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Astrochemie - wat beteken bevriesing?

Astrochemie - wat beteken bevriesing?


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Ek het onlangs na 'n video oor die fisika en chemie in skywe met planetêre aanwas gekyk, en die spreker noem op 'n sekere punt 'vriespunt en UV-dissosiasie'. Is bevriesing 'n suiwer chemiese term, of is dit spesifiek vir hierdie proses? Is dit baie belangrik in planetêre vorming?


Uitvries is inderdaad 'n chemiese term. Dit gebeur in die middelvlak van aanwasskywe waar digtheid hoog genoeg is om UV-ionisasie / chemiese dissosiasie te blokkeer en die verhitting van die sentrale ster te beperk. Niemand het blykbaar nog daarin geslaag om 'n leekvriendelike artikel oor die onderwerp op te stel nie, maar hierdie verwysings gee die kern:

Protostars en planete V

Akkretieeskyfies 1: tydens stervorming

Organiese materie in die ruimte (IAU S251) Evolusie van organiese materie

Vanaf ref 2:


Wat beteken bevriesing?

Ek neem hierdie semester 'n kosmologiekursus en ek verstaan ​​nie regtig die konsep van bevriesing nie. Hier is 'n kort paragraaf uit ons lesing.

Dit is die ding wat ek nie verstaan ​​nie: Waarna verwys die "ooreenstemmende deeltjie"? Is dit $ C $ en $ D $ of $ A $? Daar word ook gesê dat "deeltjie $ A $ heeltemal verdwyn". Maar byvoorbeeld in die proses: $ nu + bar < nu> leftrightarrow e ^ <+> + e ^ <-> $, as deeltjie $ A $ die neutrino is, moet dit binne 'n paar sekondes heeltemal verdwyn na die oerknal. Hoe kan neutrino's vandag bestaan? Ek verstaan ​​ook nie die verskil tussen 'ontkoppel' en 'uitvries' nie. Is dit dieselfde ding?


Die Kavli-stigting V & # 038A: Astrochemie en die oorsprong van die lewe

Deur: The Editors of Sky & amp Telescope 20 September 2018 0

Kry sulke artikels na u posbus gestuur

Die Kavli-pryswenner Ewine van Dishoeck van 2018 bespreek die persoonlike en professionele reis na die astrochemie, van groot kampeeruitstappies tot die bereiking van internasionale konsensus oor groot-begrotingsterreine.

Op mikroskopiese vlak openbaar die landskappe in die ruimte ware chemiese fabrieke van ongelooflike kompleksiteit.
ALMA (ESO / NRAO / NAOJ

NIE ALLE RUIMTE NIE is so 'n dorre plek. Sterrestelsels is propvol stowwerige wolke wat ryk bredies van molekules bevat, wat wissel van eenvoudige waterstofgas tot komplekse organiese stowwe wat lewensbelangrik is. Die lewenswerk van Ewine van Dishoeck was om te begryp hoe al hierdie kosmiese bestanddele in die vorming van sterre en planete meng.

Van Dishoeck is 'n chemikus van opleiding en rig haar oë vinnig na die kosmos. Sy was baanbrekerswerk in baie vooruitgang op die gebied van die astrochemie, en gebruik die nuutste teleskope om die inhoud van uitgestrekte wolke te openbaar en te beskryf. Van Dishoeck het eweneens laboratoriumeksperimente en kwantumberekeninge gevolg terra firma om die afbreek van kosmiese molekules deur sterlig te verstaan, asook die omstandighede waaronder nuwe molekules soos Lego-stene saamstapel.

"Vir haar gesamentlike bydraes tot waarnemings-, teoretiese en laboratorium-astrochemie, wat die lewenssiklus van interstellêre wolke en die vorming van sterre en planete toelig," het van Dishoeck die 2018 Kavli-prys in astrofisika ontvang. Sy is slegs die tweede laureaat op enige gebied wat as enigste ontvanger van die prys oor sy geskiedenis onderskei is.

Om meer te wete te kom oor haar deurbraak in die astrochemie en wat volgende in die veld is, het The Kavli Foundation met Van Dishoeck van haar kantoor in die Leiden-sterrewag aan die Universiteit van Leiden in Nederland gepraat, net voordat sy 'n personeelbraai bygewoon het. Van Dishoeck is 'n professor in molekulêre astrofisika en die gekose president van die Internasionale Astronomiese Unie (IAU).

Die volgende is 'n geredigeerde transkripsie van die bespreking van die rondetafel. Van Dishoeck is die geleentheid gebied om haar opmerkings te wysig of te wysig.

Ewine van Dishoeck, wenner van die 2018 Kavli-prys in astrofisika. Van Dischoeck is 'n pionier op die gebied van astrochemie, die studie van molekules in die ruimte en die rol daarvan in die oorsprong van sterre en planete.
Peter Badge / Typos1

DIE KAVLI-STIGTING: Wat vertel astrochemie ons van onsself en die heelal waarin ons leef?

EWINE VAN DISHOECK: Die algemene verhaal wat deur die astrochemie vertel word, is wat is ons oorsprong? Waar kom ons vandaan, hoe is ons gebou? Hoe het ons planeet en son gevorm? Dit lei ons uiteindelik om die basiese boustene vir die son, die aarde en ons te ontdek. Dit is soos Legos — ons wil weet watter stukke in die Lego-gebou vir ons sonnestelsel was.

Die mees basiese boustene is natuurlik die chemiese elemente, maar hoe hierdie elemente saamvoeg om groter boustene - molekules - in die ruimte te skep, is van kardinale belang om te verstaan ​​hoe alles anders ontstaan ​​het.

TKF: U en ander navorsers het nou meer as 200 van hierdie molekulêre boustene in die ruimte geïdentifiseer. Hoe het die veld in die loop van u loopbaan ontwikkel?

EVD: In die 1970's het ons begin agterkom dat baie ongewone molekules, soos ione en radikale, relatief baie in die ruimte voorkom. Hierdie molekules ontbreek of het ongepaarde elektrone. Op aarde hou hulle nie lank aan nie, want hulle reageer vinnig met enige ander saak wat hulle ontmoet. Maar omdat die ruimte so leeg is, kan ione en radikale tienduisende jare lewe voordat hulle iets raakloop.

Nou is ons besig om die molekules in die hart van die streke waar nuwe sterre en planete vorm, te identifiseer, op hierdie oomblik. Ons is verby om geïsoleerde ione en radikale na meer versadigde molekules te sien. Dit sluit in organiese [koolstofbevattende] molekules in die eenvoudigste vorms, soos metanol. Van die basiese metanol-boublok kan u opbou tot molekules soos glikolaldehied, wat 'n suiker is, en etileenglikol. Albei is 'prebiotiese' molekules, wat beteken dat hulle benodig word vir die uiteindelike vorming van lewensmolekules.

Waar die astrochemiese veld verder beweeg, is dit nie nodig om 'n inventaris van molekules te neem nie en om te probeer verstaan ​​hoe hierdie verskillende molekules gevorm word. Ons probeer ook verstaan ​​waarom ons groter hoeveelhede van sekere molekules in bepaalde kosmiese streke teenoor ander soorte molekules kan vind.

TKF: Wat u nou net gesê het, laat my aan 'n analogie dink: Astrochemie gaan nou minder daaroor om nuwe molekules in die ruimte te vind - soos dierkundiges wat nuwe diere in die oerwoud soek. Die veld handel nou meer oor die 'ekologie' van hoe die molekulêre diere op mekaar inwerk, en waarom daar soveel van 'n sekere soort hier in die ruimte is, maar so min daar, ensovoorts.

EVD: Dit is 'n goeie analogie! Terwyl ons die fisika en die chemie van hoe sterre en planete vorm, verstaan, is 'n belangrike deel om uit te vind waarom sommige molekules in sekere interstellêre streke volop is, maar "uitgestorwe" is, net soos diere ook in ander streke is.

As ons u metafoor voortsit, is daar inderdaad baie interessante interaksies tussen molekules wat met dierekologie vergelyk kan word. Temperatuur is byvoorbeeld 'n bepalende faktor in die gedrag en interaksies van molekules in die ruimte, wat ook die aktiwiteit van diere beïnvloed en waar hulle woon, ensovoorts.

Die oorgang van blou na groen merke in hierdie illustrasie dui die koolstofmonoksied-sneeu in die ster TW Hydrae aan. Die sneeu help stofkorrels om aan mekaar te kleef, wat noodsaaklik is vir die vorming van planete en komete.
B. Saxton & amp A. Angelich / NRAO / AUI / NSF / ALMA (ESO / NAOJ / NRAO)

TKF: Om terug te keer na die boublokkie-idee, hoe werk die opbouproses in astrochemie presies?

EVD: 'N Belangrike konsep in die bou van molekules in die ruimte is een wat ons uit die alledaagse lewe hier op aarde ken, wat fase-oorgange genoem word. Dit is wanneer 'n vaste stof in 'n vloeistof smelt, of 'n vloeistof in gas verdamp, ensovoorts.

Nou in die ruimte het elke molekule sy eie 'sneeu-lyn', wat die verdeling is tussen 'n gasfase en 'n vaste fase. So, byvoorbeeld, het water 'n sneeuland waar dit van watergas na waterys gaan. Ek moet daarop wys dat vloeibare vorme van elemente en molekules nie in die ruimte kan bestaan ​​nie omdat daar te min druk is op die aarde as gevolg van die druk van die planeet se atmosfeer.

Terug na die sneeulyne, ontdek ons ​​nou dat dit 'n baie belangrike rol speel in die vorming van die planeet, wat baie chemie beheer. Een van die belangrikste Lego-boustene, so te sê, wat ons gevind het, is koolstofmonoksied. Ons is bekend met koolstofmonoksied op aarde omdat dit byvoorbeeld by verbranding geproduseer word. Ek en my kollegas het in die laboratorium in Leiden getoon dat koolstofmonoksied die beginpunt is om baie meer komplekse organiese stowwe in die ruimte te maak. Koolstofmonoksied wat uit 'n gas na 'n vaste fase vries, is 'n belangrike stap om Lego-boustene waterstof toe te voeg. Deur dit te doen, kan u steeds groter en groter molekules soos formaldehied bou [CH2O], dan metanol, na glycolaldehyde soos ons bespreek het, of u kan selfs na meer komplekse molekules soos glycerol [C3H8O3].

Dit is maar een voorbeeld, maar dit gee u 'n idee van hoe 'n opbouproses in die astrochemie afspeel.

TKF: U het pas u laboratorium by die Leiden-sterrewag, die Sackler-laboratorium vir astrofisika, genoem, wat volgens my die eerste astrofisikalaboratorium is. Hoe het dit ontstaan ​​en wat het u daar bereik?

EVD: Dit is reg. Mayo Greenberg, 'n baanbreker-astrochemikus, het die laboratorium in die 1970's begin en dit was die eerste in sy soort vir astrofisika ter wêreld. Hy het afgetree en toe het ek die laboratorium aan die gang gehou. Uiteindelik het ek in die vroeë negentigerjare direkteur van hierdie laboratorium geword en was dit tot ongeveer 2004, toe 'n kollega leierskap aangeneem het. Ek werk steeds saam en voer eksperimente daar uit.

Wat ons in die laboratorium bereik het, is die uiterste toestande in die ruimte: die koue en die bestraling daarvan. Ons kan die temperature in die ruimte weergee tot 10 kelvin [–442 grade Fahrenheit –260 grade Celsius], wat net 'n bietjie bo absolute nul is. Ons kan ook die intense ultravioletstraling in sterlig herskep waaraan molekules onderwerp word in streke van nuwe stervorming.

Waar ons egter misluk, is om die leegheid van die ruimte, die vakuum weer te gee. Ons beskou 'n ultrahoë vakuum in die laboratorium as tussen 10 8 en 10 10 [honderd miljoen tot 10 miljard] deeltjies per kubieke sentimeter. Wat sterrekundiges 'n digte wolk noem, waar ster- en planeetvorming plaasvind, het slegs ongeveer 10 4, of ongeveer 10 000 deeltjies per kubieke sentimeter. Dit beteken 'n digte wolk in die ruimte is steeds 'n miljoen keer leër as die beste wat ons in die laboratorium kan doen!

Maar dit werk uiteindelik tot ons voordeel. In die uiterste vakuum van die ruimte beweeg die chemie wat ons wil verstaan ​​baie, baie stadig. Dit sal eenvoudig nie in die laboratorium gebeur nie, waar ons nie 10 000 of 100 000 jaar kan wag totdat die molekules mekaar moet bots en interaksie kan hê nie. In plaas daarvan moet ons in staat wees om die reaksie binne 'n dag te doen om iets te leer op die tydskale van 'n menswetenskaplike loopbaan. Ons bespoedig dus alles en kan dit wat ons in die laboratorium sien, vertaal na die veel langer tydskale in die ruimte.

'N Close-up van die yskoue vakuumkamer by die Sackler-laboratorium vir astrofisika, met 'n kunstenaarsindruk van gliserol en die stervormende gebied IRAS 16293-2422. Van Dishoeck het die laboratorium gelei vanaf die negentigerjare, wat die ekstreme toestande in die ruimte herskep.
Harold Linnartz

TKF: Benewens die laboratoriumwerk, het u gedurende u loopbaan 'n verskeidenheid teleskope gebruik om molekules in die ruimte te bestudeer. Watter instrumente was noodsaaklik vir u navorsing en waarom?

EVD: Nuwe instrumente was gedurende my hele loopbaan van deurslaggewende belang. Sterrekunde word regtig gedryf deur waarnemings. Om steeds sterker teleskope in nuwe golflengtes van lig te hê, is soos om met ander oë na die heelal te kyk.

Om u 'n voorbeeld te gee, het ek in die laat tagtigerjare teruggekeer na Nederland toe die land sterk betrokke was by die Infrarooi Ruimtewaarneming, of ISO, 'n missie onder leiding van die Europese Ruimte-agentskap. Ek het baie gelukkig gevoel dat iemand anders al 20 jaar lank die harde werk gedoen het om die teleskoop te laat realiseer, en ek kon dit graag gebruik! ISO was baie belangrik omdat dit die infrarooi spektrum oopgemaak het waar ons al hierdie spektrale handtekeninge, soos chemiese vingerafdrukke, van ys, insluitend water, kon sien, wat belangrike rolle speel in ster- en planeetvorming en in die geval van water, is natuurlik lewensbelangrik. Dit was 'n wonderlike tyd.

Die volgende baie belangrike missie was die Herschel Space Observatory, waarby ek persoonlik al in 1982 betrokke was as gegradueerde student. Vanuit die chemiese kant was dit duidelik dat Herschel 'n primêre missie vir interstellêre molekules was, en veral om die waterroete. ' Maar eers moes ons die wetenskaplike saak aan ESA rig. Ek het 'n aantal jare na die VSA gegaan en daar soortgelyke besprekings onderneem, waar ek gehelp het om die wetenskaplike saak vir Herschel aan Amerikaanse finansieringsagentskappe te rig. Dit was alles 'n groot druk totdat die missie uiteindelik in die laat 1990's goedgekeur is. Toe het dit nog tien jaar geneem om te bou en bekend te stel, maar ons het uiteindelik ons ​​eerste data gekry aan die einde van 2009. Dus van 1982 tot 2009 - dit was 'n lang termyn!

TKF: Wanneer en waar het u liefde vir ruimte en chemie wortel geskiet?

EVD: My belangrikste liefde was altyd vir molekules. Dit het op hoërskool begin met 'n baie goeie chemie-onderwyser. Baie hang af van regtig goeie onderwysers en ek dink nie mense besef altyd hoe belangrik dit is nie. Ek het eers besef toe ek op universiteit is, dat fisika net soveel plesier het as chemie.

TKF: Watter akademiese weg het u gevolg om uiteindelik astrochemikus te word?

EVD: Aan die Universiteit van Leiden het ek my meestersgraad in chemie gedoen en was ek oortuig dat ek met die teoretiese kwantumchemie wou voortgaan. Maar die professor in die veld in Leiden is oorlede. Ek het dus begin soek na ander opsies. Ek het op daardie stadium regtig nie veel van sterrekunde geweet nie. Dit was my destydse kêrel en huidige man, Tim, wat pas 'n stel lesings oor die interstellêre medium gehoor het, en Tim het vir my gesê: 'Weet jy, daar is ook molekules in die ruimte!' [Gelag]

Ek het begin ondersoek instel na die moontlikheid om 'n tesis oor molekules in die ruimte te doen. Ek het van die een professor na die ander gegaan. 'N Kollega in Amsterdam het my vertel dat ek na Harvard moes gaan om saam met professor Alexander Dalgarno regtig op die gebied van astrochemie te gaan. Terwyl dit gebeur het, het ek en Tim in die somer van 1979 in Kanada gereis om 'n Algemene Vergadering van die Internasionale Astronomiese Unie in Montreal by te woon. Ons het uitgevind dat satellietvergaderings voor die Algemene Vergadering gehou is, en dat een daarvan eintlik in hierdie spesifieke park waar Tim en ek gekamp het, plaasgevind het. Die idee wat ons gehad het, was: "Wel, miskien moet ons van hierdie geleentheid gebruik maak en hierdie professor Dalgarno al gaan sien!"

Natuurlik het ons al hierdie kamptoerusting en klere gehad, maar ek het een skoon rok by my gehad wat ek aangetrek het. Tim het my na die satellietvergadering gery, ons het my kollega van Amsterdam gekry, en hy het gesê: "O, goed, ek stel u voor aan professor Dalgarno." Die professor het my na buite geneem, ons het vyf minute gesels, hy het my gevra wat ek gedoen het, wat my vaardigheid in astrochemie was, en toe het hy gesê: "Klink interessant, waarom kom u nie vir my werk nie?" Dit was natuurlik 'n belangrike oomblik.

Dis hoe dit alles begin het. Ek was sedertdien nog nooit spyt nie.

TKF: Was daar ander belangrike oomblikke, miskien vroeg in u kinderjare wat u op die weg van wetenskaplike geplaas het?

EVD: Eintlik, ja. Ek was ongeveer 13 jaar oud en my pa het pas 'n sabbatsjaar in San Diego, Kalifornië, gereël. Ek neem afskeid van my hoërskool in Nederland, waar ons meestal lesse in Latyn en Grieks en natuurlik ook wiskunde ontvang het. Maar ons het nog niks in terme van chemie of fisika gehad nie, en biologie het eers ten minste een of twee jaar later begin.

Op die hoërskool in San Diego het ek besluit om onderwerpe wat baie anders was, te bestudeer. Ek het byvoorbeeld Spaans geneem. Daar was ook die moontlikheid om wetenskap te doen. Ek het 'n baie goeie onderwyser gehad, wat 'n Afro-Amerikaanse vrou was, wat destyds in 1968 nogal ongewoon was. Sy was net baie inspirerend. Sy het eksperimente gehad, sy het vrae gehad en dit het my regtig reggekry om my tot die wetenskap te lok.

'N Kunstenaar se indruk van die Herschel Space Observatory met sy waarnemings van stervorming in die Rosette Nebula in die agtergrond. Van Dishoeck en ander het Herschel gebruik op soek na interstellêre molekules.
ESA - C. Carreau

TKF: Kyk nou vorentoe na die belofte van die Atacama Large Millimeter / submillimeter Array (ALMA), wat etlike jare gelede geopen is en een van die mees ambisieuse en duurste astronomieprojekte op die grond is wat ooit geïmplementeer is. Die astrofisikus Reinhard Genzel gee u erkenning aan die internasionale konsensus agter hierdie sterrewag. Hoe het u ALMA aangevoer?

EVD: ALMA was 'n ongelooflike sukses as die première sterrewag in hierdie spesiale reeks millimeter- en submillimeterlig wat 'n belangrike venster is om molekules in die ruimte waar te neem. ALMA bestaan ​​vandag uit 66 radioteleskope met 7- en 12-meter-konfigurasies wat oor 'n hoë vlakte in Chili strek. Dit was 'n baie lang pad om te kom waar ons nou is!

ALMA is die resultaat van die drome van duisende mense. Ek was een van die twee lede van die Europese kant van die Amerikaanse wetenskaplike advieskomitee vir ALMA. Ek het die Noord-Amerikaanse wetenskapgemeenskap goed geken vanaf my ses jaar werk in die VSA. Die twee kante, sowel as Japan, het baie verskillende konsepte vir ALMA gehad. Die Europeërs het gedink aan 'n teleskoop wat gebruik kon word vir die diep, heel vroeë heelal-chemie, terwyl die Noord-Amerikaners veel meer nadink oor grootskaalse, hoë-resolusie-beelding, waarvan een groep praat oor die bou van agt meter teleskope, die ander ongeveer 15 meter teleskope.

Ek was dus een van die mense wat gehelp het om die twee argumente bymekaar te bring. Ek het gesê: "As u 'n baie groter verskeidenheid bou, wen ons almal." Die plan was om 'n groter aantal teleskope in een skikking bymekaar te bring, eerder as afsonderlike skikkings, wat nie so kragtig is nie. En dit is wat gebeur het. Ons gee die toon aan om saam te werk aan hierdie fantastiese projek eerder as om mededingers te wees.

TKF: Watter nuwe grense begin ALMA in die astrochemie?

EVD: Die groot sprong wat ons met ALMA maak, is in ruimtelike resolusie. Stel jou voor dat jy na 'n stad van bo kyk. Die eerste Google Earth-beelde was baie swak - jy kon amper niks sien nie, 'n stad was 'n groot vlek. Sedertdien het die beelde al hoe skerper geword namate die ruimtelike resolusie verbeter het met die kameras aan boord van satelliete. Tans kan u die kanale [in Nederlandse stede], die strate en selfs individuele huise sien. U kan regtig sien hoe die hele stad saamgestel is.

Dieselfde gebeur nou met die geboorteplekke van planete, dit is hierdie klein skywe rondom jong sterre. Hierdie skywe is honderd tot duisend keer kleiner as die wolke waarna ons voorheen gekyk het waar sterre gebore is. Met ALMA zoom ons in in die streke waar nuwe sterre en planete vorm. Dit is regtig die toepaslike skale om te verstaan ​​hoe die prosesse werk. En ALMA, uniek, het die spektroskopiese vermoëns om 'n baie wye verskeidenheid molekules wat by daardie prosesse betrokke is, op te spoor en te bestudeer. ALMA is 'n fantastiese stap vorentoe van alles wat ons voorheen gehad het.

Op 4 September 2018 ontvang Ewine van Dishoeck die Kavli-prysmedalje van sy majesteit, koning Harald V van Noorweë.
Fredrik Hagen / NTB scanpix

TKF: Die nuwe teleskope wat u gedurende u loopbaan gebruik het, is buitengewoon. Terselfdertyd is ons steeds beperk tot wat ons in die kosmos kan sien. As u vooruit dink aan toekomstige generasies teleskope, wat is dit die beste wat u hoop om te sien?

EVD: Die volgende stap in ons navorsing is die James Webb-ruimteteleskoop [JWST], wat in 2021 begin. Met JWST sien ek baie daarna uit om organiese molekules en water op nog kleiner skale en in verskillende dele van die planeet te sien- vormsones as wat met ALMA moontlik is.

Maar ALMA sal nog lank noodsaaklik wees vir ons navorsing — nog 30 tot 50 jaar. Daar is nog soveel wat ons met ALMA moet ontdek. ALMA kan ons egter nie help om die binneste deel van 'n planeetvormende skyf te bestudeer nie, op die skaal van waar ons Aarde gevorm het, net 'n entjie van die son af. Die gas in die skyf is daar baie warmer, en die infrarooi lig wat dit uitstraal, kan vasgevang word deur 'n instrument wat ek en my kollegas vir JWST help implementeer het.

JWST is die laaste missie waaraan ek gewerk het. Weereens het ek toevallig betrokke geraak, maar ek was in 'n goeie posisie met my Amerikaanse vennote en kollegas om te help. 'N Aantal van ons van die Europese en Amerikaanse kant het bymekaargekom en gesê:' Haai, ons wil hierdie instrument laat gebeur en ons kan dit in 'n 50/50-vennootskap doen. '

TKF: Gegewe u werk aan die boustene waaruit sterre en planete bestaan, lyk die kosmos geskik of selfs bevorderlik vir die lewe?

EVD: Ek sê altyd dat ek die boustene voorsien, en dan is dit aan die biologie en chemie om die res van die verhaal te vertel! [Gelag] Uiteindelik maak dit saak van watter soort lewe ons praat. Praat ons net oor die mees primitiewe, eensellige lewe waarvan ons weet dat dit vinnig op aarde ontstaan ​​het? Gegewe al die bestanddele wat ons beskikbaar het, is daar geen rede waarom dit op geen van die miljarde eksoplanete wat ons nou ken, om miljarde ander sterre kan draai nie.

Om na die volgende stappe van die meersellige en uiteindelik intelligente lewe te gaan, verstaan ​​ons nog min hoe dit uit die eenvoudiger lewe blyk. Maar ek dink dit is veilig om te sê gegewe die vlak van ingewikkeldheid, is dit minder waarskynlik dat dit so gereeld soos byvoorbeeld mikrobes sal voorkom.

TKF: Hoe sal die gebied van astrochemie ons help om die vraag te beantwoord of daar vreemde lewens in die heelal bestaan?

EVD: Die bestudering van die chemie van eksoplanetatmosfeer is wat ons sal help om hierdie vraag te beantwoord. Ons sal baie potensiële aardagtige eksoplanete vind. Die volgende stap sal wees om spektrale vingerafdrukke, wat ek vroeër genoem het, in die atmosfeer van die planete te soek. In hierdie vingerafdrukke sal ons spesifiek na "biomolekules" of kombinasies van molekules soek wat kan dui op die teenwoordigheid van een of ander vorm van lewe. Dit beteken nie net water nie, maar suurstof, osoon, metaan en meer.

Ons huidige teleskope kan daardie vingerafdrukke in die atmosfeer van eksoplanete net-net opspoor. Daarom bou ons die volgende generasie reuse-teleskope op die grond, soos die Extremely Large Telescope, met 'n spieël wat ongeveer drie keer so groot is as vandag. Ek is betrokke by die wetenskaplike saak daarvoor en ander nuwe instrumente, en biohandtekeninge is regtig een van die hoofdoelwitte. Dit is die opwindende rigting waar astrochemie sal gaan.


Bruce Springsteen & # 8217s nie vertel nie

Wat sê Bruce Springsteen is 'n Tiende Laan Freeze-Out? Hy sê dat hy nie weet nie. Musikante sê dit dikwels, hulle wil nie hul luisteraars se interpretasies bederf nie. Maar onlangs, in sy Super Bowl-blog, het Springsteen geskryf: & # 8220During & # 8220Tenth Avenue & # 8221 Ek vertel die storie van my band ... en ander dinge & # 8220wanneer die verandering in die stad aangebring is & # 8221 & # 8230 & # 8221.

Aanlyn is aanhangers geneig om saam te stem met & # 8220The Boss & # 8221. Hulle sê dit is 'n liedjie oor hoe Springsteen in die middel 70's sy E Street Band gestig het. Maar hulle sê dat hulle nie weet wat 'n Tiende Laan Freeze-Out is nie.

Tiende Laan? E Street ontmoet 10de Laan in Belmar, New Jersey. Springsteen is gebore in Long Branch, New Jersey.

Nou weet ons waar die Tiende Laan in die liedtitel vandaan kom en dit dui daarop dat die lied oor Springsteen se vormende musiekjare gaan.

E Street ontmoet 10de Laan, Belmar

3. Astrochemie in ander omgewings

Alhoewel die chemie wat tot dusver bespreek is, gekonsentreer het op die streke wat verband hou met stervorming, speel molekules ook 'n belangrike rol in ander astrofisiese streke waarin gasfase, plasmaraaksies belangrik kan wees. In hierdie afdeling bespreek ons ​​twee sulke streke, die vroeë heelal in die eerste 1000 Myr na die oerknal en in die sirkelvormige omhulsels van ou sterwende sterre.

3.1. Vroeë heelal

Die konvensionele beeld van die ontstaan ​​van die Heelal begin met die oerknal waaruit ruimte en tyd, en die elemente wat die materiële heelal vorm, geskep is. In hierdie uitbreidende en verkoelende heelal was botsings van protone, neutrone en elektrone vinnig genoeg om slegs die ligelemente - H, He, Li en hul isotope die belangrikste - te skep voordat die uitbreiding die nukleosintese effektief 'bevries' het. Sterrekundiges meet afstande in die heelal deur die kosmologiese rooi verskuiwing, Z, as gevolg van die uitbreiding van die heelal, soos:

waar en is die golflengtes van die uitgestraalde en waargenome lig. Die verband tussen rooi verskuiwing en die ouderdom van die heelal op die tydstip waarop die lig uitgestraal is, hang af van die besonderhede van die kosmologiese model wat 'n mens aanneem, maar is eweredig aan groot Z. Namate die heelal uitgebrei het, het die aanvanklike plasma afgekoel en weer in die sogenaamde 'rekombinasie-era', wat met 'n rooi verskuiwing begin het. Z, ongeveer 800–1000, of ongeveer vyfhonderdduisend jaar na die oerknal, toe die gastemperatuur tot 8000 K gedaal het, en voortgegaan het tot die re-ionisering daarvan as gevolg van die eerste generasie massiewe sterre op ongeveer 'n ouderdom van ongeveer 250 Myr. In hierdie era word molekulêre waterstof gevorm deur gasfase prosesse wat die volgende insluit:

Hierdie twee roetes kom gewoonlik by verskillende rooi verskuiwings voor omdat die ioon makliker deur fotone vernietig word as en nie volop is voordat die heelal voldoende afgekoel het om die vorming van hoë-energie fotone te voorkom nie. Vorming van via pieke by en via by. Hierdie spesifieke reaksies het trae, snelheidsbeperkende stappe sodat die hoeveelheid gevorm klein is, met 'n breukvloed van. Ander molekules vorm ook, veral HD en LiH, in reaksies soos:

Die oorvloed van sulke molekules bly klein, maar omdat albei 'n permanente elektriese dipoolmoment het, kan hulle bydra tot die verkoeling van die gas. is egter die dominante koelmiddel en die gas verkoel van 4000 K tot 200 K. Hierdie groot daling in temperatuur veroorsaak 'n afname in die interne druk van die gas, en ten spyte van die feit dat die Heelal self uitbrei, laat die vermindering van die swaartekrag toe om voort te gaan en die eerste sterre en sterrestelsels wat gevorm het. 'N Uitstekende oorsig van die chemie in pre-galaktiese gas en die minihalo's van proto-sterrestelsels kan gevind word in Glover (2011). Hy toon aan dat, aangesien die digtheid en temperatuur van die heelal mettertyd verander, die gedetailleerde afkoeling van die gas en die massas van die strukture wat gevorm word, baie sensitief is vir die spesifieke waardes van die koerskoëffisiënte oor 'n wye temperatuurbereik. 'N Uitgebreide oorsig van die chemie van die ligatome wat in die oerknal geskep is, word gegee deur Galli en Palla (2013).

Die eerste generasie sterre in die heelal kan dan die swaarder elemente - C, N, O, ens. - deur sterre nukleosintese voortbring en hierdie elemente terugbring na die interstellêre medium deur supernova-ontploffings en sterwinde. Alhoewel ons nie die eerste molekule, HD en LiH, waarneem nie, is die molekule CO in verskeie sterrestelsels opgespoor tot rooiverskuiwing van 6 (Wang et al 2010). Die rekord is in die kwasar SDSS J1148 + 5251 om ongeveer 890 Myr na die oerknal (Walter et al 2003). Hierdie voorwerp het meer as molekulêre gas en vorm sterre teen 'n snelheid van 3000, ongeveer 1000 keer die waarde in die Melkweg.

3.2. Sirkelvormige koeverte

Molekules vorm ook baie doeltreffend in koel sterre. Sterre met massas in die reeks 1-8 beëindig hul lewens deur massa in 'n sterwind na die interstellêre medium te verloor - sterre met 'n hoër massa word supernovas en gee materiaal plofbaar terug. Aan die einde van hul kernverbrandingsfase is die sterre baie groot, met fotosferiese radiusse in die orde van 200–300, en relatief koel met effektiewe temperature van 2000–3000 K, en staan ​​bekend as die asimptotiese reuse-tak (AGB) -sterre . Hierdie winde, wat gewoonlik 'n snelheid van 10-25 km het, verwyder uiteindelik oor 'n paar 10 000 jaar die buitenste lae van die steratmosfeer en vorm 'n planetêre newel met 'n sentrale, warm, wit dwergster.

Die aard van die molekules en die chemie wat voorkom in die omringende omhulsels (CSE's) wat deur die massaverlies gevorm word, hang af van die totale koolstof-tot-suurstof-, C / O-verhouding en van die eienskappe van drie hoofradiale sones rondom die sentrale ster . Hierdie CSE's kan baie ryk wees aan molekules, veral die koolstofryke: die argetipe hiervan, die ster IRC + 10216 of CW Leo, met 'n massaverlieskoers van 2 en 'n uitbreidingsnelheid van 14,5 km, bevat meer as 80 molekules insluitend baie koolstofketting spesies, soos gevind in donker wolke, en verskeie metaalhaliede, insluitend NaCl, KCl en AlCl, molekules wat nog in interstellêre wolke opgespoor moet word.

Die chemie wat in CSE's voorkom, kan beskou word as om voort te gaan in drie streke afgebaken deur radiale afstand vanaf die sentrale ster, met 'n fotosferiese (sterre) radius van 'n paar cm. Daar moet op gelet word dat sterre UV-fotone nie belangrik is in die chemie nie, aangesien die sterre koel is.

3.2.1. Fotosferiese chemie.

By die hoë digthede, meer as en die temperatuur wat in die fotosfeer ervaar word, tipies 2500–3500 K, te warm vir stofkorrels om te oorleef, word molekules gevorm in plaaslike termodinamiese ewewig (LTE). Drie-liggaam botsings tussen neutrale spesies oorheers - een van die min astrochemiese situasies waar dit die geval is - en molekulêre oorvloed word bepaal deur die vrye energie van Gibbs te minimaliseer:

waar is die aantal mol spesies i en die chemiese potensiaal daarvan:

met die Gibbs-vrye energie van spesies i, P die totale druk van die gas, en. LTE vorm by voorkeur molekules met 'n hoë dissosiasie-energie, veral CO is die molekule wat die meeste voorkom na aanleiding van tipiese toestande van C-ryk en O-ryk AGB-sterre. In C-ryke sterre word alle beskikbare suurstof in CO vasgebind (bindingsenergie 11,2 eV). Die oortollige koolstof beland in oorvloedige spesies soos HCN en CS, met stikstof verdeel in molekules soos en HCN. Waarnemings van al hierdie spesies, met die uitsondering van, kan naby die fotosfeer gedoen word deur middel van infrarooi absorpsie en emissiespektroskopie. In O-ryke sterre is CO, O en SiO die meeste O-draende spesies.

By die modellering van die chemie van AGB-sterre is dit dikwels so dat LTE-berekeninge gebruik word om die oorvloed van 'ouer'-spesies in te stel wat dan na die buitenste streke van die CSE vloei. Daar is egter twee belangrike prosesse wat die oorvloed van LTE steur.

3.2.2. Polsings en stofvorming.

Die binneste streke van die CSE is nie stabiele strukture nie, aangesien AGB-sterre gewoonlik op tydskale van 1-3 jaar pols. These sub-sonic pulsations generated in the interior of the star drive compression waves through the atmosphere steepening into shocks. Such shocks lose energy either radiatively, when the density is high and the shocks can be treated as isothermal, or by adiabatic expansion when the density is low. Detailed models of these shocks have been made by Bowen (1988) who showed that strong shocks occur on a cyclic basis and create an extended atmosphere in which the shock velocity decreases as the gas expands. A particular parcel of gas which receives an outward impulse roughly follows a ballistic trajectory before falling back towards the stellar surface under the influence of gravity. If it experiences a second shock before it returns to its initial position, it attains a net outward momentum and can drive mass loss.

Willacy and Cherchneff (1998) studied the chemistry in the inner 5 induced by these periodic shock waves on a molecular gas whose initial composition is determined by LTE. The chemistry is dominated by neutral–neutral reactions which, if they can occur faster than the dynamical time-scales, can alter LTE abundances dramatically. Key reactants at these high temperatures and densities are atomic hydrogen and O atoms formed by collisional dissociation of and CO. In C-rich stars, these O atoms can react with to form OH and O, while atomic silicon, the dominant form of the element in LTE, reacts with OH to form SiO, increasing the latter abundance by more than a factor of 100 compared to its LTE value and giving closer agreement with the abundance observed close to the photosphere.

Shock chemistry, driven by underlying pulsations, does seem to be required to explain the relatively high abundances of O-bearing molecules, including OH, O and CO, detected in IRC+10216 in recent years. Cherchneff (2012) gives an excellent summary of the physics and chemistry of this inner region and shows that, in addition to O-bearing molecules, shock chemistry can produce large abundances of chlorides such as HCl, AlCl and NaCl, as also observed.

AGB stars are also the major producer, perhaps up to 80%, of dust particles in the Galaxy. Infrared observations show that the dust composition is either amorphous carbon in C-rich stars or silicates in O-rich stars. The formation of these are not well understood although it is clear that it occurs within a few stellar radii. Initial research on dust formation in carbon stars invoked classical nucleation theory in which solids condense out of a cooling gas once the partial pressure of a particular species exceeds its vapour pressure. Nucleation theory describes growth from gas-phase monomers and identifies a critical cluster size above which growth by addition of a monomer is energetically favoured. This approach has had only limited success in its application to AGB stars. For O-rich stars, there is no monomer out of which the observed silicates can grow whilst in C-rich stars, there are kinetic bottlenecks in the formation of the first few ring molecules, and in both types the short dynamical time-scales can mitigate against grain formation. Pulsations again seem to be critical. The levitation of material in the atmosphere, the density increase caused by the propagation of shock waves, and the fast cooling post-shock, have been included in a kinetic description of the chemistry in C-rich stars (Cherchneff (2012) and references therein). In this model for IRC+10216, she showed that the abundance of benzene peaked at a fractional abundance of at around 3 . Assuming that benzene is converted to coronene, , through a series of H-abstraction, acetylene-addition reactions, and that this is a proxy for the dust mass, she showed that dust masses consistent with those observed can be achieved.

In O-rich stars, the dominant dust component is amorphous silicate with evidence also for crystalline silicates. The most abundant oxide in the gas after CO in the dust-forming zone is SiO which has a condensation temperature of around 600 K, much lower than the observed dust temperature, around 1000 K. It is thus likely to be the more refractory oxides, such as TiO, , AlO and , which form the first condensates on which further grain growth can occur. Corundum, , is the most abundant Al-containing molecule and can condense out of the gas below 1000 K (Sharp and Huebner 1990)—some 90% of all pre-solar oxide grains found in meteorites contain corundum that condensed in O-rich AGB stars. LTE conditions, however, are unlikely to hold given stellar pulsations and the generation of periodic shock waves but the identification of the detailed chemical reactions that form the smallest molecular clusters is still elusive. Kinetic models of the chemistry are difficult to describe although Gail and Sedlmayr (1998) have shown that solid may provide the seed nuclei on which silicates condense—the low abundance of Ti compared to Si and Mg, however, may be problematic in this scenario. Goumans and Bromley (2012) have investigated the thermodynamics of small cluster formation in a 1000 K gas of , SiO, Mg and O and find that the homomolecular nucleation of SiO stops at the dimer, whereas Mg can be incorporated exothermically into silicon oxides when the number of oxygen atoms is larger than that of the metal atoms.

Once formed, dust grains become the most important absorber of stellar photons and the transfer of photon momentum to the dust, and subsequently to the gas through collisions, initiates a rapid acceleration of the gas and drives the mass-loss process. As the gas and dust flows outwards, collisions between them are possible although a comparison between the gas-grain collision time and the expansion time shows that this is important only within cm for typical conditions. There has been, as yet, little attempt to study the gas-dust interaction in this zone, where both the gas and the grains are hot, but there is evidence that molecule formation mediated by this interaction does occur. For example, 10 m observations of silane, , in IRC+10216 (Keady and Ridgway 1993) shows that it is formed at radii beyond 40 —similar results hold for and . The increased abundances of these and other hydrides in this region may imply, as it does in the case of hot molecular cores, that molecules are being formed on the surfaces of dust grains through hydrogenation of atoms, although other explanations are possible.

Consider O which was detected in IRC+10216 through submillimetre satellite observations (Melnick et al 2001). This observation was a surprise since neither the LTE models for the inner chemistry nor the models of the outer CSE predicted water. This observation, which was followed by observations of OH and CO in the same star, led to suggestions that water was formed by the evaporation of icy comets orbiting within the CSE (Melnick et al 2001), or that it could be formed in the dust growth zone by the Fischer–Tropsch mechanism on the surface of iron grains (Willacy 2004). Subsequent observations of high-excitation transitions using the Herschel Space Observatory (Decin et al 2010) showed unequivocally that water is warm, several hundred K, and confined to the inner envelope. Cherchneff (2011) argued that this is consistent with recent shock models, although several of the key rate coefficients are unknown or highly uncertain. Agúndez et al (2010) used the observed clumpy nature of the CSE to postulate that external UV photons can penetrate deep into the inner regions of the envelope and drive the photodissociation of molecules such as SiO and CO which release O atoms into the gas phase— CO is optically thick to dissociating photons. The O atoms then react with in the warm gas to form OH and water.

3.2.3. Photochemistry in the outer envelope.

In the very outer reaches of the circumstellar envelope, external UV photons can disrupt the chemistry, giving rise a rich soup of radicals and ions that can react further. An interesting outcome in some CSEs, as discussed below, is that the chemistry produces relatively high abundances of anions, one of the few regions in the ISM in which they are formed in observable quantities.

To understand the underlying physical properties and chemistry of the gas, let us assume that gas and dust flow out from the star in a steady, uniform, spherically symmetric flow at terminal velocity v and mass-loss rate and which is irradiated by external UV photons from the interstellar radiation field. In this case, we can use conservation of mass to derive the abundance as a function of radius. We can then write the radial number density of , , the radial column density of from radial distance r to infinity, N , and the radial extinction in the UV due to dust, as:

Here the mass-loss rate is measured in , the radial distance in cm, the terminal velocity in km and is the dust-to-gas mass ratio, where 0.01 is its typical value in the interstellar medium. It is likely to vary from object to object in AGB stars, with a typical value of perhaps 0.003. The temperature profile of the gas is determined by adiabatic expansion and molecular line and dust thermal cooling but can be well approximated by a power-law distribution , with around 0.6–0.7. At an injection radius of 2 cm, the density is about 3 , the temperature is 220 K and the radial visual extinction, , about 7 mag, for parameters typical of those in IRC+10216 (McElroy et al 2013).

One sees from these equations, that since external UV photons begin to interact with outflowing parent species once the UV extinction falls below about 10 mags, that is, at a radius of around cm for parameters typical of AGB stars. One should note, however, that three of the major parent species, namely , and CO experience self- and mutual-shielding against photodestruction. Indeed the photodissociation rate is negligible to distances typically in excess of 1 parsec ( cm) from the star. In C-rich AGB stars, the most important parents for driving chemistry are and HCN. The photodissociation of HCN gives rise to CN which is itself photodissociated to N and C atoms, with the latter photoionized in the very outer envelope. Thus, external photons cause the formation of molecular shells, whose radial position depend on the underlying flow properties and the photon flux. Acetylene can be both ionized, to form , and dissociated, to form H, , C and , sequentially. The result is that one finds a region in the CSE where abundant photons, radicals and ions co-exist at relatively high density, , and cold temperatures, 100–10 K, a situation that is relatively rare in astronomy. Collisions between these reactive species then give rise to the molecular complexity observed in C-rich CSEs through reactions described in section 2.2.

One of the interesting aspects of the chemistry is its propensity to form carbon-chain molecules and anions— , , , , , have been detected in IRC+10216—in relatively high abundance indeed the total anion abundance is found to exceed that of free electrons in some parts of the outer envelope (Millar et al 2007, Cordiner and Millar 2009). Figure 16 from McElroy et al (2013) shows the radial distributions of a number of important linear hydrocarbon molecules and anions. We note that in IRC+10216, the observed ratios for / H and / H are 0.09 and 0.26, respectively (Kasai et al 2007, Remijan et al 2007).

Figure 16. Top left: plot of the fractional abundances, relative to , of cyanopolyynes as a function of envelope radius using the Rate12 model (solid lines) compared with the results from Cordiner and Millar (2009) (dotted lines). Top right: Plot of fractional abundances of polyynes as a function of envelope radius for the Rate12 model including anion chemistry (solid lines) and excluding anion chemistry (dashed lines). Bottom left: plot of fractional abundances of polyyne anions as a function of envelope radius. Bottom right: comparison of the fractional abundances of various cations and electrons, including anion chemistry (solid lines) and excluding anion chemistry (dashed lines). The fractional abundance for the 'anions included' model is shown, for reference, with a dot-dashed line (McElroy et al (2013) © ESO.)

The cyanopolyynes, N are formed via neutral-neutral reactions between CN and the polyynes:

Large carbon-chain molecules often possess large electron affinities and can undergo radiative attachment with electrons, with rate coefficients that generally increase with size of the neutral (Herbst and Osamura 2008). Thus , because of the relatively large abundance of H and fast radiative attachment of electrons to H, is the dominant anion in the outer CSE. The formation of the cyanopolyyne anions occurs by radiative attachment as well as through reactions between N atoms and anions (Eichelberger et al 2007):

Figure 16, top right panel, shows the interesting result that the presence of these large hydrocarbon anions act to enhance the formation of large hydrocarbon chain molecules in the outer CSE as noted previously for dark clouds (Walsh et al 2009). A unique impact on the CSE chemistry, however, is that the free electron abundance can be depressed by an order of magnitude below the anion abundance in the range 0.3–1.0 cm in figure 16. This reduction in electron abundance leads to the decreased importance of dissociative electron recombination as a loss mechanism for cations, see the lower right panel in figure 16, with cations increasing in abundance by factors of 10–1000. The lower right panel also shows the radial abundance of which is the dominant carrier of negative charge in the region 3–6 cm.

The chemical reactions that synthesise molecules in the CSE are thus identical to those occurring in cold dark clouds. In the latter, however, the chemistry is acting to transform atoms to molecules, whereas in the envelopes of AGB stars, the chemistry acts to transform stable molecules formed in and near the photosphere to atoms and atomic ions which return to the interstellar medium to begin the process of cloud formation and collapse, star and planet formation, stellar evolution and star death, and another cycle in the history of chemistry in the Galaxy.


Astrophysics & Astrochemistry

Like any of the big disciplines in science Astrochemistry is difficult to define and many aspects have to be considered. Any contribution towards a comprehensive picture of what Astrochemistry is is highly welcome. Please contact the Editor to submit your personal view or to get a link to your website [click].

The Wikipedia definition (23.10.2007):

Astrochemistry is the study of the chemical elements found in outer space, generally on larger scales than the Solar System, particularly in molecular gas clouds, and the study of their formation, interaction and destruction. As such, it represents an overlap of the disciplines of astronomy and chemistry. On the Solar System scale, the study of chemical elements is usually called cosmochemistry.

Astrochemistry involves the use of telescopes to measure various aspects of bodies in space, such as their temperature and composition. Findings from the use of spectroscopy in chemistry laboratories can be employed in determining the types of molecules in astronomical bodies (e.g. a star or an interstellar cloud). The various characteristics of molecules reveal themselves in their spectra, yielding a unique spectral representation corresponding for a molecule. However, there are limitations on measurements due to electromagnetic interference and, more problematic, the chemical properties of some molecules. For example, the most common molecule (H2, hydrogen gas), does not have a dipole moment, so it is not detected by radio telescopes. Much easier to detect with radio waves, due to its strong electric dipole moment, is CO (carbon monoxide). Over a hundred molecules (including radicals and ions) have been reported so far, including a wide variety of organic compounds, such as alcohols, acids, aldehydes, and ketones. There have been claims regarding interstellar glycine, the simplest amino acid, but with considerable accompanying controversy. Research is progressing on the way interstellar and circumstellar molecules form and interact, and this research could have a profound impact on our understanding of the origin of life on earth.

The sparseness of interstellar and interplanetary space results in some unusual chemistry, since symmetry-forbidden reactions cannot occur except on the longest of timescales. For this reason, molecules and molecular ions which are unstable on Earth can be highly abundant in space, for example the H3+ ion.


The song tells the story of the formation of the E Street Band. The meaning of the title is unclear. Even Springsteen himself says in the Born to Run documentary Wings for Wheels: The Making of Born to Run: "I still have no idea what it means. But it's important." [1]

The song's protagonist, "Bad Scooter", is a pseudonym for Springsteen himself (as indicated by the initials they share). In the third verse, "Big Man joined the band" refers to the now deceased Clarence Clemons, the band's long-time saxophonist.

As stated by Springsteen in the Wings for Wheels documentary, the idea for the composition of the horn intro was Steven Van Zandt's. Despite all of this, the single was a chart dud, getting no higher than #83 on the Billboard Hot 100 in early 1976. However, it has always had a strong following on album-oriented rock radio and amongst Springsteen's fan base.

    – electric guitar, vocals, horn arrangement – bass – drums – piano – tenor saxophone, bridge talking – trumpet, flugelhorn – tenor saxophone – baritone saxophone – trombone – horn arrangement

"Tenth Avenue Freeze-Out" has become a staple of Springsteen's E Street Band concert tours, with regular appearances from the 1975 and on the Born to Run tours through the 1984 legs of the Born in the U.S.A. Tour, with one of the latter documented on the later Live/1975–85, and the 1988 Tunnel of Love Express. It then returned with a featured regular spot on the 1999–2000 Reunion Tour, often used as an introduction of the band. An extended 20-minute version was captured on the subsequent Bruce Springsteen & The E Street Band: Live in New York City release, and was frequently played during most of the legs of the 2007–2008 Magic Tour and during the 2009 Working on a Dream Tour. It opened the four-song set at Springsteen and the band's high-profile half-time appearance at Super Bowl XLIII, which included Springsteen pointing out that the verse about "the Big Man" joining the band was the important part of the song.

A slower version of this song was played during the Born to Run tours, on December 31, 1975 in Philadelphia.

After Clemons' death, Springsteen used the song as a memorial/tribute to both him and the late Danny Federici on the Wrecking Ball Tour, the first E Street Band tour without Clemons. During the song's third verse of "Big Man joined the band", Springsteen paused the song where Clemons' sax solo would traditionally be performed while a video of Clemons and Federici played on the stage screens. On the High Hopes and River 2016 tours, Springsteen removed the pause from performances of the song, but kept the video tribute. [ aanhaling nodig ]

Springsteen joined his longtime friend Billy Joel on stage at Madison Square Garden on July 18, 2018 to perform the song (along with "Born to Run") for Joel's 100th appearance at MSG.


Bruce Springsteen: Tenth Avenue Freeze-Out Meaning

Tear drops on the city
Bad Scooter searching for his groove
Seem like the whole world walking pretty
And you can't find the room to move
Well everybody better move over, that's all
'Cause I'm running on the bad side
And I got my back to the.

I always thought it was about women or hookers
in NYC. If you cant make a plan you get the
'Freeze-Out'.

Or, maybe Scooter (The Boss) was chasing a girl in NJ and she was the freezer-outer. on
10th Avenue.

I lived in Fiji in 1985 and had 10th Ave spray
painted on my tile floor Just for effect.

Dummies,
Bruce and I are the same age. Both the only son. Both with access to cars. When I was a kid we would get a bunch of boys, 16-18 years old, and go riding in some kid's car. In this case it was mine. It had electric windows, a Chevy Chevelle. What a piece of sth it was, but my daddy let me drive it. We would ride all over Atlanta and North Georgia, like Bruce would ride all over Jersey and NYC. Anyway, the driver or the front passenger would play this cruel game called "Freeze Out". In the cold of the winter, when we would ride, we would roll the windows down and holler "Freeze Out", and leave the windows down until someone started crying, begging for mercy, or praying. I suspect he has done the same thing and either did not want to talk about it, or it's something dummies like us have no idea about.

A rigid tight song by Bruce Springsteen, that may not be the best song to listen to many times as you get older in these days if you have a problem with your sciatic nerve. But it is still a great song especially if you are young being in the spiritual warfare on a cold day by freezing somebody's ass out from all of the heat he was giving from the inside that makes you fight out of the circumstances of the city streets by coming together with Bruce in the ''Tenth Ave Freeze Out''song waiting for one of the members to be picked up on E-Street from where the name of the band came from. This song reminds me by the Bible verse when Jesus gave the Apostles sole authority to bind and loose things on Earth. ''Whatever you shall bind on Earth, shall be bound in Heaven and whatever you shall loose on Earth shall be loosed in Heaven''.

Bad Scooter is Bruce. B.S. Same initials. Its about forming the band. He's "all alone" til "They made that change uptown and the Big Man" joined the band!" Bruce's 1st pianist, Dave Sancious, actually lived on E Street in Belmar, NJ. It intersects with 10th Ave. in Belmar. Bruce himself, on the Born to Run DVD said that he has no idea what "10th Ave Freeze Out" means. I don't believe that. He has also said that Sancious was always late when they picked him up. Hence. 10th Ave Freeze Out. In Clarence's book, he said that it was on one of those waits on E Street that Bruce, Clarence,Garry and Danny were trying to name the band. According to Clarence, Bruce said "we spend so much time on this fuin street. we should call it the E Street Band!" Voila.

This song is about how Bruce meet the E Street Band and if you don't believe me check out Bruce's acceptance speech during his induction into the rock and roll hall of fame he even admits it and hows he meet every single member


Astrochemistry - what does freeze-out mean? - Sterrekunde

Tenth Avenue Freeze-out

Songfacts®:

This song tells the story of the E Street Band coming together. On Springsteen's first album in 1973, he played a lot of the instruments himself and loaded the songs with lyrics. The band was far more pronounced on their next album, released later that year, which incorporated their name: The Wild, the Innocent & the E Street Shuffle.

By the time Springstreen released Born To Run in 1975, his E Street band was crucial to the sound. Later on, Springsteen released the albums Nebraska en The Ghost Of Tom Joad without the band, but they didn't sell nearly as well as the ones they played on.

The "Big Man" in the third verse is Clarence Clemons. Springsteen met him in 1971 when Clemons came into a club called the Student Prince in Asbury Park, New Jersey, where Bruce was playing. It was a stormy night, and the door flew off the hinges when Clemons opened it. Springsteen would talk about how he "Literally blew the door off the place."

In Clemons' autobiography Big Man: Real Life and Tall Tales, he explained: "It was one of those nor'easters - cold, raining, lightning and thunder. Now, this is God's honest truth. I open the door to the club and a gust of wind blew the door right out of my hand and down the street. So here I am, a big black guy, in Asbury Park, with lightning flashing behind me. I said to Bruce, 'I want to sit in.' He says, 'Sure, anything you want.'" Clemons was working as a social worker at the time and playing in a Jersey Shore bar band when he got his big break with Bruce.

Comments: 7

  • Gary from Windham As we all know 10AFO is about Bruce teaming up with Clemons. Bruce was playing small E street clubs while Clemons & Co. played the hipper 10th Ave Jazz Scene. Bruce, wanting to play the more serious, earthy music, didn't have an in, and watching Clemons style and playing with many fine musicians of the day made him yearn to be a part of it ! But nobody thought they needed a singer, especially a vocalist like Bruce to take their music to the next level. Springsteen felt like he was "all alone" and being "frozen-out". I'm not sure what 'changed' with the Big Man that lead him to accept a role with Springsteen but Bruce knew that with Clemons and his ability to bring a powerhouse rhythm section he was finally gonna be able to realize his dreams and 'Bust The City In Half".
  • John Smith from Nyc I'm pretty sure Tenth Avenue Freeze Out is about 10th avenue in Hells Kitchen. There's a photo of Bruce Spingsteen standing on the corner 53rd and 10th avenue taken in 1979. Plant Record where he recorded some of Born To Run is in Hell's Kitchen. The Power Station Studio where he recorded a lot in the 70s is on 10th avenue. With lines like "Teardrops on city" "Stranded in the jungle" "The night is dark but the sidewalk's bright and lined with the light of the living" "From a tenement window a transistor blasts" "Turn around the corner things got real quiet real fast" If that's not 10th avenue in Hell's Kitchen in the 1970's i don't know what is.
  • Arin from San Francisco, Ca First of all, Springsteen doesn't only sing about NJ.
    Try this:
    There is a famous Tenth Avenue. In Manhattan. Hell's Kitchen to be exact. Back in the 70s Bruce and his bandmates played a lot of shows in small clubs (i.e. CBGBs) in the West Village which abuts Hell's Kitchen. This is decades before gentrification, so really mean streets. Think the Warriors movie without the goofy costumes.

You're a performer, with your friends, walking around Manhattan after a gig, drunk on a rainy night (tear drops on the city), maybe looking to hook up. Maybe you go take a piss or duck into a store and you look around and your friends are scattered. You might get jumped, you're on tenth avenue in Hell's Kitchen. You're lost, you're all alone and you can't find your way home.

A radio blares from a tenement window gives some comfort but then you turn a corner and it gets really quiet. Things just got much worse.

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Laws and Fiduciary Duty

Historically, freeze-outs by controlling shareholders have faced differing levels of legal scrutiny.

In the 1952 case of Sterling v. Mayflower Hotel Corp., the Supreme Court in Delaware established a fairness standard that would apply to all mergers, including freeze-outs. It ruled that when an acquiring company and its directors "stand on both sides of the transaction, they bear the burden of establishing the merger's entire fairness, and it must pass the test of careful scrutiny by the courts."

Although the law was once hostile to freeze-outs, they are generally more accepted in corporate acquisitions these days. Courts generally require that as part of a fair transaction, an acquisition should have both a business purpose and fair compensation for shareholders.

Corporate charters may contain a freeze-out provision that allows an acquiring company to purchase the stock of minority shareholders for fair cash value within a defined period of time after the acquisition is completed.


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