Izici Ezithinta Isimo Sezinkanyezi
Imithala "imizi" emikhulu endaweni yonke, equkethe izinkanyezi eziyizigidigidi kuya kwezigidigidi, igesi, uthuli oluphakathi kwezinkanyezi, kanye ne-dark matter engabonakali, ethonya ngamandla ngamandla adonsela phansi. Uma sibheka izithombe zemithala, sizobona ukuthi inezinhlobo ezahlukene zezimo: ezinye ziyizindilinga ezisontekile kahle (ezijikelezayo), ezinye zibonakala ziyindilinga noma ziyi-oval ngaphandle kwesakhiwo sengalo esicacile (eziyi-elliptical), kanti ezinye zibonakala "zingcolile" (zingajwayelekile). Umbuzo uwukuthi, kungani imithala inezinhlobo ezahlukene kangaka? Impendulo ilele ekuhlanganisweni kwezinto zefiziksi ze-cosmic ezisebenza eminyakeni eyizigidigidi. Nazi izici eziyinhloko ezithonya ukuma kwemithala.
1. Amandla adonsela phansi kanye nesisindo esiphelele
Amandla adonsela phansi “ungumakhi” oyinhloko wemithala. Isisindo esiphelele—isisindo esihlanganisiwe sezinkanyezi, igesi, uthuli, kanye ne-dark matter—sinquma ukuthi umthala ungabopha kanjani izingxenye zawo ngokuqinile. Imithala emikhulu kakhulu ivame ukuba namandla adonsela phansi aqinile, okwenza isakhiwo sayo sangaphakathi sizinze kakhudlwana, kodwa futhi isengozini enkulu yezehlakalo ezinkulu njengokuhlangana neminye imithala.
Isisindo sithinta nobuningi bezinto. Uma izinto zigxile phakathi nendawo, umthala ungaba neqhubu eliphakathi elibonakalayo. Ngokuphambene nalokho, uma ukusatshalaliswa kwesisindo kukhulu kudiski, umthala ojikelezayo ungabonakala "uncane" ngezingalo ezivelele.
2. Izinto ezimnyama nesimo se-halo
Iningi lesisindo somthala empeleni liqukethwe ngaphakathi kwe-halo yento emnyama eyizungezile. Nakuba ingakhiphi ukukhanya, into emnyama yakha "uhlaka lwamandla adonsela phansi" oluqondisa ukuvela komthala. Ukuma kanye nokuhlushwa kwethonya le-halo yento emnyama:
– Isivinini sokujikeleza kwezinkanyezi negesi emabangeni ahlukene ukusuka enkabeni.
– Ukuqina kwediski ye-galactic (kungakhathaliseki ukuthi yakha kalula izingalo ezijikelezayo noma iphazamiseka kalula).
– Kungenzeka ukuthi kube nebha (isakhiwo sebha) phakathi komthala.
Uma i-halo yento emnyama “ikhuluphele” noma ingalingani, umthala ungaphambuka kalula lapho uxhumana nomakhelwane bawo bendawo yonke.
3. Umfutho we-angular kanye nokujikeleza
Omunye wemehluko obaluleke kakhulu phakathi kwemithala yezinkanyezi ejikelezayo ne-elliptical ukujikeleza. Lapho amafu amakhulu egesi endaweni yonke yokuqala ewa ngaphansi kwamandla adonsela phansi, cishe ayehlala enokujikeleza okuncane (umfutho we-angular). Lokhu kujikeleza kwashesha njengoba ifu licindezeleka—njengomuntu oskeyitha eqhweni edonsa izingalo zakhe ukuze ajikeleze ngokushesha.
– Imithala ejikelezayo ngokuvamile inokujikeleza okunamandla ukuze izinto zakhe isakhiwo sediski.
– Imithala yezinkanyezi ezi-elliptical ivame ukubuswa ukunyakaza okungahleliwe kwezinkanyezi zazo, kunokuba kujikelezwe njalo, ngakho-ke ukuma kwazo “kukhukhumala” kakhulu njengebhola noma i-oval.
Ubukhulu bomfutho we-angular kanye nendlela "okwabelwana ngayo" phakathi kwezingxenye zomthala kuyizinto ezibalulekile ekunqumeni ukuthi umthala uzoba yi-spiral evamile noma i-elliptical ebushelelezi.
4. Okuqukethwe kwegesi kanye nomsebenzi wokwakheka kwezinkanyezi
Igesi iyinto eluhlaza yokwakheka kwezinkanyezi. Imithala ecebile ngegesi ivame ukwakha izinkanyezi ngenkuthalo futhi ivame ukuba nezakhiwo zamadiski ezihlukile kanye nezingalo ezijikelezayo. Izingalo ezijikelezayo azizona nje "imizila yezinkanyezi," kodwa kunalokho ziyizindawo zamagagasi okucindezela acindezela igesi, akhuthaza ukuzalwa kwezinkanyezi ezintsha.
Ngokuphambene nalokho, imithala engenagesi ivame ukuba “midala” futhi ingabi nandaba—ukwakheka kwezinkanyezi zayo kuye kwehla noma kwayeka. Imithala eminingi ye-elliptical iwela kulesi sigaba; ibuswa izinkanyezi ezindala, ezibomvu futhi ayinawo umoya opholile owanele wokwakha izingalo ezivelele ezijikelezayo.
5. Ukushayisana nokuhlangana kwemithala
Ukusebenzisana kwe-intergalactic kuyisici esiphawulekayo esivame ukushintsha kakhulu ukuma kwemithala. Endaweni yonke, imithala ayivamile ukuba yodwa; eminingi ikhona ngamaqoqo noma ngamaqembu, okwenza amathuba okuyibona abe phezulu kakhulu.
– Ukuhlangana okukhulu (imithala emibili enobukhulu obufanayo) kungabhubhisa isakhiwo sediski ejikelezayo futhi kukhiqize imithala ye-elliptical. Lokhu kushayisana kuphazamisa ukuzungeza kwezinkanyezi, kushintsha ukujikeleza kwazo okuvamile kube ukunyakaza okungahleliwe.
– Ukuhlangana okuncane (imithala emikhulu “edla” imithala emincane) kungaqinisa idiski, kwakha ama-halo ezinkanyezi, noma kubangele ukwakheka kwemigoqo namasongo.
Izimpawu zezinkanyezi eziye zahlangana zihlanganisa imisila yolwandle, izimo ezingalingani, noma imifudlana yezinkanyezi emide.
6. Indawo ezungezile: amaqoqo, amaqembu, kanye namasimu
Indawo lapho umthala uhlala khona inquma kakhulu ukuma kwawo. Imithala emiqongweni eminyene ivame ukubhekana nengcindezi evela kugesi oshisayo we-intergalactic (i-intracluster medium). Izinqubo ezifana nokukhumula ingcindezi ye-ram-pressure zingasusa igesi emithalazweni ehamba ngokushesha ngaphakathi kweqoqo, zisuse izinto zokusetshenziswa zokwakheka kwezinkanyezi. Ngenxa yalokho, imithala ingaguquka isuke emiqondweni eluhlaza okwesibhakabhaka esebenzayo iye kweminye engenzi lutho, evame ukuba nokubukeka okubushelelezi.
Okwamanje, imithala ezindaweni ezithule (ezindaweni ezizungezile) ivame ukugcina igesi yayo isikhathi eside futhi ivame ukuhlala ijikeleza. Ngenxa yokuthi kuneziphazamiso ezimbalwa zangaphandle, isakhiwo sediski singaqhubeka izigidigidi zeminyaka.
7. Impendulo evela kuma-supernovae kanye nemigodi emnyama emikhulu kakhulu
Enkabeni yemithala eminingi kukhona umgodi omnyama omkhulu kakhulu. Uma "udla" igesi, umsebenzi wenuzi we-galactic nuclear (AGN) ungakhipha amandla amaningi ngendlela yemisebe kanye namajethi ezinhlayiya. La mandla angafudumeza noma akhiphe igesi, acindezele ukwakheka kwezinkanyezi. Isenzakalo esifanayo senzeka ngezinga elincane nge-supernovae, ukuqhuma kwezinkanyezi ezinkulu ezifaka amandla endaweni ephakathi kwezinkanyezi.
Lokhu kusabela kuthinta ukuma komthala ngokungaqondile: njengoba igesi ikhishwa noma ishiswa, idiski ingaba “lush” kancane ukuze izingalo ezijikelezayo zibonakale zibuthakathaka, futhi umthala uhamba kancane uye esigabeni esingenzi lutho.
8. Ukungazinzi kwangaphakathi: imigoqo, amasongo, kanye nokuqina kwamadiski
Ukuma kwemithala akuthonywa nje yizici zangaphandle. Ngaphakathi, imithala ingaba nokungazinzi kwamandla adonsela phansi, okudala izakhiwo ezihlukile:
– Amabha: Imithala eminingi ejikelezayo inesakhiwo sebha ephakathi. Amabha “angasakaza” igesi iye enkabeni, ibangele ukwakheka kwezinkanyezi noma inikeze umgodi omnyama omkhulu kakhulu.
– Amasongo: akhiwe ngenxa yokujikeleza noma ngenxa yokusebenzisana kwamandla adonsela phansi.
– Ukuqina kwediski: kungenzeka ngenxa yokuphazamiseka okuncane okuphindaphindiwe noma ukushisa okunamandla, okwenza umthala ubonakale “ukhuluphele” uma ubhekwa ohlangothini.
Lokhu kungalingani kushintsha ukubukeka kwemithala ngokuhamba kwesikhathi, ngisho nangaphandle kokushayisana okukhulu.
9. Umlando wokwakheka kanye nobudala bezinkanyezi
Ukuma komthala "kuyirekhodi" lomlando wawo. Imithala eyakheka ngokushesha, yahlangana kaningi ekuqaleni, noma yalahlekelwa yigesi kusenesikhathi kungenzeka ukuthi ikhule ibe ama-elliptical. Ngokuphambene nalokho, imithala eyakhula kancane futhi yagcina ukutholakala kwegesi okuzinzile kungenzeka ukuthi ibe ama-spiral. Ubudala benani lezinkanyezi nakho kuyinkomba: ama-spiral avame ukuba nenhlanganisela yezinkanyezi ezincane nezindala, kuyilapho ama-elliptical ebuswa yizinkanyezi ezindala.
Isiphetho
Ukuma komthala akuyona "isiphetho" esinqunyiwe, kodwa kunalokho umphumela wokuvela kwesikhathi eside okuthonywe amandla adonsela phansi, ukujikeleza, okuqukethwe yigesi, izinto ezimnyama, ukusebenzisana neminye imithala, ngisho nezimo zemvelo yendawo yonke. Imithala ethandekayo ejikelezayo, ama-elliptical abushelelezi, kanye nemithala engavamile engahlelekile konke kuyizinhlobo zenqubo efanayo yomzimba, ehluka kuphela emikhondweni yayo yomlando. Ukuqonda lezi zici kusisiza sibone imithala hhayi nje njengezinto ezinhle esibhakabhakeni, kodwa njengezinhlelo ezinamandla ezishintsha njalo, ezikhula, futhi ezivumelana nezimo esigabeni esikhulu sendawo yonke.
