对火星轨道变化问题的最后解释(1/4)
!--go--
作者君在作品相关中其实已经解释过这个问题。
不过仍然有人质疑——“你说得太含糊了”,“火星轨道的变化比你想象要大得多!”
那好吧,既然作者君的简单解释不够有力,那咱们就看看严肃的东西,反正这本书写到现在,嚷嚷着本书bug一大堆,用初高中物理在书中挑刺的人也不少。
以下是文章内容:
long-termintegrationsandstabilityofplanetaryorbitsinoursolarsystem
abstract
wepresenttheresultsofverylong-termnumericalintegrationsofplanetaryorbitalmotionsover109-yrtime-,atleastinoursimpledynamicalmodel,seemstobequitestableevenoverthisverylongtime--frequencyoscillationsusingalow-passfiltershowsusthepotentiallydiffusivecharacterofterrestrialplanetarymotion,'ssecularperturbationtheory(∼∼±4gyr).however,therearenoapparentsecularincreasesofeccentricityorinclinationinanyorbitalelementsoftheplanets,whichmayberevealedbystilllonger-±–plutosystemhavebeenmaintainedoverthe1011-yrtime-
1introduction
thequestionofthestabilityofoursolarsystemhasbeendebatedoverseveralhundredyears,-,‘stability’,
amongmanydefinitionsofstability,hereweadoptthehilldefinition(gladman1993):actuallythisisnotadefinitionofstability,,startingfromacertaininitialconfiguration(chambers,wetherill&boss1996;ito&tanikawa1999).,about±,(yoshinaga,kokubo&makino1999).ofcoursethisstatementcannotbesimplyappliedtosystemswithstableorbitalresonancessuchastheneptune–
inadditiontothevaguenessoftheconceptofstability,theplanetsinoursolarsystemshowacharactertypicalofdynamicalchaos(sussman&wisdom1988,1992).thecauseofthischaoticbehaviourisnowpartlyunderstoodasbeingaresultofresonanceoverlapping(murray&holman1999;lecar,franklin&holman2001).however,itwouldrequireintegratingoveranensembleofplanetarysystemsincludingallnineplanetsforaperiodcoveringseveral10gyrtothoroughlyunderstandthelong-termevolutionofplanetaryorbits,
fromthatpointofview,manyofthepreviouslong-termnumericalintegrationsincludedonlytheouterfiveplanets(sussman&wisdom1988;kinoshita&nakai1996).,thelongestnumericalintegrationspublishedinjournalsarethoseofduncan&lissauer(1998).althoughtheirmaintargetwastheeffectofpost-main-sequencesolarmasslossonthestabilityofplanetaryorbits,theyperformedmanyintegrationscoveringupto∼&lissauer'spaper,-main-,theyfoundthatthecrossingtime-scaleofplanetaryorbits,whichcanbeatypicalindicatoroftheinstabilitytime-scale,,thejovianplanetsremainstableover1010yr,&lissaueralsoperformedfoursimilarexperimentsontheorbitalmotionofsevenplanets(venustoneptune),whichcoveraspanof∼,butitseemsthattheterrestrialplanetsalsoremainstableduringtheintegrationperiod,
ontheotherhand,inhisaccuratesemi-analyticalsecularperturbationtheory(laskar1988),laskarfindsthatlargeandirregularvariationscanappearintheeccentricitiesandinclinationsoftheterrestrialplanets,especiallyofmercuryandmarsonatime-scaleofseveral109yr(laskar1996).theresultsoflaskar'
inthispaperwepresentpreliminaryresultsofsixlong-termnumericalintegrationsonallnineplanetaryorbits,coveringaspanofseveral109yr,andoftwootherintegrationscoveringaspanof±,-termintegrationsisthatsolarsystemplanetarymotionseemstobestableintermsofthehillstabilitymentionedabove,atleastoveratime-spanof±,inournumericalintegrationsthesystemwasfarmorestablethanwhatisdefinedbythehillstabilitycriterion:notonlydidnocloseencounterhappenduringtheintegrationperiod,butalsoalltheplanetaryorbitalelementshavebeenconfinedinanarrowregionbothintimeandfrequencydomain,-termnumericalintegrations,weshowtypicalexamplefiguresasevidenceoftheverylong-,wehavepreparedawebpage(access),whereweshowraworbitalelements,theirlow-passfilteredresults,variationofdelaunayelementsandangularmomentumdeficit,andresultsofoursimpletime–
insection2webrieflyexplainourdynamicalmodel,--termvariationofplanetaryorbitsusingalow-,wepresentasetofnumericalintegrationsfortheouterfiveplanetsthatspans±-
2descriptionofthenumericalintegrations
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