Astronomija

Je li moguće da su neke zvijezde već crne rupe, ali mi vidimo svjetlost koja se emitira prije nego što postane crna rupa?

Je li moguće da su neke zvijezde već crne rupe, ali mi vidimo svjetlost koja se emitira prije nego što postane crna rupa?

Za zvijezde koje vidimo da gori gorivo velikom brzinom, koje su vrlo sjajne (ili bilo koja zvijezda po tom pitanju dovoljno daleko od nas) može li biti da su to već crne rupe (dovoljno velike), a mi smo samo vidjeti svjetlost emitiranu tijekom glavne faze? Pa, ako je, je li sigurno reći da je većina zvijezda već mrtva koju vidimo?

Edit: Cijenim sve odgovore. Ovo je fascinantno štivo. Također mrzim što moram odabrati "odgovor" kad bih od svih dokučio nešto.


Ovisi što mislite pod pojmom "vidjeti". Pretpostavljam da mislite golim okom. Napravimo grube izračune kako bismo procijenili izglede.

Najdalja jedina zvijezda vidljiva golim okom je Deneb, procijenjena udaljenost oko 1550 svjetlosnih godina. Većina zvijezda vidljivih golim okom mnogo je bliža. Budući da čak i ona vrsta zvijezde koja stvara crnu rupu živi nekoliko milijuna godina, očekivali bismo da je možda čak jedna dovoljno velika zvijezda od tisuću stvorila crnu rupu za vrijeme dok je njihova svjetlost bila na putu do nas.

Postoji oko 5000 zvijezda vidljivih golim okom pod dobrim uvjetima, ali tek stotinjak dovoljno masivnih da formiraju crne rupe. Dakle, na temelju toga, šanse su da postoji najviše jedna takva zvijezda, a vjerojatno niti jedna.

Da biste to procijenili na drugi način, uzmite u obzir da u galaksiji u stoljeću postoji prosječno jedna supernova. Uspoređujući udaljenost do najudaljenije vidljive zvijezde s promjerom galaksije, pretpostavljam da možemo vidjeti najviše 1/2500. Mliječne staze, pa bismo trebali očekivati ​​da samo jedna vidljiva zvijezda ide u supernovu svakih 250 000 godina. Podijelivši da prema udaljenosti u svjetlosnim godinama do najudaljenijih vidljivih zvijezda, imamo samo otprilike jednu priliku na stotinu da je bilo koja od vidljivih zvijezda postala supernova za vrijeme dok je njihovo svjetlo bilo na putu do nas.

Jedno je upozorenje da sam te podatke dobio iz različitih izvora, na temelju Googleovih pretraživanja. Međutim, čini se jasnim da izgledi nisu dobri. Nadamo se da će netko od stručnjaka pružiti bolje podatke.


Ne, mislim da većini zvijezda dovoljno velikih da mogu stvoriti crne rupe treba nekoliko milijuna godina da to učine od rođenja do smrti. Budući da zvijezde u Mliječnom putu možemo vidjeti samo do nekoliko desetaka tisuća svjetlosnih godina, samo oko 1% njih trebalo bi se srušiti u crnu rupu otkad su emitirali svjetlost koju sada ovdje vidimo.

Ali mnoge iste divovske zvijezde promatrane u galaksiji Andromeda, koja je udaljena 2+ milijuna svjetlosnih godina, mogle bi se pretvoriti u crne rupe "danas". Budući da je njihovo lagano vrijeme putovanja usporedivo s njihovim životnim vijekom. Kad bi netko mogao promatrati tako mlade divovske zvijezde udaljene više od 0,1 milijarde svjetlosnih godina, mogao bi s pouzdanjem reći da su se SVE pretvorile u crne rupe sada dok svjetlost njihovog prošlog zvjezdanog života dolazi do nas.


Sigurno je reći da je pristojan broj zvijezda koje danas vidimo mrtve. Prostor je beskonačan pa je sigurna pretpostavka da postoje zvijezde udaljene preko milijardu svjetlosnih godina koje nisu živjele milijardu godina. Stoga će umrijeti prije nego što njihovo svjetlo dospije na Zemlju. Uz to, što je veća masa zvijezde, brže sagorijeva gorivo, pa je vjerojatnost da će zvijezde koje postanu crne rupe još uvijek živa. Nemam konkretne primjere zvijezda koje će vjerojatno postati crne rupe u "budućnosti", ali je vrlo vjerojatno. Budućnost stavljam u navodnike jer se to dogodilo prije 500 milijuna godina, ali zvijezda je udaljena 501 milijun svjetlosnih godina, tako da činjenica da se urušava u crnu rupu neće doći do nas još milijun godina. Teško je konceptualno objasniti.

Kao primjer: Zvijezda A udaljena je 400 milijuna svjetlosnih godina. To znači da je potrebno 400 milijuna godina da svjetlost dođe ovdje. Vidimo zvijezdu kakva je bila prije 400 milijuna godina. Da se zvijezda A službeno "stvorila" (započela fuziju u svojoj jezgri) prije 350 milijuna godina i srušila u crnu rupu prije 10 milijuna godina, još ne bismo uopće vidjeli svjetlost zvijezde, ali to bi već bila crna rupa. Za 50 milijuna godina vidjeli bismo kako zvijezda počinje nastajati, a za 390 milijuna godina vidjeli bismo kako se zvijezda urušila u crnu rupu.


Nisu sve zvijezde koje umru postale crne rupe. Samo oni stvarno, stvarno masivni, "divovi" koje su ih nazvali. Rijetki su. Nijedna zvijezda vidljiva golim okom sa Zemlje nije dovoljno masivna da bi mogla biti crne rupe. Znanstvenici mogu odrediti masu zvijezde pomoću Hertzsprung-Russellovog dijagrama.

Međutim, to je mogući scenarij, samo ne na Zemlji.

Moguće je jer će svjetlost koju emitira živa zvijezda putovati zauvijek dok je ne upije materija na svom putu. Dakle, zvijezda može biti mrtva eonima prije nego što svjetlost napokon upije nešto poput vanzemaljskog planeta i vanzemaljskih očiju - daleko i dugo nakon što je svjetlosna zvijezda dostigla status crne rupe. Samo što je specifično za Zemljinu situaciju da vidljive zvijezde nisu crne rupe jer njihove mase nisu dovoljno velike.


https://xkcd.com/1342/ i http://www.explainxkcd.com/wiki/index.php/1342:_Ancient_Stars

https://xkcd.com/1440/ i http://www.explainxkcd.com/wiki/index.php/1440:_Geese

može li biti da su to već crne rupe (dovoljno velike), a mi upravo vidimo svjetlost koja se emitira tijekom glavne faze?

Za neke zvijezde, da, moglo bi biti. Postoje određene zvijezde koje možemo pojedinačno promatrati i za koje vjerujemo da bi u svakom trenutku mogle više-manje postati supernova. Betelgeuse je vjerojatno najpoznatiji primjer. Udaljen je 640 svjetlosnih godina, mogao bi prijeći u supernovu tipa II u bilo kojem trenutku (očekuje se u sljedećih milijun godina, ali bi se mogao dogoditi u sljedećih 640 godina koliko ga promatramo, kao da se to već dogodilo). Kad to postane, mogla bi postati crna rupa (iako je puka neutronska zvijezda također na kartama, vjerujem i vjerojatno vjerojatnije).

Nadalje, kada promatramo daleku galaksiju sigurno je (što se tiče naših teorija) da su neke zvijezde koje doprinose svjetlu iz te galaksije u međuvremenu postale crne rupe. Međutim, s obzirom da pojedine zvijezde u tim galaksijama ne razlučujemo čak ni s našim najboljim teleskopima, mogli biste se posvađati hoćemo li zvijezde "vidjeti" ili ne.

je li sigurno reći da je većina zvijezda već mrtva što ih vidimo?

Zvijezde u našoj galaksiji, Mliječni put, br. Prekriven je tek oko 100.000 svjetlosnih godina, sadrži 100 milijardi - 1 bilijun zvijezda, od kojih pojedinačno možemo "vidjeti" samo mali udio. Većina njih je vrlo blizu, najudaljenijih oko 1500 svjetlosnih godina i većine oni uopće nisu kandidati za supernovu, a kamoli kandidati za crnu rupu. Čak i dopuštajući naše najbolje teleskope, i dalje rješavamo samo mali dio zvijezda pojedinačno.

Galaksija vjerojatno doživi otprilike jednu supernovu svakih 50-100 godina. Pa čak i ako su sve to bile vidljive zvijezde (a nisu: čak i od najvećih zvijezda u galaksiji, golim okom se može vidjeti samo mali udio), a sve supernove rezultirale su crnim rupama (što oni ne čine) t), tada bi najviše 15-30 zvijezda vidljivih golim okom već mogle biti crne rupe, a samo do 1000-2000 zvijezda u cijeloj galaksiji, bez obzira na vidljivost, nalazi se u vremenu između odlaska supernove i zemlje koja ulazi u budućnost svjetlosni konus te supernove. Ovaj krajnje labava gornja granica nikako nije "većina zvijezda koje vidimo", a zapravo su šanse da niti jedna zvijezda koju vidite kad pogledate prema noćnom nebu već nije crna rupa. Moglo bi biti da niti jedan od njih nikada neće biti.

Također je malo vjerojatno da je bilo koja zvijezda koju promatrate golim okom mrtva, budući da je njihov životni vijek otprilike 10 milijuna godina (što je najveće) do milijardi godina, a udaljenost od zemlje iznosi 1500 svjetlosnih godina ili manje. No, postoji nekoliko zvijezda, poput Betelgeuse, za koje znamo da su pri kraju svog života i da bi stoga mogle biti "već mrtve" u ovom smislu.

Koristeći teleskope možemo vidjeti neke pojedinačne zvijezde u obližnjim galaksijama, ili ih barem posredno promatrati, jer osvjetljavaju maglice koje vidimo, udaljene i do nekoliko desetaka milijuna svjetlosnih godina (mislim da su to obično plavi supergiganti ). Oni od njih koji će se pretvoriti u crnu rupu možda imaju životni vijek manji ili jednak udaljenosti od nas. Nije nužno da sve ili čak većina njih postanu crne rupe, nisam siguran što je tipično za dotične vrste zvijezda, ali za one zvijezde limenka reći da su mnoge ili većina već crne rupe. Najudaljenije pojedinačno riješene zvijezde su na ovaj ili onaj način mrtve.

Ako nam dopustite da "vidimo" svaku zvijezdu u vrlo udaljenoj galaksiji, iako niti jednu ne možemo riješiti pojedinačno prije nego što postanu supernova, tada se brojevi opet mijenjaju, ali moj instinkt je da nije tako "većina" svemira koji je vidljiv već je urušen u crne rupe. No zvijezde su možda mrtve iako nisu crne rupe. Možemo vidjeti galaksije udaljene više od 10 milijardi svjetlosnih godina, što je otprilike čitav život zvijezde poput Sunca. Da biste smislili "najviše", prvo se morate dogovoriti što se smatra zvijezdom, a zatim istražiti kakve zvijezde sadrže te galaksije. Ako na kraju zaključite da su većina zvijezda (u usporedbi sa Suncem) malene male crveno-smeđe stvari s životnim vijekom u desecima milijardi godina, tada većina zvijezda već nije mrtva bez obzira na to koliko su udaljene od galaksije u :-) S druge strane, svjetliji objekti koji doprinose većini onoga što promatramo teleskopom u najudaljenijim galaksijama, sigurno umru za daleko manje od nekoliko milijardi godina.

Imajte na umu da je u posebnoj relativnosti koncept "istodobnog" pomalo teško utvrditi. Ali slijedio sam konvenciju da, ako je nešto udaljeno X svjetlosnih godina, tada se sve što iz njega promatramo između sada i X godine od sada "već dogodilo". Nemamo nužno pravo s mjesta na kojem stojimo reći da se to "već dogodilo", jer nije u našem prošlom svijetlom konusu, ali dovoljno dobro :-)


Moguće je. Recimo da je Čovječanstvo nastalo prije 195.000 godina (najstariji pronađeni fosil humanoida) i da je vrlo masivna zvijezda bliža od 195.000 svjetlosnih godina otišla u supernovu ili čak implodirala u crnu rupu sa 195000 godina, postoji vjerojatnost da ju je neki humanoid možda vidio. Povijesno gledano, ljudi su u prošlosti dokumentirali da vide supernove i ako bi bilo koja od njih bila dovoljno masivne zvijezde, onda bi to mogla biti formacija crne rupe kojoj smo svjedočili. Međutim, na područjima opisanim opisima svjedoka ne postoje crne rupe, ali je traženje jedne moguće moguće, samo se nadamo da nije baš bliska našem sustavu. Rezultirajući GRB mogao bi vam pokvariti dan.


Lipanj 2021. Feature & # 8211 Ljeto crne rupe

Ako postoji bilo koja druga vrsta nebeskog objekta koja je sposobna generirati toliko znatiželje i čuđenja kao crna rupa, onda ne znam što bi to mogla biti. Kad god radim bilo kakvu vrstu astronomskog dosega, s bilo kojom dobnom skupinom, sigurno će se postaviti pitanje o crnim rupama (iako se i pitanja o postojanju vanzemaljaca pokazuju prilično popularnima). I mogu se povezati s entuzijazmom koji ljudi imaju prema tim zadivljujućim kreacijama Prirode. Na samo spominjanje crnih rupa, postajem sav nesvestica i vjerojatno ću vam otjerati uho o njima. U stvari, moj prijatelj je u šali predložio da se opremim znakom oko vrata koji govori nešto u sljedećem smislu:

Barem mislim da se šali. Kad bolje razmislim, on za početak nije toliko dobar prijatelj, pa koga zanima što misli, zar ne? U svakom slučaju, na ovomjesečnom blogu želim vam reći o crnim rupama, što su one, kako znamo što o njima znamo i gdje na ljetnom nebu potražiti općenita područja u kojima se nalaze dvije dobro poznate crne rupe . Očito je da se po samoj svojoj prirodi crne rupe ne mogu vidjeti izravno, ali nekako je cool kad možete ukazati na područje na nebu i reći sebi, "Da, TAMO upravo u ovom trenutku vreba crna rupa." Čimbenik hladnoće koji dolazi iz ovog mjeseca na blogu Night Sky nije iz stvarnog "viđenja", već iz "znanja".


Horizont događaja

Iako (r = 2m ) nije stvarna singularnost, tamo se događaju zanimljive stvari. Za (r & lt 2m ), znak (g_) postaje negativan, dok (g_) je pozitivan. U našem potpisu + & minus & minus & minus, ovo ima sljedeće tumačenje. Za liniju svijeta materijalne čestice, (ds ^ 2 ) trebao bi biti kvadrat čestice & rsquos odgovarajućeg vremena i uvijek mora biti pozitivan. Da čestica ima konstantnu vrijednost (r ), za (r & lt 2m ), imala bi (ds ^ 2 & lt 0 ), što je nemoguće.

Vremenski i svemirski znakovi koordinata (r ) i (t ) zamijenjeni su, pa (r ) djeluje poput vremenske koordinate.

Prema tome, za dovoljno kompaktan objekt da je (r = 2m ) vanjska strana, (r = 2m ) je horizont događaja: budući svjetlosni čunjevi prevrću se toliko daleko da ne dopuštaju da se uzročne veze povežu s prostornim vremenom izvana. U relativnosti se horizonti događaja ne javljaju samo u kontekstu njihovih svojstava crnih rupa, a neke od implikacija na crne rupe već su razmatrane u odjeljku 6.1.

Gravitacijsko vremensko širenje u Schwarzschildovom polju, u odnosu na sat u beskonačnosti, dato je kvadratnim korijenom (g_) komponenta metrike. To ide na nulu na horizontu događaja, što znači da će, na primjer, foton emitiran iz horizonta događaja biti beskrajno pomaknut kad dosegne promatrača u beskonačnosti. To ima smisla, jer se foton tada ne može otkriti, baš kao što bi bio i da je iz njega emitiran iznutra horizont događaja.


Zašto je svemir prazan

Izvanzemaljski život je vjerojatan, ali ne možemo ga vidjeti. Stoga bi mogao biti slučaj da negdje na putanji životnog razvoja postoji masovni i zajednički izazov koji okončava vanzemaljski život prije nego što postane dovoljno inteligentan i raširen da ga možemo vidjeti - sjajan filtar.

Ovaj filtar može imati različite oblike. Moglo bi biti da je krajnje malo vjerojatno imati planet u zoni Zlatokose - uski pojas oko zvijezde u kojem nije ni vruće ni prehladno da bi život postojao - a taj planet sadrži organske molekule sposobne za akumuliranje u život. Promatrali smo mnoštvo planeta u zoni Zlatokose različitih zvijezda (na Mliječnom putu procjenjuje se 40 milijardi), ali možda još uvijek nisu tamo uvjeti za život.

Veliki filtar mogao bi se dogoditi u najranijim fazama života. Kad ste bili u srednjoškolskoj biografiji, mogli biste vam izbušiti refren "mitohondriji su snaga stanice." Svakako jesam. Međutim, mitohondriji su u jednom trenutku bile zasebna bakterija koja je živjela svoje vlastito postojanje. U nekom trenutku na Zemlja, jednostanični organizam pokušao je pojesti jednu od ovih bakterija, osim što se, umjesto da se probavi, bakterija udružila sa stanicom, proizvodeći dodatnu energiju koja je omogućila stanici da se razvija na načine koji vode do viših oblika života. ovo bi moglo biti toliko malo vjerojatno da se to dogodilo samo jednom na Mliječnom putu.

Ili bi filtar mogao biti razvoj velikih mozgova, kao i mi. Napokon, živimo na planetu punom mnogih bića, a vrsta inteligencije koju su ljudi imali dogodila se samo jednom. Možda je nadasve vjerojatno da živa bića na drugim planetima jednostavno ne trebaju razvijati energetski zahtjevne neuronske strukture potrebne za inteligenciju.


Središnji dio galaksije

Koncept masivnih crnih rupa u središtima nekih galaksija potkrepljen je teorijskim istraživanjima stvaranja vrlo masivnih zvijezda. Zvijezde

KLJUČNI POJMOVI

Binarni sustav & # x2014 Bilo koji sustav dvaju zvjezdanih objekata koji se okreću jedan oko drugog pod utjecajem njihove kombinirane gravitacije.

Galaksija & # x2014 Velika zbirka zvijezda i nakupina zvijezda koja sadrži od nekoliko milijuna do nekoliko bilijuna zvijezda.

Opća relativnost & # x2014 Teorija gravitacije koju je iznio Albert Einstein 1915. godine koja u osnovi opisuje gravitaciju kao iskrivljenje prostora-vremena zbog prisutnosti materije.

Međuzvjezdani materijal & # x2014 Bilo koji materijal koji se nalazi između zvijezda. Sastoji se od materijala iz kojeg nastaju nove zvijezde.

Savršen radijator & # x2014 Poznato i kao crno tijelo (ne treba ga miješati s crnom rupom). Bilo koji objekt koji apsorbira svu energiju zračenja koja padne na njega i potom ponovno zrači tu energiju. Zračena energija može se okarakterizirati jednom ovisnom varijablom, temperaturom.

Kvantna gravitacija & # x2014 Teorija koja proizlazi iz primjene kvantnih principa na interakciju između dva objekta koja se obično pripisuju gravitaciji.

Kvantna mehanika & # x2014 Teorija koja je razvijena iz kvantnog principa Maxa Plancka & # x2019 da bi opisala fiziku vrlo malog. Kvantni princip, u osnovi, kaže da energija dolazi samo u određenim nedjeljivim količinama označenim kao kvanti. Svaka fizička interakcija u kojoj se izmjenjuje energija može razmijeniti samo integralni broj kvanta.

više od stotinu puta (i manje od oko milijun puta) masa sunca ne može nastati jer će eksplodirati iz nuklearne energije oslobođene tijekom njihovog stezanja prije nego što se zvijezda može smanjiti dovoljno da je sama gravitacija održi. Međutim, ako kolaps oblaka međuzvjezdane građe sadrži više od oko milijun puta veću masu od sunca, kolaps će se dogoditi tako brzo da nuklearni procesi pokrenuti kolapsom neće moći zaustaviti kolaps. Kolaps će se nastaviti nesputano sve dok objekt ne stvori crnu rupu.

Čini se da su takvi objekti potrebni za razumijevanje promatranog ponašanja materijala u središtu nekih galaksija. Doista je sada sigurno da crne rupe borave u središtima mnogih normalnih galaksija, uključujući Mliječni put. Dokazi potječu od gibanja oblaka plina u blizini galaktičkog središta i detekcije rafala rendgenskih zraka iz galaktičkog središta, kakvih bi obično proizvodila supermasivna crna rupa koja guta tvar.


Crne rupe

Odgovor uključuje gravitaciju i unutarnji pritisak unutar zvijezde. Te dvije stvari se međusobno suprotstavljaju - gravitacijska sila zvijezde koja djeluje na komad materije na površini zvijezde htjet će uzrokovati da ta materija padne prema unutra, ali unutarnji pritisak zvijezde, djelujući prema van, na površini, htjet će da bi stvar odletjela prema van. Kada se ove dvije uravnoteže (tj. Jednake su snage), zvijezda će zadržati svoju veličinu: niti se kolaps neće proširiti. Takav je slučaj trenutno sa Suncem, pa čak i sa Zemljom.

Međutim, kad zvijezdi ponestane nuklearnog goriva i stoga nastavi gubiti energiju s površine (emitira svjetlosnu energiju), a pritom neće nadoknaditi izgubljenu energiju nuklearnom fuzijom (nema više nuklearnog goriva), gravitacija će pobijediti unutarnju pritisak i zvijezda će se polako sužavati ili će se brzo srušiti, ovisno o detaljima unutarnje strukture i sastava. Gravitacija pobjeđuje nad unutarnjim tlakom zvijezde, jer je taj tlak proizveden normalnim, vrućim plinom, a taj plin gubi energiju dok zvijezda zrači energijom s površine.

Zvijezda tako može završiti kao crna rupa. Ovisi samo o tome hoće li se kolaps zaustaviti na nekoj manjoj veličini kad drugi izvor pritiska (osim onoga što proizvodi uobičajeni, vrući plin) postane dovoljno jak da uravnoteži unutarnju gravitacijsku silu. Postoje i drugi oblici pritiska, osim onih koje stvara vrući plin. Pritiskom ruke na ploču stola omogućit ćete vam da doživite jedan od ovih ostalih pritisaka - radni stol se gura prema vama, zaista može podnijeti vašu težinu (gravitacijsku silu)! Pritisak koji radni stol drži krutim prema vašoj težini uzrokovan je silama između atoma u radnom stolu.

Nadalje, elektroni unutar atoma moraju se međusobno izbjegavati (na primjer, ne mogu svi biti u istom atomskom & quotorbit & quot; --- to se naziva & quotthe princip isključenja & quot). Stoga, da imamo kolekciju elektrona koji se slobodno kreću, oni bi se i međusobno izbjegavali: što jače sabijate kolekciju (što je manji volumen u kojem su ograničeni) to se više pobune protiv pritiska --- pritisak se suprotstavlja vašem zatvaranju elektroni.

Ovaj & quotelectron izbjegavajući & quot; pritisak može postati dovoljno jak da se suprotstavi gravitacijskim silama unutar zvijezde otprilike mase Sunca kad je zvijezda gravitacijom stisnuta na otprilike promjer Zemlje. Tako se zvijezdi masivnoj poput Sunca može spriječiti da postane crna rupa kad se sruši na veličinu Zemlje, a unutarnji & qutelectron izbjegavanje & quot; tlak (nazvan & quotdegenerirani tlak elektrona & quot;) postane dovoljno jak da zadrži zvijezdu gore. Ova vrsta pritiska ne ovisi o energetskom sadržaju zvijezde - čak i ako zvijezda i dalje gubi energiju sa svoje površine, tlak će i dalje zadržavati zvijezdu. Naše Sunce nikada ne može postati crna rupa.

Međutim, ako je zvijezda masivnija od otprilike 3 do 5 Sunčevih masa, gravitacijske sile bit će joj veće, a unutarnji izrođeni elektronski tlak nikada neće biti dovoljan da zaustavi njezin kolaps. Ispada da se neutroni također mogu pokoravati principu isključenja, a neutroni će se stvarati u izobilju kada se masivna zvijezda sruši, ali čak ni neutronska degeneracija ne može zaustaviti kolaps masivnih zvijezda - sve preko 3 do 5 Sunčevih masa ne može se zaustaviti, već postat će crna rupa prema trenutnom razmišljanju.

Kako se mijenja vrijeme u crnoj rupi?

Pa, u određenom smislu to se uopće ne mijenja. Ako biste ušli u crnu rupu, otkrili biste kako gledate kako otkucava istom brzinom kao i uvijek (pod pretpostavkom da ste i vi i sat preživjeli prolazak u crnu rupu). Međutim, brzo biste pali prema centru gdje bi vas ubile ogromne plimne sile (npr. Sila gravitacije u vašim nogama, ako biste prvo pali nogama, bila bi mnogo veća nego u vašoj glavi i bili biste istegnuti ).

Iako vaš sat kako ga vi vidite ne bi promijenio brzinu otkucaja, baš kao ni u posebnoj relativnosti (ako išta o tome znate), netko drugi vidio bi na vašem satu različitu brzinu otkucaja od uobičajene, a vi biste vidjeli njegov sat otkucavati različitom brzinom od uobičajene. Na primjer, ako biste se postavili neposredno ispred crne rupe, dok biste zatekli kako vaš vlastiti sat otkucava normalnom brzinom, vidjeli biste kako sat prijatelja na velikoj udaljenosti od rupe otkucava mnogo bržom brzinom nego tvoja. Taj bi prijatelj vidio kako njegov vlastiti sat otkucava normalnom brzinom, ali vaš sat otkucava mnogo sporije. Dakle, ako ste neko vrijeme ostali malo izvan crne rupe, a zatim se vratili da se pridružite svom prijatelju, otkrili biste da je prijatelj ostario više nego što ste vi imali tijekom vaše razdvojenosti.

Primjenjuje li se jednadžba E = mc ^ 2 na crnu rupu?

E = mc ^ 2 je uvijek istina. Na primjer, u slučaju crne rupe, postoje nagađanja da crne rupe mogu kvantno-mehaničkim trikom zračiti energijom i da bi se njihova masa u tom procesu smanjivala.

Ako ništa ne putuje brzinom svjetlosti, osim svjetlosti, kako crna rupa također može povući svjetlost u sebe?

Put koji slijedi svjetlosna zraka može saviti gravitirajuće tijelo, čak i Zemlja (iako je savijanje u tom slučaju vrlo malo). Ovaj je učinak izmjeren za svjetlost zvijezde dok je prolazila kroz Sunce tijekom pomrčine Sunca. Ovo savijanje svjetlosnih zraka povećava se s povećanjem jačine gravitacijskog polja. Crna rupa je jednostavno regija u kojoj je učinak na svjetlost toliko velik da svjetlost ne može pobjeći iz regije.

Koji je najbolji dokaz za postojanje crnih rupa? Je li sve to zapravo samo teorija?

Astronomi su pronašli pola-desetak binarnih zvjezdanih sustava (dvije zvijezde koje se okreću jedna oko druge) gdje je jedna od zvijezda nevidljiva, ali ipak mora biti tamo, jer povlači dovoljno gravitacijske sile na drugu vidljivu zvijezdu da bi ta zvijezda mogla kružiti oko svoje zvijezde zajedničko težište I masa nevidljive zvijezde znatno je veća od 3 do 5 Sunčevih masa. Stoga se smatra da su ove nevidljive zvijezde dobar kandidat za crne rupe. Također postoje dokazi da u središtima mnogih galaksija i kvazara postoje supermasivne crne rupe (oko 1 milijarde Sunčevih masa). U ovom potonjem slučaju druga objašnjenja izlaza energije kvazarima nisu tako dobra kao objašnjenja korištenjem supermasivne crne rupe. (Vidite, kad materija padne u gravitacijsko polje, njena brzina, a time i energija, raste. Ako istodobno upada puno tvari i kovitla se oko crne rupe na disku nalik prometnoj gužvi u slijepoj ulici) -sac, tada će trenje između različitih dijelova materije pretvoriti velik dio te brzine-energije prikupljene tijekom pada u toplinu koja se zrači. Na taj način materija koja okružuje supermasivnu crnu rupu može zračiti više energije po gramu goriva koje se može osloboditi bilo kojim drugim mehanizmom koji poznajemo, uključujući nuklearnu fuziju.)

Čuo sam da crna rupa svjetluca i zrači kad god nešto padne u njezin horizont događaja. Što to znači i zašto se to događa?

Nisam siguran na što osoba misli, ali pretpostavit ću. Možda se odnose na ono što se događa dok materijal pada u crnu rupu djelovanjem akrecijskog diska. Kako se velike količine materijala približavaju crnoj rupi, materijal će se općenito naći u strukturi nalik disku u orbiti s rupom u središtu (tj. Izgledat će pomalo poput izuzetno gužve Sunčevog sustava). Disk će biti izuzetno vruć zbog trenja između materijala s različitim orbitalnim brzinama pri malo drugačijim radijusima orbite. Tako će disk zračiti puno svjetlosti. Velik dio ulazne kinetičke energije materijala zrači se kroz ovaj proces trenja-toplina-svjetlost. To je ono što dovodi do ekstremne svjetline kvazara, a ovaj postupak čini nas sposobnim (moguće) pronaći crne rupe zvjezdane mase koje su dio dvostrukog zvjezdastog sustava. U potonjem slučaju, materijal koji pada sa susjedne zvijezde stvara akrecijski disk oko crne rupe, a disk emitira X-zrake (X-zrake emitira izuzetno vruća tvar, baš kao i ne tako vruća nit. žarulje emitira vidljivu svjetlost). U slučaju kvazara, supermasivna crna rupa (milijarda Sunčevih masa ili tako nešto) leži u središtu galaksije, a plin u blizini crne rupe čini akrecijski disk oko rupe. Rendgenski zraci i drugi oblici svjetlosti su rezultat.

Ni u jednom od ovih slučajeva svjetlost se ne emitira i dopire do nas ispod horizonta događaja crne rupe. Ništa ne može pobjeći ispod horizonta događaja.

Možete li vidjeti crnu rupu? Kako izgleda crna rupa?

Ne izravno. Ništa, čak ni svjetlost ne može pobjeći iz crne rupe.

S druge strane, možete vidjeti kako se neki vatromet događa u blizini crne rupe. Kako plin pada u crnu rupu (možda dolazi od obližnje zvijezde), plin će se zagrijavati i sjajiti, postajući vidljiv. Tipično, plin neće emitirati samo vidljivu svjetlost, već i energičnije fotone poput X-zraka. Ono što bismo očekivali vidjeti (ako bi se naši teleskopi mogli dovoljno "uvećati") bio bi užareni rotirajući disk s crnom rupom u središtu diska. Pogledajte gornje odgovore.

[Napomena urednika, travanj 2019 .: 10. travnja, suradnja teleskopa Event Horizon objavila je prvu sliku crne rupe. Slika je super masivne crne rupe u galaksiji M87 udaljenoj oko 50 milijuna svjetlosnih godina. Ova slika je ispod i prikazuje emisiju (radio stanice valne duljine 1,3 mm) s akrecijskog diska koji okružuje crnu rupu. Više informacija o ovoj slici može se naći u samoj istraživačkoj grupi https://eventhorizontelescope.org]

Prva slika crne rupe koju je snimio teleskop Event Horizon.

[Napomena urednika prosinac 2018 .: Film iz 2014. godine & quotInterstellar & quot prikazuje znanstveno precizan prikaz onoga što bi se vidjelo kad bi se pogledala crna rupa. Sljedeća slika prikazuje isječak iz filma. Svjetlost koju vidite je od plina o kojem smo prethodno razgovarali. ]

Ovaj pogled na crnu rupu stvoren je uz pomoć fizičara i nobelovca Kippa Thornea i preko 30 drugih. Rezultirajuća simulacija dovela je do objavljivanja 3 znanstvena rada. Za više informacija možete pročitati knjigu Kippa Thornea: The Science of Interstellar, ISBN-13: 978-0393351378]

Koliko velika može dobiti crna rupa?

Nema ograničenja koliko velika može biti crna rupa. Međutim, najveće crne rupe za koje mislimo da postoje nalaze se u središtima mnogih galaksija i imaju mase ekvivalentne oko milijardu sunca (tj. Milijardu Sunčevih masa). Njihovi polumjeri bili bi znatan udio radijusa našeg Sunčevog sustava.

Koliko mala može biti crna rupa?

Prema Općoj relativnosti (teorija koja predviđa i objašnjava većinu karakteristika crnih rupa), ne postoji donja granica veličine crne rupe. Ali, puna teorija o tome kako gravitacija djeluje također mora uključivati ​​kvantnu mehaniku, a takva teorija tek treba biti izgrađena. Neki nagovještaji iz nedavnog rada na ovoj teoriji sugeriraju da crna rupa ne može biti manja od oko & quot10 do-the - (- 33) & quot cm u radijusu --- 0,000000000000000000000000000000001 cm. Na toj će se skali male veličine čak i naizgled glatka priroda prostora razbiti u & quotrat-zamku & quot; tunela, petlji i drugih isprepletenih struktura! Barem to sugerira trenutni rad.

U odnosu na prvo pitanje, zašto se unutarnje elektronske sile zvijezde ne povećavaju istom brzinom kao gravitacijske sile?

Ukratko, degenerirani tlak elektrona u zvijezdi ovisi o gustoći plina na specifičan način koji nema izravnu ovisnost o tome kako su gravitacija i gustoća povezani. Ako želite matematički odnos, njegov: tlak je proporcionalan gustoći povišenoj na 5/3 snage. Ova snaga određena je svojstvima kvantne mehanike (i nema nikakve veze s gravitacijom). S druge strane, gravitacijska sila na površini (na primjer) zvijezde proporcionalna je masi zvijezde i obrnuto proporcionalna kvadratu njezinog radijusa (zbog Newtonovog univerzalnog zakona gravitacije!) Ako pokušam izraziti ova površinska gravitacija u smislu gustoće zvijezde (to je prosječna gustoća), smatram da je M / r ^ 2 proporcionalna gustoći puta x. Pa, vidite, & quotdensity puta r & quot nije nešto poput & quotdensity podignute na 5/3 snage. & Quot

Will an observer falling into a black hole be able to witness all future events in the universe outside the black hole?

The normal presentation of these gravitational time dilation effects can lead one to a mistaken conclusion. It is true that if an observer (A) is stationary near the event horizon of a black hole, and a second observer (B) is stationary at great distance from the event horizon, then B will see A's clock to be ticking slow, and A will see B's clock to be ticking fast. But if A falls down toward the event horizon (eventually crossing it) while B remains stationary, then what each sees is not as straight forward as the above situation suggests.

As B sees things: A falls toward the event horizon, photons from A take longer and longer to climb out of the "gravtiational well" leading to the apparent slowing down of A's clock as seen by B, and when A is at the horizon, any photon emitted by A's clock takes (formally) an infinite time to get out to B. Imagine that each person's clock emits one photon for each tick of the clock, to make it easy to think about. Thus, A appears to freeze, as seen by B, just as you say. However, A has crossed the event horizon! It is only an illusion (literally an "optical" illusion) that makes B think A never crosses the horizon.

As A sees things: A falls, and crosses the horizon (in perhaps a very short time). A sees B's clock emitting photons, but A is rushing away from B, and so never gets to collect more than a finite number of those photons before crossing the event horizon. (If you wish, you can think of this as due to a cancellation of the gravitational time dilation by a doppler effect --- due to the motion of A away from B). After crossing the event horizon, the photons coming in from above are not easily sorted out by origin, so A cannot figure out how B's clock continued to tick.

A finite number of photons were emitted by A before A crossed the horizon, and a finite number of photons were emitted by B (and collected by A) before A crossed the horizon.

You might ask What if A were to be lowered ever so slowly toward the event horizon? Yes, then the doppler effect would not come into play, UNTIL, at some practical limit, A got too close to the horizon and would not be able to keep from falling in. Then A would only see a finite total of photons form B (but now a larger number --- covering more of B's time). Of course, if A "hung on" long enough before actually falling in, then A might see the future course of the universe.

Bottom line: simply falling into a black hole won't give you a view of the entire future of the universe. Black holes can exist without being part of the final big crunch, and matter can fall into black holes.

For a very nice discussion of black holes for non-scientists, see Kip Thorne's book: Black Holes and Time Warps [ISBN: 978-0393312768]

Could black holes be used as an energy source?

There a great deal of information on the potential use of a black hole as a source of energy. (Of course, it should be mentioned that one must first acquire a black hole! At least in the case of the Sun, we already have the Sun!) An excellent source of information on black holes, written for the layperson, is Kip Thorne's excellent book: Black Holes and Time Warps. I suggest you consult it for "all the information [I] could possibly give" you.

In brief, a rotating black hole can store a huge amount of energy in its rotation. This energy is actually accessible since the rotation is imposed on the space outside the hole. In principle, therefore, energy can be extracted from the rotation of the black hole. Exactly what mechanism is used is a potentially complicated story.

I read somewhere that in the VERY distant future black holes could leak and disperse. Can that happen? If it can, how?

As yoy probably know, any object falling into a black hole cannot get out. However, over a very long time, particles of matter "leak" out of a black hole. So, even if all of the objects in the universe were to end up in black holes, after a long, long time, the holes would gradually lose their matter, and the matter would disperse througout the universe (as a thin gas of particles).

The process by which black holes lose matter is called Hawking radiation, after Stephen Hawking, the person who first figured out how it might happen. How it happens is a complicated story. One way of looking at the story uses concept of "virtual particles." At any moment, particle-antiparticle pairs are appearing and disappearing at any location, even just near the event horizon ("surface") of a black hole. These pairs exist for a short time, so short that we cannot measure their masses accurately enough to even know that they are there (however, we do know of their presence by the other effects they cause). But, for a pair near a black hole, one of the particles may fall into the hole, leaving the other without a partner the particle left behind can't be quickly annihilated by its now missing partner (which is what happens normally). So the lonely particle left behind finds itself no longer "virtual," but now "real," just like any particle in your body. Since this particle is now real, it contains some amount of mass, and that mass has been supplied by the energy of the black hole (through the hole's gravity): the now real particle exists because it has taken mass from the black hole. Thus, gradually, mass leaves the black hole in the form of new particles appearing outside the hole. This process by which black holes lose mass is very slow (at least for massive black holes made from stars), so the time it would take for a typical black hole to eventually disappear is very long. (For a black hole of a mass equal to the mass of the Sun, the entire process would take about 10^66 years, or 1 with 66 zeros after it.)


Astronomers Just Upsized an Iconic Black Hole

New evidence suggests the first known black hole is bigger than previously thought, which may force scientists to reconsider their understanding of how giant stars give rise to black holes.

Scientists think stellar-mass black holes, which contain up to a few times the sun's mass, form when giant stars die and collapse in on themselves. The first black hole ever discovered was Cygnus X-1, located within the Milky Way in the constellation of Cygnus, the Swan. Astronomers saw the first signs of the black hole in 1964 via gas it sucked away from a closely orbiting blue supergiant star. As this gas spiraled into the black hole, it became so hot it emitted high-energy X-rays and gamma-rays that satellites could detect.

A trio of studies in 2011 suggested Cygnus X-1 was located about 6,070 light-years from Earth, but the new research suggests the black hole is actually about 7,240 light-years away. Because other characteristics of the object are calculated based on distance, the new calculation argues that Cygnus X-1 is quite a bit larger than scientists had realized.

To estimate the black hole's distance, scientists use the so-called parallax technique, which examines Cygnus X-1 compared to its background. "If you hold a finger at arm's length and close one eye and then the other, you will see it [your finger] appear to move from one spot to another in comparison with more distant background objects," James Miller-Jones, an astrophysicist at the Curtin University node of the International Center for Radio Astronomy Research in Perth, Australia, lead author on the new study and co-author on some of the 2011 research, told Space.com. "Using that same idea, one can calculate how far away Cygnus X-1 was by looking at it from different vantage points as Earth moved around the sun."

The 2011 work analyzed the light from the black hole's companion star to help estimate the star&rsquos diameter. With this measurement, researchers calculated other details of the partnership, such as the black hole's mass, suggesting it was about 14.8 times that of the sun.

However, the 2011 research did not collect data from the black hole throughout a full orbit around its companion star. Without that information, the prior work could not fully account for how these orbital motions might affect the distance and mass estimates.

In the new study, Miller-Jones and his colleagues analyzed observations of Cygnus X-1 from the Very Long Baseline Array (VLBA), a giant radio telescope made of 10 dishes scattered across the U.S. Over the course of six 12-hour-long observations carried out on consecutive days, the researchers monitored the full orbit of the black hole.

Using the parallax technique on this new data combined with the 2011 data, the scientists found the black hole may be farther away that previously thought, about 7,240 light-years from Earth.

These new findings led the researchers to revise what models of the motions of Cygnus X-1's companion star, which in turn led to a new estimated mass for the black hole &mdash about 21.2 times that of the sun. This size makes Cygnus X-1 the largest stellar-mass black hole detected to date with observations of light. (Gravitational-wave observatories such as LIGO that detect ripples in the fabric of space and time have detected larger stellar-mass black holes, including one about 50 times the sun's mass.)

These findings suggest that the stars that form stellar-mass black holes may not lose as much material via winds as previously thought. "The mass of a black hole is set by how massive a star it started off as," Miller-Jones said. "Stars lose mass as winds blowing off their surface, and massive stars generate more powerful winds. The most massive stars can have very powerful winds, and lose a lot of mass through them before they form black holes."

The newfound giant size of Cygnus X-1 therefore suggests the stars that form stellar-mass black holes can be larger than previously thought. "Previous models predicted the most massive black hole a massive star in our Milky Way galaxy should be able to make should only be about 15 times the mass of the sun," Miller-Jones said. "So finding something 21 times the mass of the sun means we have to revise our estimates of how much mass these massive stars are losing."

The updated estimates of the black hole's mass and distance also helped revealed the object is spinning very close to the speed of light, "faster than any other black hole found to date," study co-author Xueshan Zhao at the Chinese Academy of Sciences in Beijing, said in a statement.

And even larger stellar-mass black holes may be waiting for scientists' attention. "Cygnus X-1 is unlikely the most massive stellar-mass black hole that can be produced," Miller-Jones said. "The question is can we identify them, and how accurately can we measure their masses?"

The scientists detailed their findings online Feb. 18 in the journal Science. Two other papers focusing on different aspects of this work also appeared Feb. 18 in The Astrophysical Journal.

Copyright 2021 Space.com, a Future company. Sva prava pridržana. This material may not be published, broadcast, rewritten or redistributed.

ABOUT THE AUTHOR(S)

Charles Q. Choi is a frequent contributor to Znanstveni američki. His work has also appeared in The New York Times, Science, Nature, Wired, i LiveScience, između ostalih. In his spare time, he has traveled to all seven continents.


The problem of artificial intelligence

Another concern was over artificial intelligence. Here the concern was not so much existential. By this, I mean the speakers were not fearful that some computer was going to wake up into consciousness and decide that the human race needed to be enslaved. Instead, the danger was more subtle but no less potent. Susan Halpern, also one of our greatest non-fiction writers, gave an insightful talk that focused on the umjetno aspect of artificial intelligence. Walking us through numerous examples of how "brittle" machine learning algorithms at the heart of modern AI systems are, Halpern was able to pinpoint how these systems are not intelligent at all but carry all the biases of their makers (often unconscious ones). For example, facial recognition algorithms can have a hard time differentiating the faces of women of color, most likely because the "training data sets" the algorithms were taught were not representative of these human beings. But because these machines supposedly rely on data and "data don't lie," these systems get deployed into everything from making decisions about justice to making decisions about who gets insurance. And these are decisions that can have profound effects on people's lives.

Then there was the general trend of AI being deployed in the service of both surveillance capitalism and the surveillance state. In the former, your behavior is always being watched and used against you in terms of swaying your purchasing decisions in the latter, you are always being watched by those in power. Jao!


What is a "Black Hole" my opinion

One other thing I just read somewhere off my phone was an article that said Black Holes have a charge. Now, it did not explain, what a "Charge" is so I'm assuming positive negative charge? I have more questions than answers about a Black Hole.

But could an exploding star violently, in the vacuum of space, cause an effect like a sucking in of Dark Matter to fill the void?

My thinking is that if you don't ask the question, the answer will always be dangling in your mind. Hvala vam

Vincenzosassone

Neil Fountaine

Neil Fountaine

IG2007

"Don't criticize what you can't understand. & quot

Neil Fountaine

Helio

If we require science to only address truths and absolutes, then you're correct. But over the centuries, we found a system that helps us have a conversation with Nature that allows us to better understand, with limitations, what explains what we observe.

Science is objective-based, so facts are its foundation. With facts we can form ideas, but the best ideas will be the ones that best describe the objective evidence, and makes predictions we can test. This idea is either a hypothesis or, if far-reaching, a scientific theory.

We can't go into BHs then come out of the EH (Event Horizon) to bring us facts as not even light can escape. But we can infer some of the things that we can't see.

Indeed, look how a black hole was first discovered. The only explanation for what was being observed -- x-rays from a very active accretion disk swirling around a tiny spot of darkness -- was a BH. Schwarzschild theorized that they might exist, though Einstein questioned that idea.

It's impossible to see the light from a blackhole itself, but we can, now with abundant observations, infer it's existence. We also can't see the Sun at night, but we have a great idea where that bright thing is at all times, nevertheless. Direct observations are always preferred, but indirect ones can work fine as well.

Questioning was is factual and what is not is the right approach to all science, but know absolutes aren't likely going to happen from whatever pieces of the puzzle you manage to acquire.

Helio

Yes, in the context of directly observable objects.

BHs force us to rethink what we are calling mass. Our experience in picking up stuff like rocks and furniture is one definition. But formally it is how something reacts to a gravitational field. [I'm trying to lose weight and the scale said I only lost a little, so I know (objectively) that I did lose a little mass. ]

There are two important barriers a stellar core has in order to oppose its core from collapsing into a BH. But the mass of the star's core will determine the outcome.

The first barrier is about electron action (degeneracy) -- it's not just an electric field due to electron density but more complicated -- that opposes the collapse. This gives you a white dwarf. Our Sun's mass is such that this is its final state for its remaining core.

But, if more massive, this barrier will very quickly give way to the more massive core (and stronger gravity) to bring it to the next barrier where something happens with the electrons combining with protons to form neutrons, but they are really going nuts in there and you don't have mass of pure neutrons. Regardless, this will produce a force that counters the extreme gravitational field it has, and it will never collapse into a BH, unless its given more mass, which would thing give us.

A BH, where the gravity, due to more mass, overcomes all other forces and it collapses into, many think, a singularity. But perhaps it comes incredibly close to one instead.

I hope this helps frame BH questions you can ask Dr. Pesce tomorrow regarding BHs.

Neil Fountaine

Helio

IG2007

"Don't criticize what you can't understand. & quot

Vincenzosassone

Voidpotentialenergy

IMO a black hole is a compression of quantum Fluctuation.
Since the quanta distance is set in the universe when you compress it you also compress time/activity/space.
A black hole is compressed matter that would like to compress forever but the compression of time/space/activity slows that compression forever.
Reason a black hole doesn't shrink forever and become an infinite point of mass and consume the entire universe.

Not a mystery object with strange physics breakdowns, just a compression of quanta distance self regulated as compression grows.

Vincenzosassone

Voidpotentialenergy

And that is the problem of classical black hole theory.
Once matter is compressed beyond the nuclear force nothing in the universe can stop it from continuing to shrink instantly and become infinite in mass.

Hawkings idea of radiation escaping is quaint but takes into no part the reason a black hole stops shrinking is size.
Or is shrinking so slowly we can't detect the shrink.

Either physics is wrong or black hole theory is wrong since we see no black hole in the universe collapse infinitely and consume the universe.

Proof that a black hole is a compression of time is the simple fact that black holes occupy different sizes in the universe so something controls them compressing and since the last force (nuclear) isn't it, then it must be a compression of time/space/activity.

We have everything from earth size black holes to solar system size black holes and no one has questioned why the difference in size.

Nothing can escape a time well and an ever increasing time well stops/slows forever a black hole shrink nicely as the last mechanism possible.
JMO

Helio

I've not heard of this, but I'm a rookie at PBHs. Do you have a source reference for this?

But matter formed them, right?

Helio

That's logical, but not testable, right? We can suppose this to be true, but infinites come with their own headaches, no doubt.

The rate is dependent on the mass. The fear that CERN would create a micro blackhole that would become all-consuming was proved to be a false assumption. Any micro mass BH immediately evaporates.

A BH doesn't increase in gravity, but only increases in its field density. If a magic wand turned the Sun into a BH, the orbit of planets would remain just as stable now as before. The mass of the, now dark, Sun would be unchanged so the gravitational field at the planets would be the same.

Voidpotentialenergy

That's logical, but not testable, right? We can suppose this to be true, but infinites come with their own headaches, no doubt.

The rate is dependent on the mass. The fear that CERN would create a micro blackhole that would become all-consuming was proved to be a false assumption. Any micro mass BH immediately evaporates.

A BH doesn't increase in gravity, but only increases in its field density. If a magic wand turned the Sun into a BH, the orbit of planets would remain just as stable now as before. The mass of the, now dark, Sun would be unchanged so the gravitational field at the planets would be the same.

You will find that each example comes with a specific mass. The black holes at the center of the galaxy are called SMBHs (Supper Massive Black Holes) because they have masses sometimes in the many billions of solar masses.

A black hole being just a time well resolves many of the mysteries of black holes.
As a time well size will appear since compression is slowed no matter what size a black hole is.
Also answers why when we go beyond the nuclear force a black hole simply doesn't collapse into an infinite mass point and put infinite gravity into the universe and consume it.

Hawkins radiation might be true or it might not but in a location that is nothing more than a time well it doesn't matter since nothing will escape an ever increasing time dialation.

Proof i think is the fact that black holes have different sizes, not mass but size.
Why black hole A is size of earth and black hole B is size of solar system when the nuclear force on both is overwhelmed in the exact same amount .
That fact with classical black hole theory has no good explanation.
As a time well it's simple time compression/mass math.

We see no infinite mass points in the universe so classical black hole theory is missing some goodies that stop or slow them forever.
Quantum compression or time compression could be the last thing that stops a black holes collapse.
They still collapse it just takes forever to happen.


Will we ever see a black hole?

The shadow of a black hole surrounded by a ring of fire in a generic simulation. Credit: T. Bronzwaer, M. Moscibrodzka, H. Falcke Radboud University

In the shadowy regions of black holes two fundamental theories describing our world collide. Can these problems be resolved and do black holes really exist? First, we may have to see one and scientists are trying to do just this.

Of all the forces in physics there is one that we still do not understand at all: Gravity.

Gravity is where fundamental physics and astronomy meet, and where the two most fundamental theories describing our world—quantum theory and Einstein's theory of spacetime and gravity (aka. the theory of general relativity) – clash head on.

The two theories are seemingly incompatible. And for the most part this isn't a problem. They both live in distinct worlds, where quantum physics describes the very small, and general relativity describes the very largest scales.

Only when you get to very small scales and extreme gravity, do the two theories collide, and somehow, one of them gets it wrong. At least in theory.

But there is once place in the universe where we could actually witness this problem occurring in real life and perhaps even solve it: the edge of a black hole. Here, we find the most extreme gravity. There's just one issue – nobody has ever actually 'seen' a black hole.

So, what is a black hole?

Imagine that the entire drama of the physical world unfolds in the theatre of spacetime, but gravity is the only 'force' that actually modifies the theatre in which it plays.

The force of gravity rules the universe, but it may not even be a force in the traditional sense. Einstein described it as a consequence of the deformation of spacetime. And perhaps it simply does not fit the standard model of particle physics.

When a very big star explodes at the end of its lifetime, its innermost part will collapse under its own gravity, since there is no longer enough fuel to sustain the pressure working against the force of gravity (yes, gravity feels like a force after all, doesn't it!).

The matter collapses and no force in nature is known to be able to stop that collapse, ever.

In an infinite time, the star will have collapsed into an infinitely small point: a singularity – or to give it another name, a black hole.

Of course, in a finite time the stellar core will have collapsed into something of a finite size and this would still be a huge amount of mass in an insanely small region and it still is called a black hole!

Black holes do not suck in everything around them

Interestingly, it is not true that a black hole will inevitably draw everything in.

In fact, whether you are orbiting a star or a black hole that formed from a star, it does not make a difference, so long as the mass is the same. The good old centrifugal force and your angular momentum will keep you safe and stop you from falling in.

Only when you fire your giant rocket thrusters to brake your rotation, will you start falling inwards.

However, once you fall towards a black hole you will be accelerated to higher and higher speeds, until you eventually reach the speed of light.

Simulated image as predicted for the supermassive black in the galaxy M87 at the frequencies observed with the Event Horizon Telescope (230 GHz). Credit: Moscibrodzka, Falcke, Shiokawa, Astronomy & Astrophysics, V. 586, p. 15, 2016, reproduced with permission © ESO

Why are quantum theory and general relativity incompatible?

At this point everything goes wrong as, according to general relativity, nothing should move faster than the speed of light.

Light is the substrate used in the quantum world to exchange forces and to transport information in the macro world. Light determines how fast you can connect cause and consequences.

If you go faster than light, you could see events and change things before they happen. This has two consequences:

  1. At the point where you reach the speed of light while falling inwards, you would also need to fly out at the speed of light to escape that point, which seems impossible. Hence, conventional physical wisdom will tell you that nothing can escape a black hole, once it has passed that point, which we call the "event horizon."
  2. It also means that suddenly basic principles of quantum information preservation are brutally violated – conserved quantum quantities can simply disappear behind a wall of silence.

Whether that is true and whether and how the theory of gravity (or of quantum physics) needs to be modified is a question of intense debate among physicists, and none of us can say which way the argument will lead in the end.

Do black holes even exist?

Of course, all this excitement would only be justified, if black holes really existed in this universe. So, do they?

In the last century strong evidence has mounted that certain binary stars with intense X-ray emissions are in fact stars collapsed into black holes.

Moreover, in the centres of galaxies we often find evidence for huge, dark concentrations of mass. These might be supermassive versions of black holes, possibly formed through the merger of many stars and gas clouds that have sunk into the centre of a galaxy.

The evidence is convincing, but circumstantial. At least gravitational waves have let us 'hear' the merger of black holes, but the signature of the event horizon is still elusive and so far, we have never actually 'seen' a black hole – they simply tend to be too small and too far and, in most cases, yes, black.

So, what would a black hole actually look like?

If you could look straight into a black hole you would see the darkest dark, you can imagine.

But, the immediate surroundings of a black hole could be bright as gasses spiral inwards –slowed down by the drag of magnetic fields they carry along.

Due to the magnetic friction the gas will heat up to enormous temperatures of up to several tens of billion degrees and start to radiate UV-light and X-rays.

Ultra-hot electrons interacting with the magnetic field in the gas will start producing intense radio emission. Thus, black holes can glow and could be surrounded by a ring of fire that radiates at many different wavelengths.

A ring of fire with a dark, dark centre

In their very centre, however, the event horizon still lurks and like a bird of prey it catches every photon that gets too close.

Radio images of the jet in the radio galaxy M87 – observed at lower resolution. The left frame is roughly 250,000 light years across. Magnetic fields threading the supermassive black holes lead to the formation of a highly collimated jet that spits out hot plasma with speeds close to the speed of light . Credit: H. Falcke, Radboud university, with images from LOFAR/NRAO/MPIfR Bonn

Since space is bent by the enormous mass of a black hole, light paths will also be bent and even form into almost concentric circles around the black hole, like serpentines around a deep valley. This effect of circling light was calculated already in 1916 by the famous Mathematician David Hilbert only a few months after Albert Einstein finalised his theory of general relativity.

After orbiting the black hole multiple times, some of the light rays might escape while others will end up in the event horizon. Along this complicated light path, you can literally look into the black hole. The nothingness you see is the event horizon.

If you were to take a photo of a black hole, what you would see would be akin to a dark shadow in the middle of a glowing fog of light. Hence, we called this feature the shadow of a black hole .

Interestingly, the shadow appears larger than you might expect by simply taking the diameter of the event horizon. The reason is simply, that the black hole acts as a giant lens, amplifying itself.

Surrounding the shadow will be a thin 'photon ring' due to light circling the black hole almost forever. Further out, you would see more rings of light that arise from near the event horizon, but tend to be concentrated around the black hole shadow due to the lensing effect.

Is this pure fantasy that can only be simulated in a computer? Or can it actually be seen in practice? The answer is that it probably can.

There are two relatively nearby supermassive black holes in the universe which are so large and close, that their shadows could be resolved with modern technology.

These are the black holes in the center of our own Milky Way at a distance of 26,000 lightyears with a mass of 4 million times the mass of the sun, and the black hole in the giant elliptical galaxy M87 (Messier 87) with a mass of 3 to 6 billion solar masses.

M87 is a thousand times further away, but also a thousand times more massive and a thousand times larger, so that both objects are expected to have roughly the same shadow diameter projected onto the sky.

Like seeing a grain of mustard in New York from Europe

Coincidentally, simple theories of radiation also predict that for both objects the emission generated near the event horizon would be emitted at the same radio frequencies of 230 GHz and above.

Most of us come across these frequencies only when we have to pass through a modern airport scanner but some black holes are continuously bathed in them.

The radiation has a very short wavelength of about one millimetre and is easily absorbed by water. For a telescope to observe cosmic millimetre waves it will therefore have to be placed high up, on a dry mountain, to avoid absorption of the radiation in the Earth's troposphere.

Effectively, you need a millimetre-wave telescope that can see an object the size of a mustard seed in New York from as far away as Nijmegen in the Netherlands. That is a telescope a thousand times sharper than the Hubble Space Telescope and for millimetre-waves this requires a telescope the size of the Atlantic Ocean or larger.

A virtual Earth-sized telescope

Fortunately, we do not need to cover the Earth with a single radio dish, but we can build a virtual telescope with the same resolution by combining data from telescopes on different mountains across the Earth.

The technique is called Earth rotation synthesis and very long baseline interferometry (VLBI). The idea is old and has been tested for decades already, but it is only now possible at high radio frequencies.

Layout of the Event Horizon Telescope connecting radio telescopes around the world (JCMT & SMA in Hawaii, AMTO in Arizona, LMT in Mexico, ALMA &APEX in Chile, SPT on the South Pole, IRAM 30m in Spain). The red lines are to a proposed telescope on the Gamsberg in Namibia that is still being planned. Credit: ScienceNordic / Forskerzonen. Compiled from images provided by the author

The first successful experiments have already shown that event horizon structures can be probed at these frequencies. Now high-bandwidth digital equipment and large telescopes are available to do this experiment on a large scale.

Work is already underway

I am one of the three Principal Investigators of the BlackHoleCam project. BlackHoleCam is an EU-funded project to finally image, measure and understand astrophysical black holes. Our European project is part of a global collaboration known as the Event Horizon Telescope consortium – a collaboration of over 200 scientists from Europe, the Americas, Asia, and Africa. Together we want to take the first picture of a black hole.

In April 2017 we observed the Galactic Center and M87 with eight telescopes on six different mountains in Spain, Arizona, Hawaii, Mexico, Chile, and the South Pole.

All telescopes were equipped with precise atomic clocks to accurately synchronise their data. We recorded multiple petabytes of raw data, thanks to surprisingly good weather conditions around the globe at the time.

We are all excited about working with this data. Of course, even in the best of all cases, the images will never look as pretty as the computer simulations. But, at least they will be real and whatever we see will be interesting in its own right.

To get even better images telescopes in Greenland and France are being added. Moreover, we have started raising funds for additional telescopes in Africa and perhaps elsewhere and we are even thinking about telescopes in space.

A 'photo' of a black hole

If we actually succeed in seeing an event horizon, we will know that the problems we have in rhyming quantum theory and general relativity are not abstract problems, but are very real. And we can point to them in the very real shadowy regions of black holes in a clearly marked region of our universe.

This is perhaps also the place where these problems will eventually be solved.

We could do this by obtaining sharper images of the shadow, or maybe by tracing stars and pulsars as they orbit around black holes, through measuring spacetime ripples as black holes merge, or as is most likely, by using all of the techniques that we now have, together, to probe black holes.

A once exotic concept is now a real working laboratory

As a student, I wondered what to study: particle physics or astrophysics? After reading many popular science articles, my impression was that particle physics had already reached its peak. This field had established an impressive standard model and was able to explain most of the forces and the particles governing our world.

Astronomy though, had just started to explore the depths of a fascinating universe. There was still a lot to be discovered. And I wanted to discover something.

In the end, I chose astrophysics as I wanted to understand gravity. And since you find the most extreme gravity near black holes, I decided to stay as close to them as possible.

Today, what used to be an exotic concept when I started my studies, promises to become a very real and very much visible physics laboratory in the not too distant future.

This story is republished courtesy of ScienceNordic, the trusted source for English-language science news from the Nordic countries. Read the original story here.


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