Ayini Amagagasi Adonsela Phansi Nokutholakala Kwawo
Amagagasi adonsela phansi angenye yezinto ezitholwe ngendlela emangalisayo kakhulu kwifiziksi yanamuhla ngoba anikeza abantu "indlela entsha" yokubuka indawo yonke. Ngenkathi izinkanyezi bezilokhu zithembele ekukhanyeni—kusukela ekukhanyeni okubonakalayo, umsakazo, i-infrared, kuya kuma-X-ray—amagagasi adonsela phansi asivumela ukuzwa "ukudlidliza" kwesikhala nesikhathi ngokwaso. Lesi simo asiyona nje inkolelo-mbono; amagagasi adonsela phansi atholakale ngokuqondile, evula isahluko esisha ocwaningweni lwendawo yonke, ikakhulukazi mayelana nezinto eziyingozi njengemigodi emnyama nezinkanyezi ze-neutron.
Ayini amagagasi adonsela phansi?
Kalula nje, amagagasi adonsela phansi angama-ripples noma "amagagasi" asakazeka ngesikhala-sikhathi ngenxa yokusheshisa kwesisindo esikhulu kakhulu. Umqondo wesikhala-sikhathi uvela ku- Albert Einstein's General Theory of Relativity (1915), ebheka amandla adonsela phansi hhayi njengamandla akhangayo, njengase-Newtonian physics, kodwa njengokugoba kwesikhala nesikhathi ngenxa yokuba khona kwesisindo namandla. Lapho inqwaba enkulu ihamba ngezindlela ezithile—isibonelo, imigodi emibili emnyama ijikelezana—ukugoba kwesikhala-sikhathi kuyashintsha ngokuguquguqukayo futhi kukhiphe ukuphazamiseka okusakazeka kuzo zonke izinhlangothi. Lokhu kuphazamiseka kubizwa ngokuthi amagagasi adonsela phansi.
Amagagasi adonsela phansi ahamba ngesivinini sokukhanya. Kodwa-ke, umphumela wawo ezintweni adlula kuzo mncane kakhulu. Cabanga ngamaphuzu amabili aqhelelene ngekhilomitha elilodwa: igagasi elidonsela phansi elidlulayo lingashintsha lelo banga ngaphansi kobubanzi beprotoni. Ngakho-ke, yize lo mbono ubukhona kusukela ekuqaleni kwekhulu lama-20, kwadingeka ubuchwepheshe obuyinkimbinkimbi kakhulu ukuze bufakazelwe.
Imithombo yamagagasi adonsela phansi endaweni yonke
Akuzona zonke izinyakazo ezinkulu ezikhiqiza amagagasi adonsela phansi alinganisekayo. Imicimbi yansuku zonke njengemoto ehambayo noma umuntu ogijimayo ikhipha amagagasi adonsela phansi ngobuchwepheshe, kodwa ubukhulu bawo buncane kakhulu ukuthi bungabonakali. Amagagasi adonsela phansi abonakalayo ngokuvamile avela ezenzakalweni zasemkhathini ezihilela izixuku ezinkulu, ukusheshisa okukhulu, kanye nokunyakaza okungalingani.
Eminye yemithombo eyinhloko yamagagasi adonsela phansi ihlanganisa:
1. Ukuhlanganiswa kwembobo emnyama
Izimbobo ezimbili ezimnyama ezizungezayo zizolahlekelwa amandla ngamagagasi adonsela phansi, izindlela zazo zizoncipha, futhi ekugcineni zizoshayisana futhi zihlangane. Lesi senzakalo sizokhiqiza isignali enamandla yamagagasi adonsela phansi.
2. Ukuhlanganiswa kwezinkanyezi ze-neutron
Inkanyezi ye-neutron iyisihluthulelo esiqinile, esisele senkanyezi enkulu. Lapho izinkanyezi ezimbili ze-neutron zihlangana, ngaphezu kokukhiqiza amagagasi adonsela phansi, lesi senzakalo singakhipha nokukhanya kuma-wavelength ahlukahlukene futhi sikhiqize izinto ezisindayo njengegolide.
3. Ama-supernovae kanye nokuqhuma okukhulu kwezinkanyezi
Ukuwa kwenhliziyo yenkanyezi ngezinye izikhathi akulingani futhi kungakhipha amagagasi adonsela phansi, yize ukuwathola kuyinselele enkulu.
4. Ukujikeleza okungaphelele kwezinkanyezi ze-neutron
Uma inkanyezi ye-neutron ijikeleza “ngokuqhuma” okuncane noma ngokungajwayelekile, ingakhipha amagagasi adonsela phansi ngokuqhubekayo.
5. Amagagasi adonsela phansi ayinhloko
Kukhona umbono wokuthi indawo yonke Izigaba zokuqala zakhiqiza amagagasi adonsela phansi “aqandisiwe” angena ngemuva kwendawo yonke. Uma kutholakala, lokhu kunganikeza izinkomba mayelana nemizuzwana yokuqala ngemva kwalokho Big Bang.
Kusukela embonweni ka-Einstein kuya ebufakazini bokuqala
U-Einstein wabikezela amaza adonsela phansi ngo-1916 (futhi wawalungisa ngo-1918) ngokusekelwe ezilinganisweni ze-General Relativity. Kodwa amashumi eminyaka, ososayensi bebephikisana ngokuthi amaza adonsela phansi angokoqobo noma ayizinto zobuciko zezibalo nje. Ubunzima buvela eqinisweni lokuthi isikhathi sendawo siyashintshashintsha; ukuqonda ukuthi yini "elinganiswayo" ngempela akulula ngaso sonke isikhathi.
Ushintsho olubalulekile lwenzeka maphakathi nekhulu lama-20 lapho inkolelo-mbono yokuhlobana kwezinto ithuthuka futhi izazi zefiziksi zaqala ukuqonda ukuthi amagagasi adonsela phansi aphethe amandla angempela. Uma uhlelo lulahlekelwa amandla ngokukhipha amagagasi adonsela phansi, khona-ke ukujikeleza noma ukunyakaza kwalo kufanele kushintshe ngendlela elinganisekayo.
Ubufakazi obungaqondile: Ama-pulsars e-Hulse–Taylor binary
Ngo-1974, izazi zezinkanyezi ezimbili—uRussell Hulse noJoseph Taylor—bathola uhlelo lwe-binary pulsar olubizwa nge-PSR B1913+16. Ama-pulsar ayizinkanyezi ze-neutron ezikhipha izimpawu zomsakazo ezivamile njenge-“lighthouses.” Ohlelweni lwe-binary, i-pulsar ijikeleza enye inkanyezi ye-neutron. Ngokumangazayo, isikhathi sokuzungeza salolu hlelo siyancipha kancane kancane: lezi zinto ezimbili ziyasondelana.
Lokhu kwehla kuvumelana kahle nezibikezelo ze-General Relativity mayelana nokulahlekelwa amandla ngamagagasi adonsela phansi. Lokhu kunikeza ubufakazi obuqinile obungaqondile bokuthi amagagasi adonsela phansi akhona. Ngenxa yalokhu kutholwa, uHulse noTaylor bathola uMklomelo weNobel kuFiziksi ka-1993.
Ukutholwa okuqondile: Ukushayisana kwe-LIGO kanye "nokuzwa" kwembobo emnyama
Naphezu kobufakazi obungaqondile obunamandla, ososayensi basaqhubeka nokufuna ukuthola ngqo: ukubamba amagagasi adonsela phansi njengoba edlula eMhlabeni. Lo mzamo ubhekene nezinselele ezinkulu ngoba ubukhulu bamagagasi buncane kakhulu. Isixazululo ukusebenzisa i-laser interferometer, ithuluzi elingalinganisa izinguquko ezincane kakhulu ebangeni.
Isebenza kanjani i-LIGO?
I-LIGO (i-Laser Interferometer Gravitational-Wave Observatory) iphrojekthi enkulu e-United States enezikhungo ezimbili eziyinhloko: eyodwa eHanford, eWashington, kanye nenye eLivingston, eLouisiana. Ngayinye inengalo ye-interferometer engamakhilomitha amane ubude. Ugongolo lwe-laser luhlukaniswe lwaba yimishayo emibili ehamba emuva naphambili eceleni kwezingalo, bese ihlangana kabusha. Lapho igagasi elidonsela phansi lidlula, lishintsha ubude obusebenzayo bezingalo kancane kakhulu, likhiqize iphethini yokuphazamiseka elinganisekayo, eshintshiwe.
Ukuba nezitholi ezimbili ezindaweni ezahlukene kubalulekile ukuqinisekisa ukuthi isignali ebonwayo ayibangelwa ukuphazamiseka kwendawo (njengokuzamazama komhlaba okuncane, ukudlidliza kwezimoto, noma ezinye izici zemvelo). Uma zombili lezi zitholi zibona iphethini ehambisanayo ngokuhamba kwesikhathi okufanelekile, isignali cishe iyona igagasi elidonsela phansi elivela emkhathini.
Ukutholwa kokuqala: GW150914
NgoSepthemba 14, 2015, i-LIGO yathola isignali kamuva eyabizwa ngokuthi i-GW150914. Lesi signali saqala ekuhlanganisweni kwemigodi emibili emnyama enobukhulu obuphindwe kayishumi kunobukhulu beLanga, okwenzeka eminyakeni engaphezu kwezigidigidi zokukhanya ukusuka eMhlabeni. Lesi senzakalo saveza "ukutshiyoza": ukwanda okusheshayo kwemvamisa kanye nobukhulu obufinyelele esicongweni njengoba imigodi emibili emnyama ihlangana, bese yehla.
Isimemezelo esisemthethweni senziwa ngoFebhuwari 2016 futhi ngokushesha sabizwa ngokuthi yingqophamlando. Lokhu kutholakala akufakazelanga nje kuphela amagagasi adonsela phansi, kodwa futhi kwaba ukutholwa kokuqala okuqondile kwesistimu yemigodi emnyama enama-binary.
Ngenxa yeminikelo yabo emikhulu ku-LIGO, uRainer Weiss, uBarry C. Barish, noKip S. Thorne banikezwe uMklomelo KaNobel weFiziksi ka-2017.
Kungani ukutholakala kwamagagasi adonsela phansi kubalulekile?
Ukutholakala kwamagagasi adonsela phansi kuvame ukubizwa ngokuthi ukuqala kwenkathi yesayensi yezinkanyezi yamagagasi adonsela phansi. Kunezizathu eziningana zokuthi kungani lokhu kuyinguquko:
1. Ukuvula “izinzwa” ezintsha ukuze kubonwe indawo yonke
Izinto eziningi zasemkhathini, njengemigodi emnyama, azikhiphi ukukhanya okubonakala kalula. Amagagasi adonsela phansi asivumela ukuthi sifunde lezi zinto ngqo ngemiphumela yazo ngesikhathi sesikhala.
2. Ukuhlola ubudlelwano obujwayelekile ngaphansi kwezimo ezimbi kakhulu
Ukuhlangana kwemigodi emnyama kuhilela amandla adonsela phansi anamandla kakhulu kanye nesivinini esikhulu kakhulu. Kuyilabhorethri yemvelo yokuhlola imibono ka-Einstein ezimweni ezimbi kakhulu okunzima ukuziphinda eMhlabeni.
3. Qonda imvelaphi yezinto ezisindayo
Ukuhlangana kwezinkanyezi ze-neutron kuye kwabonakala kuhlotshaniswa nokwakheka kwezinto ezisindayo ngenqubo ye-r (ukubanjwa kwe-neutron okusheshayo). Lokhu kusiza ukuphendula umbuzo: aqhamukaphi ama-neutron? imvelaphi yegolide neplatinum endaweni yonke?
4. Ukudweba imephu yenani lemigodi emnyama nezinkanyezi ze-neutron
Ngokuthola okuningi, ososayensi bangalinganisa ukusatshalaliswa kwesisindo, amazinga okuhlangana, kanye nomlando wokwakheka kwalezi zinto ezincane.
I-Penutup
Amagagasi adonsela phansi ayizikhukhula zesikhathi sendawo ezabikezelwa ngu-Einstein eminyakeni engaphezu kwekhulu edlule futhi ekugcineni zaqinisekiswa ngobufakazi obungaqondile kuma-pulsar amabili kanye nokutholwa okuqondile yi-LIGO ngo-2015. Lokhu kutholakala akuyona nje impumelelo yobuchwepheshe, kodwa ushintsho endleleni abantu ababheka ngayo indawo yonke: manje sesingakwazi "ukulalela" indawo yonke, hhayi ukuyibuka nje kuphela. Njengoba ochwepheshe abasha kanye nokusebenzisana komhlaba wonke (njenge-Virgo eYurophu, i-KAGRA eJapane, kanye ne-LISA ehleliwe emkhathini) ithuthuka, ikusasa lezinkanyezi zamagagasi adonsela phansi kulindeleke ukuthi licebe nakakhulu, lisisondeze ezimpendulweni zezimfihlakalo ezinkulu kakhulu zendawo yonke.
