Mhepo yepakutanga yepasi ndeimwe yemisoro inonakidza uye yakaoma kunzwisisa kana tichiongorora matangiro epasi redu uye hupenyu pachahwo. Kunzwisisa kuti yakatanga sei, izvo zvayakatanga kuita, uye kuti yachinja sei nekufamba kwenguva haingobatsiri kuti tinzwisise zvakaitika kare, asi zvinotipawo ruzivo nezve dzimwe nyika dzinogarwa.
Kare mhepo isati yaumbwa neokisijeni nenitrogen sezvatinoiziva nhasi, yakaputirwa muchikamu chinodzivirira kubva kumwaranzi yezuva, mhepo yakapoteredza pasi yakanga iri mhoteredzo yakaipa., akazara nemagasi ane chepfu uye asina kana chisaririra choupenyu sezvatinohunzwisisa. Kuburikidza nemiitiro yakaoma kunzwisisa yejoloji, makemikari, uye zvipenyu, shanduro yechinyakare iyoyo yakapa nzvimbo kune mhoteredzo yakaita kuti kushanduka kwezvinhu zvipenyu kubvire.
Chii chinonzi mhepo yakapoteredza pasi uye nei ichikosha kuupenyu?
Muchadenga (atmosphere) ndiyo gasi layer yakatenderedza mutumbi wedenga, apa, Nyika. Iyo yakawanda kupfuura musanganiswa wakapfava wemagasi: inoshanda sechidziviriro nhovo uye tembiricha regulator., uye yakakosha pakusimudzira nekuchengetedza hupenyu.
Parizvino, mhepo yepanyika inoumbwa zvikuru nenitrogen (78%), oxygen (21%) uye musanganiswa wemagasi asara akadai secarbon dioxide, argon, water vapor uye ozone.. Asi kuumbwa uku hakuna kugara kwakadai, uye kushanduka kwayo kwakaratidzwa nekuchinja kukuru kwemabhiriyoni emakore.
Mamirioni Ekutanga Makore: Mhirizhonga yeHadean
Makore angangoita mabhiriyoni mana nemazana mashanu apfuura, Nyika yakaumbwa kubva mugore reguruva remucosmic uye gasi rakapa kusimuka kweSolar System.. Mumakore mashoma ekutanga emamiriyoni, anozivikanwa seHadean eon, pamusoro penyika yaive gungwa remagma yakanyungudutswa, uye mamiriro ekunze panguva iyoyo aive asina kugadzikana zvakanyanya uye kwenguva pfupi.
Munguva iyi yekutanga, pasi rakabhombwa zvakanyanya nemameteorite muchiitiko chinozivikanwa seLate Heavy Bombardment., makore ari pakati pe4.100 ne3.800 bhiriyoni apfuura. Kukanganisa uku kwakaunza makemikari anopisa semvura, ammonia, uye methane, zvichibatsira mukuumbwa kwemhepo yekutanga nemakungwa.
Chinhu chakakosha chakaperekedza nyonganiso iyi yekutanga kwaive kusikwa kweMwedzi. Chinhu chakaenzana nepuraneti chinonzi Theia chinofungidzirwa kuti chakabonderana nePasi, chikaburitsa zvidimbu zvakapa kuti satellite yedu ibude. Ichi chiitiko chakakanganisawo zvakanyanya chimiro chekutanga chemhepo nekuda kwesimba rakaburitswa.
Mhepo yekutanga yePasi: zvikamu uye maitiro
Mushure mezviitiko zvechisimba zvakanyanya zveHadean, Nyika zvishoma nezvishoma yakatanga kutonhora, ichibvumira kuumbwa kweganda rakasimba.. Muchirevo chechinyorwa chino, chatinoziva semamiriro ekutanga akagadzikana kana kuti chinyakare chakabuda.
Yakanga isina okisijeni yemahara, asi yainyanya kuumbwa nemagasi anoputika: carbon dioxide (CO2), mhute yemvura (H2O), methane (CH4ammonia (NH3), sarufa (SO2) uye nitrogen (N2). Iyi cocktail ine gasi yakagadzira mhepo inoderedza, zvichireva kuti yaifarira maelektroni-kuwana kemikari maitiro, akatarisana neaya anoitika muhupo hweokisijeni.
Yakanyanya kuwanda methane uye kabhoni dhayokisaidhi yaiita seane simba greenhouse magasi., iyo yakabvumira nyika kuchengetedza kupisa kwakakwana kuchengetedza mvura yemvura, kunyange zvazvo Zuva rechidiki rakabudisa chete 70% yekupisa iyo ikozvino inopenya.
The faint sun paradox: Nyika yakagara sei ichidziya?
Imwe yemibvunzo inonyanya kunetsa pamusoro pekushanduka kwepasi ndeyekuti mvura yemvura yaigona kuchengetedzwa sei pamusoro pePasi kana Zuva raive risinganyanyi kupenya.. Chiitiko ichi chinozivikanwa semudiki asina simba reZuva gangaidzo.
Tsananguro inobvumwa zvikuru yechakavanzika ichi chiri mukuumbwa chaiko kwemamiriro echinyakare.. Kunze kwecarbon dioxide, methane, iyo inoshanda zvakapetwa ka20 kusvika ku25 segasi rinopisa, yakaita basa rinokosha mukuchengeta tembiricha yepasi rose yakakwirira.
Pamusoro pezvo, zvimwe zvinhu zvakaita sekudziya kwemvura nekuda kwekuva pedyo kweMwedzi kana kuwanda kwezvinhu zveradioactive mukati mepasi zvakapawo kupisa.. Kubatanidzwa kwezvinhu zvose izvi kwakabvumira makungwa kuti arambe ari mumamiriro emvura, mamiriro makuru ekubuda kwehupenyu.
Humbowo hwekutanga hwe geological: Tinoziva sei kuti mhepo yaive yakaita sei?
Ruzhinji rweruzivo rwedu pamusoro pemhepo yekutanga runobva mukuongororwa kwematombo ekare.. Izvi zvinosanganisira sedimentary formations, fluid inclusions, stromatolites uye isotopic kuongorora.
Muenzaniso wakajeka ndeye maBIF kana mabhendi esimbi maumbirwo, iyo inoratidza kuchinjika maseru e iron oxides uye silica. Izvi zvakaumbwa apo simbi ine ferrous (Fe2+) mugungwa akatanga kuita oxidize uye kunaya nekuita neokisijeni inogadzirwa nemhando dzehupenyu dzepakutanga dzephotosynthetic.
Kune rimwe divi, zvicherwa zvakaita se pyrite (FeS2) iripo mumatombo ekare anoratidza kuti mhoteredzo yaityisa, sezvo iyi mineral isingagoni kuumba muhupo hwemhepo yakasununguka.
Inclusions yemagasi akabatwa akawanikwa zvakare mumakristasi ekare., izvo zvinobvumira kuumbwa kwemuchadenga kwedzimwe nhambo kuvakwa patsva nemwero wakafanira wekururama. Kubatanidza zvese izvi zvinongedzo, zvave zvichikwanisika kuronda kushanduka kunofambira mberi kubva mumhepo isina oxygen kune imwe yakapfuma muO.2.
The biological revolution: cyanobacteria uye Great Oxidation Chiitiko
Kubuda kwecyanobacteria kunoratidza imwe yenguva dzakakosha munhoroondo yemhepo.. Aya mabhakitiriya ephotosynthetic, achiripo nhasi, akatanga kushandisa chiedza chezuva uye carbon dioxide kubudisa simba, achigadzira okisijeni sechinhu chinobva kunze.
Kwemazana emamiriyoni emakore, okisijeni yakabudiswa yakatorwa nemakungwa nematombo. Kunyanya, yakaita nesimbi yakanyungudutswa, zvichikonzera kunaya kwesimbi okisidhi uye kuumbwa kwemaBIF ambotaurwa. Okisijeni payakazozara pakazotanga kuungana mumhepo.
Chiitiko ichi, chinozivikanwa seGreat Oxidation, chakaitika makore angangoita 2.400 bhiriyoni apfuura uye chakave nemhedzisiro inoparadza uye yekuchinja panguva imwe chete.. Mhando dzakawanda dzeanaerobic hadzina kukwanisa kurarama munzvimbo itsva yeoxidizing, nepo dzimwe dzakagadzira nzira dzekushandisa okisijeni, senge aerobic cellular respiration.
Kuchinja kwemamiriro ekunze uye kutanga kunyura
Imwe mhedzisiro yeGreat Oxidation Chiitiko kwaive kudzikiswa kwemumhepo methane, kuita neokisijeni kuumba carbon dioxide nemvura. Sezvo methane yaive gasi regreenhouse rine simba, kuderera kwayo kwakakonzera kuderera kwakanyanya kwekushisa kwepasirese.
Izvi zvakapa kusimuka kune kunoonekwa sekutanga kukuru kwechando paPasi: iyo Huronian glaciation.. Mamwe masayendisiti anotenda kuti chiitiko ichi chinogona kunge chakanyanyisa zvekuti Nyika ikaita "snowball" yakaoma nechando, chiitiko chichiri kukakavara asi chine musoro.
Munguva yeProterozoic eon, mamwe matatu akakosha glaciations akaitika, ane nguva uye hukuru zvichiri kuongororwa. Nyika yakatenderera pakati penguva inodziya neinotonhora, kazhinji nekuda kwekusaenzana kudiki mumagasi egreenhouse, chiitiko chekuputika kwemakomo, plate tectonics, uye kutenderera kwepuraneti.
Mhepo uye kubuda kwezvisikwa zvakaoma
Nemazinga eokisijeni akakwira, kusvetuka kwekushanduka-shanduka kune zvipenyu zveeukaryotic kwakagoneka.. Aya ane nucleus uye organelles akatsanangurwa akadai semitochondria uye chloroplasts, ayo anoshandisa okisijeni kugadzira simba zvakanyanya kupfuura kuvirisa kweanaerobic.
Uku kufambira mberi kwemaserura kwakakurumidza kubvumira kubuda kwezvisikwa zvakawanda, izvo zvaizoshanduka kuita mhuka dzakaoma uye hupenyu hwezvirimwa.. Iyo ozone layer (O) yakaumbwa zvakare3)
Kuenzanisa pakati pechinyakare nechazvino mamiriro
| Gesi | Primitive Atmosphere | Current Atmosphere |
|---|---|---|
| Nitrogen (N2) | Inowanikwa muzvikamu zvidiki | ~ 78% |
| Okisijeni (O2) | Zvishoma kana kusavapo | ~ 21% |
| carbon dioxide (CO2) | Zvakawanda kwazvo | ~ 0.04% |
| Methane (CH4) | Inowanikwa muhuwandu hwakawanda | Trace |
| Mvura yemvura (H2O) | Yakasiyana-siyana, asi yakawanda | Variable zvinoenderana nemamiriro ekunze |
Mhepo semuyedzo wekudzidza mamwe mapuraneti
Ruzivo rwekushanduka kwePasi pano pasi (atmospheric evolution) rinoshandiswawo kuongorora mamiriro ekunze pane mamwe masimba emuchadenga., seMars, Venus kana exoplanets. Kudzidza maitiro avo kunobatsira kuona kuti vangatsigira hupenyu here kana kuti vakambodaro.
Saizvozvowo, kunzwisisa kuti misiyano midiki mumagasi inogona kutanga shanduko huru mumamiriro ekunze uye biosphere chinhu chakakosha pakunzwisisa kusasimba kwechiyero chazvino.. Izvi zvine mashandisirwo akananga mukuongorora kushanduka kwemamiriro ekunze kwazvino paNyika.
Kubva paupfu hwesilicate hweHadean kusvika pakuvepo kweozone mune yazvino stratosphere, mhepo yePasi yakave chigadzirwa chekudyidzana uye chine simba maitiro.. Geology, biology, uye nyeredzi zvinopindirana kugadzira rondedzero iyi inopa zvinoreva kune kwatakabva uye neramangwana redu.