DOCSLIB.ORG

Maxwell and the Rings of Saturn

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text

Load more

newsletter

OF THE James Clerk Maxwell Foundation

Issue No.5 Spring 2015

Maxwell and the Rings of Saturn

by Professor Andrew Whitaker, Emeritus Professor of Physics, Queen’s University, Belfast

LeVerrier,ortobeworthyofthecredit bestowedonhimbyBritainand,in particular,Cambridge.

ThefundsfortheAdamsPrizewere

providedbyalumniofAdams’Cambridge

college,St.John’s,andtheprizewasin thegiftoftheUniversity.AiryandChallis

A v ie w o f t h e r ing s o f S atur n ( fro m G ribbin , J oh n a nd Goodwin , S imo n ( 1998) . E mpir e o f t h e S un : P lanets an d M oon s o f t h e S ola r S ystem . C onstable , L ondon.)

wereheavilyinvolvedinchoosingtopics

Againstthisbackground,whywas

MaxwellconsideredtheringsofSaturn

tobe‘th e m os t r emarkabl e b odie s i n t he

heavens’,secondonly,inhisopinion,to thespiralnebulae.Yetitseemsextremely unlikelythathewouldhavedevoted asubstantialamountoftimeand efforttodeterminingtheirstructure mathematicallyhadthetopicnotbeen chosenin1855asthesubjectofthe AdamsPrizeof1856. inthefirstfewyearsoftheprize,andin Maxwell’syearWilliamThomsonwas alsoanexaminer.Thomson,laterLord Kelvin,had,ofcourse,beenProfessorof NaturalPhilosophyatGlasgowUniversity since1846,butretainedverystronglinks withCambridgethroughouthiscareer. ThustheinstitutionoftheAdamsPrize andthequalityoftheprize-winning essaysmayberegardedasanelementof academicrivalrywithFrance,anditis quitelikelythatMaxwellsawhisheavy laboursinthisway.

Maxwellpreparedtoputinsomuchwork overseveralyearsontheringsofSaturn? Admittedlytheprizewassubstantial– £130,orperhaps£13,000intoday’sterms, andthiswasrathermorethanathirdof hisfullyear’ssalaryatAberdeen.Butitis morelikelythatthereasonsfortaking onthechallengewere,firstly, personal prestige,but,secondly,andevenmore importantly,thewishtomaintainor increasethescientificstatureofBritain andinparticularCambridgeUniversity.

Thedeadlineforsubmissionwas December1856,andMaxwellsubmitted hisattempt–theonlyone–justbefore thedeadline.Hewasawardedtheprize inJune1857,butcontinuedtoworkon thetopicforafurtheryear,finally
TheAdamsPrizewasinstitutedin recognitionforthecontributionofthe youngCambridgemathematicianJohn CouchAdams,madeonlyeightyears earlier,tothediscoveryofthenew planetNeptune.Hiscontribution,
Asearlyas1610,Galileohadobserved structureaboutSaturn,thoughitwas ChristianHuygensin1656whowasable toidentifyitsringnatureandJeanCassini, acenturylater,whodiscoveredthat therewere,infact,twoconcentricrings separatedbyadarkband.Shortlybefore thesettingoftheAdamsPrizetopic, severalastronomersidentifiedaninner darkring,whichwaspartiallytransparent. publishinghisresultsasabookin1859. ThiswasatatimewhenMaxwellhada greatrangeofotherinterestsandduties. FromMarch1855,hemustcertainlyhave beenabsorbedbyhisfirststudieson electromagnetism.InApril1856his fatherdied,andevenapartfromthetime requiredforgrieving,hespentmuch efforttakingoverthechargeofthefamily estate.Also,inFebruary1856,justbefore hisfatherdied,hehadappliedforthe vacantChairofNaturalPhilosophyat Aberdeen’sMarischalUniversity, requiringhimtotaketimerequesting testimonials.Hewasdulyappointedand tookuphispostinNovemberofthatyear, andthis,ofcourse,requiredhimto prepareteachingandalsotowriteand presentaninaugurallecture. though,wasdisputed,particularlyin France.Adamshadtoldthesenior Cambridgeobservationalastronomers, GeorgeBiddellAiryandJamesChallis, ofhispredictionofthepositionofthe planetasearlyasSeptember1844,buthe hadnotpublishedhiswork,andno searchhadbeenmadefortheplanet beforetheFrenchmathematicianUrbain LeVerrierpublishedasimilarprediction, andwasalsoabletopersuadethe GermanastronomerJohannGalleto searchfortheplanet.Gallespeedilymet withcompletesuccessinSeptember 1847.Toputitmildly,Frenchscientists werenotconvincedthatAdamsdeserved tosharethehonourofthediscoverywith

Therewere,ofcourse,manyideasabout thestructureoftherings,inparticular whethereachringwassolidorconsisted ofalargenumberofrocks.Howeverthere wasverylittlerigorousmathematical analysis,and,asAirypointedout,eventhe conclusionsofthegreatmathematician Pierre-SimonLaplacewere somewhat flawed,thoughmanyofhisarguments werevalid–heshowedthattherings couldnotbeauniformsolidbutclaimed theythereforemustbeanirregularsolid.

ꢀ

newsletter

OF THE James Clerk Maxwell Foundation

SowemayconsiderMaxwell’sworkas detailedrigorousandcomprehensive neighbouringregions,thesystemmoving towardsequilibrium.YetMaxwell’s neareroneofitsneighbours,itwouldseem thatgravitationwouldacttodecrease furtherthedistancebetweenthetwo satellites.Butthereverseoccurs,andfor thesamereasondiscussedinthefluidcase. Whenasatellitespeedsup,itswingsout fromitsorbit,andsoessentiallyitsangular speeddecreases.Thesituationisindeed stable. mathematicsonanessentiallyblankcanvas. mathematicsshowstheoppositeeffect occurring.
Maxwell’smethodswerenotactuallyvery

advanced,consistingofpotentialtheory, mainlyusinglineardifferentialequations, TaylorseriesandFourieranalysis,butthe
Supposeaportionoffluidneedstoincrease itsspeedaroundtheplanetinorderthatthe systemshouldmovetowardsequilibrium. analysiswassophisticatedandexceptionally Asitincreasesitsspeed,thebalance sure-footed.Ingeneral,hesearchedfor equilibriumconfigurationsofplanetand ring,andthenusedTaylorseriestostudy whetheranysuchconfigurationmightbe stabletosmalldisturbances. betweengravitationalattractionand centrifugalforceisbroken,andthisportion offluidmovesoutwards.Thusitspathhas alargercircumferenceandsoitsangular speeddecreases. Socomparedtoadjacent portionsofthering,itisgoingbackwards, andtheexpectedcatchingupistotally stymied.Thusthedisturbancedoesnot
Itmustberememberedthatthereismore thanonering,andMaxwellproceededto investigateasystemoftworings,eachofthe sameformasthesingleringjustdiscussed. Complicatedphenomenamayoccur;if,for example,awaveinoneringisinresonance withadifferenttypeofwaveintheother
Maxwellwasfirstabletoshowthatthecases ofauniformringoranon-uniformringdid notleadtostablesolutions.Hedid,though, findahighlybizarrecaseofstability–a uniformringloadedataparticularpoint withaveryheavyweight.Theconditions forstabilityofthis,somewhatodd,type ofringwerestringent;theratioofthe displacementofthecentreofgravityofthe ringtoitsradiusmustbebetween0.8159 and0.8279,andtheweightatthespecial pointmustbebetween4.43and4.81times thatoftherestofthering.Amusingas thissolutionwas,itwasclearfromdirect observationthatitborenorelationtothe actualringsystem,soMaxwell’soverall conclusionwasthateachringwasnota solidsystem.

resultinarestoringeffectbutinanincreasing ring,acombinedwavemayincrease divergencefromequilibrium.Inotherwords afluidringsystemisintrinsicallyunstable.

Maxwellwastowritethat:“Thi s e ffec t i s v ery remarkabl e a s s howin g t h e d estructiv e e ffec t o f a n a pparentlyconservativ e f orce.”

withoutlimitleadingtocollapseofthering system.Maxwellargued,though,thatthe ringsystemcouldexistforaverylongtime withoutsuchdestruction. Maxwellknew,ofcourse,thathisregular ringswereanover-simplification,and attemptedtogeneralizetoanirregular distributionofsatellites;itseemslikelythat thesethoughtsledtohisimportantwork onkinetictheory.
AsMaxwellpointedout,thefactthatSaturn itselfcouldbeseenthroughtheinnerdark ringinitstruepositionindicatedthe correctnessofthissuggestion.Thelight mustbepassingthroughgapsinthering; iftheringwerefluidtheimagewouldbe refracted.Thustheonlypossibilityseems tobethateachringconsistsofavery largenumberofunconnectedsatellites. NowthechallengewasforMaxwellto showthestabilityofsuchasystem.
Maxwell’sexplanationhasbroadlybeen foundtobecorrectbytheVoyagermission ofthe1980sandtheCassiniprobeof2009. Eachringconsistsofanimmensenumber ofparticles–mostlyicebutsomerocks– eachrotatingattheappropriatespeedfor itsdistancefromSaturn.Eachring,though, consistsofmuchvariationofbrightness – maximaandminimawithtotalgapsand ringletsofveryhighdensity.Itisnicetonote

thatthereisaMaxwel l g a pandaMaxwell ringlet.

Maxwellnowconsideredthepossibilitythat theringsystemwasfluid,whichinitially attractedhim.Naturallyinordertobalance centrifugaleffects,theringmustrotate.His methodwastoanalyzewavemotioninthe ringandtoconsiderwhethersuchwaves willbestable.Letusimagine,forexample, aplacewhere,aspartofthewavemotion aroundthering,theringisthick,andfor stability,fluidshouldmoveawaytothe
Maxwellmodelledthesituationwitha systemofequivalentrocksorsatellites spacedequallyroundthering,and calculatedwhetheranydisturbancewould leadtoawavetravellingroundtheringora totaldisruptionofthesystem.Atfirstsight, thesecondpossibilityseemedlikely,forifa particularsatelliteisdisturbedsoastobe

William Dyce Cay (1838-1925), Civil Engineer

James Clerk Maxwell’s mathematical cousin

by Professor Roland Paxton, MBE, FICE, FRSE, Hon. Professor Heriot-Watt University; Vice-Chair, Institution of Civil Engineers (ICE) Panel For Historical Engineering Works ; Trustee of the James Clerk Maxwell Foundation

WilliamDyceCay,secondsonofRobertDundas Cay,W.S.,lawyerandbrotherofFrancesCaythe motherofJamesClerkMaxwell(1831–79)was bornon28March1838at18RutlandSt.Edinburgh. HewaseducatedattheRev.Wm.Bliss’sschool, Peeblesfrom1844–53andEdinburghUniversity where,in1856,heobtaineditshighest mathematicalprize,theStraitonGoldMedal and1stprizeinthe2ndDivisionoftheNatural Philosophyclass.
Inobtainingtheseawards,Cayacknowledgedthat

the‘tuitio n a n d e xample’gainedfromhiscousin

(Maxwell)onlongwalksfromtheestateatGlenlair,

Kirkcudbrightshire,in1855had‘ha d g oo d e ffect’. Thiswaseventhough‘befor e I h a d g o t t o t he bottom o f o n e e xampl e h e h a d r ushe d o f f i nt o a nother’!In1856

MaxwellwentwithCaytoBelfastandintroduced himtohisfriendJamesThomson(elderbrother of William,laterLordKelvin),Engineerto BelfastWaterworksand,from1857,Professor of EngineeringatQueensCollege,Belfast.

Willia m D yc e C a y © I C E A rchives

newsletter

OF THE James Clerk Maxwell Foundation

Cay’ s G lenlai r r oa d b ridg e – 4 5f t s pa n © K . M cCrae
Aberdee n H arbou r a fte r i mprovement Groome’s Gazetteer 1882

CayservedasapupilunderThomson from1856–58,completinghisfour-year apprenticeshipinNovember1860asan assistantresidentengineerwithleading EdinburghconsultingengineersB.andE. Blyth.Heworkedontheconstructionof the60-milePortpatrickRailway(from CastleDouglas)fromthefirm’sCreetown siteofficeandafterwardsinitsEdinburgh office.Interestingly,aresidentengineer contemporaryonthisprojectwas Maxwell’sfellowEdinburghAcademical, AllanD.Stewart(1831–94–aCambridge University9thwranglerin1853,theyear beforeMaxwellbecame2ndwrangler). Stewartlatercontributedsignificantlyto thedesignoftheTayandForthBridges, includingtheForthsuspensionbridge (abandonedinthewakeoftheTayBridge failure)inthefeasibilityreportonwhich itwasnotedthatheapplied‘Professor

Cler k M axwell’ s d iagram s o f f orce s … w ith muc h s kill’.

  • Caythenembarkedonhismost
  • Inconstructingtheharbourentrance,

importantcivilengineeringworkas ResidentHarbourEngineeratAberdeen from1867–80.Hisdirectionofmajor improvementstotheharbour(seemap) includedchannelizingaboutamileofthe riverDeeandconstructionofthepresent SouthBreakwater(1050ftlong)–see illustrations. stillinservice,Cayadoptedconcrete, inpreferencetotraditionalrubbleand masonry,usingabout15,000tonsof PortlandCementinliquidconcreteand largeblocks.Fullwidthsinglepours rangeduptoathenremarkable1,300 tons.Hedesignedtheplantandstaging andimplemented,from1872,anew modeofdepositingliquidconcretefrom ahopperbargeto20ftbelowLowWater injutebagsholdingupto100tons.

Cayalsodesignedsteam-operated bargesforcarryingdredgedmaterial andaconcretemixingmachine.His experimentalworkincludedquantifying theincreasedearlystrengthofcement briquettesmadewithsaltwater. Althoughhedidnotinventtheconcrete bagtechnique,hewasthefirsttouseiton alargescaletofitabreakwatersoleneatly toanundressedfirmfoundation, minimisingcostlyexcavation.Cay’s achievementatAberdeenwasillustrated inVernon-Harcourt’sHarboursand Docksclassictextbookand,thathe

deserved‘grea t c redit’,wasalsopublicly

acknowledgedbyothereminent
FromJune1862toAugust1863Cay workedasresidentengineerontheTurin andSavonaRailwayunderitschief engineerJamesAbernethy,thenfortwo yearsinLondonasanassistanttoA.M. Rendel,returningtoScotlandfrom 1865–67aschiefassistanttoJames Leslie,EdinburghWaterworksEngineer. InatestimonialtoLeslie,Maxwell,who hadreturnedtoGlenlairafterresigning hisNaturalPhilosophychairatKing’s College,London,wroteofCay:

Sout h B reakwate r b ein g b uil t u nder Cay’ s d irection MPICE 39

engineersincludingAbernethyand SirJohnHawkshaw.

Cay’sinnovationsearnedhimabronze medalattheRoyalMiningEngineering andIndustrialExhibitionatNewcastleupon-Tynein1887andaBrisbaneMedal fromtheRoyalScottishSocietyofArts in1888.Bythenhisconcreteinbags technique(althoughoflimitedlater applicationassheetsteelandtheuseof compressedairdeveloped)hadbeenused atBuckie,Lerwick,Arbroath,Fraserburgh andNewhaven(Sussex)harbours,and NewPlymouthBreakwater(Ngamotu), NewZealand.

‘Hi s m athematica l k nowledg e i s s oun d a nd h e h a s m ad e a s pecia l s tud y o f i ro n a n d s tone bridges , s om e o f t h e r esult s o f w hic h h e h as bee n i n t h e h abi t o f c ommunicatin g t o m e … A s ke w b ridg e h a d t o b e e rected , b u t s om e o f th e s tones … were not properly shaped. Mr . C a y h oweve r d esigne d t h e c orrec t f orm … a n d t h e b ridg e w a s e recte d a ccordin g t o hi s p lans . M r . C a y h a s m ad e a d esign of a bridg e f o r m e a cros s t he th e R ive r U r r w hich I i nten d t o h av e e xecute d n ex t S pring ’(1866

–stillinservice,seeabove).
Bythe1870sCayhadbecomealeading memberofhisprofession.

Breakwate r e n d a n d L ighthouse

ꢀ

HewaselectedtotheInstitutionofCivilEngineers(AM,1864;M, 1872);FRSSA(1867)andFRSE(1882).From1880–1907hepractised inEdinburghasaconsultingengineer,firstlyat8SouthCharlotte Street,from1882–98at107APrincesStreetandthenfrom1Albyn Place.WorkonwhichhewasengagedincludedharboursatBuckie andLerwick,reconstructionofthedockentranceatArbroathand advisingonRoyalBridgeovertheDeeatBallater.In1908hewentto Londonand,forabouttenyears,tookanofficeat39VictoriaStreet.

Cay’sprogressivepracticeformedthesubjectofhisinfluential paperspublishedbytheInstitutionofCivilEngineers(ICE)and RoyalScottishSocietyofArts.Hiscareerwasalsoremarkableforthe largenumberofvaluablecontributionshemadetoICEProceedings from1873–1922.Subjectsincludedstabilityofchannelsandwalls, sandtravel,trainingofrivers,barsatmouthsoftidalestuaries, reductionofwaveaction,coasterosion,useandtestingofconcrete, groynes,harbourlayoutanddredging.Manyrelatedtospecific projectsathome,alsoinHolland,France,Panama,Japan,South Africa,Ceylon,BurmaandIndiaincludinga£760,000proposalfor anouterharbouratMadras.Healsowrotetechnicalarticlesfor Chambers’Encyclopaedia.

Cay’ s B reakwate r s til l p rotect s A berdee n H arbou r a fte r 1 4 0 y ears Postcar d 1 910

Caynevermarriedandlivedduringthelatterpartofhislifeatthe JuniorCarltonClubinLondonorathotelsinvariousplaces.Hewas amemberofthisandnumerousotherclubsincludingtheOriental Club,London;theUniversityClub,Edinburgh;theRoyalNorthern Club,Aberdeen;theHon’bleCompanyofEdinburghGolfers, Musselburgh;theAberdeenGolfClub;andoftheCasino,Savona. Hediedonthe2December1925inanursinghomeatFolkestone afterashortillness.

Inhis‘Recollections’ofMaxwell,Caynotesthathe(Maxwell)was

‘ver y f on d o f societ y a n d c onversatio n … H e t oo k m uc h p leasur e i n m y studyin g a n d w a s u nwearie d i n e xplainin g d ifficultie s a n d w rot e o u t f or m e a t reatis e o n h ydrostatics , h ydrodynamics , s tatics , d ynamic s a nd soli d g eometr y … A lthoug h c lea r o n p ape r h e w a s n o t s o i n v iva-voce explanations’ . ‘ 1857 , I w en t t o b e b es t m a n a t h i s m arriag e a t A berdeen’. ‘Whe n h e w a s p rofesso r a t K ing’ s C ollege , L ondon , I r emembe r h is explainin g t o m e t h e r eason s w hic h m ad e h i m g iv e u p t ha t p os t v iz . t hat th e s tudent s d i d n o t c ar e f o r i nstructio n e xcep t i n e ngineerin g o r p ractical mathematica l s ubjects’.

Mainsources:ICEArchives;MS.AbstractfromCay’s‘Family

Book’(1865),TestimonialbyMaxwellforW.D.Cay,26Sept.1865, ‘RecollectionsofJamesClerkMaxwell(1854-64)byW.D.Cay, 30April1881’,forcopiesofwhichtheauthorthanksJamesBrown

(Cayrelative);Th e T ime s4Dec.1925,1;Engineerin g11Dec.1925, 749;PRS EXLVI(1925–26);TRSS AXII(1891);MPIC E37-212

(1873–1922);Vernon-HarcourtL.V.Harbour s…,1885;PaxtonR.

&ShipwayJ.Civi l E ngineerin g H eritag e S cotland,2007.

Book Review: Faraday, Maxwell and the Electromagnetic Field

by Forbes N. & Mahon. B. (2014), Prometheus books, Amherst, New York.

Thisexcellentbookweavestogetherthehistoryof FaradayandMaxwellandthegradualuncovering ofthesecretsofmagnetismandelectricity.Today, wetakeforgrantedradio,televisionandmobile phonesbutitistooeasilyforgottenthat,inthe past,thesecretsofmagnetismandelectricity werenotknownand,asthebookshows,it requiredtheimmensecreativeeffortsofmany scientificmentouncoverthesecrets(e.g.Gilbert, Coulomb,Volta,Davy,Oersted,Ampère,Faraday, Kelvin(Thomson),Maxwell,Hertz,Heaviside, Fitzgerald,Lodge,Marconi).Thestoryofthe discoveryofthesecretsofelectricityand
AlthoughFaradaywasignorantofmathematics,

Recommended publications
  • James Clerk Maxwell

    James Clerk Maxwell

    James Clerk Maxwell JAMES CLERK MAXWELL Perspectives on his Life and Work Edited by raymond flood mark mccartney and andrew whitaker 3 3 Great Clarendon Street, Oxford, OX2 6DP, United Kingdom Oxford University Press is a department of the University of Oxford. It furthers the University’s objective of excellence in research, scholarship, and education by publishing worldwide. Oxford is a registered trade mark of Oxford University Press in the UK and in certain other countries c Oxford University Press 2014 The moral rights of the authors have been asserted First Edition published in 2014 Impression: 1 All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, without the prior permission in writing of Oxford University Press, or as expressly permitted by law, by licence or under terms agreed with the appropriate reprographics rights organization. Enquiries concerning reproduction outside the scope of the above should be sent to the Rights Department, Oxford University Press, at the address above You must not circulate this work in any other form and you must impose this same condition on any acquirer Published in the United States of America by Oxford University Press 198 Madison Avenue, New York, NY 10016, United States of America British Library Cataloguing in Publication Data Data available Library of Congress Control Number: 2013942195 ISBN 978–0–19–966437–5 Printed and bound by CPI Group (UK) Ltd, Croydon, CR0 4YY Links to third party websites are provided by Oxford in good faith and for information only.
  • “The Cloud of Unseeing”: Myths Transformed and Pseudo-Scientific

    “The Cloud of Unseeing”: Myths Transformed and Pseudo-Scientific

    Journal of Tolkien Research Volume 6 | Issue 2 Article 4 2018 “The loudC of Unseeing”: Myths Transformed and Pseudo-scientific nI terpretations of the Book of Genesis Kristine Larsen Central Connecticut State University, [email protected] Follow this and additional works at: https://scholar.valpo.edu/journaloftolkienresearch Part of the Biblical Studies Commons Recommended Citation Larsen, Kristine (2018) "“The loudC of Unseeing”: Myths Transformed and Pseudo-scientific nI terpretations of the Book of Genesis," Journal of Tolkien Research: Vol. 6 : Iss. 2 , Article 4. Available at: https://scholar.valpo.edu/journaloftolkienresearch/vol6/iss2/4 This Conference Paper is brought to you for free and open access by the Library Services at ValpoScholar. It has been accepted for inclusion in Journal of Tolkien Research by an authorized administrator of ValpoScholar. For more information, please contact a ValpoScholar staff member at [email protected]. Larsen: “The Cloud of Unseeing” 1 Note: This paper was delivered at the Tolkien Seminar, Kalamazoo, MI, on May 9, 2018. The referenced handout is reproduced as an appendix at the end. As more than one astute reader of The Silmarillion has mused, how could life – especially plant life – exist in Middle-earth before the creation of the Sun and Moon? After all, in those early days in Arda after the destruction of the Two Lamps, the Two Trees – the progenitors of the Sun and Moon – only lit the Blessed Lands. Tolkien himself was troubled by these scientific inconsistencies, going back at least as far as 1948. That year he loaned to Katherine Farrer a copy of a radical, experimental version of his creation myth termed by Christopher Ainulindalë C* (called the “Round World Version” by Tolkien) (MR 39).
  • The Contrivance of Neptune Downloaded from by DESY-Zentralbibliothek User on 27 November 2019

    The Contrivance of Neptune Downloaded from by DESY-Zentralbibliothek User on 27 November 2019

    NEPTUNE The contrivance of Neptune Downloaded from https://academic.oup.com/astrogeo/article-abstract/57/5/5.28/2738843 by DESY-Zentralbibliothek user on 27 November 2019 Davor Krajnović looks back 170 mid-19th century was, however, very dif- ferent from now. State observatories were years to the planetary discovery not research institutes in the present sense, that startled the world – an but primarily factories producing useful interplay of scientific triumph data, from time-keeping to charting the and human weakness. skies. The use of the observatory tele- scopes was at the discretion of the director and, as an assistant, Galle “ e planète, dont vous avez had to ask for permission to observe signalé la position, réellement for his own private research. Lexiste.” This is the opening The director of the Berlin sentence of an extraordinary letter Observatory, Encke, was aware sent by Johann Gottfried Galle from of Le Verrier’s theory that a more the Berlin Observatory to Jean Joseph distant planet perturbs the motion Urbain Le Verrier on 25 September of Uranus, and did not think much 1846: “The planet whose position you of it. But when Galle approached him predicted really exists.” One can only with the letter, he agreed that it presented imagine the emotions of Galle while a “moral commitment” to Galle to look writing it, or those of Le Verrier reading for the planet. The standard story (e.g. it three days later in Paris. This sentence Turner 1911, Grosser 1962, Standage 2000) announced the most remarkable confir- 1 This 2002 Hubble image of Neptune shows it in is that Encke reluctantly gave permission mation of a theoretical prediction in the detail unimaginable to the 19th-century scientists to Galle to observe that night, but Galle’s history of science.
  • John Couch Adams: Mathematical Astronomer, College Friend Of

    John Couch Adams: Mathematical Astronomer, College Friend Of

    John Couch Adams: mathematical astronomer, rsta.royalsocietypublishing.org college friend of George Gabriel Stokes and promotor Research of women in astronomy Davor Krajnovic´1 Article submitted to journal 1Leibniz-Institut für Astrophysik Potsdam (AIP), An der Sternwarte 16, D-14482 Potsdam, Germany Subject Areas: xxxxx, xxxxx, xxxx John Couch Adams predicted the location of Neptune in the sky, calculated the expectation of the change in Keywords: the mean motion of the Moon due to the Earth’s pull, xxxx, xxxx, xxxx and determined the origin and the orbit of the Leonids meteor shower which had puzzled astronomers for almost a thousand years. With his achievements Author for correspondence: Adams can be compared with his good friend George Davor Krajnovic´ Stokes. Not only were they born in the same year, e-mail: [email protected] but were also both senior wranglers, received the Smith’s Prizes and Copley medals, lived, thought and researched at Pembroke College, and shared an appreciation of Newton. On the other hand, Adams’ prediction of Neptune’s location had absolutely no influence on its discovery in Berlin. His lunar theory did not offer a physical explanation for the Moon’s motion. The origin of the Leonids was explained by others before him. Adams refused a knighthood and an appointment as Astronomer Royal. He was reluctant and slow to publish, but loved to derive the values of logarithms to 263 decimal places. The maths and calculations at which he so excelled mark one of the high points of celestial mechanics, but are rarely taught nowadays in undergraduate courses.
  • American Astronomer

    American Astronomer

    Past, present, future- it is all in the sky Galileo Galilei(1564-1642) Physicist Mathematician Astronomer Philosopher Galileo Galilei Galileo was also named „the father of modern observational astronomy” , „the father of modern physics” , „the father of science” and „the father of modern science” Stephen Hawking said about him that he was responsible for the birth of modern science Galileo has also worked in applied science and technology, improving compass construction techniques. Galileo improved the telescopes The discovery of the satellites of the planet Jupiter One day while Galileo is looking at the planet Venus, using a telescope, he noticed 3 fixed, almost invisible stars. After a period of study, he realized that the stars orbit the planet. After a while he noticed the 4th star that Galileo called the Medici Stars. Today the stars are called the Galilean Satellites The study of Saturn's rings Galileo Galilei was the first to notice Saturn's rings. Initially he was believed that the rings were two celestial bodies. Repeated studies gave the astronomer a headache. However, he failed to identify them exactly. The study about the moon After the discovery of the largest satellites of Jupiter, he observed a series of special elements about the moon. He discovers the phenomenon of libration. Then, he guesses that there are mountains and craters on the moon, aș a result of the shadows he sees. The „discover” of Neptun After observing the Milky Way, Galileo looks through the telescope and unknowingly observes the planet Neptune. Without knowing it, he discovered a new planet. The heliocentric theory Most of Galileo's astronomical theories confirmed the heliocentric theory that the Earth and other planets spin around the Sun.
  • Tremoring Transits: Railways, the Royal Observatory and the Capitalist Challenge to Victorian Astronomical Science

    Tremoring Transits: Railways, the Royal Observatory and the Capitalist Challenge to Victorian Astronomical Science

    BJHS 53(1): 1–24, March 2020. © The Author(s), 2019. Published by Cambridge University Press on behalf of British Society for the History of Science. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons. org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. doi:10.1017/S0007087419000529 First published online 11 October 2019 Tremoring transits: railways, the Royal Observatory and the capitalist challenge to Victorian astronomical science EDWARD J. GILLIN* Abstract. Britain’s nineteenth-century railway companies traditionally play a central role in histories of the spread of standard Greenwich time. This relationship at once seems to embody a productive relationship between science and capitalism, with regulated time essential to the formation of a disciplined industrial economy. In this narrative, it is not the state, but capitalistic private commerce which fashioned a national time system. However, as this article demonstrates, the collaboration between railway companies and the Royal Greenwich Observatory was far from harmonious. While railways did employ the accurate time the obser- vatory provided, they were also more than happy to compromise the astronomical institution’s ability to take the accurate celestial observations that such time depended on. Observing astro- nomical transits required the use of troughs of mercury to reflect images of stars, but the con- struction of a railway too near to the observatory threatened to cause vibrations which would make such readings impossible. Through debates over proposed railway lines near the observa- tory, it becomes clear how important government protection from private interests was to pre- serving astronomical standards.
  • Historical & Cultural Astronomy

    Historical & Cultural Astronomy

    Historical & Cultural Astronomy Series Editors: WAYNE ORCHISTON, University of Southern Queensland, Australia ([email protected]) MARC ROTHENBERG, Smithsonian Institution (retired), USA ([email protected]) CLIFFORD CUNNINGHAM, University of Southern Queensland, Australia ([email protected]) Editorial Board: JAMES EVANS, University of Puget Sound, USA MILLER GOSS, National Radio Astronomy Observatory, USA DUANE HAMACHER, Monash University, Australia JAMES LEQUEUX, Observatoire de Paris, France SIMON MITTON, St. Edmund’s College Cambridge University, UK CLIVE RUGGLES, University of Leicester, UK VIRGINIA TRIMBLE, University of California Irvine, USA GUDRUN WOLFSCHMIDT, Institute for History of Science and Technology, Germany TRUDY E. BELL, Sky & Telescope, USA More information about this series at http://www.springer.com/series/15156 Editor-in-Chief William Sheehan Trudy E. Bell • Carolyn Kennett • Robert W. Smith Editors Neptune: From Grand Discovery to a World Revealed Essays on the 200th Anniversary of the Birth of John Couch Adams Editor-in-Chief William Sheehan Independent Scholar Flagstaff, AZ, USA Editors Trudy E. Bell Carolyn Kennett Sky & Telescope Independent Scholar Lakewood, OH, USA Helston, Cornwall, UK Robert W. Smith Department of History and Classics University of Alberta Edmonton, AB, Canada ISSN 2509-310X ISSN 2509-3118 (electronic) Historical & Cultural Astronomy ISBN 978-3-030-54217-7 ISBN 978-3-030-54218-4 (eBook) https://doi.org/10.1007/978-3-030-54218-4 © The Editor(s) (if applicable) and The Author(s), under exclusive license to Springer Nature Switzerland AG 2021 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifcally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microflms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed.
  • The Giant of Gravel Hill a Poem with Slides Delivered to The

    The Giant of Gravel Hill a Poem with Slides Delivered to The

    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Apollo The Giant of Gravel Hill A poem with slides delivered to the Cambridge Astronomical Association by Mark Hurn (Departmental Librarian, Institute of Astronomy) on Friday 13 December 2013. In celebration of 175 years of the Northumberland Telescope (1838-2013). 1 I am the giant of Gravel Hill I hope you have some time to kill I have a tale about the past to tell, So listen up and listen well. For many long year the hill was bare, Until astronomers built something there. It was in the year 1823 SLIDE That Cambridge built an observatory Old Tom Plume’s money paid the bills [Thomas Plume 1630-1704] He left them with the best of wills The astronomers left the smoky city And found this hill in fields right pretty The observatory had a house each end, One for the Prof, one for his friend. Along one side the ‘scopes peeped out To see the stars and roundabout! The other side a library started For all the books they had collected Some were old and some were dusty Some were very, very musty! And on the top there was a dome Where a 4 inch telescope had its home An architect, John Mead by name Designed it all to win his fame The astronomers were rather happy, But just one thing was rather crappy All the telescopes were rather small And hardly saw the stars at all! What they needed was a bigger lens SLIDE A bigger one than all their friends A great big object glass was what they sought And in Paree, there was one to be bought The glass from Cauchoix’s workshop came Around by that old River Seine Across it was eleven inches, plus a bit And for Cambridge that would do the trick But who could stump up that much cash? But a nobleman to cut a dash Of Northumberland he was the Duke [Hugh Percy 3rd Duke 1785-1847 devt.
  • Tremoring Transits: Railways, the Royal Observatory and the Capitalist Challenge to Victorian Astronomical Science

    Tremoring Transits: Railways, the Royal Observatory and the Capitalist Challenge to Victorian Astronomical Science

    BJHS 53(1): 1–24, March 2020. © The Author(s), 2019. Published by Cambridge University Press on behalf of British Society for the History of Science. This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons. org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited. doi:10.1017/S0007087419000529 First published online 11 October 2019 Tremoring transits: railways, the Royal Observatory and the capitalist challenge to Victorian astronomical science EDWARD J. GILLIN* Abstract. Britain’s nineteenth-century railway companies traditionally play a central role in histories of the spread of standard Greenwich time. This relationship at once seems to embody a productive relationship between science and capitalism, with regulated time essential to the formation of a disciplined industrial economy. In this narrative, it is not the state, but capitalistic private commerce which fashioned a national time system. However, as this article demonstrates, the collaboration between railway companies and the Royal Greenwich Observatory was far from harmonious. While railways did employ the accurate time the obser- vatory provided, they were also more than happy to compromise the astronomical institution’s ability to take the accurate celestial observations that such time depended on. Observing astro- nomical transits required the use of troughs of mercury to reflect images of stars, but the con- struction of a railway too near to the observatory threatened to cause vibrations which would make such readings impossible. Through debates over proposed railway lines near the observa- tory, it becomes clear how important government protection from private interests was to pre- serving astronomical standards.
  • Tale-Of-Two-Vectors-Published.Pdf

    Tale-Of-Two-Vectors-Published.Pdf

    dialectica dialectica Vol. 63, N° 4 (2009), pp. 397–431 DOI: 10.1111/j.1746-8361.2009.01207.x A Tale of Two Vectorsdltc_1207 397..432 Marc Lange† Abstract Why (according to classical physics) do forces compose according to the parallelogram of forces? This question has been controversial; it is one episode in a longstanding, fundamental dispute regarding which facts are not to be explained dynamically. If the parallelogram law is explained statically, then the laws of statics are separate from and (in an important sense) “transcend” the laws of dynamics. Alternatively, if the parallelogram law is explained dynami- cally, then statical laws become mere corollaries to the dynamical laws. I shall attempt to trace the history of this controversy in order to identify what it would be for one or the other of these rival views to be correct. I shall argue that various familiar accounts of natural law (Lewis’s Best System Account, laws as contingent relations among universals, and scientific essentialism) not only make it difficult to see what the point of this dispute could have been, but also improperly foreclose some serious scientific options. I will sketch an alternative account of laws (including what their necessity amounts to and what it would be for certain laws to “transcend” others) that helps us to understand what this dispute was all about. 1. A forgotten controversy in the foundations of classical physics Today’s classical physics textbooks tell us without ceremony that forces, as vectors (i.e. directed quantities), combine by “vector addition”. A force applied at a point can be represented by an arrow from that point in the force’s direction with a length proportional to the force’s magnitude (see figure 1a).

  • Robert Smith (1689-1768) and His Prizes at Cambridge University June Barrow-Green

    This article was downloaded by: [University of Edinburgh] On: 15 April 2010 Access details: Access Details: [subscription number 917677783] Publisher Taylor & Francis Informa Ltd Registered in England and Wales Registered Number: 1072954 Registered office: Mortimer House, 37- 41 Mortimer Street, London W1T 3JH, UK Annals of Science Publication details, including instructions for authors and subscription information: http://www.informaworld.com/smpp/title~content=t713692742 'A Corrective to the Spirit of too Exclusively Pure Mathematics': Robert Smith (1689-1768) and his Prizes at Cambridge University June Barrow-Green To cite this Article Barrow-Green, June(1999) ''A Corrective to the Spirit of too Exclusively Pure Mathematics': Robert Smith (1689-1768) and his Prizes at Cambridge University', Annals of Science, 56: 3, 271 — 316 To link to this Article: DOI: 10.1080/000337999296418 URL: http://dx.doi.org/10.1080/000337999296418 PLEASE SCROLL DOWN FOR ARTICLE Full terms and conditions of use: http://www.informaworld.com/terms-and-conditions-of-access.pdf This article may be used for research, teaching and private study purposes. Any substantial or systematic reproduction, re-distribution, re-selling, loan or sub-licensing, systematic supply or distribution in any form to anyone is expressly forbidden. The publisher does not give any warranty express or implied or make any representation that the contents will be complete or accurate or up to date. The accuracy of any instructions, formulae and drug doses should be independently verified with primary sources. The publisher shall not be liable for any loss, actions, claims, proceedings, demand or costs or damages whatsoever or howsoever caused arising directly or indirectly in connection with or arising out of the use of this material.

  • Bibliography for James Clerk Maxwell

    Bibliography Entries for papers [and books] are arranged in this order: Author; title; periodical [place]; date; volume; pages; priority; location; notes. 1849 Maxwell, James Clerk. ‘On the theory of rolling curves.’ Trans. Roy. Soc. Edinb., 1849, XVI, 519-540. Read 19.2.1849. SP, I, ii, 4-29. Royal Observatory Lib., Edinburgh: (offprint). [Maxwell’s first printed paper. An earlier paper, read in 1846, was not printed until 1851.] 1851 Maxwell, James Clerk. ‘On the description of oval curves, and those having a plurality of foci.’ By Mr Clerk Maxwell junior; with remarks by Professor Forbes. Proc. Roy. Soc. Edinb., April 1851 (1844-1850), II, 89-91 & plate II. Read 6.4.1846. SP, I, i, 1-3. [The first paper by Maxwell to be read, it was evidently not taken very seriously, being belatedly printed in 1851. The original manuscript survives in the Royal Society of Edinburgh.] 1853 Maxwell, James Clerk. ‘On the equilibrium of elastic solids.’ Trans. Roy. Soc. Edinb., 1853, XX, 87-120. Read 18.2.1850. SP, I, iiia, 30-73. [See also ‘Solutions of problems’, 1854.] Maxwell, James Clerk. ‘On a particular case of the descent of a heavy body in a resisting medium.’ Camb. & Dublin Math. J., 1854, IX, 145-148. Read, Trinity College, 5.4.1853. SP, I, v, 115-118. JCM Lib.: Swainson, Charles Anthony (1820-1887)*. ‘Solutions of problems.’ Camb. & Dublin Math. J., February 1854, IX, 7-19. SP, I, iiib, 74-79 [printed with ‘On the equilibrium of elastic solids.’]. [Continuation of ‘Solutions of problems’, 1853, VIII, 178-187 & ‘Problems’ (1- 7), 1853, VIII, 188-189.