Nebula vs Galaxy
Nebulae thiab galaxies yog lub ntuj ceeb tsheej sib sib zog nqus uas tsuas pom tau meej meej nrog kev pab ntawm lub tsom iav. Nrog lub qhov muag liab qab lossis lub tshuab hluav taws xob qis qis ob hom khoom tuaj yeem pom tau tias yog thaj chaw fuzzy nyob rau hmo ntuj. Yog li ntawd nyob rau hauv cov theem pib ntawm kev loj hlob ntawm astronomy tsis meej pem tshwm sim thiab nyob rau hauv tej lub sij hawm lawv nqa txawm hnub no.
Nebula
Nebulae yog cov khoom loj ntawm cov pa nruab nrab hnub qub thiab cov hmoov av. Feem ntau nebulae tuaj yeem txhais tau tias yog thaj tsam denser ntawm interstellar nruab nrab accreting nyob rau hauv lub ntiajteb txawj nqus; lwm tus yog cov seem ntawm cov hnub qub tom qab kawg ntawm lawv lub neej. Lawv feem ntau muaj hydrogen thiab helium. Tab sis lwm cov ntsiab lus tseem tuaj yeem suav nrog me me tab sis sib txawv. Yog hais tias lub nebula nyob ze ntawm cov khoom siv hnub qub uas muaj zog heev xws li cov hnub qub hluas thiab lwm yam khoom siv hluav taws xob, cov gasses hauv nebulae yuav dhau los ua ionized.
Nebula feem ntau pom zoo li qhov kaj ci ntsa iab nyob rau hmo ntuj. Lawv tshwm sim nyob rau hauv ntau xim thiab duab, feem ntau ua rau lawv cov npe siv (tsis yog astronomical designations) xws li Cat's Eye, Ant, California, Nees Head thiab Eagle nebulae.
Peb pawg tseem ceeb ntawm nebulae yog emission nebulae, tsaus nebulae, thiab xav txog nebulae. Emission nebulae yog cov huab cua interstellar nrog cov yam ntxwv emission kab spectrum. Lub zog qhov chaw, xws li cov hnub qub kub kub thiab cov pob zeb ntawm cov qhov dub, ionize cov nruab nrab nruab nrab ntawm lub hnub qub nyob ib puag ncig lawv, thiab cov roj ntsha zoo siab emit hluav taws xob nyob rau hauv sib txawv wavelengths. Peb saib cheeb tsam no ua ib lub nebula. Lub Orion nebula yog ib qho piv txwv classic ntawm emission nebula; Nws yog lub hnub qub thib peb hauv rab ntaj ntawm Orion, Tus Saib Xyuas. Lub Orion nebula spans.5° nyob rau hmo ntuj thiab nyob deb li ntawm 1500 light years. Nws muaj li ntawm 300 hnub ci ntau ntawm cov khoom, thiab nws yog ib cheeb tsam nrog cov tub ntxhais hluas O thiab B hom hnub qub yug hauv nebula. Cov hnub qub hluas no ua rau cov gasses ci. Plaub lub hnub qub pom ci ntsa iab nyob rau hauv lub nebula yog hu ua Trapezium.
Dub nebulae yog huab cua huab cua uas tsis tawm hluav taws xob hauv qhov pom ntau zaus, tab sis lawv tau nyob hauv thaj chaw ci ntsa iab, ua rau lawv pom tau. Nees taub hau nebula thiab Bernard 86 yog cov piv txwv ntawm cov nebulae tsaus. Reflection nebula scatters thiab qhia txog lub teeb los ntawm cov hnub qub nyob ze thiab tsis tawm lub teeb. NGC 6726 thiab NGC 2023 yog qhov kev xav ntawm nebulae.
Nebulae muaj feem cuam tshuam nrog lub neej ntawm cov hnub qub. Cov hnub qub yog tsim (yug) hauv nebulae. Ib lub nebula los yog ib cheeb tsam gaseous cog lus los tsim ib tug protostar. Tom qab pib ntawm nuclear fusion, nws rov emits ib co huab hwm coj mus rau ib puag ncig tsim ib tug protoplanetary nebula. Tom qab lub hnub qub ua tiav nws lub neej nrog lub supernova, cov txheej txheej gaseous raug tua mus rau qhov chaw nyob ib puag ncig. Ib zaug ntxiv, cov seem tau pom zoo li lub nebula, feem ntau hu ua planetary nebula.
Galaxy
Galaxy yog cov khoom loj ntawm cov hnub qub thiab cov huab cua loj hauv ntiaj teb. Cov hnub qub loj ntawm cov hnub qub no tsis tau txheeb xyuas thiab kawm tau zoo kom txog rau thaum lig 18th thiab 19th centuries. Tom qab ntawd cov no raug suav hais tias yog nebulae. Cov ntawv sau hnub qub no nyob ib puag ncig ntawm Milky Way, uas yog peb cov hnub qub sau. Yog li ntawd, nws yog qhov nyuaj rau kev paub qhov txawv ntawm lub galaxy thiab nebula nrog lub qhov muag liab qab lossis lub tsom iav me me. Feem ntau ntawm cov khoom nyob rau hauv lub ntuj tsaus ntuj yog peb lub galaxy, tab sis yog tias koj saib ze, koj tuaj yeem txheeb xyuas lub galaxy ntxaib ntawm Milky Way, Andromeda Galaxy.
Edwin Hubble tau tshawb fawb ntau ntawm cov galaxies thiab faib cov raws li lawv cov duab thiab cov qauv thiab categorized lawv. Ob pawg loj ntawm lub galaxies yog kauv thiab lub elliptical galaxies. Raws li cov duab ntawm cov kauv caj npab, Kauv galaxies tau muab faib ua ob pawg raws li Kauv galaxies (S) thiab Barred Spiral galaxies (Sb).
Kauv galaxies muaj kauv caj npab nrog lub hauv paus pob. Qhov nruab nrab ntawm lub galaxy muaj lub hnub qub siab ceev heev thiab zoo li ci ntsa iab nrog cov pob txha txuas rau saum toj thiab hauv qab ntawm lub dav hlau galactic. Kauv caj npab kuj yog thaj chaw nrog lub hnub qub siab dua, uas yog vim li cas cov cheeb tsam no pom tau zoo li cov kab ci ntsa iab. Lub interstellar nruab nrab nyob rau hauv cov cheeb tsam no yog illuminated los ntawm lub zog ntawm lub hnub qub. Cov chaw tsaus nti tseem muaj cov nruab nrab ntawm nruab nrab, tab sis lub hnub qub ceev yog qhov tsawg los ua kom pom cov cheeb tsam no, ua rau lawv pom kev tsaus dua lwm thaj chaw. Feem ntau, kauv galaxies muaj kwv yees li 109 rau 1011 hnub ci ntau thiab muaj luminosity ntawm 10 8 thiab 2×1010 hnub ci luminosity. Txoj kab uas hla ntawm cov kauv galaxies tuaj yeem sib txawv ntawm 5 kiloparsecs txog 250 kiloparsecs.
Elliptical galaxies muaj cov yam ntxwv oval zoo nyob rau hauv lawv cov cheeb tsam sab nrauv thiab ib qho kev tsim xws li caj npab kauv tsis pom. Txawm hais tias elliptical galaxies tsis pom cov qauv sab hauv, lawv kuj muaj cov nucleus denser. Kwv yees li 20% ntawm cov galaxies hauv lub ntiaj teb yog elliptical galaxies. Lub galaxy elliptical tej zaum yuav muaj 105 rau 1013 hnub ci ntau thiab tuaj yeem tsim luminosity ntawm 3 × 10 5rau 10 11 hnub ci luminosities. Txoj kab uas hla yuav nyob ntawm 1 kiloparsec mus rau 200 kiloparsec. Lub galaxy elliptical muaj qhov sib xyaw ntawm Population I thiab Population II hnub qub hauv lub cev.
Dab tsi yog qhov txawv ntawm Nebula thiab Galaxy?
• Cov cheeb tsam ntom ntom hauv nruab nrab nruab nrab uas paub qhov txawv ntawm thaj chaw ib puag ncig yog hu ua nebula.
• Galaxies yog cov qauv loj ntawm cov hnub qub thiab cov hnub qub ua ke los ntawm lub ntiajteb txawj nqus. Lawv kuj muaj qhov nruab nrab nruab nrab ntawm lub hnub qub, uas ua rau nce mus rau nebula.
