Ibhande Le-Asteroid Esimisweni Selanga
Ibhande le-asteroid lingenye yezakhiwo ezithakazelisa kakhulu ohlelweni lwelanga, ligcina "amabhlogo okwakha" asele ekwakhekeni kwamaplanethi. Uma sicabanga ngebhande le-asteroid, sivame ukucabanga ngesifunda esiminyene nesiyingozi sedwala, esihlanganiswe ndawonye, njengento ethile ephuma kwifilimu yesayensi. Eqinisweni, ibhande le-asteroid livulekile kakhulu kunalokho okucatshangwayo: ibanga eliphakathi kwama-asteroid likhulu, okwenza ithuba lokushayisana okuqondile libe lincane kakhulu. Noma kunjalo, lesi sifunda sisabalulekile kwisayensi, sisebenza njengenqolobane yemvelo esisiza siqonde ukuthi uhlelo lwelanga lwakhiwa futhi lwavela kanjani.
Iyini ibhande le-asteroid?
Ibhande le-asteroid liyisifunda esimisweni sonozungezilanga esigcwele izinto ezincane, ezinamatshe, nezensimbi ezizungeza iLanga, ezitholakala phakathi kwemizila ye-Mars ne-Jupiter. Lezi zinto zibizwa ngokuthi ama-asteroids noma amaplanethi amancane. Ubukhulu bazo busukela kumamitha ambalwa kuya kumakhulu amakhilomitha. Ngokuvamile, ibhande eliyinhloko le-asteroid linwebeka ebangeni elingamayunithi ezinkanyezi angaba ngu-2,1 kuya ku-3,3 (AU) ukusuka eLangeni (1 AU ilingana nebanga elijwayelekile phakathi koMhlaba neLanga elingamakhilomitha ayizigidi ezingu-150).
Leli bhande liqukethe izigidi zama-asteroid, kodwa isisindo sawo sonke sincane kakhulu kuneseplanethi. Isisindo esihlangene sebhande lonke lama-asteroid singamaphesenti ambalwa kuphela esisindo seNyanga. Lokhu kubonisa ukuthi, naphezu kwenani lawo elikhulu, ama-asteroid ngamanye ngokuvamile mancane futhi ahlakazekile.
Umsuka webhande le-asteroid
Umbuzo ojwayelekile mayelana nebhande le-asteroid uthi: kungani amaplanethi engakhekanga lapho? Ekuqaleni kwesimiso selanga, eminyakeni engaba yizigidi eziyizinkulungwane ezingu-4,6 eyedlule, igesi nothuli kudiski ye-protoplanetary kwahlangana kwaba amaplanethi, amanye awo aguquka aba amaplanethi. Esifundeni esiphakathi kweMars neJupiter, le nqubo kwakufanele ngabe yenzeka, kodwa ukudonsa kukaJupiter kwakunzima kakhulu. Ukudonsa kukaJupiter kwalesi sikhulu segesi kwadala ukuphazamiseka kwe-orbital kanye nokuzwana okwakhulisa izinga lokushayisana phakathi kwamaplanethi. Ngenxa yalokho, esikhundleni sokuhlangana nokukhula, izinto eziningi zabhujiswa futhi zaqhekeka, okwaholela enanini lama-asteroid esilibonayo namuhla.
Ngamanye amazwi, ibhande le-asteroid lingabhekwa “njengendawo yokuthuthukiswa ephazamisekile.” Kukhona izakhi zokwakha amaplanethi, kodwa indawo eguquguqukayo ayizinzile ekukhuleni okuqhubekayo kwamaplanethi amakhulu.
Isakhiwo kanye nokuguquguquka: hhayi nje "iqoqo lamatshe"
Ibhande le-asteroid aliyona indawo efanayo. Ezinye izingxenye "zingenalutho" kanti ezinye "ziminyene" ngenxa yethonya lomsindo wamandla adonsela phansi kaJupiter. Esinye isici esaziwayo yizikhala zeKirkwood, eziyizikhala phakathi kwamaqembu ama-asteroid asemabangeni athile ukusuka eLangeni. Lezi zikhala zivela ekuphendukeni kwe-orbital: isibonelo, ezindaweni ezithile, ama-asteroid azojikeleza iLanga ngezikhathi ezilula kunesikhathi sikaJupiter (njenge-3:1, 5:2, njalo njalo). Lezi zindawo zenza ukujikeleza kwama-asteroid kungazinzile ngokuhamba kwesikhathi, okubangela ukuba asuswe kulezo zindawo.
Ngaphezu kwalokho, kunemindeni yama-asteroid, amaqembu ama-asteroid anemingcele efanayo yokuzungeza futhi okucatshangwa ukuthi avela emzimbeni womzali oyedwa owahlukana ngenxa yomthelela omkhulu. Ngokutadisha le mindeni, ososayensi bangalandelela umlando wokushayisana kwebhande lama-asteroid futhi balinganisele ubudala bezehlakalo zokuqhekeka.
Izakhamuzi ezinkulu kunazo zonke: iCeres, iVesta, iPallas, neHygiea
Ezinye izinto ezisebhandeni le-asteroid zikhulu kakhulu futhi zivelele. Edume kakhulu yiCeres, ebhekwa njengeplanethi encane. ICeres inobubanzi obungaba ngu-940 km futhi ikhombisa ubufakazi beqhwa lamanzi kanye nezinqubo ze-geological ezingaba khona esikhathini esidlule. ICeres iyathakazelisa ngoba ihlanganisa igebe phakathi kwezwe elinamatshe nelibandayo: ayi "yomile" njengamanye ama-asteroid, kodwa futhi ayi "yiqhwa ngokuphelele njengama-satellite angaphandle eplanethi.
Ngaphandle kweCeres, kukhona iVesta nePallas, ama-asteroid amabili amakhulu asebonwe isikhathi eside. IVesta ibaluleke kakhulu ngoba ibonisa umehluko wangaphakathi—njengomhlaba omncane—futhi kucatshangwa ukuthi ingumthombo wama-meteorite athile atholakala eMhlabeni. Umsebenzi wasemkhathini we-NASA we-Dawn wajikeleza iVesta neCeres, udweba izindawo zazo futhi unikeza idatha eningiliziwe ngokwakheka kwazo nomlando wazo.
Ukwakheka kwe-asteroid: kucebile ngezinhlobonhlobo, kucebile ngolwazi
Akuwona wonke ama-asteroid afanayo. Ngokusekelwe ku-spectrum yawo yokukhanya kanye nezakhiwo ezibonisa ukukhanya (i-albedo), ama-asteroid ngokuvamile ahlukaniswa ngezinhlobo eziningana eziyinhloko:
1. Uhlobo C (olune-carbonaceous): olucebile nge-carbon, olunombala omnyama, futhi oluvame kakhulu ebhandeni. Eziningi kucatshangwa ukuthi ziqukethe izinto zakudala ezivela ohlelweni lwelanga lwakuqala.
2. Uhlobo S (i-silicaceous): lukhanya kakhulu, lucebile ngamaminerali e-silicate kanye ne-nickel-iron.
3. Uhlobo M (lwensimbi): olubuswa yinsimbi, ikakhulukazi insimbi kanye ne-nickel, okucatshangwa ukuthi yizinsalela zenhliziyo yento eyahlukaniswa yabe isibhujiswa.
Lokhu kuhlukahluka kwezakhiwo kusikisela ukuthi ibhande le-asteroid “liyimyuziyamu” yendawo yonke. Amanye ama-asteroid ahlala engashintshi kusukela ekuqaleni kwesimiso sonozungezilanga, kanti amanye abhekane nokushisa okukhulu, ukuhlukahluka, kanye nokushayisana.
Ubudlelwano phakathi kwama-meteorite nokuphila eMhlabeni
Amanye ama-meteorite awela eMhlabeni avela ebhandeni le-asteroid. Ukushayisana ebhandeni kungaveza izingcezu ezincane, ezibe sezicindezelwa yizinto ezidonsela phansi kanye nemisebe (njengomphumela we-Yarkovsky), zishintsha imijikelezo yazo, kanye nezinye izindlela ezingenayo ezihlangana nomjikelezo woMhlaba. Ngokutadisha ama-meteorite elabhorethri, ososayensi bangafunda ukwakheka kwamakhemikhali kanye nobudala bezinto zesistimu yelanga ngaphandle kokuthumela njalo imisebenzi kuma-asteroid.
Ngaphezu kwalokho, kuye kwacatshangwa ukuthi izinto eziguquguqukayo ezifana namanzi nama-molecule ezinto eziphilayo kungenzeka ukuthi zilethwe kancane eMhlabeni omncane ngemithelela evela ezithweni ezincane, kufaka phakathi ama-asteroid athile acebile ngamanzi. Nakuba ama-comet nawo adlale indima ebalulekile, ama-asteroid ohlobo lwe-C avame ukucashunwa njengabathwali bezinto ezingaba negalelo ekwakhiweni kwezindawo okuhlalwa kuzo.
Usongo lwe-asteroid: luyingozi kangakanani?
Ibhande le-asteroid livame ukuhlotshaniswa nosongo lokushayisana noMhlaba. Kubalulekile ukuhlukanisa: iningi lama-asteroid lihlala ngaphakathi kwebhande futhi alisondeli eMhlabeni. Okukhathaza kakhulu yizinto eziseduze noMhlaba (ama-NEO), ama-asteroid noma ama-comet anemizila esondela koMhlaba. Amanye ama-NEO avela ebhandeni le-asteroid, njengoba ephushelwe ngaphandle yi-resonance yeJupiter noma okunye ukusebenzisana kwamandla adonsela phansi.
Imizamo yanamuhla yokuqapha isibhakabhaka ithole ama-NEO amaningi futhi ibale amathuba omthelela. Izindaba ezinhle ukuthi izinto eziningi ezinkulu ezingadala inhlekelele yomhlaba wonke zitholakale futhi zalandelwa. Kodwa-ke, inselele isalokhu yokuthola izinto ezinobukhulu obungamashumi kuya kwamakhulu amamitha—okwanele ukubangela umonakalo wesifunda—ikakhulukazi uma zivela eziqondisweni okunzima ukuzibona, njengaseduze neLanga.
Ngakho-ke, ucwaningo lokuvikela amaplanethi luthuthuka ngokushesha, okuhlanganisa nobuchwepheshe bokuphambuka kwe-trajectory njengoba kuvivinywe emsebenzini we-DART (NASA), owashintsha ngempumelelo umjikelezo we-asteroid encane ngokusebenzisa imiphumela ye-kinetic.
Ibhande le-asteroid kanye nekusasa lokuhlola
Ngaphandle kokubaluleka kwayo kwesayensi nokuphepha, ibhande le-asteroid liphinde libe nesithakazelo esikhathini esizayo sokuhlola isikhala kanye nezomnotho. Amanye ama-asteroid aqukethe izinsimbi eziyigugu nezinto ezingasetshenziswa, njengensimbi, i-nickel, futhi mhlawumbe namanzi ngesimo seqhwa. Amanzi abaluleke kakhulu esikhaleni ngoba angahlukaniswa abe yi-hydrogen kanye ne-oxygen ukuze kube uphethiloli werokhethi noma asetshenziselwe ukusekela impilo.
Nakuba umqondo wokumba ama-asteroid usabhekene nezinselele zomthetho zobuchwepheshe, izindleko, kanye nezamazwe ngamazwe, ucwaningo ngezinsizakusebenza zama-asteroid luyaqhubeka. Ngesikhathi esifanayo, imisebenzi efana ne-OSIRIS-REx kanye ne-Hayabusa iletha amasampula e-asteroid eMhlabeni, okuletha inkathi entsha "ye-space geology" esekelwe kumasampula omhlaba wangempela.
I-Penutup
Ibhande le-asteroid liyisifunda esibalulekile ohlelweni lwelanga esiphethe izinkomba zesikhathi esidlule: indlela amaplanethi akheka ngayo, indlela izinto ezidalwe ngayo, nokuthi ukushayisana kwayibumba kanjani indawo esiyibonayo namuhla. Phakathi kweMars neJupiter, izigidi zezidumbu ezincane ziyajikeleza, izinsalela zezinqubo zasemkhathini ezingazange ziqede ukwakha iplanethi. Kusukela kuplanethi encane iCeres, umndeni wama-asteroid azalwa ngokushayisana kwasendulo, kuya kuma-meteorite awele eMhlabeni futhi aba yizinto zokufunda, ibhande le-asteroid lixhumanisa umlando wesimiso selanga nokuphila kwanamuhla eplanethini yethu. Ngokuhlolwa okwandayo, ibhande le-asteroid aliyona nje into yokuthakazelisa, kodwa futhi liyindawo yokucwaninga yemvelo futhi mhlawumbe ngolunye usuku liyisisetshenziswa sempucuko yabantu ngale koMhlaba.
