Laplace

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D'Alembert (2 kuvaa)

Pierre-SimonLaplace,Frenchmathematicianandastronomer,AcademicianoftheFrenchAcademyofSciences.Heisthemainfounderofcelestialmechanicsandoneofthefoundersofastronomicalchemistry.Heisalsothefounderofanalyticalprobabilitytheory,sohecanbesaidtobeapioneerofappliedmathematics.BornonMarch23,1749inBeaumont-en-Hanoge,Calvados,northwesternFrance,hewasaprofessorofmathematicsattheParisMilitaryAcademy.In1795,heservedasaprofessorattheParisPolytechnicSchoolandlaterattheNormalSchoolofHigherEducation.In1799healsoservedasdirectoroftheFrenchLongitudeBureau,andservedasMinisteroftheInteriorintheNapoleonicgovernmentfor6weeks.HewaselectedasamemberoftheFrenchAcademyin1816,andin1817heservedasthedeanoftheAcademy.DiedinParisonMarch5,1827.Intheprocessofstudyingtheproblemofcelestialbodies,Laplacecreatedanddevelopedmanymathematicalmethods.TheLaplacetransform,Laplacetheorem,andLaplaceequationnamedafterhimareusedinvariousfieldsofscienceandtechnology.Thefieldhasawiderangeofapplications.

LaplacewasborninBeaumont,Normandy,France.Hisfatherwasafarmer.Heshowedoutstandingmathematicstalentssincehisyouth.Attheageof18,helefthomeandwenttoParisanddecidedtoworkinmathematics.SohebroughtaletterofrecommendationtoD'Alembert,afamousFrenchscholaratthetime,butwasrefusedbythelatter.LaplacesentapaperonmechanicstoD'Alembert.ThepaperwassoexcellentthatD'Alembertwassuddenlysohappytobehisgodfather,andLaplacewasrecommendedtoteachatthemilitaryschool.

Afterthat,heworkedwithLavoisierforaperiodoftime,andtheymeasuredthespecificheatofmanysubstances.In1780,thetwoofthemprovedthattheheatrequiredtodecomposeacompoundintoitsconstituentelementsisequaltotheheatreleasedbytheseelementswhenformingthecompound.Thiscanbeseenasthebeginningofthermochemistry,anditisalsoanothermilestoneintheadvancementofthelawofconservationofenergyafterBraque’sresearchonlatentheat,whichwasfinallybornafter60years.

Henkilökohtainen panos

Laplacefocusedhisattentiononthestudyofcelestialmechanics.HeappliedNewton'slawofuniversalgravitationtotheentiresolarsystem.In1773,hesolvedafamousproblematthetime:explainwhytheorbitofJupiterisconstantlyshrinking,whiletheorbitofSaturnisconstantlyexpanding.Laplaceusedmathematicalmethodstoprovetheinvarianceoftheaverageplanetarymotion,thatis,theorbitalsizeoftheplanetonlychangesperiodically,andprovedtobethethirdpowerofeccentricityandinclination.ThisisthefamousLaplacetheorem.Afterthat,hebegantostudythestabilityofthesolarsystem.Inthesameyear,hebecameanassociatememberoftheFrenchAcademyofSciences.

From1784to1785,hefoundthatthegravitationalcomponentofacelestialbodytoanyparticleoutsideitcanbeexpressedbyapotentialfunction,whichsatisfiesapartialdifferentialequation,thefamousLaplaceequation.In1785hewaselectedamemberoftheAcademyofSciences.

In1786,itwasprovedthattheeccentricityandinclinationofplanetaryorbitsarealwayskeptsmallandconstant,andcanbeadjustedautomatically.Thatis,theperturbationeffectisconservedandperiodic,andwillnotaccumulateordissolve.LaplacenoticedthattheaveragemotionsZ1,Z2,andZ3ofJupiter'sthreemainmoonsobeythefollowingrelationship:Z1-3×Z2+2×Z3=0.Similarly,theaveragemotionsY1,Y2,Y3,andY4ofthefourmoonsofSaturnalsohaveasimilarrelationship:5×Y1-10×Y2+ Y3+4×Y4=0. Myöhemmät sukupolvet väittivät, että näiden satelliittien välillä oli vertailukelpoisuutta, mikä oli ajanikkunan käsite.

Itwasdiscoveredin1787thattheaccelerationofthemoonisrelatedtotheeccentricityoftheearth'sorbit,whichtheoreticallysolvedthelastanomalyobservedinthedynamicsofthesolarsystem.

In1796,hisbook"OntheSystemoftheUniverse"cameout.Thebookputforwardthenebulahypothesisabouttheoriginofplanetsthathadasignificantinfluenceonthelater.Inthisbook,independentofKant,heproposedthefirstscientifictheoryoftheoriginofthesolarsystem-NebulaTheory.Kant’snebulatheorywasproposedfromaphilosophicalpointofview,whileLaplaceenrichedthenebulatheoryfromtheperspectiveofmathematicsandmechanics.Therefore,peopleoftenrefertothenebulatheoryofthetwoofthemas"Kant-LaplaceNebulaTheory"..

Hehasbeenengagedinthestudyofthetheoryofmotionoflargeplanetsandthetheoryofmotionofthemoonforalongtime,especiallyhepaidspecialattentiontothestudyofsolarsystemcelestialbodyperturbation,thegeneralstabilityofthesolarsystemandthedynamicsofsolarsystemstability.Alargenumberofimportantresultshavebeenobtainedonthebasisofsummarizingpreviousstudies.Theseresultsareconcentratedinthe5volumesand16volumesofthemasterpiece"CelestialMechanics"publishedfrom1799to1825.Thetermcelestialmechanicswasfirstproposedinthisbook,whichisarepresentativeworkofclassicalcelestialmechanics.Therefore,heisknownastheFrenchNewtonandthefatherofcelestialmechanics.In1814,Laplaceputforwardascientifichypothesis,assumingthatifanintelligentorganismcandeterminethecurrentstateofmovementfromthelargestcelestialbodytothelightestatom,itcancalculatethepastandfuturestatesoftheentireuniverseaccordingtothelawsofmechanics.LatergenerationscalledtheintelligentcreatureheassumedastheLaplacedemon.

Healsomadegreatcontributionstomathematics,especiallyprobabilitytheory.

Hehaspublishedmorethan270papersonastronomy,mathematicsandphysics,withatotalofmorethan4006pages.Amongthemostrepresentativemonographsare"CelestialMechanics"(TraitédeMécaniqueCéleste,15volumes,16volumes,1799-1825),"TheoryoftheUniverseSystem"(Expositiondusystèmedumonde,1796,Chinesetranslation,1978edition)and"ProbabilityAnalysis"Theory"(TheorieAnalytiquedesProbabilites,1812).

Napoleonin kanssa

LaplaceusedtobeNapoleon’steacher,sohehadanindissolublebondwithNapoleon.Laplaceisamasterinmathematics,alittlemaninpolitics,heisalwaysloyaltothedominantside,andislookeddownuponbyothers.Napoleononceridiculedhimforbringingtheinfinitesimalspirittothecabinet.ThepoliticalchangessweepingFrance,includingtheriseandfallofNapoleon,didnotsignificantlyinterrupthiswork.Althoughhewasapoliticalman,hisprestigeandhisabilitytoapplymathematicstomilitaryproblemsprotectedhim,andhealsoowedhimanunadmirablepoliticalattitude.Ability.

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