Imibono Ngamandla Amnyama Nezinto Ezimnyama
Indawo yonke esiyibukayo—izinkanyezi, amaplanethi, igesi ephakathi kwezinkanyezi, kanye nemithala—imelela ingxenye encane nje yendawo yonke. Kusukela ngasekupheleni kwekhulu lama-20, izazi zendalo yonke ziye zaqiniseka ngokwengeziwe ukuthi ingxenye enkulu kunazo zonke yendawo yonke empeleni ayibonakali kithi. Amagama amabili avame ukuvela kule ngxoxo yizinto ezimnyama kanye namandla amnyama. Womabili “amnyama” ngoba awakhiphi, awamunci, noma awabonisi ukukhanya ngendlela ebonakala kalula; nokho, izindima zawo kanye nezakhiwo zawo ezisolwayo zihlukile kakhulu. Lesi sihloko sixoxa ngemibono eyinhloko mayelana nezinto ezimnyama kanye namandla amnyama, ubufakazi bokubuka obuwasekelayo, kanye nezinselele isayensi yanamuhla esabhekene nazo.
Kungani Sidinga Umqondo “Wobumnyama”?
Ku-cosmology, imibono kufanele ivumelane nedatha yokubuka. Lapho izazi zezinkanyezi zilinganisa ijubane lokujikeleza kwemithala, indlela ezigoba ngayo ukukhanya (i-gravitational lensing), kanye namaphethini emisebe asele ku-Big Bang (Cosmic Microwave Background/CMB), imiphumela iphakamisa ukuthi kukhona "okuthile" okuthonya amandla adonsela phansi kanye nokuvela kwendawo yonke. Kodwa lokho "okuthile" akubonakali kuyizinto ezikhanyayo njengezinkanyezi.
Ngakolunye uhlangothi, ngezinga elikhulu kakhulu le-cosmic, ukubonwa kwe-supernovae yohlobo lwe-Ia ngasekupheleni kweminyaka yama-1990 kwembule iqiniso elimangalisayo: ukwanda kwendawo yonke akunciphisi ijubane, kodwa kunalokho kuyashesha. Ukuze kuchazwe lokhu kusheshisa, kwakudingeka ingxenye enengcindezi engemihle eyayicindezela isikhala nesikhathi ukuze ikhule ngokushesha nangokushesha. Le ngxenye kamuva yabizwa ngokuthi amandla amnyama.
Izinto Ezimnyama: Imibono Eyinhloko Nobufakazi
1. Ijika Lokujikeleza Kwe-Galaxy
Esinye sezingcezu zobufakazi ezivamile zezinto ezimnyama sivela ekulinganisweni kwamajika okujikeleza kwemithala ejikelezayo. Ngokusho kwamandla adonsela phansi e-Newtonian, ijubane lezinkanyezi ezizungeza isikhungo somthala kufanele lehle njengoba ibanga likhula ukusuka enkabeni. Kodwa-ke, kuyabonakala okuphambene nalokho: ijubane livame ukuhlala liphezulu futhi "liyisicaba" kude kakhulu emaphethelweni omthala. Lokhu kusikisela ukuthi kunesisindo esengeziwe esisatshalaliswa kabanzi, sakha i-halo yezinto ezimnyama ezungeze umthala.
2. Ilensi Yokudonsa Amandla
Ngokusho kokuhlobana okuvamile, i-mass golds spacetime, ngakho-ke ukukhanya okudlula eduze kwe-mass enkulu kuyagoba. Ezinhlelweni eziningi ze-cosmic (ama-galaxy clusters, ama-single galaxy), imiphumela ye-gravitational lensing ikhombisa inani elikhulu le-mass kunokubalwa yi-luminous matter. Isibonelo esidumile yi-Bullet Cluster, lapho ukusatshalaliswa kwe-mass (okulandelwa yi-gravitational lensing) kuhlukaniswa ne-hot gas ekhanyayo (ebonakala kuma-X-ray). Lesi simo sivame ukubhekwa njengokusekela okuqinile kweqiniso lokuthi i-dark matter iyisici sangempela, kunokuba kube nje umbono ongalungile we-gravity.
3. Imisebe Yangemuva Yendawo Yonke (i-CMB) kanye Nesakhiwo Esibanzi
I-CMB igcina "umkhondo" wezimo endaweni yonke yokuqala. Amaphethini amancane okuguquguquka ku-CMB, uma ehlaziywa, anikeza izilinganiso zokwakheka kwendawo yonke. Imiphumela iyahambisana namamodeli asikisela ukuthi indawo yonke yakhiwe cishe yi-~5% yezinto ezivamile, ~27% izinto ezimnyama, kanye ~68% amandla amnyama (izinombolo zingahluka kancane kuye ngesethi yedatha). Izinto ezimnyama nazo ziyasiza ekuchazeni ukuthi izakhiwo ze-cosmic—kusukela emithaleni kuya ezinhlamvini ezinkulu—zingakheka kanjani ngokushesha njengoba kubonwe.
Izinto Ezimnyama Ezingadingeki: Kusukela Ezinhlayiyeni Ezintsha Kuya Ezimbotsheni Ezimnyama Eziyinhloko
Ithiyori yendaba emnyama ethandwa kakhulu icabanga ukuthi iwuhlobo lwendaba ngesimo sezinhlayiya esingakayitholi ku-physics yezinhlayiya.
1. I-WIMP (Izinhlayiya Ezinkulu Ezisebenzisana Kancane)
Ama-WIMP ake abhekwa njengabaholi ngoba ayengavela ngokombono kumamodeli anwetshiwe e-particle physics futhi akhiqize ngokwemvelo ubuningi "obufanele" bendawo yonke (ngokuvamile obubizwa ngokuthi "isimangaliso se-WIMP"). Kodwa-ke, izivivinyo ezahlukahlukene zokuthola ngqo (isb., ukusebenzisa ama-detector angaphansi komhlaba) kuze kube manje zehlulekile ukuthola isignali ekholisayo.
2. I-Axion
I-axion iyinhlayiya ecatshangelwayo ekuqaleni eyahlongozwa ukuxazulula inkinga ku-theory of strong interactions (QCD). Ama-Axion angaba lula kakhulu kodwa abe maningi kakhulu, ngaleyo ndlela anikele ngenani elikhulu lesisindo esiphelele futhi asebenze njengezinto ezimnyama "ezibandayo".
3. Ama-neutrino angenamafutha
Ngokungafani nama-neutrino avamile, asebenzisana kancane, ama-neutrino angenamagciwane kunzima nakakhulu ukuwabona. Uma ekhona, angasebenza njengezinto ezimnyama "ezifudumele", athonye ukwakheka kwesakhiwo esikalini esithile.
4. Izinto ze-MACHO nezincane
Kuye kwacatshangelwa abantu abafaka izicelo ezifana namaplanethi aqinile, izinkanyezi ezibuthakathaka, noma ezinye izinto ezincane (ama-MACHO), kodwa ucwaningo lwe-microlensing lubonisa ukuthi aziningi ngokwanele ukuchaza izinto ezimnyama. Kukhona nomqondo wemigodi emnyama yokuqala (eyakhiwe endaweni yonke yasendulo), kodwa ukulinganiselwa kokubuka kwenza kube nzima ukuba yiyo yodwa incazelo yazo zonke izinto ezimnyama.
Okunye: Ukuguqulwa Kwamandla Adonsela Phansi (MOND kanye Nabangane)
Esikhundleni sokwengeza “into engabonakali,” abanye ososayensi baye basikisela ukuthi ukuqonda kwethu amandla adonsela phansi esikalini se-galactic kunephutha. Imibono efana ne-MOND (Modified Newtonian Dynamics) iguqula imithetho kaNewton yokusheshisa okuncane kakhulu, okuvumela ukuthi ama-rotation curve achazwe ngaphandle kwento emnyama.
Kodwa-ke, inselele enkulu yemibono yamandla adonsela phansi eguquliwe ukuchaza bonke ubufakazi ngesikhathi esisodwa—ikakhulukazi izenzakalo ezifana ne-Bullet Cluster kanye nokuvumelana kwe-CMB. Kube nentuthuko ye-MOND ehlobene (isb., i-TeVeS), kodwa kuze kube manje, amamodeli e-dark matter abe “aphelele” kakhulu ekufakeni idatha ehlukahlukene.
Amandla Amnyama: Ayini Futhi Kungani Kucatshangwa Ukuthi Akhona?
Amandla amnyama aphakanyisiwe ukuchaza ukwanda okusheshayo kwendawo yonke. Ngaphakathi kohlaka lokuhlobana okuvamile, lokhu kusheshisa kungabangelwa yisakhi samandla esinengcindezi engemihle. Kalula nje, lapho amandla amnyama eba maningi, isikhala sikhula ngokushesha esikalini sendawo yonke.
Ubufakazi obuyinhloko bamandla amnyama buhlanganisa:
– I-supernovae yohlobo lwe-Ia isebenza “njengamakhandlela ajwayelekile” okukala amabanga omkhathi. I-supernovae ekude ibonakala ifiphele kunalokho obekulindelwe uma ukwanda kuhamba kancane.
– I-CMB kanye ne-baryon acoustic oscillations (BAO) zinikeza “umbusi we-cosmic” wokulandelela umlando wokwanda.
– Ukusatshalaliswa kwezakhiwo ezinkulu ezithintekayo ngamazinga okwanda.
Ithiyori Yamandla Amnyama: Kusukela Ku-Cosmological Constant kuya ku-Quintessence
1. I-Cosmological Constant (Λ)
Incazelo elula kakhulu yi-cosmological constant ka-Einstein: amandla angenalutho ahlala eqinile ngokuhamba kwesikhathi. Imodeli ejwayelekile ye-cosmology yanamuhla ivame ukubhalwa ngokuthi i-ΛCDM, lapho i-Λ ingamandla amnyama kanti i-CDM “into emnyama ebandayo.” Le modeli iphumelela ngokumangalisayo ekuchazeni idatha eningi.
Inkinga: lapho izazi zefiziksi zizama ukubala amandla e-vacuum kusuka ku-quantum theory, imiphumela iba mikhulu kakhulu kunalokho okubonwayo—umehluko ungaba mubi kakhulu. Lokhu kwaziwa ngokuthi inkinga eqhubekayo ye-cosmological.
2. I-Quintessence
Kulo modeli, amandla amnyama awawona ahlala njalo, kodwa avela ensimini ye-scalar enamandla eshintsha ngokuhamba kwesikhathi. Lokhu kuvumela ukuthi ubuningi bamandla amnyama buguquke, okungase (ngokombono) kunciphise "ukungajwayelekile" kwe-cosmological constant. Kodwa-ke, lo modeli kumele uhunyushwe ngokucophelela ukuze kugwenywe ukuphikisana nedatha yokubuka ekhombisa ukuziphatha kwamandla amnyama eduze ne-constant.
3. Amandla Amnyama “ePhantom” kanye Nobudlelwano Obushintshiwe
Kunamamodeli avumela ipharamitha yesimo samandla amnyama (w) ukuthi ibe ncane kune--1 (“phantom”), okungenzeka iholele ezimweni ezimbi kakhulu njenge-Big Rip. Kukhona nezindlela eziguqula inkolelo-mbono yamandla adonsela phansi ezikalini ezinkulu (isb., amandla adonsela phansi f(R)) ukuze ukusheshisa kuvele ngaphandle kwengxenye ehlukile yamandla amnyama.
Izinselele kanye Neziqondiso Zocwaningo Lwesikhathi Esizayo
Nakuba i-ΛCDM isibe yimodeli "ejwayelekile" ye-cosmology, imibuzo eminingi eyisisekelo isavulekile:
– Iyini i-dark matter particles? Kungani zingakatholakali elabhorethri?
– Ingabe amandla amnyama ayinto engaguquki ngempela? Noma ayashintsha ngokuhamba kwesikhathi?
– Ukucindezeleka kwe-Hubble: izilinganiso zesilinganiso sokukhula samanje sendawo yonke (H0) ezivela ku-CMB kanye nezilinganiso zendawo ngezinye izikhathi azifani kahle, okuphakamisa amathuba e-physics entsha.
Amaphrojekthi ahlukahlukene okubuka nokuhlola ayaqhubeka ukuze kuxazululwe lokhu: izinhlolovo ze-galaxy enkulu, izilinganiso ze-gravitational lens ezinembile kakhudlwana, izizukulwane ezintsha zezinhlayiya, kanye nokumapha okuningiliziwe kwama-BAO. Intuthuko yokubala nayo isiza ekulingiseni ukwakheka kwesakhiwo se-cosmic, ukuhlukanisa phakathi kwezimo ze-dark matter kanye nezinye izindlela.
I-Penutup
Izinto ezimnyama kanye namandla amnyama kuyimibono emibili ebalulekile ebumba ukuqonda kwethu kwanamuhla kwendawo yonke. Izinto ezimnyama "zibonakala" ngokuyinhloko ngethonya lazo lamandla adonsela phansi emithalazweni nasemaqenjini emithala, kuyilapho amandla amnyama avela esidingweni sokuchaza ukwanda okusheshayo kwendawo yonke. Nakuba kungekho noyedwa oqondakala ngokugcwele, imodeli ye-ΛCDM, ehlanganisa lokhu okubili, iphumelele kakhulu ekufaneni nokubonwa okuningi.
Kodwa le mpumelelo ayisona isiphetho sendaba. Eqinisweni, "ubumnyama" obumboza ingxenye enkulu yendawo yonke bubonisa ukuthi kusenezingqimba zefiziksi eziyisisekelo ezingakatholakali. Njengoba ubuchwepheshe bokubuka bucija futhi izivivinyo zezinhlayiya ziba bucayi kakhulu, sisondela ekuphenduleni imibuzo emikhulu: ingabe into emnyama iyinhlayiya entsha, ingabe amandla amnyama ayimpahla yendawo engenalutho, noma ingabe sidinga ukubuyekeza ukuqonda kwethu amandla adonsela phansi ngokwawo.
