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Chapter 8 Black holes and spinoffs（第1页）

Chapter8Blackholesandspin-offs

Blackholesdon'tjustsuck

IfoureyescouldobservetheskyatradiooratX-raywavelengths，wewouldseethatsomegalaxiesarestraddledbyvastballoonsorlobesofplasma。Thisplasmaschargedparticlesthatmoveatspeedsclosetothespeedoflightandradiatepowerfullyacreofwavelengths。Theplasmalobesexhibitedbysomeofthesegalaxies（examplesofactivegalaxies'）arecreatedbyjets，travellingatspeedssofastthattheyareparablewiththespeedoflight，thataresquirtedoutfromtheimmediatesurroundingsofablackhole，outsideitseventherPenroseshowediermshowextraofthespinenergyofablaitserghtbepossibleinprinciple。RogerBlandfordandRomanZnajekhaveshowlyhowtheeoredinaspinningblackholecouldactuallybetraoeledmagherebyprovidethepowertoproducetheserelativistia。Therearealsootherexplanationsforthemeismbywhichjetsarelaunnearblackholes。However，whichoftheseiscorrectisthesubjectofadexgtresearch。

&hemeism（s）turnouttobe，thesejetsarehighlyfoatedflowsejetheviityoftheblackhole，butofcourseoutsidetheeventhoriziowee，iyspasteadtheyarefilledwithaverydiffuseaermedtheiicmedium。Whesimpiergalacticmedium，shockwavesformwithinwhichspectacularparticleacodtheenergizedplasmawhiatedifromheblackholebillowsupandflowsoutoftheimmediateshion。Astheplasmaexpands，itimpartsenormousquantitiesytotheiicmedium。Therearemanyiheseplasmajetsextendingovermillionsoflight-years。Thusblackholeshavetremendousiylightyearsbeyohorizons。Inthischapter，Iwilldescribetheierasofblackholesonandwiththeirsurroundings。

AsdisChapter6，atthetreof（probably）mostgalaxiesisablackhole，ontowhichmatteraccretes，givioemissioromagicradiation。Suchgalaxiesarecalledactivegalaxies。Ihesegalaxies，theprocessofaisextremelyeffedtheresultingemissionofradiatioremelyluminous。Suchgalaxiesarecalledquasars（atermwhichderivesfriionasquasi-stellarradiosources'，vastlydistant，highlyluminouspointsofradioemission）。WehatquasarsarethesitesofthemostpowerfulsustainedenergyreleaseknownintheUniverse。Quasarsradiateenergyacrossalloftheeleagrum，fromlohradiowaves，throughoptical（visual）wavelengths，toX-raysaheradiolobes，mentionedabove，beespeciallydramaticbecausetheyextendacrossdistancesofoverhuhousandsoflight-years（seeFigure19）。Theenergyradiatedatradiowavelengthsarisesfromthelobes-reservoirsizedplasma，poweredbyjetsthattranspyovervastdistanspace。Highlyerons（highlyeicheremearemelyclosetothespeedoflight）experienceforcesacrosstheirdireoftravelfromtheambieicfieldsthatpervadetheplasmalobeswithinwhichtheyaretravelling。

19。Thisisaradioimageofagiantquasar，spanningoveronemillionlight-yearsi。

Thisaccausesthemtoemitphotonsofradiation（whichmayberadihlyeashthsstill，allthetoX-rays）knownassynradiation。

Togiveasehescaleofthepowerproducedbyquasars，siderthefollowiheLEDsbywhoselightIamoweroutputoftenwatts。Theyareillumiyfrommylocalpowerstationwhichproducesafewbillionwatts（abillionwattsis109wattsawatt）。TheSunoutputsabout4x1026watts，morethanahundredmillionbilliofromthispowerstatialaxy，theMilkyWay，orethanahundredbillionstars，anditspoweroutputisapproag1037watts。ButthepowerproducedbyaquasarextheGalacticpoweroutputbymorethanafaber，thispemittednotbyagalaxyofonehundredbillionstarsbutbytheprocessesgoingonaroundasingleblackhole。Suchradiationcoulddosiderabledamagetothehealthofliviureshereoh，soitisjustaswellforusthattherearenoexamplesofsuchpowerfulquasarstalaxy!

&sinquasarsarethoughttopersistforabillionyearsorless，aatesofthespeedatwhichtheseobjects'jetsgrowasofthesizetheyhavegrownoutto。Asimplerelatioweeimeaherefivesaguidetothelikelyduratioyinthequasarsthatareobservedacrosstheos。

Astheseradio-emittiheirmagicfieldsweakenasdotheinternal&#iesoftheindividualelethelobes。Thesetwoeffectsservetodimiyoftheradiationwithtimeandwithdistaheblackhole;howdramaticallythisiyfallsoffdependsonhowmanyhighlyeronsthereareparedwithhowmaiesthereare。It'sapropertyofsynradiatiohemagrengthis，themetictheeleeedtobetoproducetheradiationatthewavelengththatyourradiotelescopeistu。Thispoundsthediminishironradiationastheplasmalobesexpandintoouterspalydotheeleslyastheplasmaexpands，butbecausethemagrengthisweakening，lyeroowhatisobservedbyyourtelesd，veryoftelyfewerofthesethahelyeleyway。Asfarasradiolobesofquasarsareed，thelightsgooutreallyquiterapidly。

Theshowisn'tover，butthespeoveovertoadifferentwavebaherremarkablehappens:thelobeslightupinX-rays。Thishappensviaasgproasi。Inthepresenceofasuffitlylargemagrosynradiationandtherebyly。AnothermeismoflythatisrelevanttoourdisherehappeioronswithphotonsthatprisetheicrowaveBaB），theradiationthatisleftoverfromtheBigBangandwhitlybathestheUniverseinaicrowaveglow。Itispossibleforsueletocollidehotohatthephotonendsupwithalythanithadbeforethearonendsupwithalotlessehanithadbeforethe（energyisservedoverall，remember）。Ofpartiterestisthatwhentheeherapidlymovirooamereohousaheenergyofarest（havingpreviouslybeehousandtimeshigherthanthis）theirenergiesareperfectlymatchedsothattheywillupscattersintotheX-rayphotoioiwithalyphotontoyieldahigh-eoanalogoustothesituationihewhitecueball（imagihisisarohoheredsnookerballs（forthepurposesofthisillustrationpleaseoverlookthefactthatthisballisn'tmovingatthespeedoflight!）andtheredballgainsalyattheexpehecueball。efully）theredballendsupihepothesable，thephoton（whiallyhadawavelengthofaboutamillimetre）acquiresaboutonemilliontimesasmuergyasithadbeforethesothatitswavelengthbeillioer。

Thedrasatellite，launASAin1999，isseoX-raywavelengthsandinfadeteb-belllobesintheX-raysjustasaradiotelesdetectthesedoublestructuresatgths。Figures20and21showindoublestructuresobservedatradiowavelengthsandingreysthedoublestruX-rays。

Infactifwewereabletomonitorthelifecyeofthesequasarsthroughoutalltheseeves（analogouslytohowabiologistmightobservethelifecyclefrspaoles，totadpoleswithlittlelegs，tolittlefrogswithstumpytails，tsts）wewouldobserveathedoublestructuresbeingradiantatradiowavelengthstobeinginglydominantintheX-rayregion。Firsttheradiostructureswouldfadebeyoytheructureswouldfadebeyoy。Ofcourse，ifthejetsweretore-start，forexampleiftheblackhetmorefuel，theswouldfuelnewradio-emittingdoublelobesandtheinglobesagain。AswehaveseeninFigures20and21，insomequasarsweseeboththeradioandtheX-raydoublestructuresatthesametimebutinothers，oheure22）。InaarkablecasesweseetheX-raydoublestructuredingtoapreviousinofjetactivity，butalsosomenewradioactivity，atadifferentahediregwhichtheoppositely-directedjetsarelaunchedhasswungrouhaspreexampleofthisphenomenonisseeninFigure21。

20。Thisgiantquasarishalfamillionlight-yearsi，andhasadouble-lobestructureatbothradio（shownastourlines）andX-ray（showningreyscale）wavelengths。

&eadihejetaxisofmanyquasarsandradiogalaxiesisapoihesteadihespinofthesupermassiveblackhole，aglikeagyroscope。Whysomeofthesejetaxesshouldpreototherswillbeansediscoverwhattrolstheangularmomehelauneartheblackhole。Whetherthisisthespinaxisoftheblackholeitself，orwhetheritistheangularmomeheioftheadispoundednodoubtbytheLehirringorBardeeersosImentionedinChapters3aively，isdmoredataarerequiredtofullyelucidatetheobservedbehaviour。But，thereareallerobjectsethatmaysuggestthatthepreofjetaxesiseverythingtodowiththeadisc'sangularmomentum。

21。Thedouble-lobestructureobservedinthisquasaratradiowavelengths[tours]showiactivitytobediffereedfromthatshowingatX-rayenergies[greyscale]（therelirevealedbyiofs）suggestingthatthejetaxismayhaveprecessedasthejetaxesinmicroquasarsdo。

22。ThisisanX-rayimageandshowsthedouble-lobestructurestraddlingthisgalaxywhilydetectableatX-raywavelengths。

Microquasars

Thequasarswehavebeendisgsofarareallsupermassiveblackholesthatlieatthetresofactivegalaxies。However，itturnsoutthatthereisanotherclassofobjectsthatbehaveverysimilarlybutareonamuch，muchsmallerscale。Theselowermassblackholesbeobservedrathere，iedwithinourownMilkyWayGalaxy，andtheyarecalledmicroquasars'。Althoughthedifferenscalesizeisvast，microquasarsinalaxyaragalacticquasarsatthetresalaxiesarebothsourajetshysicalproperties。Bothofthesearethoughttobepoweredbythegravitationalinfallofmatterontoablackhole。Intheicroquasar，theblackholehasamassparablewiththatoftheSun。Inthecaseofapowerfulextragalacticquasar，themassofitsblackholebeahundredmilliontimeslargerthanthemassofourSun。Asfarastheastrophysicistised，animportantadvahelocalexamplesisthatbeinglessmassive，theyevolvemuchmorerapidly，ontimescalesofdaysratherthanmilliohecaseofquasars。heless，asinthecaseofquasars，thejetswhicharesquirtedoutfromreofalltheactivityarelaunoutsidetheeventhorizon，andverylikelyfromtheiheadisc。

eismsareatplay，andthereisn'tasimplerelatiohespeedatwhichajetislauhemassoftheblackholewithwhichitisassothethejetsintheblaicroquasarcalledusX-3thereareoswhewhichthejetplasmamovesawayfromtheblackholearefoundtovary。Thishasbeeime-lapseastrosinwhichobservationsatsuccessivetimesallowustodetermithejetplasmaishurtlingawayfromtheviityoftheblaeasurementshaveshownononeothejetspeedtobe81%ofthespeedoflightwhereasfouryearslatertobe67%ofthatspeed。Thereishatthejetspeedismerelyredugwithtime，siasspeedsinthismicroquasarappeartohavebeenwitnessedonanumberofossisdiscjetspeedsseemtocharaotherwellknownmicralaxy，calledSS433，thatIshalldesmoredetailbelow。Thejetspeedinthismicroquasarseemstogequiteabitaswell，iywherebetween20and30%ofthespeedoflightoverjustafe>

&yofsymmetry

Figure23sheofSS433，amicralaxy，whichisamere18，000light-yearsdistantfromus。Thestrikingzigzagcorkscrewpatterureoftheplasmajetsastheyappeartousontheplaheindividualbolidesofplasmathatmakeupthejetsaremovingattremevarybetween20and30%ofthespeedoflight。Thediresalongwhichthebvarieswithtimeinaverypersistentlyperiodifacttheaxisalongwhichthejetsarelaunchedpremuchthesamewayasdoesthepaddleofakayakist，intheframeofreferehekayak，exesohanseveralseds。Thissamebehaviourisapparentlytakileastsure21）albeitinthatsuotionthatpropriatelytime-samplethegestakingplace。

&ailedappearahezigzagcorkscrewpatternontheskydepehephysisofthebolides，aswellasthetimewheionismade。Oheremarkablefeaturesofthejetsistheirsymmetry:thephysisofthepoheeasterareequalandoppositetothosei:whenonebolideofplasmaisat28%ofthespeedoflight，sotooisitsterpartiely-directedjet;foradifferentbolideofplasmamovingat22%ofthespeedoflight，sotoowillitsterpartiely-directedjet。Thefaejetappearstohaveazigzagstructurewhiletheotherappearstohavearatherdifferentcorkscrewpatternisaceofthejetplasmaalwaysmovingatspeedsparablewiththespeedoflight，andwell-kicaberrationsthatodersuchces。ThepowerradiatedbythismicroquasarisrathermodestrelativetothatalacticquasarbutitisstillvastinparisontothepoweroftheSunwhichseemssomeuny，havingatotalluminosityofonly4x1026watts，afactorofahuhousahatradiatedfromthemicrure23。

23。ThejetsofthemicroquasarSS433astheyappearatradiowavelengths。

&launch

TheVirgoClusterisaclusterofwelloverathousaoverfiftymillioantfromtheMilkyWay。AtitsheartisagiantgalaxycalledM87（aionofMessier87，listedialogueproducedbytheFrenerCharlesMessier）。And，atitsheart，isasupermassiveblackholewhosemassisthreebillioofourSuingfromthisisastrhtjet，asshowninFigure24。

24。Ajetofplasmasquirtedoutatspeedsclosetothatoflight，fromthesupermassiveblackholeattheheartoftheM87galaxy。

Thisjetisreadilyvisibleatopticalwavelengths，atradiowavelengths，andatX-raywavelengths。ItisthoughtthattheinfalliesatarateoftwotothreeSun'sworthofmassperyear，oralnucleuswhereaiondiscofthesortdesChapter6isthoughttobeatwork。Thespeedatwhichthisjetpropagatesawayfromitslaunt，likelyattheiregioiondisc，isveryclosetothespeedoflight，aoitasarelativisticjet。JetspeedsclosetothespeedoflightarerevealedbysuccessivemwiththeVLBAiIintroduChapter7，andtheHubbleSpaceTelesddraX-raysatelliteswhichareeachaboveEarth'satmosphereandthusattaiivitythaniftheywereontheground。At50millionlight-yearsfromEarthamovingatthespeedoflightwouldmoveacrosstheskyatfourmilli-ardsperyear。Whenwesiderthatanardis13600ofadegree，thenfour-thousandthsofthismaysouiomeasure，butsuchseparationsareeasilyresolvablewithaheVLBA。TheVLBAhasalreadyimagedthebaseofthisjettowithihanaboutthirtySchwarzschildradiiofitssupermassiveblackhole。

Figure25sholeofthelobesandplumesofradioemittingplasmafedbytherelativistithesupermassivebla87。

Bywayoffurtherillustrationthatexpansivelobesareassociatedwithrelativisticjets，Figure26sholethatextends6degreesacrossthesky，andisshowntogiveasenseofscalewithrespecttothetelescopearrayusedtomaketheobservatioelescope，usedbyIlanaFeainandhercolleagues，wastheAustraliaTelespactArray。

Themeismsbywhichrelativisticjetsarelauheviityofablaainmuchclosertojetoadallreaso。heless，variousilinesofreseartirelyieamsbasediriesaroundtheworldseemtobeimplyingthatthepreponderanceofevidethebasigdetailsarecorredthebroadpicture，however，themeismsaailedfungarejectural，butbeiedamidioios。Proofdoesn'tbeloevidenceverymuchdoes。Wearehinderedbethemostadvangteiquesdeployedtodayotseparateahesmallestregiooftheenergyisreleased，butthisiswherenumericalsimulationsonpowerfulputerssdthelimitationsoftteology。Isfromsimulatiolaunadiscsthatfullyatfeyeffectsarejustbeingpublished。Thesesimulations，withknownisandaxioms，allowjetsanddiscstoevolvetosize-scaleswheretheirpropertiesfrostate-of-the-artobservations。

25。Theradio-emittiarefedbytherelativistiatingoutofthesupermassiveblackholeatthe87galaxy。

SoknowaboutthemassesofblackholesintheUseemsthattheyfallintotwomai，thosethathavemassessimilartothoseofstars。ThesestellarmassblaeiweenarouytimesthemassofourSuarsthathaveburheirfuel。

26。positepictureshotiooraliaTelespactArray，andaradioimageoftaurusA。

&herearethesupermassiveblackholeswhichgoallthetoabouttenbillionsolarmasses。Aswehavediscussed，thesearefouresofgalaxiesingourooheextraordinarypheivegalaxiesandquasars。

&alkedaboutthingsfallingintoablackhole，butenswhenablackholefallsintoablackhole?Thisisnotanabstractquestioisknownthatblackholebinariesexist。Insuchobjectstwoblackholesareinorbitarouher。Itisthoughtthat，beissionofgravitationalradiation，theblackholesinabinarywillbegintolyandspiraliher。Iagesofthisspiralliivityispushedtpointandtheblackholessuddeoasingleblackholewithaohorizon。TheehemergeroftwosupermassiveblackholesinabiaggeriiallymorethaiarsinthevisibleUofthisenergyisdumpedintogravitationallesiureofspacetime，whichpropagateacrosstheUhespeedoflight。Thehuntisonforevidehesewaves。Theideaisthatasagravitationalassesbyamaterialobject，likealongrod，itslengthwillfluctuateupanddoplesiimecurvatureflhit。Ifyoumeasurethesetihges，usingateiquesuchaslaseriheamethodtodetectgravitationalroducedelsewhereintheUhground-andspace-basedgravitatioors，examplesofwhichhavebeenbuiltandmoreoflaentialtopialsfromblaergers。Infact，gravitationalwavesaresodifficulttodetectthatyouroohaveanyceofsuchexperimentsw，andablaergerishighoofdidatesforsugsources。Atthetimeravitationalwaveshavelydetected，buttheexperimentsareongoing。

Ourbesttheravity，whiEinstein'sgeheoryofrelativity，hassurvivedtlesstestssisdis1915。Ithasbeenshoweragreemehaon'stheorywhichitsupplanted。Heyisevergoieduptoitslimits，youfideblackholeswillprovetobetheultimatetestinggroundofthisodernphysics。WheregravityisthemostihesmallestregioquasshouldbeimportalywheregeymightbreakdowmightalsobethatgeybreaksdestheUniverse。Ofcourse，ahottopicatpreseenessofgeytoexplaiedexpansionoftheUhelargestscales。Possibledeviationsawayfromgeyarebeingdiswithacceleratedexpansiy。Ifgravitatioeergersofblackholes，orifobservatioendofthefualphysicswhichotheviityofthesefasgobjethere'sagoodcethatwewillbeabletoseehowwellEinstein'stheoryholdsuporwhetheritobereplaethingnew。

Whydowestudyblackholes?

Thereareanumberofreasatingblackholesatheyopeionofphysicsparameterspacethatisotherwisesimplyihebudgetsofeveional。Blasrepreseremeelore，andassuchprobetheextremesofphysics。Theybrihgeyandquantumphysicswhoseunifihasbeenadremainsverymutierofphysics。Asedreasonisthattryiandblaenaarousesfasisandmanythoughtfullaypeople，aebylebestimulatedbysdmotivatedtolearnaboutthealmightymagheUniversearoundus。Athirdandperhapssurprisingreasohlyspin-offs。Howcouldblackholeresearceivablygeourlives?Theaithasalreadydoneso。AsItypethesefihislittlebookintomylaptop，itsimultaneouslybacksupmyworkontomyUyserverviathe802。11WiFiprotocol。Thisintridcleverteergeddirectlyoutofasearchforapartiature，atradiowavelengths，ofexplodingblackholesledbyRoestamodelsuggestedby（nowAstronomerRoyal，Lord）MartinRees。IngeniineersinAustralia，ledbyJohnO'Sullivan，inthecourseofdevisinginterferencesuppressionalgorithmsforthetriessofdetegsubtlesignalsfromdistantspacerealizedthatthesecouldbeappliedtotransformunihereoh。Blackholesthereforehavethepowertorewritephysiviginatioioeology。Therearemanyspin-offsfromblackholes-waybeyohorizons。