Plowman:

Freres and faytors han founden suche questions
To please with this proude men seththe pestilence tyme;
Thei de-foulen vre fey at festes ther thei sitten.
For nou is vche boye bold brothel and other,
To talken of the trinite to beon holden a syre,
And fyndeth forth fantasyes vr faith to apeyre;
And eke de-fameth the fader that vs alle made,
And craken aȝeyn the clergie crabbed wordes.

(Friars and imposters have devised such questions
To please these proud men since the pestilence time,
They befoul our faith when they sit at feasts.
For now is one boy a bold brothel and another
Talking of the Trinity so as to be held as an authority [or wretch],
And putting forth fantasies that damage our faith;
And also defame our Father that made us all,
And uttering wicked words against the clergy.)

By c.1450, the meaning of brothel had narrowed to one specific type of undesirable person, the female prostitute. The narrowing was probably influenced by the noun bordel, also meaning prostitute.

This sense appears in a Middle English translation of Boccaccio’s De mulieribus claris (Of Illustrious Women). The section on the goddess Venus includes the following lines which tell of so-called “sacred prostitution” that, at least according to Herodotus and Ovid, in book ten of his Metamorphoses, allegedly compelled all women of Cyprus to commit at least one act of prostitution in a temple dedicated to the goddess:

Wyves and maydens also she dydd compel
To vse the flesh in open strumpetry
And ordeyned places therin for-to ly,

The which in Englond stves men do call,
A bordello-howse of swyth vnthryftyness,
To exercise actys venereal
Permytted for this encheson, doubtless,
To avoyde more vnclenness;
And ȝit men deme it in many place elsewhere
To be as son spede of a brothel as theere.

(Wives and maidens she also did compel
To use their bodies in open stumpetry
And ordained places for them to lay.

That which in England men call stews,
A bordello-house of great liberality,
To exercise venereal acts
Permitted for the reason, doubtless,
Of avoiding more uncleanness;
And yet men deem it in many other places
To as readily engage a brothel as there.)

(Historians today generally discount the idea that sacred prostitution actually happened, at least not as imagined in the written sources.)

The compound brothel-house appears by 1521, in Alexander Barclay’s poem The Boke of Codrus and Mynalcas:

But suche as be riche and in promocion
Shall haue my writyng but in derisyon
For in this season great men of excellence
Hath to poemys no greatter reuerence
Than to a brothell or els a brothelshous
Madde ignorance is so contagyous.

(But those who are rich and of advanced rank
Shall hold my writing but in derision;
For in this season great men of excellence
Have for poems no greater reverence
Than for a brothel or else a brothel-house.
Foolish ignorance is so contagious.)

And by the end of the sixteenth century the -house was dropped, and brothel had come to designate a place of prostitution. From Henry Smith’s 1592 Satans Compassing the Earth:

I doe verely thinke that some here did come from as bad exercises as the deuill himselfe: and that when they doo depart from this place, they will returne to as badde exercises againe, as the Deuill did: Some vnto the Tauerns, and some vnto the Alehouses, and some vnto Stages, and some vnto Brothels, and some vnto dicing, and some vnto quarrelling, and some vnto cosening.

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Sources:

Barclay, Alexander. The Boke of Codrus and Mynalcas. London: Richard Pynson, 1521, sig.b4v–cr. Early English Books Online (EEBO).

“The Battle of Maldon.” In Elliott Van Kirk Dobbie, ed., The Anglo-Saxon Minor Poems. The Anglo-Saxon Poetic Record 6. New York: Columbia UP, lines 237b–43, 13. Oxford, Bodleian Library, MS Rawlinson B.203,

Dictionary of Old English: A to I, 2018, s.v. breoþan, v.

Langland, William. The Vision of William Concerning Piers the Plowman in Three Parallel Texts, vol. 1 of 2. Walter W. Skeat, ed. Oxford: Clarendon Press, 1886, A-Text, Passus 11, lines 58–65, 291–92. HathiTrust Digital Archive.

Middle English Dictionary, 2019, s.v. brothel, n., bretheling, n.

Oxford English Dictionary, third edition, June 2022, s.v. brothel, n., brethel, n., bretheling, n.; second edition, 1989, s.v. brethe, v.

Schleich, Gustav, ed. Die Mittelenglische Undichtung von Boccaccios De Claris Mulieribus.  Palaestra, 144, 1924, lines 803–12, 40. London, British Library, MS Additional 10304. HathiTrust Digital Archive.

Smith, Henrie. Satans Compassing the Earth. London: Thomas Scarlet, 1592, sig. B6r. Early English Books Online (EEBO).

“Ten Abuses.” In Richard Morris, ed. An Old English Miscellany. Early English Text Society, OS 49. London: N. Trübner , 1872. London, British Library, Cotton MS. Caligula A.ix, fol. 248v. Corpus of Middle English Prose and Verse.

Image credit: Joachim Beuckelaer, 1562. Walters Art Museum. Public domain image.

Kuiper belt objects

Kuiper-belt objects (blue) with the sun and giant planets marked. Distances, but not sizes, are to scale.

10 April 2023

The Kuiper belt is the region of the solar system beyond Neptune ranging from 30 to 50 astronomical units (AU, an AU is some 93 million miles, or 150 million kilometers, equivalent to the distance from the Earth to the Sun.) The Kuiper belt is the region of origin for the short-period comets, i.e., those that take less than 200 years to orbit the sun. The belt is named for astronomer Gerard Kuiper.

In 1943, astronomer Kenneth Edgeworth suggested that material from the primordial solar system might exist in the region beyond Neptune and such material might occasionally wander into the inner solar system. In 1951, Gerard Kuiper made a similar postulation, but believed that such primordial trans-Neptunian material no longer existed because Pluto, which he assumed was the size of Earth, would have cleared it out. Neither Edgeworth nor Kuiper provided any evidence for the existence of such a belt of material, only postulation. As a result, the name is something of a misnomer, as neither Edgeworth nor Kuiper were firm in their suggestions. And if anyone should get credit for the idea it should be Edgeworth. As a result, the region is sometimes referred to as the Edgeworth-Kuiper belt.

Kuiper belt was coined by three astronomers in 1988. Martin Duncan, Thomas Quinn, and Scott Tremaine created a mathematical model to characterize the behavior of the short-period comets and determined that they originated in a region beyond Neptune. The name first appears in an article in the journal Science on 18 March 1988, prior to the formal publication of their paper:

Ruling out the Oort cloud, the modelers next tried a belt of low-inclination comets near Neptune’s orbit. The idea dates back to a suggestion by Gerard Kuiper in 1951 that it would only be natural to find some debris from the formation of the solar system beyond Neptune.

[…]

There are hurdles yet for the “Kuiper belt.” One is finding a means of bringing comets from the belt into Neptune-crossing orbits, which is where they were at the beginning of the simulation.

The formal article by the trio was published in the Astrophysical Journal on 15 May 1988:

In this Letter we present the key results of a set of extensive numerical simulations of gravitational scattering of comets by the giant planets, designed to determine whether the most likely source of the SP [short-period] comets is the Oort cloud or the Kuiper belt.

[…]

To summarize, the SP comets cannot be produced by planetary scattering of comets from the Oort cloud, or any other isotropic parent population. A comet belt (the "Kuiper belt”) containing a fraction of an Earth mass and located in the outer parts of the solar system is plausible on cosmogonic grounds and appears to offer the most promising source for the SP comets, although the mechanisms by which the comets are supplied to planet-crossing orbits remains unclear.

Besides the comets, the Kuiper belt is home to at least eight larger objects that qualify for the status of dwarf planet. There are two other known dwarf planets in the solar system: Ceres in the asteroid belt and Sedna (see below), which orbits at a distance beyond the Kuiper belt and is the farthest known solar system object.

Pluto (see Pluto), discovered in 1930, is the most well-known of the Kuiper-belt objects.

Quaoar was the second Kuiper-belt object to be discovered. That was on 4 June 2002 by astronomers Chad Trujillo and Mike Brown. It is named for the creator spirit of the Tongva people, an Indigenous people of Southern California. Quaoar’s moon is Weywot, named for the deity’s son.

Sedna was discovered by Brown, Trujillo, and David Rabinowitz on 14 November 2003. It is the solar system object the farthest from the sun, that we know of. Technically, it is not a Kuiper belt object as it orbits beyond the belt but too close to be in the Oort cloud, ranging from 84 to 937 AU. In Inuit mythology, Sedna is the goddess of the sea and marine animals and the ruler of the Inuit underworld. Brown and his team suggested the name for her because of the planet’s cold temperature due to its distance from the sun.

Orcus was discovered on 17 February 2004 by Brown, Trujillo, and Rabinowitz and named for one of the Etruscan and Roman gods of the underworld, and in later Roman mythology he was conflated with Pluto.

Salacia probably qualifies as a dwarf planet, but too little is known about it to be sure. It was discovered by Henry Roe, Mike Brown, and Kristina Barkume on 22 September 2004. It was officially named in 2011 after a Roman goddess of the sea, the consort of Neptune.

Haumea has a contentious discovery, with two teams claiming that honor in 2004. Brown, Rabinowitz, and Trujillo discovered the planet on 28 December 2004 on images taken on 6 May 2004 and published the discovery online on 20 July 2005. A Spanish team, led by José Luis Ortiz Moreno found the planet on images taken in March 2003 and published the discovery on 27 July 2005. It later was revealed that the Spanish team had accessed Brown’s telescope observation logs prior to his announcement. Ortiz admitted to looking at Brown’s logs but only to search for images confirming his own discovery. In its naming announcement, the International Astronomical Union (IAU), which is responsible for officially naming celestial objects, did not credit either team, but the name chosen was one suggested by Brown. Haumea is the Hawaiian goddess of childbirth and fertility.

Eris is another one credited to Brown, Trujillo, and Rabinowitz, this time on 5 January 2005. The name Eris was proposed by Brown and accepted by the IAU on 14 September 2006. Eris is the Greek goddess of discord and strife. The planet Eris has a moon, named Dysnomia, after the daughter of the goddess Eris.

Makemake is yet another discovered by Brown, this time on 31 March 2005. Makemake is the Rapa Nui creator and fertility deity. The name was suggested by Brown and adopted by the International Astronomical Union (IAU) in July 2008. Brown said of the name:

We consider the naming of objects in the Solar System very carefully. Makemake's surface is covered with large amounts of almost pure methane ice, which is scientifically fascinating, but really not easily relatable to terrestrial mythology. Suddenly, it dawned on me: the island of Rapa Nui. Why hadn't I thought of this before? I wasn't familiar with the mythology of the island so I had to look it up, and I found Makemake, the chief god, the creator of humanity, and the god of fertility. I am partial to fertility gods. Eris, Makemake, and 2003 EL61 [i.e., Haumea] were all discovered as my wife was 3-6 months pregnant with our daughter. I have the distinct memory of feeling this fertile abundance pouring out of the entire Universe. Makemake was part of that.

Gonggong was discovered on 17 July 2007 by Megan Schwamb, a graduate student of Mike Brown. It was named after a Chinese water god in an online poll run by the discovery team. The god Gonggong is often depicted as a red-headed human with a snake’s body. He is attended to by a snake-monster named Xiangliu, for whom the planet Gonggong’s moon is named.

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Sources:

Duncan, Martin, Thomas Quinn, and Scott Tremaine. “The Origin of Short Period Comets.” The Astrophysical Journal, 328, 15 May 1988, L69, L72. SAO/NASA Astrophysics Data System.

Edgeworth, Kenneth E. “The Evolution of Our Planetary System.” Journal of the British Astronomical Association, 53.6, July 1943, 181–88. SAO/NASA Astrophysics Data System.

International Astronomical Union (IAU). “Fourth Dwarf Planet Named Makemake” (Press Release IAU0806), 19 July 2008.

———. “IAU Names Dwarf Planet Eris” (Press Release IAU0605), 14 September 2006.

———. “IAU Names Fifth Dwarf Planet Haumea.” (Press Release IAU 08070), 17 September 2008.

Kerr, Richard A. “Comet Source: Close to Neptune.” Science, 239, 18 March 1988, 1372/2–1373/1. ProQuest.

Kuiper, Gerard P. “On the Origin of the Solar System.” In J.A. Hynek, ed. Astrophysics: A Topical Symposium. New York: McGraw-Hill, 1951, 357–424 at 400–403. Archive.org.

Minor Planet Center. Minor Planet Circular, 20 November 2002, 47170. (PDF)

———. Minor Planet Circular, 26 November 2004, 53177. (PDF)

———. Minor Planet Circular, 6 November 2016, 73984. (PDF)

———. Minor Planet Circular, 5 February 2020, 121135. (PDF)

Oxford English Dictionary, third edition, September 2007, s.v. Kuiper belt, n.

Image credit: WilyD, 2015. Wikimedia Commons. Licensed under a  Creative Commons Attribution-Share Alike 3.0 Unported license.

cadmium

Two blocks of cadmium, one an oblong bar and the other a cube

7 April 2023

Cadmium is a soft, silvery-white metal with atomic number 48 and symbol Cd. Its etymology is quite straightforward, coming from the Latin cadmia (zinc oxide) as it was first isolated from zinc oxide sold in German pharmacies. Cadmium is often found mixed with zinc in ores.

It was so dubbed by its discoverer, Friedrich Stromeyer in 1817:

Dieses sind die bis jetzt über dieses Metall von mir gemachten Erfahrungen. So unvollkommen dieselben auch noch sind, so trage ich hiernach doch kein Bedenken dieses Metall für ein wirklich neues und von allen übrigen wesentlich verschicdenes Metall, zu, halten. Da ich dasselbe zuerst in den Zinkoxyden aufgefunden habe, so nehme ich hiervon Anlafs es Kadmium zu nennen.

(These are the experiences I have had with this metal so far. However imperfect they may still be, I have no hesitation in considering this metal to be a really new metal that is essentially different from all the others. As I first found it in the oxides of zinc, I take the occasion to call it cadmium.)

The name quickly became established in most European languages.

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Sources:

Miśkowiec, Pawel. “Name Game: The Naming History of the Chemical Elements: Part 2—Turbulent Nineteenth Century.” Foundations of Chemistry, 8 December 2022 (online).

Oxford English Dictionary, second edition, 1989, s.v. cadmium, n., cadmia, n.

Stromeyer, Friedrich. “Ein Neu Entdecktes Metall und Analyse Eines Neuen Minerals.” Journal für Chemie und Physik. 21, 1817, 303. HathiTrust Digital Archive.

Photo credit: Heinrich Pniok, 2010. Wikimedia Commons. Licensed under a Creative Commons Attribution-NonCommercial-NonDerivative 3.0 (US) License.