Astronomija

Ali bi bilo mogoče v planetarnem sistemu blizu galaktičnega jedra videti supermasivno črno luknjo?

Ali bi bilo mogoče v planetarnem sistemu blizu galaktičnega jedra videti supermasivno črno luknjo?


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Razumem, da sevanje na planetih blizu središča galaksije skorajda onemogoča življenje na teh planetih in da človek ne more zares "videti" črne luknje. Če pa bi lahko stali na površini planeta, ki kroži okoli zvezde blizu ali znotraj galaktičnega jedra, bi lahko teoretično pogledali v nebo in videli odsotnost svetlobe / zvezd, ki kažejo na lokacijo osrednje supermasivne črne luknje?

Ali bi bilo predaleč, da bi ga videli, ovirali bi ga ostanki ali premalo, da bi ga opazili?


Na nebu je ne bi mogli videti kot črno lito, ker je veliko premajhna. To je le 17-krat večji od polmera našega sonca, česar seveda ne morete videti kot disk niti iz zunanjih krajev našega sončnega sistema. Kaj ti lahko je veliko večje območje svetlobe in drugega sevanja snovi, ki pade vanjo.


Če je črna luknja aktivna, kar pomeni, da še vedno zajema snov iz svoje okolice, bo imela naokoli velik akrecijski disk, kar je edini način, da odstrani kotni moment za snov, ki pade vanjo.

Kot rezultat tega razprševanja se bo vsa zadeva ogrela in oddajala sevanje. Ta disk bo dokaj velik in bo tako dobro viden kot svetel predmet na nebu.

Ta stran prikazuje sliko takega diska, ki jo je posnel Hubble:

Strogo rečeno, ni mogoče videti črne luknje neposredno, saj bo njen pogled prekrit s svetlobo, ki jo oddaja disk.

Prisotnost diska pa bo omogočila opazovanje črne luknje zaradi njenega gravitacijskega učinka.


Obstaja stvar, imenovana gravitacijsko leče, kar pomeni, da bi se svetloba, ki prihaja izza črne luknje, upognila proti njej, in ker ima galaktično jedro veliko zvezd, bi lahko videli, da namesto črne pike na nebu veliko kopičenje svetlobe v položaju črne luknje in okoli nje.

Nisem prepričan, kako dobesedno je "lečenje", zato ne vem, ali obstaja žarišče, ki temelji na gravitaciji in energiji svetlobe in ali bi bilo od te žarišča pomembno, kje je planet.

http://www.cfhtlens.org/public/what-gravitational-lensing (google bo zagotovil več povezav, če ga iščete)


Mavrični oblak.

Vir sevanja iz črnih lukenj so snovi, ki spiralizirajo v črno luknjo, segrevajo, ko je "padla" in sprostila svojo gravitacijsko potencialno energijo. Tudi to je sevanje črnega telesa, vendar tokrat običajna: bolj vroči so oddajniki, krajša je valovna dolžina. To sevanje prihaja od črne luknje, ne iz same luknje.

https://physics.stackexchange.com/questions/24958/how-can-a-black-hole-emit-x-rays

Rentgenski žarki prihajajo iz vročega plina, ki kroži okoli črne luknje v akrecijskem disku. Medtem ko plin kroži zaradi magnetnih napetosti, izgublja energijo in kotni zagon, tako da počasi spiralira proti črni luknji. Orbitalna energija se pretvori v toplotno energijo, pri čemer se plin ogreje na milijone stopinj, zato v rentgenskem pasu nato odda sevanje črnih teles.

Ko se plin približa kot nekajkrat večji od polmera obzorja, se potopi v črno luknjo, tako da medtem ko nekateri rentgenski žarki še vedno lahko uidejo tik pred obzorjem, jih večina pošlje zunaj.

Teleskopi za odkrivanje črnih lukenj iščejo najbolj energijske žarke, ki jih oddajajo najbolj vroča območja plina, ki so najbližja luknji. Ne moremo stati na planetu, pogledati gor in videti žarke. Toda upoštevajte: če je zelo vroč plin, je zraven njega manj vročega plina in zraven tistega, ki je manj vroč. Hladneje kot je črno telo, daljša je valovna dolžina oddanega sevanja. Nekje v tem postopoma hladnejšem oblaku je plin, ki oddaja sevanje v vidni valovni dolžini.

Tu trdim, da bi morala postopna sprememba temperature tega oblaka, ki je vedno bolj oddaljen od najbolj vročega plina, postopno spreminjati oddajane frekvence. Prva vidna svetloba bi bila v skrajni vijolični barvi, najbližji luknji. To bo stopnjevalo skozi modro in zeleno dlje in nato rdeče na najbolj hladnem delu oblaka.

Ta napoved ne bi smela veljati samo za črne luknje, ampak tudi za kateri koli oblak plina, ogrevan od znotraj. Zdaj pa poglej ... gremo.

https://www.space.com/12051-bright-nebula-photo-supergiant-star-betelgeuse.html

Mavrični oblak črne luknje bo bolj simetričen od tega. Zvezda te volje nehote izbruhuje, toda luknja vsesava plin, tako da bo to simetrična spirala.



"Kozmični mikroskop" razkriva izvor galaktičnih vetrov, ki jih proizvajajo supermasivne črne luknje (astronomija / kozmologija)

Skupina raziskovalcev pod vodstvom Giustine Vietri iz Italijanskega nacionalnega inštituta za astrofiziko (INAF) je s preučevanjem vzorca oddaljenih galaksij, katerih svetloba nas doseže iz vesoljne dobe, ko je bilo vesolje staro le tri milijarde let, sledila vetrom, ki pihajo v "Aktivne" galaksije le nekaj svetlobnih let od supermasivnih črnih lukenj, ki sedijo v galaktičnih jedrih. Nova študija dokazuje, kako lahko ti vetrovi, ki potujejo do milijonov kilometrov na uro, vplivajo na medzvezdni plin na merilih deset tisoč svetlobnih let.

Tor prahu okoli SMBH © ESA / Hubble

Večina supermasivnih črnih lukenj, ki se skrivajo v galaksijah, kot je tista v središču naše Rimske ceste, je neškodljivih in pogoltne kvečjemu občasno zvezdo ali plinski oblak, ki si upajo preblizu. Majhen odstotek pa je v velikih pretresih, ki hitro požirajo okoliško snov preko akrecijskega diska, ki se segreje in oddaja sevanje po elektromagnetnem spektru. Iz teh signalov je mogoče v astronomskih opazovanjih prepoznati "aktivne" galaksije, ki gostijo tako blazne črne luknje.

Niti najbolj "požrešne" črne luknje pa niso sposobne pojesti vsega materiala v svoji okolici, sprožiti ogromne vetrove, ki odvržejo del tega materiala in se lahko širijo po galaktičnih lestvicah. Astrofiziki že leta razpravljajo o pomenu tovrstnih vetrov in njihovih možnih učinkih na razvoj gostiteljskih galaksij s pomočjo povratnih mehanizmov, ki bi lahko uravnavali rast centralne črne luknje in nastajanje novih zvezd.

"Zelo pomembno je razumeti, kako se je vesolje razvilo," komentira Giustina Vietri iz INAF-a v Milanu, prva avtorica nove študije, ki prvič uporablja reprezentativni vzorec, ki analizira učinek takšnih vetrov na različne lestvice v galaksijah. aktivnih galaksij. "V tej študiji smo poskušali osvetliti eno trenutno najbolj razpravljanih vprašanj: povezavo med centralnimi supermasivnimi črnimi luknjami in njihovimi gostiteljskimi galaksijami."

Rezultati, objavljeni v Astronomy & amp Astrophysics, so del projekta SUPER (SINFONI Survey for Unveiling the Physics and Effect of Radiative feedback), ki je že pripravil dva prispevka iste skupine raziskovalcev. Projekt je bil ustvarjen z namenom proučevanja izpusta plina iz galaktičnih središč z uporabo instrumenta SINFONI na zelo velikem teleskopu ESO v Čilu.

"SINFONI je spektrograf s celovitim poljem, ki deluje v bližnjem infrardečem območju in uporablja prilagodljivo optiko za zbiranje spektrov razširjene vire visoke ločljivosti," pojasnjuje Vincenzo Mainieri iz ESO, glavni raziskovalec projekta SUPER in soavtor nove študije. "Glede na prejšnje instrumente, ki so se uporabljali za spektroskopske preglede aktivnih galaksij, nam SINFONI omogoča prostorsko ločevanje plina".

Zahvaljujoč podatkom, pridobljenim s sistemom SINFONI, je ekipa prvič sistematično analizirala reprezentativni vzorec 21 aktivnih galaksij in prvič sistematično preučila povezavo med črnimi luknjami in njihovimi gostiteljskimi galaksijami. To pomeni, da jim ni bilo treba izbirati galaksij, kjer je bila prisotnost vetrov že znana. Opazovanja so razkrila prisotnost galaktičnih vetrov v vseh preučenih virih. Rezultat kaže, kako razširjeni so ti pojavi v vesoljni dobi, ki ji pripadajo te galaksije, ko je bilo naše 13,8 milijarde let staro vesolje staro le 3 milijarde let.

"Ti vetrovi, ki potujejo s hitrostjo med 3 in 7 milijoni km / h, segajo do dvajset tisoč svetlobnih let od središča svojih gostiteljskih galaksij," dodaja soavtorica Michele Perna iz INAF v Firencah in Centro de Astrobiología v Madridu, Španija.

Nato so raziskovalci spremljali vetrove vse do njihovega izvora, v bližini pošastnih črnih lukenj, z uporabo astronomskega "mikroskopa" - ki je v arhivih analiziral optični spekter teh galaksij.

»Linije, ki jih oddajajo ionizirani atomi ogljika, ki jih vidimo v spektrih Sloanove digitalne raziskave neba, nastajajo le nekaj svetlobnih let stran od črne luknje in razkrivajo, kako so na njih prisotni tudi vetri ioniziranega materiala, odkriti s SINFONI razmeroma majhne lestvice, v osrčju galaksij, "pojasnjuje Vietri. "S tem bi lahko prvič povezali prisotnost izlivov iz bližine črne luknje na lestvice galaksij".

Rezultati kažejo, kako so vetrovi, ki jih opazujemo na majhnih razdaljah od osrednje črne luknje, odvisni od njenih lastnosti - na primer stopnje prirastka ali svetlosti galaktičnega jedra, ki ga nato povzroči aktivnost črne luknje. Poleg tega bi ti vetrovi lahko vplivali na plin vse do obrobja svojih galaksij. V prihodnosti bodo raziskovalci poskušali slediti tem vetrovom v še večjem obsegu, da bi še naprej preučevali vpliv, ki ga lahko imajo črne luknje na razvoj galaksij.

Študija je objavljena v Astronomy & amp Astrophysics v prispevku “SUPER III. Širokoregijske lastnosti AGN pri z∼2 "G. Vietri, V. Mainieri, D. Kakkad, H. Netzer, M. Perna, C. Circosta, CM Harrison, L. Zappacosta, B. Husemann, P. Padovani , M. Bischetti, A. Bongiorno, M. Brusa, S. Carniani, C. Cicone, A. Comastri, G. Cresci, C. Feruglio, F. Fiore, G. Lanzuisi, F. Mannucci, A. Marconi, E Piconcelli, A. Puglisi, M. Salvato, M. Schramm, A. Schulze, J. Scholtz, C. Vignali, G. Zamorani.


Gravitacijski val brcne pošastno črno luknjo iz galaktičnega jedra

Astronomi so odkrili supermasivno črno luknjo, ki jo je iz središča oddaljene galaksije izginila tako velika moč gravitacijskih valov.

Čeprav je bilo drugje osumljenih več podobnih črnih lukenj, zaenkrat še niso potrdili nobenega. Astronomi menijo, da je ta objekt, ki ga je odkril NASA-in vesoljski teleskop Hubble, zelo močan primer. Prevarantova črna luknja, ki tehta več kot milijardo soncev, je najbolj masivna črna luknja, ki so jo kdajkoli izrinili iz osrednjega doma.

Raziskovalci ocenjujejo, da je bila za odstranitev črne luknje potrebna enakovredna energija 100 milijonov supernov, ki so istočasno eksplodirale. Najbolj verjetna razlaga za to pogonsko energijo je, da so pošastni objekt sprožili gravitacijski valovi, sproščeni z združitvijo dveh zajetnih črnih lukenj v središču gostiteljske galaksije.

Prvič je napovedal Albert Einstein, gravitacijski valovi so valovi v vesolju, ki nastanejo ob trku dveh masivnih predmetov. Valovi so podobni koncentričnim krogom, ki nastanejo, ko se v ribnik vrže zajeten kamen. Lani je Laser Interferometer Gravitational-Wave Observatory (LIGO) astronomom pomagal dokazati, da obstajajo gravitacijski valovi, tako da jih je zaznal iz zveze dveh črnih lukenj zvezdne mase, ki sta nekajkrat bolj masivni od sonca.

Hubblova opazovanja svojeglave črne luknje so presenetila raziskovalno skupino. "Ko sem to prvič videl, sem mislil, da vidimo nekaj zelo nenavadnega," je povedal vodja ekipe Marco Chiaberge z Znanstvenega inštituta za vesoljski teleskop (STScI) in univerze Johns Hopkins iz Baltimoreja v zvezni državi Maryland. "Ko smo združili opazovanja Hubbla, rentgenskega observatorija Chandra in raziskave Sloan Digital Sky Survey, je vse kazalo na isti scenarij. Količina podatkov, ki smo jih zbrali, od rentgenskih žarkov do ultravijolične in bližnje infrardeče svetlobe, je zagotovo večja kot za katerega koli drugega kandidata za prevarantske črne luknje. "

Chiabergejev članek bo objavljen v izdaji časopisa Astronomija in astrofizika.

Hubblove slike, posnete v vidni in bližnji infrardeči svetlobi, so dale prvi namig, da je bila galaksija nenavadna. Slike so razkrile svetel kvazar, energijski podpis črne luknje, ki leži daleč od galaktičnega jedra. Črnih lukenj ni mogoče neposredno opazovati, so pa vir energije v središču kvazarjev - intenzivnih, kompaktnih žarkov sevanja, ki lahko zasenčijo celotno galaksijo. Kvazar, imenovan 3C 186, in njegova gostiteljska galaksija sta v kopici galaksij oddaljena 8 milijard svetlobnih let. Skupina je odkrila značilnosti galaksije med Hubblovim raziskovanjem oddaljenih galaksij, ki so sprožile močne eksplozije sevanja v vrtoglavih združitvah galaksij.

"Pričakoval sem, da bom videl veliko galaksij, ki se združujejo, in pričakoval sem, da bom videl neurejene gostiteljske galaksije okoli kvazarjev, vendar v resnici nisem pričakoval, da bom videl kvazar, ki je bil očitno odmaknjen od jedra galaksije z redno obliko," Chiaberge odpoklican. "Črne luknje prebivajo v središču galaksij, zato je nenavadno videti kvazar, ki ni v središču."

Ekipa je izračunala razdaljo črne luknje od jedra s primerjavo porazdelitve zvezdne svetlobe v gostiteljski galaksiji s porazdelitvijo običajne eliptične galaksije iz računalniškega modela. Črna luknja je od središča potovala več kot 35.000 svetlobnih let, kar je več kot razdalja med soncem in sredino Rimske ceste.

Na podlagi spektroskopskih opazovanj Hubbla in Sloanove raziskave so raziskovalci ocenili maso črne luknje in izmerili hitrost plina, ujetega blizu behemotskega predmeta. Spektroskopija deli svetlobo na njene sestavne barve, s katerimi lahko merimo hitrosti v vesolju. "Na naše presenečenje smo odkrili, da plin okoli črne luknje leti od centra galaksije s hitrostjo 4,7 milijona milj na uro," je dejal član ekipe Justin Ely iz STScI. Ta meritev je tudi merilo hitrosti črne luknje, ker je plin gravitacijsko pritrjen na predmet pošasti.

Astronomi so izračunali, da se črna luknja premika tako hitro, da bi v treh minutah potovala od Zemlje do Lune. To je dovolj hitro, da črna luknja čez 20 milijonov let pobegne iz galaksije in za vedno potuje po vesolju.

Posnetek Hubbla je razkril zanimiv namig, ki je pomagal razložiti trmasto lokacijo črne luknje. Gostiteljska galaksija ima šibke značilnosti v obliki loka, imenovane plimski repi, ki jih ustvarja gravitacijski vlek med dvema trčečima galaksijama. Ti dokazi kažejo na možno povezavo med sistemom 3C 186 in drugo galaksijo, od katerih ima vsaka centralne, masivne črne luknje, ki so se sčasoma lahko združile.

Na podlagi teh vidnih dokazov so raziskovalci skupaj s teoretičnim delom razvili scenarij, ki opisuje, kako bi lahko črno luknjo izgnali iz osrednjega doma. Po njuni teoriji se dve galaksiji združita in njuni črni luknji se usedeta v središče novonastale eliptične galaksije. Ko se črne luknje vrtinčijo med seboj, se gravitacijski valovi odnesejo kot voda iz brizgalne trave. Ogromni predmeti se sčasoma približujejo drug drugemu, ko oddajajo gravitacijsko energijo. Če dve črni luknji nimata enake mase in hitrosti vrtenja, močneje oddajata gravitacijske valove vzdolž ene smeri. Ko dve črni luknji trčita, prenehata proizvajati gravitacijske valove. Nato se združena črna luknja nato odbije v nasprotni smeri najmočnejših gravitacijskih valov in požene kot raketa.

Raziskovalci imajo srečo, da so ujeli ta edinstven dogodek, saj vsaka združitev črne luknje ne povzroči neuravnoteženih gravitacijskih valov, ki črno luknjo poganjajo v nasprotni smeri. "Ta asimetrija je odvisna od lastnosti, kot sta masa in relativna usmerjenost osi vrtenja zadnjih lukenj pred združitvijo," je dejal član ekipe Colin Norman iz STScI in univerze Johns Hopkins. "Zato so ti predmeti tako redki."

Alternativna razlaga za odmični kvazar, čeprav malo verjetna, predlaga, da svetel objekt ne prebiva v galaksiji. Namesto tega se kvazar nahaja za galaksijo, toda Hubblova slika daje iluzijo, da je na isti razdalji kot galaksija. Če bi bilo temu tako, bi morali raziskovalci v ozadju zaznati galaksijo, ki gosti kvazar.

Če je interpretacija raziskovalcev pravilna, lahko opažanja dajejo trdne dokaze, da se lahko supermasivne črne luknje dejansko združijo. Astronomi imajo dokaze o trkih črnih lukenj pri zvezdnih masnih črnih luknjah, vendar je postopek uravnavanja supermasivnih črnih lukenj bolj zapleten in ni popolnoma razumljen.

Ekipa upa, da bo Hubble znova uporabila v kombinaciji z velikim milimetrskim / submilimetrskim nizom Atacama (ALMA) in drugimi objekti za natančnejše merjenje hitrosti črne luknje in njenega plinskega diska, kar bo morda prineslo večji vpogled v naravo tega bizarni predmet.

Vesoljski teleskop Hubble je projekt mednarodnega sodelovanja med NASA in ESA (Evropska vesoljska agencija). NASA-jev center za vesoljske lete Goddard v Greenbeltu v zvezni državi Maryland upravlja teleskop. Znanstveni inštitut za vesoljski teleskop v Baltimoru izvaja Hubblove znanstvene operacije. STScI za NASA upravlja Združenje univerz za raziskave v astronomiji, Inc., v Washingtonu, DC.

Izjava o omejitvi odgovornosti: AAAS in EurekAlert! ne odgovarjamo za točnost objav novic, objavljenih na EurekAlert! s prispevanjem institucij ali za uporabo kakršnih koli informacij prek sistema EurekAlert.


Planeti, ki hitijo v bližini svetlobne hitrosti? Možno je, pravi študija.

Znanstveniki želijo vedeti, ali se lahko planeti oblikujejo v bližini supermasivne črne luknje v jedru galaksije. Če je tako, bi jih črna luknja lahko izstrelila v vesolje z ogromno hitrostjo, ki bi se z našega vidika lahko približala svetlobni hitrosti.

Globoko v osrčju Rimske ceste, kjer se skriva supermasivna črna luknja, so razmere tako kaotične, da planeti - in morda življenje - ne morejo nastati: Ali pa lahko?

Majhna skupina astronomov predlaga en način za odgovor na vprašanje, vsaj če se nanaša na planete: spremljajte zavrnitve Rimske ceste - zvezde, ki jih je osrednja črna luknja galaksije brcnila proti medgalaktičnemu vesolju - za znake planetov.

Takšni planeti - ki krožijo okoli zvezde ali potujejo sami - so zaenkrat hipotetični. Središče galaksije je tako zavito v prah, da je lov na planete, kot se izvaja v naši galaktični soseski, zaman.

Toda posamezne izvržene zvezde, ki so jih poimenovali hiperhitrostne zvezde, ker jih vržejo s tako veliko hitrostjo, so vse prej kot hipotetične. Poročali so, da je prvi zvezdni hitrostnik zapustil galaksijo leta 2005. Od takrat je seštevek zrasel na najmanj 16 zvezd o hiper hitrosti.

Lov na več v halou galaksije, kjer so najbolj očitna, nato pa spremljanje, ali je podpis tranzita planeta čez obraz zvezde, bi pomagal rešiti vprašanje, ali je središče galaksije gostoljubno za nastanek planetov, pojasnjuje Avi Loeb , astronom iz Harvard-Smithsonian Centra za astrofiziko v Cambridgeu, Massachusetts.

Ko portfelj Kamale Harris raste, raste tudi nadzor

Je eden od soavtorjev prispevka, objavljenega v Monthly Notices of the Royal Astronomical Society v Veliki Britaniji, ki preučuje mehanizem izmetov in kako se lahko lovi.

Z prizadevanji za lov na planete, kot je NASA-ina misija Kepler, ki je našla na stotine potrjenih planetov, pri čemer je vsaj 2000 kandidatov čakalo v krilih na potrditev, bi se zdela smiselna ideja, da zvezde v galaktičnem središču gostijo tudi planete.

Toda več dejavnikov bi lahko vplivalo na tamkajšnje planete, pojasnjuje dr. Loeb.

Širše območje okoli črne luknje je žarišče nastajanja zvezd. Zvezde so tam približno milijonkrat bolj gosto nabito kot zvezde v sončni soseščini. V galaktičnem središču so zvezde, ki običajno nastanejo, bolj masivne kot sonce, vroče gorijo in letejo okoli galaktičnega središča s hitrostjo več kot 2 milijona milj na uro, v primerjavi s soncem približno pol milijona milj na uro.

V teh utesnjenih, turbulentnih razmerah bi zvezdni disk prahu in plina težko visel skupaj toliko časa, da bi lahko planeti nastali.

Kljub temu nekatera opazovanja namigujejo, da bi lahko planeti nastali blizu središča Rimske ceste.

Na primer, raziskovalci so opazili zanimive dogodke, podobne vžigalnikom, ko se material segreje, stisne in nato pogoltne skozi izredno gravitacijsko vleko črne luknje. Dokazi kažejo, da material morda ni zvezda, temveč asteroidi - planetarni gradniki.

Razmišljanje: vžig obsojene soncu podobne zvezde bi se zgodil približno enkrat na 10.000 let in trajal mesece, je lani jeseni opazila ekipa astronomov z univerze Leicester v Veliki Britaniji in Amsterdamske univerze na Nizozemskem. Toda opazovalci so zaznali vsakodnevne rakete, ki bi trajale nekaj ur.

V začetku tega leta so raziskovalci odkrili, kaj so razlagali kot plinski oblak, ki pade v črno luknjo. Ena od možnih razlag: Oblak je prvotno krožil okoli zvezde z majhno maso, vendar se je osvobodil, da je nahranil črno luknjo. Prisotnost plinskega oblaka v bližini galaktičnega jedra bi tudi nakazovala, da tam obstajajo planetarni gradniki.

Kaj pa bi se zgodilo s planetarnimi sistemi po bližnjem srečanju s supermasivno črno luknjo?

Loeb in kolegi so menili, da planeti krožijo okrog binarnih zvezd na razdalji 2000 astronomskih enot od osrednje črne luknje galaksije - ali približno 2000-krat več kot od Zemlje do sonca. Če bi zvezde vsebovale po en ali dva planeta Jupitrove lestvice, bi lahko gravitacijske interakcije med zvezdami in črno luknjo eno zvezdo in njeno potomstvo odvrteli iz galaksije.

Preostali zvezdi bi odvzeli planete, ki bi jih prav tako lahko vrgli. Ekipa je izračunala, da bi lahko ti planeti brez zvezd v pravih pogojih zapustili galaksijo s hitrostjo nekaj odstotkov svetlobne hitrosti. Medtem bi se zdaj brez planeta zapuščena zvezda preselila bližje črni luknji.

"Razen subatomskih delcev ne vem, da bi kakšna galaksija tako hitro zapustila našo galaksijo", kot so najhitrejši ubežni planeti v simulacijah ekipe, je dejal Idan Ginsburg, podiplomski študent na Dartmouth College v Hannovru v zvezni državi NH in vodilni avtor novega članka , v pripravljeni izjavi.

Loeb pravi, da bi moral planet ostati vezan na izvrženo zvezdo, da kroži zelo blizu zvezde. To bi tudi znatno povečalo možnost, da bi veliki zemeljski teleskopi opazili učinek, ki bi ga imeli ti planeti na svetlobo zvezde, ko prehajajo skozi sonce.

Zgodbe o monitorju, ki vas zanimajo, dobite v nabiralnik.

Če obstajajo hiperhitrostni planeti ali planetarni sistemi in če imajo dovolj občutljivega življenja, da bi to opazili, "bi bila ta vožnja zelo razburljiva," pravi Loeb.

Planetni sistem bi se gibal počasneje kot nevezani planet, a načeloma bi lahko še vedno živel, dodaja. Ugiba se, da bi se lahko zanesel v pospešeno širitev vesolja, sčasoma pa dosegel hitrosti, ki bi se z razgledne točke, vezane na Zemljo, približale svetlobni hitrosti.


Raziskave kažejo, da so planeti okoli supermasivnih črnih lukenj zdaj mogoči

Gledano skoraj po robu turbulentni disk plina, ki se vrti okoli črne luknje, dobi nor dvogrbi videz. Ekstremna gravitacija črne luknje spremeni poti svetlobe, ki prihaja iz različnih delov diska, kar ustvarja ukrivljeno sliko. Ekstremno gravitacijsko polje črne luknje preusmerja in izkrivlja svetlobo, ki prihaja iz različnih delov diska, vendar natančno to, kar vidimo, je odvisno od našega vidnega kota. Največje popačenje se pojavi pri ogledu sistema skoraj po robu. Zgornja slika je NASA-ina simulacija, kako bi lahko izgledala Črna luknja.

Kredit: Nasin center za vesoljske lete Goddard / Jeremy Schnittman

Vsaka galaksija ima svoje srce v epicentru in kot vaše človeško srce je to srce bistvenega pomena tudi za galaksijo, v kateri obstaja. Supermasivna črna luknja je vesolje in znanost ta organ. V primeru naše Rimske ceste je lokacija te črne luknje v Galaktičnem jedru, rotacijskem središču naše galaksije, ali mestu Saggitarius A, kompaktnem astronomskem radijskem viru.

Preden začnemo vedeti več o planetih okoli črne luknje, moramo vedeti, kaj natančno je črna luknja. To je območje prostora-časa, kjer je moč gravitacije tako močna, da ji celo svetloba ne more uiti. Potem ko črna luknja nastane, absorbira vse, kar prestopi določeno mejo, znano tudi kot obzorje dogodkov. Vsaka črna luknja ima okoli sebe krof v obliki prahu in plinov, ki se imenuje torus.

Različni vidiki simulacije. Vir slike: Nasin center za vesoljske lete Goddard / Jeremy Schnittman

Z absorpcijo drugih zvezd in mešanjem z drugimi črnimi luknjami dobimo tako imenovano supermasivno črno luknjo. Supermasivna črna luknja ima lahko maso, ki je štiri milijone večja od mase sonca, ki sedi v središču našega sončnega sistema.

Toda glede na najnovejše raziskave Japonskega nacionalnega astronomskega observatorija bi lahko planeti krožili okoli njih.

Prej smo imeli idejo, da so planeti nastali samo iz protoplanetarnih diskov, ki so bili sestavljeni iz prahu in plina okoli zvezd. Toda ta zadnja raziskava navaja, da se lahko planeti razvijejo tudi iz torusa okoli SMBH (Supermasivna črna luknja).

Umetniški prikaz supermasivne črne luknje. Slika: NASA

& # 8220 Torus SMBH ima maso približno 100.000-kratno maso sonca, kar je milijardokrat več kot masa prahu na protoplanetarnem disku, & # 8221 pravi profesor Eiichiro Kokubo in sodelavci iz Nacionalnega astronomskega observatorija Japonska v izjavi. Da prah v torusu tvori planet, potrebujemo različne temperature v oblakih (tam igrajo vlogo črne luknje). Prašni disk okoli črnih lukenj je tako močan, da se močno sevanje iz osrednje regije ustavi in ​​nastanejo območja z nizko temperaturo.

Če je temperatura dovolj nizka, se prah lahko združi in tvori protoplanet, ki je primarna stopnja pri gradnji planeta. Iz teh regij lahko nastanejo majhni ledeni delci, ki lahko sčasoma prerastejo v zemeljske svetove. Oddaljenost od črnih lukenj je lahko približno deset svetlobnih let od črne luknje, pri čemer je planet desetkrat večji od mase našega planeta Zemlja.

To lahko privede do planetarnega sistema okoli črnih lukenj. To je osupljivo odkritje, če upoštevamo dejstvo, da so razmere tam zelo ostre in razdražljive. Članek ekipe bo objavljen v Astrophysics Journal.

Prijavite se, če želite, da pišete za nas, če radi pišete in želite videti svoje članke Apple News, Google News, in več.


Nova opazovanja potrjujejo galaktično teorijo supervalov

Potrditev ključne teze o teoriji galaktičnega supervalova je trajalo več kot 30 let, zdaj pa so našli neovrgljive dokaze. Opazovanja aktivne galaksije PDS 456, posnete z vesoljskim teleskopom NASA & # 8217s NuSTAR (Nuclear Spectroscopic Telescope Array), ki deluje od junija 2012, in z vesoljskim teleskopom Evropske vesoljske agencije XMM-Newton zdaj kažejo na prisotnost izredno visokega hitrostni veter se izotropno odmika od središča galaksije v vse smeri s hitrostjo do 30% svetlobne hitrosti. Pred tem so astronomi domnevali, da vetrovi, ki jih proizvajajo aktivna galaktična jedra, izhajajo predvsem iz njihovih polov v obliki curkov.

Leta 1983 sem doktoriral. v disertaciji sem nasprotoval temu modelu, ki dokazuje, da kozmični žarki iz aktivnih galaktičnih jeder (kvazarji, blazerji, Seyfertove galaksije itd.) sevajo v vse smeri, ne le proti polom, in da prednji žarek sinhrotronskega sevanja ultrarelativističnega kozmičnega žarki dajejo iluzijo, da so zaprti kot curki, ker so zaradi sevanja vesoljni žarki, ki prihajajo skoraj neposredno proti nam, edini, katerih sevanje lahko vidimo. Napačna interpretacija astronomske skupnosti, da pojav curka povzročajo kozmični žarki, ki se počasi premikajo navzven v obliki namagnetene plazme, je leta zavajala astronomsko skupnost, ko je mislila, da so curki skoraj pravokotni na naš vidni kot in da je njihov vesoljski žarki in plini uhajajo predvsem s polov galaksije. Konvencionalna teorija je imela, da se je gibanje plina v disku galaksije gibalo predvsem navznoter proti njenemu središču, da je napajalo njeno supermasivno jedro (zmotno mišljeno kot & # 8220črna luknja & # 8221). Ta model izpodbijam že 32 let v svoji disertaciji v reviji iz leta 1987: Vesolji kozmičnih žarkov iz Galaktičnega centra in njihov nedavni vpliv na zemeljsko okolje, v knjigi Zemlja pod ognjemin v različnih spletnih objavah:
• https://starburstfound.org/superwaveblog/?p=334
• https://starburstfound.org/superwaveblog/?p=195
• https://starburstfound.org/superwaveblog/?p=16
• https://etheric.com/fermi-gamma-ray-evidence-superwaves-traveling-outward-galactic-center/
• https://etheric.com/msnbc-interviews-paul-laviolette/

PDS 456 je aktivna galaksija, oddaljena več kot 2 milijardi svetlobnih let (z = 0,18), katere jedro gre skozi fazo kvazarja, ki oddaja sevanje s hitrostjo

10 47 ergov na sekundo, hitrost približno 100 bilijonov krat večja od našega lastnega galaktičnega jedra. Z uporabo teh novih teleskopov so astronomi lahko spektroskopsko zaznali emisijske in absorpcijske značilnosti visokohitrostnih atomov železa, ki se skupaj z drugim ioniziranim plinom pretakajo iz njegovega galaktičnega središča. Ugotovili so, da se te spektroskopske značilnosti ujemajo s tistim, kar astronomi imenujejo profil P Cygni, spektroskopski podpis blueshift / redshift, ki ga ionizirani plin pretaka navzven v vse smeri v obliki krogle ali sferične lupine. Opazovali so veter okoli 700 a.j. iz galaktičnega jedra (

700-krat večja od oddaljenosti Sonca do Zemlje) in opazili, da se širi navzven pod trdnim kotom najmanj 2π, torej na vsaj polovici površine krogle, kar pomeni, da je dejansko pihalo navzven v vse smeri.

Zelo verjetno bodo podobne kroglaste izlive vetra našli tudi v drugih galaksijah. Ta ugotovitev izpodbija običajni pogled, da so te supermasivne črne luknje jedra, ki jih napaja padajoči material. Ker ta skupina priznava, da ob tako močnem vetru, kot ga vidijo (10 46 erg / sekundo), ne bi bilo mogoče, da bi material padel v jedro in tako spodbujal opažene emisije. Black hole theorists side step this by suggesting that the “black hole’s” activity was fired up at an earlier date when such a wind was absent and that now the presence of this wind will have a limiting effect to cause the black hole’s activity to shut off. Such reasoning, in my opinion, is pure fantasy. The high velocity wind is there because the core is active, and the core is active not because material is falling into it, but because of its intrinsic energy production through spontaneous energy creation, the phenomenon of genic energy production predicted by subquantum kinetics and proven by numerous a posteriori observations.

These recent findings support the subquantum kinetics cosmology which has long proposed that most of the stars in galaxies are formed by matter expelled outward from a galaxy’s core and that is why dwarf elliptical galaxies eventually adopt a spiral shape and then progressively grow in size. These findings then support the subquantum kinetics view of why there is a close correspondence between the mass of a galaxy’s core (Mother star) and its total mass.


Opombe

[1] The precise measure of the stellar mass in Holmberg 15A, reported in the study described below in the article, is (2.5 ± 0.64) × 10¹² solar masses.

[2] Although far away, Holmberg 15A is considered from a cosmological point of view a galaxy of the local Universe, meaning by this expression that region of the observable Universe, which, due to its relative spatial and temporal proximity, contains galaxies in an evolutionary phase comparable to that of the Milky Way. Indeed, the 800 million years or so that light from Holmberg 15A traveled to reach the Earth are only a modest fraction of the age of the Universe, which is 13.8 billion years old. As a result, they are also a small fraction of the evolutionary history of galaxies, which began just a few hundred million years after the Big Bang.

[3] Roughly 10,000−16,000 light-years.

[4] The precise values ​​indicated in the study are (2.75 ± 2.22) × 10¹⁰ solar luminosities and (1.24 ± 1.00) × 10¹¹ solar masses.

[5] (4.0 ± 0.8) × 10¹⁰ solar masses, including the uncertainty margin resulting from the data.

[6] The gravitational sphere of influence is defined in the study as the radius within which a mass exactly equal to that of the SMBH is enclosed. In the case of Holmberg 15A, the radius of the gravitational sphere of influence of its SMBH reported in the study is 3.8 ± 0.37 kiloparsecs.

[7] Outside the event horizon of a black hole, there is a spherical volume, within which the light remains trapped following almost circular orbits until it falls into the black hole or escapes to infinity. It is this light that forms the photonic ring observed by the Event Horizon Telescope in the famous image of the black hole at center of M87, published in April 2019.


The Fate of Planets Near Galactic Center

It was Gregory Benford who used the wonderful phrase ‘the first hard science fiction convention’ to describe what happened at the 100 Year Starship Symposium. It was an apt choice of words. ‘Hard’ science fiction refers to SF that goes out of its way to get the science right, and in which the scientific and technical details play a major role in the development of the plot. Science fiction critic P. Schuyler Miller evidently coined the term in one of his reviews for Astounding Science Fiction back in the 1950s. In many ways, the Symposium operated under a science fictional meme.

Science fiction at its best exists to paint possibilities for us. Some scientific speculations may be remarkable in their own right but only become vivid when portrayed by writers who can make the background science into a scenario that plays out in fictional terms. An obvious case is the classic Isaac Asimov tale “Nightfall,” published in Osupljivo’s September, 1941 issue. Asimov took us to a place that knew night only once every 2000 years because of the configuration of the six suns in its planetary system. His craft painted a world few would have imagined, and showed us the consequences of its existence upon a civilization there.

All these musings were triggered by the latest news from the University of Leicester, and I’d love to see the science fiction story that might emerge when ‘hard’ SF tackles its findings. Surely someone will tell the story of a civilization too close to galactic center (speaking of places that are well lit!), and the consequences as radiation levels begin to rise to untenable levels on a world too near the central black hole. If interstellar flight is possible, surely it would happen here as a means of species survival.

For black holes seem to be common at galactic center in many galaxies, and in particular the supermassive ones that lurk at the center of galaxies like our Milky Way. Huge cloaks of dust obscure many of these, and a team of scientists led by Sergei Nayakshin at Leicester thinks that collisions between planets and asteroids occurring at speeds up to 1000 kilometers per second could be the cause. Nayakshin’s team argues that the accretion disc around supermassive black holes will eventually form planets, and that planets and asteroids that formed in the outer regions of the disc would be stripped away by the close passage of stars in the disc, given the tight quarters at galactic center.

Released from their host stars, these solids and planets orbit the SMBH independently. Since the velocity kick required to unbind them from the host is in km/s range, whereas the star’s orbital velocity around the SMBH is ∼ 1000 km/s, orbits of the solids are initially only slightly different from that of their hosts. AGN gas discs are expected to be very geometrically thin (e.g., Nayakshin & Cuadra 2005), and if they always lay in the same plane (e.g., the disc galaxy’s mid-plane) then the resulting distribution of solids would be quite thin and planar as well.

So far so good, but planets in this scenario seem bound to come to grief:

However, there is no particularly compelling reason for a single-plane mode of accretion in AGN as the inner parsec is such a tiny region compared with the rest of the bulge (Nayakshin & King 2007), and chaotically-oriented accretion may be much more likely…

Collisions are bad enough, but the planets would have already been sterilized as they orbited the supermassive black holes, says Nayakshin in a related news release:

“Too bad for life on these planets, but on the other hand the dust created in this way blocks much of the harmful radiation from reaching the rest of the host galaxy. This in turn may make it easier for life to prosper elsewhere in the rest of the central region of the galaxy.”

The team takes its lead from the zodiacal dust in our own Solar System, known to be the result of collisions between solid objects like asteroids and comets. And its work may help us understand how black holes grow and affect the galaxies within which they reside. The dust and gas in the inner regions of our own galaxy, much of which might have been expelled or destroyed by this process, would otherwise have contributed to the formation of more stars and planets. The black hole at galactic center would have thus played a significant role in the evolution of the Milky Way.

Slika: ‘Light echo’ of dust illuminated by a nearby star V838 Monocerotis as it became 600,000 times more luminous than our Sun in January 2002. The flash is believed to have been caused by a giant collision of some kind, e.g., between two stars or a star and a planet. Collisions of smaller objects, such as asteroids or minor planets near a supermassive black hole could also be dramatic due to the huge collision velocities and would release a lot of dust. Credit: NASA/ESA.

The paper is Nayakshin, et al., “Are SMBHs shrouded by ‘Super-Oort’ clouds of comets and asteroids?” in press at Mesečna obvestila Royal Astronomical Society (preprint). The science fiction story based on it remains to be written.

Comments on this entry are closed.

A civilization to close to the galactic center would probably find themselves in the proverbial frying pan. Planets near the center would experience far more exposure to gamma rays, x-rays, and cosmic rays. My question is, how did complex life and a technological civilization evolve so near the galactic center in the first place? Some scientists theorize there is a “galactic habitable zone” which is friendly to complex life, like us, but anywhere close to the galactic center is well out of this theoretical GHZ!! Any thoughts?

This new research is interesting. Finally, someone is telling us why the galactic center is shrouded in dust- all they told us before is that you can’t see the black hole because visible light cannot penetrate the dust cloud.

Back to the civilization that must escape from the rising radiation levels near the galactic center- wouldn’t high radiation levels make space travel extremely hazardous? If the radiation levels have risen high enough that even a thick atmosphere is not shielding enough, how could a starship survive? If you want to escape dangerous radiation levels, you have to leave your neighborhood altogether.

The distance from Earth to the galactic center is 25000-28000 lys. How far would this civilization need to go to escape the dangerous radiation levels?

Space travel might be easier near the galactic center. There are large clouds of hydrogen near the galactic center, which will make the fusion ramjet a lot more practical. The stars are more densely packed, which will be an incentive for any budding starflight program. If you only have to travel one lightyear instead of four to reach a nearby star, interstellar travel will be easier than it is in our neighborhood.

Once stellar explosions start turning up the heat in their neighborhood, these aliens will turn their ramjets out from the galactic center and head for cooler, safer regions of space. Areas without dangerous gamma rays and x-rays, densely packed stars, nearby novas, and a giant black hole lurking nearby.

However, I think the dangerous radiation and nearby novas would wipe any life before they build interstellar ramjets. I prefer our neighborhood- there might not be any free fuel, but it is a lot safer.

Would a voyage to the galactic center in a starship with a hyperdrive be heroic exploration or insanity?

Speaking of hard sci-fi and galactic centers surely a mention of Greg Egan’s Incandescence is warranted.

(I must mention that if Egan is new to you, then Diaspora is a must read.)

Hi Paul
Stephen Baxter’s “Exultant” in its opening scenes is set amongst the asteroids around the Milky Way’s SMBH. The Core region does get more interesting, the more we study it.

I’ve only just cracked open this paper but something immediately struck me as odd in their reasoning.

First, where did the metals come from that formed these stellar systems near the AGN? Fragmentation beyond a certain threshold distance from the accretion disk. But how did they come to be in the accretion disk to begin with? That must have been from older novae near the AGN, and brought into the accretion disk along with non-metals (hydrogen).

So suggests to me there is a partial recycling of accretion disk material going on, where a portion falls into the SMBH, another portion into the SMBH jets, and the rest into (the paper’s hypothesized) fragments forming these stellar systems. I am having difficulty seeing how this would allow large clouds of metals to exist and have the effects suggested in the paper.

Second, while there are great differences in the opacity of metal (dust) clouds and hydrogen, even if all the material in these putative stellar systems gets pummeled into dust clouds it is still only a small fraction the mass of their stellar parents, and over time I would think that the stellar winds alone would greatly out-mass all the expelled metals.

It just doesn’t feel right. Maybe I’ll have to read further into the paper.

I wrote a long series of novels about these problems (though without this recent research), the Galactic Center Series. I supposed the Center was the best place to live if you were a machine intelligence — plentiful energy resources, indifference to radiation levels, unconcerned with planets as life sites since one could live in raw, radiated space.
It still seems that way to me. I doubt life will evolve nearer than 1000 or more light years from the devouring black hole squatting at the Center.
Yet I supposed humans would go there, seeking the answer to why machine intelligences sought out organic life like us and sought to exterminate it. The astrophysics I did on the magnetic structures around the black hole — which interestingly don’t occur in the Andromeda galaxy — led me to write the rest of the series, after the first two novels.
The Center realm remains the most fascinating region of our galaxy, though not I think a zone for life.

One recent study of the GHZ, Gowanlock, Patton and McConnell (2011) concluded that although the risk from supernovae to the biosphere in the inner galaxy was far greater, the favourable planet-forming conditions made it the most habitable region of the galaxy (i.e. there are sufficient planets there to compensate for the large fraction that experience supernova sterilisation events). From that paper:

From Sections 4.1 and 4.2, we see that SN sterilizations on their own make the inner Galaxy the least hospitable for complex life. However, regarding the planet-metallicity correlation without the effects of SNe makes the inner Galaxy the most hospitable for complex life. When both factors are taken into account, the inner Galaxy is ∼10× more hospitable than the outer Galaxy (Figure 9). This finding indicates that the impact of metallicity on planet formation appears to dominate over the effects of SN sterilizations. Furthermore, the inside-out scenario of Galaxy formation permits the inner region to be more habitable than the outskirts. Neither SN sterilizations nor metal-poor environments are capable of rendering any region inhospitable to complex life at the present day.

Of course this is unlikely to be the final word on the issue…

Andy: What form does this “sterilization” take? I thought a supernova was quite weak even just a few light years away, and a thick atmosphere like the Earth’s does not really let any ionizing radiation through, or does it? If this “sterilization” is just about potential damage to the ozone layer, that would hardly qualify as a life extinguishing event, I think.

Cockroaches, and many bacteria, can tolerate high levels of radiation. I don’t know how they manage it, but life on planets near the galactic center could do the same. Life might take longer to develop, but once it does, *all* life on the planet might be like cockroaches, able to tolerate practically any environment.

Welp.
Larry Niven has us all almost trumped.
Pierson’s Puppeteers are taking their whole kit and caboodle of a Fleet of Worlds out of the galactic center, or where they were near the center.

Say, Greg, I think you said you had some idea to trump Larry?
Didn’t some Russian astronomer have an idea is moving the whole solar system with a big mirror around the sun?

Anybody ever written a story where ‘solid state’ intelligence evolves in a hostile radiation environment , such as near the galactic core.
Then goes on to build ‘wet ware’ things like humans?

The Milky Way and Andromeda galaxy are on a collision course. In about 3 billion years, the two galaxies will collide. That can’t be good for us!
How would one move the Milky Way?
I would say that would take a Kardashev type X!

Eniac: the model for supernova sterilisation used for that analysis is surprisingly enough discussed in the paper. Read section 3.1…

Fred Hoyle’s novel “The Inferno” featured the Milky Way’s centre becoming a full-on quasar. More importantly he used this unlikely scenario to illustrate a factor that I have never seen formally addressed. Unlike supernovas, the power of a galactic core event can be so great as to completely disrupt the galaxy’s magnetic field. In the novel this opened the possibility of every system, even in the galactic disc, being bathed in radiation from the quasar that was so intense that it could completely strip a planet’s atmosphere, but I can’t help but think of milder possibilities such as those highlighted by the cyclical occurrences of mass extinctions on Earth tending to coincide with periods when our system is at locations with the least protection from our galaxy’s field.

My question is how resilient is the bulge of our galaxy to such magnetic field disruptions and how real is the possibility that disruptions thereof by (a series of) core events can play a greater role in the development of higher life than this field does in the disc?

Andy: As I suspected, they appear to assume that a supernova closer than 8 pc will strip aways the ozone layer which will then “sterilize” the planet. I would like to submit these caveats:

1) The ozone layer might be more resilient than we think
2) Something else might replace the ozone layer
3) Life may survive the lack of ozone layer
4) There may be stars with less UV where no ozone layer is needed
5) Bigger planets may have a thicker atmosphere and no need for an ozone layer
6) … etc. etc.

I think there are so many caveats that it is unrealistic to assume that we have any idea about what distance a supernova needs to be to “sterilize” planets. Therefore the inner limit of the GHZ may well be the event horizon of the black hole, or at least not too far from it.

@andy: yes, while most authors, such as Lineweaver, consider the GHZ as an annular ring at about 6-10 kpc from the galactic center, Gowanlock, Patton and McConnell (‘A Model of Habitability Within the Milky Way Galaxy’) model it from 2.5 kpc (or possibly even closer) to at least 12 kpc from the center, with the density of habitable planets in the inner region about 10x as high as in the outer region, also resulting in a rather high estimate of the number of habitable planets in the MW galaxy.

Stephen: scorpions are also known to tolerate very high levels of radiation.

A.A. Jackson: the ‘collision’ of the MW with Andromeda will not be a real collision, but rather a merging of the two galaxies, not uncommon in the history of the universe. Because of the huge distances between the individual stars, there will hardly be any real stellar collisions, in fact very few stars will even be caught in each other’s gravity field (to become secondary binary stars, a very rare event). What may happen is that stars may be disrupted in their galactic orbits and there will probably be a (relatively short duration) outburst of new star formation.

The description of Hoyle’s “Inferno” makes me think of Donald Moffitt’s duology “Second Genesis”/”The Genesis Quest” about an off-shoot of humanity being made by aliens in a distant Galaxy (M101) from radio transmission data. The second book features a very interesting take on the Fermi Paradox based on periodic extinctions, akin to Hoyle’s concept.

The book is now rather out-of-date – eg. M101 is now known to be 21 Mly away, not 37 Mly as was previously thought – but periodic extinctions still drop out of the fossil data. One wonders just what Galaxies do every so often…

One more thought: Isn’t the ozone layer derived from atmospheric oxygen? That would mean that for most of its life Earth did not have one to begin with. Any calculations of GHZ based on supernovas stripping the ozone layer would then be blatantly invalid.

And please all remember that ionizing radiation does not penetrate the atmosphere, so no cockroaches or scorpions required. For UV, there could be a permanent cloud layer, or we could have life that is undersea or underground.

@Eniac: ozone has been detected on both Mars and Venus, there isn’t much of it though…

To me, it would make just as much sense that strong X-rays generate more ozone directly than they destroy indirectly by generating nitrous oxide.

Anyway, after all this and some reading I am now quite convinced that a supernova cannot have a lasting ill effect on life (much less “sterilization”) unless it is close enough to literally fry the place, i.e. provides as much energy as the sun. For the strongest supernovas, this would be less than one light year, which should be an unlikely occurrence even quite close to the galactic center. I would be happy to hear reasons why I am wrong.

Eniac, although I agree with you that supernovas are probably nor such a big risk, your 1 ly ‘safe distance’ may be a bit too optimistic: as I wrote in the previous post (Widening the Red Dwarf Habitable Zone), there are some studies indicating that the most dangerous supernovas, Type Ia, may harm a planet (atmosphere, biosphere) up to about 30 ly.

It shouldn’t be too difficult to make some base caslculations: how much radiation of various types (visible light + IR, UV, X-ray, gamma) reaching our upper atmosphere would be harmful per unit area?
It would be easy to calculate how much that would be at a given distance for a supernova of a particular type.

there are some studies indicating that the most dangerous supernovas, Type Ia, may harm a planet (atmosphere, biosphere) up to about 30 ly.

Well, yes, but what I have come to realize (please tell me if I am wrong) is that those “some studies” are based on the destruction of the ozone layer as the mechanism for sterilization. To me, that is not conclusive (not even close) for all the reasons you will discover if you read my other posts on this matter.

Anyway, after all this and some reading I am now quite convinced that a supernova cannot have a lasting ill effect on life (much less “sterilization”) unless it is close enough to literally fry the place, i.e. provides as much energy as the sun. For the strongest supernovas, this would be less than one light year, which should be an unlikely occurrence even quite close to the galactic center. I would be happy to hear reasons why I am wrong.

What about the expanding shell of high-velocity gas? Sten Odenwald answered the question of what would happen if Betelgeuse went supernova, and the expanding shell of gas would push the suns magnetosphere so far in it would touch the orbit of the Earth.

Apparently, the detonation of Betelgeuse would not be too dangerous for life on Earth, but travelers in interplanetary space would need extra shielding.

Betelgeuse is 160 parsecs (520 light-years) distant. If you were much closer, say within a dozen light years, I’d imagine that the expanding shell of gas might have much worse effects on habitable planets. Do you have any thoughts on this damage mechanism?

Here is what Sten Odenwald hast to say about Betelgeuse going supernova.

Betelgeuse is 160 parsecs (520 light years) distant. If we just consider what could happen as a result of its expanding shell of gas, typical shell velocities are about 10,000 kilometers/sec. The shell would arrive here about 100,000 years after we see the star brightened. The shell would carry perhaps 10 times the mass of the Sun or some 2 x 10^58 protons. The flux of particles in a shell with a radius of 160 parsecs would be about 140,000 protons per second per square centimeter. The solar wind flux, by comparison is about 300 million protons/sec/square centimeter at the Earth’s orbit. So, although detectable, the flux from Betelgeuse probably won’t do much biological damage compared to what the Sun does. However, because the Betelgeuse flux is traveling at 10,000 kilometers/sec compared to the 450 kilometers/sec of the solar wind, the Betelgeuse flux has an effective pressure that is (10,000/450)^2 = 490 times stronger than the solar wind, and spread out over a region much larger than the size of the solar system. This would probably cause the Sun’s magnetopause to collapse from its present radius near 100 AU, to possibly less than the orbit of the Earth. Also, the Earth’s magnetosphere would be compressed, which would cause the energies of the particles in the van Allen belts to be amplified. The environment outside the van allen radiation belts would probably be ‘lethal’ for human exploration of the solar system.

There is also the x-ray flux to contend with. Inside this shell, which would probably take many decades to pass by, there is a bubble of plasma consisting of electrons and magnetic fields which produce copious amounts of X-ray light. We would be subjected to this x-ray flux for 10s of thousands of years until the expanding supernova remnant has aged sufficiently to quench this production mechanism. These X-rays, of the ‘soft’ variety’ would not get down to the Earth’s surface thanks to atmospheric shielding, but travelers in interplanetary space would need some additional shielding from the secondary electrons generated as these x-rays strike the skin of their spacecraft and liberate additional electrons.

I’ve just noticed that you and Ronald were only discussing radiation and the stripping of the ozone layer- but I’d think that the impact of the expanding shell of gas at close range might be bad. Se motim? Or is the expanding shell of gas only going to affect the ozone layer, which you don’t seem to think is going to be lethal for life?

Christopher Phoenix, very interesting information from Sten Odenwald, that you passed on.
However, there is one little flaw with the expaning shell/proton flux as described, or maybe not even a flaw, but a detail to bear in mind that makes this proton flux considerably less dangerous:
Quote:
“However, because the Betelgeuse flux is traveling at 10,000 kilometers/sec compared to the 450 kilometers/sec of the solar wind, the Betelgeuse flux has an effective pressure that is (10,000/450)^2 = 490 times stronger than the solar wind”.
This � times srtonger than solar wind’ is *per proton*.
The amount of protons is only 140,000/300 million = about 0.0005

Which means that the total proton energy from Betelgeuse at this distance would only be about 23% of the solar wind.

It’s a pity Odenwald does not elaborate on the amount of X-ray (or did he?).

The shock continuously slows down over time as it sweeps up the ambient medium, but it can expand over hundreds of thousands of years and over tens of parsecs before its speed falls below the local sound speed.

50 ly, so I am afraid Sten Odenwald is mistaken about the speed with which the Betelgeuse ejecta would arrive here. More likely, they would never arrive at all, having slowed down to a crawl and eventually dissipated before making it 10% of the way. Nevertheless, it seems likely that supernova ejecta could be comparable with the solar wind in density or energy somewhat further away than the 0.5 ly or so that it takes for the electromagnetic radiation energy to be reduced below solar levels. It is not going to kill anything on Earth, but it may cause radiation damage to space craft and unlucky astronauts.


Planets around Supermassive Black Holes are now possible, research reveals

Seen nearly edgewise, the turbulent disk of gas churning around a black hole takes on a crazy double-humped appearance. The black hole’s extreme gravity alters the paths of light coming from different parts of the disk, producing the warped image. The black hole’s extreme gravitational field redirects and distorts light coming from different parts of the disk, but exactly what we see depends on our viewing angle. The greatest distortion occurs when viewing the system nearly edgewise. Above image is a NASA simulation of how a Black Hole might look like.

Kredit: NASA’s Goddard Space Flight Center/Jeremy Schnittman

Every galaxy has its heart in the epicenter, and as your human heart, this heart is also vital to the galaxy it exists in. A supermassive black hole is what this organ is in terms of space and science. In the case of our Milky Way, the location of this Black Hole is at the Galactic Core, the rotational center of our galaxy, or the site of the Saggitarius A, a compact astronomical radio source.

Before we jump into knowing more about the planets around a black hole, we need to know what a Black Hole is exactly. It is a region of space-time where the power of gravity is so strong that even light can’t escape from it. After being formed, a black hole absorbs anything that crosses a specific boundary, also known as the event horizon. Each black hole has a doughnut-shaped formation of dust and gases around it, which is called a torus.

The various aspects of the simulation. Image Source: NASA’s Goddard Space Flight Center/Jeremy Schnittman

By absorbing other stars and mixing up with other black holes, we get what is known as a supermassive black hole. A supermassive black hole can have a mass four million times the mass of the sun sitting at the center of our solar system.

But according to the latest research by the National Astronomical Observatory of Japan, it may be possible for planets to orbit them.

Earlier, we had the notion that planets only formed from protoplanetary disks, which were made up of dust and gas found around stars. But this latest research states that planets may also develop from the torus around an SMBH (Supermassive Black Hole).

An artistic rendering of a supermassive black hole. Image: NASA

“The torus of an SMBH has a mass of about 100,000 times the mass of the sun, which is a billion times the mass of the dust in a protoplanetary disk,” says Professor Eiichiro Kokubo and colleagues from the National Astronomical Observatory of Japan in a statement. For the dust in a torus to form a planet, we need different temperatures in the clouds (which is where the black holes play a part). The dust disk around the black holes is so intense that the strong radiation from the central region is stopped and the low-temperature areas are formed.

If the temperature is low enough, the dust can cluster together to form a protoplanet, which is a primary stage in the building of a planet. Small icy particles can be formed from these regions, which can eventually grow into Earth-sized worlds. The distance from the black holes can be as close as just ten light-years away from the black hole with the planet being ten times the mass of our planet Earth.

This can lead to a planetary system around the black holes. This is an astounding find when taken into the fact that the conditions there are very harsh and raspy. The team’s paper is going to be published in the Astrophysics Journal.

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Gravitational Wave Kicks Monster Black Hole Out of Galactic Core

The Hubble Space Telescope captured an image of a quasar named 3C 186 that is offset from the center of its galaxy. Astronomers hypothesize that this supermassive black hole was jettisoned from the center of its galaxy by the recoil from gravitational waves produced by the merging of two supermassive black holes.

This image, taken by NASA's Hubble Space Telescope, reveals an unusual sight: a runaway quasar fleeing from its galaxy's central hub. A quasar is the visible, energetic signature of a black hole. Black holes cannot be observed directly, but they are the energy source at the heart of quasars -- intense, compact gushers of radiation that can outshine an entire galaxy. The green dotted line marks the visible periphery of the galaxy. The quasar, named 3C 186, appears as a bright star just off-center. The quasar and its host galaxy reside 8 billion light-years from Earth. Researchers estimate that it took the equivalent energy of 100 million supernovas exploding simultaneously to jettison the black hole. The most plausible explanation for this propulsive energy is that the monster object was given a kick by gravitational waves unleashed by the merger of two hefty black holes at the center of the host galaxy. The Hubble image combines visible and near-infrared light taken by the Wide Field Camera 3.

This illustration shows how gravitational waves can propel a black hole from the center of a galaxy. The scenario begins in the first panel with the merger of two galaxies, each with a central black hole. In the second panel, the two black holes in the newly merged galaxy settle into the center and begin whirling around each other. This energetic action produces gravitational waves. As the two hefty objects continue to radiate away gravitational energy, they move closer to each other over time, as seen in the third panel. If the black holes do not have the same mass and rotation rate, they emit gravitational waves more strongly in one direction, as shown by the bright area at upper left. The black holes finally merge in the fourth panel, forming one giant black hole. The energy emitted by the merger propels the black hole away from the center in the opposite direction of the strongest gravitational waves.

FOR RELEASE: 1:00 pm (EDT) March 23, 2017

Gravitational Wave Kicks Monster Black Hole Out Of Galactic Core

Newswise — Astronomers have uncovered a supermassive black hole that has been propelled out of the center of a distant galaxy by what could be the awesome power of gravitational waves.

Though there have been several other suspected, similarly booted black holes elsewhere, none has been confirmed so far. Astronomers think this object, detected by NASA's Hubble Space Telescope, is a very strong case. Weighing more than 1 billion suns, the rogue black hole is the most massive black hole ever detected to have been kicked out of its central home.

Researchers estimate that it took the equivalent energy of 100 million supernovas exploding simultaneously to jettison the black hole. The most plausible explanation for this propulsive energy is that the monster object was given a kick by gravitational waves unleashed by the merger of two hefty black holes at the center of the host galaxy.

First predicted by Albert Einstein, gravitational waves are ripples in space that are created when two massive objects collide. The ripples are similar to the concentric circles produced when a hefty rock is thrown into a pond. Last year, the Laser Interferometer Gravitational-Wave Observatory (LIGO) helped astronomers prove that gravitational waves exist by detecting them emanating from the union of two stellar mass black holes, which are several times more massive than the sun.

Hubble's observations of the wayward black hole surprised the research team. "When I first saw this, I thought we were seeing something very peculiar," said team leader Marco Chiaberge of the Space Telescope Science Institute (STScI) and Johns Hopkins University, in Baltimore, Maryland. "When we combined observations from Hubble, the Chandra X-ray Observatory, and the Sloan Digital Sky Survey, it all pointed towards the same scenario. The amount of data we collected, from X-rays to ultraviolet to near-infrared light, is definitely larger than for any of the other candidate rogue black holes."

Chiaberge's paper will appear in the March 30 issue of Astronomy & Astrophysics.

Hubble images taken in visible and near-infrared light provided the first clue that the galaxy was unusual. The images revealed a bright quasar, the energetic signature of a black hole, residing far from the galactic core. Black holes cannot be observed directly, but they are the energy source at the heart of quasars - intense, compact gushers of radiation that can outshine an entire galaxy. The quasar, named 3C 186, and its host galaxy reside 8 billion light-years away in a galaxy cluster. The team discovered the galaxy's peculiar features while conducting a Hubble survey of distant galaxies unleashing powerful blasts of radiation in the throes of galaxy mergers.

"I was anticipating seeing a lot of merging galaxies, and I was expecting to see messy host galaxies around the quasars, but I wasn't really expecting to see a quasar that was clearly offset from the core of a regularly shaped galaxy," Chiaberge recalled. "Black holes reside in the center of galaxies, so it's unusual to see a quasar not in the center."

The team calculated the black hole's distance from the core by comparing the distribution of starlight in the host galaxy with that of a normal elliptical galaxy from a computer model. The black hole had traveled more than 35,000 light-years from the center, which is more than the distance between the sun and the center of the Milky Way.

Based on spectroscopic observations taken by Hubble and the Sloan survey, the researchers estimated the black hole's mass and measured the speed of gas trapped near the behemoth object. Spectroscopy divides light into its component colors, which can be used to measure velocities in space. "To our surprise, we discovered that the gas around the black hole was flying away from the galaxy's center at 4.7 million miles an hour," said team member Justin Ely of STScI. This measurement is also a gauge of the black hole's velocity, because the gas is gravitationally locked to the monster object.

The astronomers calculated that the black hole is moving so fast it would travel from Earth to the moon in three minutes. That's fast enough for the black hole to escape the galaxy in 20 million years and roam through the universe forever.

The Hubble image revealed an interesting clue that helped explain the black hole's wayward location. The host galaxy has faint arc-shaped features called tidal tails, produced by a gravitational tug between two colliding galaxies. This evidence suggests a possible union between the 3C 186 system and another galaxy, each with central, massive black holes that may have eventually merged.

Based on this visible evidence, along with theoretical work, the researchers developed a scenario to describe how the behemoth black hole could be expelled from its central home. According to their theory, two galaxies merge, and their black holes settle into the center of the newly formed elliptical galaxy. As the black holes whirl around each other, gravity waves are flung out like water from a lawn sprinkler. The hefty objects move closer to each other over time as they radiate away gravitational energy. If the two black holes do not have the same mass and rotation rate, they emit gravitational waves more strongly along one direction. When the two black holes collide, they stop producing gravitational waves. The newly merged black hole then recoils in the opposite direction of the strongest gravitational waves and shoots off like a rocket.

The researchers are lucky to have caught this unique event because not every black-hole merger produces imbalanced gravitational waves that propel a black hole in the opposite direction. "This asymmetry depends on properties such as the mass and the relative orientation of the back holes' rotation axes before the merger," said team member Colin Norman of STScI and Johns Hopkins University. "That's why these objects are so rare."

An alternative explanation for the offset quasar, although unlikely, proposes that the bright object does not reside within the galaxy. Instead, the quasar is located behind the galaxy, but the Hubble image gives the illusion that it is at the same distance as the galaxy. If this were the case, the researchers should have detected a galaxy in the background hosting the quasar.

If the researchers' interpretation is correct, the observations may provide strong evidence that supermassive black holes can actually merge. Astronomers have evidence of black-hole collisions for stellar-mass black holes, but the process regulating supermassive black holes is more complex and not completely understood.

The team hopes to use Hubble again, in combination with the Atacama Large Millimeter/submillimeter Array (ALMA) and other facilities, to more accurately measure the speed of the black hole and its gas disk, which may yield more insight into the nature of this bizarre object.

The international team of astronomers in this study consists of M. Chiaberge (STScI and Johns Hopkins University), J. Ely (STScI), E. Meyer (University of Maryland Baltimore County), M. Georganopoulos (University of Maryland Baltimore County and NASA Goddard Space Flight Center), A. Marinucci and S. Bianchi (Università deli Studi Roma Tre, Italy), G. Tremblay (Yale University), B. Hilbert and J. Kotyla (STScI), A. Capetti (INAF - Osservatorio Astrofisico di Torino, Italy), S. Baum (University of Manitoba, Canada), F.D. Macchetto (STScI), G. Miley (University of Leiden, Netherlands), C. O’Dea (University of Manitoba), E. Perlman (Florida Institute of Technology), W. Sparks (STScI) and C. Norman (STScI and Johns Hopkins University).

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

For images and more information about the study and Hubble, visit:

Donna Weaver / Ray VillardSpace Telescope Science Institute, Baltimore, Maryland410-338-4493 / 410-338-4514 [email protected] / [email protected]

Marco ChiabergeSpace Telescope Science Institute andJohns Hopkins University, Baltimore, Maryland 410-338-4980 [email protected]