Astronomija

Zašto planete i sateliti u Sunčevom sistemu izgledaju toliko divlje ako dolaze iz više ili manje iste materije?

Zašto planete i sateliti u Sunčevom sistemu izgledaju toliko divlje ako dolaze iz više ili manje iste materije?


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Prvo, planete. Imamo Merkur koji je stjenovit, bez atmosfere. Ali onda imamo Veneru, koja je potpuno drugačija: gusta atmosfera, vrlo vruća, geološki aktivna. Zatim Zemlja - plava, puna vode. Mars, suprotno: crveno kao ništa drugo. Jupiter i Saturn su prilično slični. Zatim Uran i Neptun, prilično slični, ali se i dalje međusobno razlikuju u boji i također se potpuno razlikuju u boji od dva gasna diva.

S druge strane: sateliti. Analizirajmo satelite Jupitera i Saturna.

Ganimed i Kalisto prilično slični, ali onda Evropa, potpuno suprotna: potpuno ledena. A onda Io, opet nešto sasvim drugo: upadljivo žuto.

Saturnovi mjeseci: uglavnom stjenoviti, ali onda, nešto sasvim drugo: Titan, s gustom atmosferom kao nijedan drugi satelit i okeanima tečnog metana.

Da je tokom formiranja Sunčevog sistema postojao protoplanetarni disk materije, ne bi li on bio prilično homogen i zbog toga bi nastao planet sličnog izgleda? Razumijem da plinski divovi ne mogu izgledati isto kao stjenovite planete, ali zašto postoje razlike čak i između stjenovitih planeta slične veličine? Doduše, u Sunčevom sistemu postoje divlje različite temperature, ovisno o udaljenosti od Sunca, što vjerovatno objašnjava neke razlike.

Ali onda ono što posebno ne razumijem su razlike između satelita. Ako se kaže da Jupiter ima disk oko materije koji kruži oko njega, a koji se na kraju formirao u satelite, ne bi li barem taj "lokalni" disk oko planete bio prilično homogen? Ali unatoč tome, razvio se u izuzetno različite satelite. Na primjer, kako se "žućkasta" stvar koncentrirala na Io, a nije se jednako rasporedila na svim Jupiterovim mjesecima?


Ova pitanja se mogu podijeliti na dva dijela; za planete i satelite.

Raznolikost planeta dijelom odražava raznolikost u pogledu hemijskog sastava protoplanetarnog diska. Znamo da UV zračenje sunca može razdvojiti složene molekule ili čak vrlo jednostavne; na primjer, kada UV zrake dijele molekule vode, rezultat su slobodni atomi vodika i kiseonika. Budući da je vodonik izuzetno lagan, oni se lako mogu transportovati u toku zvezdanih vetrova. Dakle, voda, da se držimo tog primjera, ako bi blizina sunca mogla na kraju biti odvojena i iscrpljena iz područja diska, ali iznad takozvane "snježne linije" UV zračenje Sunca bilo je toliko slabo da to nije moglo događaju se često i tako molekuli vode (koji su vrlo teški u odnosu na pojedinačne atome vodonika) ostaju tamo. To samo objašnjava dihotomiju između unutrašnjih i vanjskih planeta u smislu sadržaja vode, pa čak i tada bi neki procesi (poput kasnog jakog bombardiranja) mogli dodati malo vode u unutrašnjost (kao što se dogodilo na Zemlji). Ali ovo obrazloženje nije samo za vodu, ugljični dioksid, amonijak, metan i stotine različitih molekula imaju svoje "linije smrzavanja". Bliže suncu ugljik ne može biti metan je hlapljivi plin koji se brzo izbacuje prema van, ali na nekim desetinama AU-a metan može ostati u stabilnim uvjetima i čak se može kondenzirati u kapljice tečnosti.

Sve ovo samo da bismo rekli da protoplanetarni disk NIJE bio homogen u pogledu hemijskog sastava i nije bio homogen u smislu gustine ili pritiska. Termički i hemijski gradijent preko maglice osigurava određenu raznolikost i složenost za čitav planetarni sistem.

Ovdje imate prekrasan dijagram koji pokazuje kako se različiti hemijski spojevi mogu kondenzirati pri različitim temperaturama i pritiscima na protoplanetarnom disku.

Takođe je priraštaj planetezimala energičniji bliže Suncu (što znači da se raspadi mogu češće događati i planeti je teško da naraste), dok se u vanjskim regijama planete mogu redovito povećavati u masi, budući da se sudari s drugim planetezimalima vrše na niže relativne brzine (zbog toga kako dvije slične orbite imaju razliku u periodima koja postaje veća kad se približite Suncu, a time i veće relativne brzine). To zajedno sa gravitacijskim interakcijama protoplaneta i ranog diska (vidi migraciju planeta i lijep model itd.) Omogućava različite brzine nakupljanja i nagomilavanje materijala različitog sastava od onoga što je pronađeno na izvornom mjestu formiranja određenog planetezimalnog . Ovo takođe pomaže zadržati široku raznolikost na planetarnim masama.

Široka raznolikost planetarnih masa polazna je točka za veće varijacije kako planete evoluiraju u vremenu i odstupaju od svojih početnih uslova. Stjenovita mala planeta (Merkur) možda ima manje toplote zarobljene unutra od veće (Zemlje), zbog manje energije koja se oslobađa manjim stopama prirasta. Stoga bi moglo brzo zahladiti i magnetosfera zbog istopljene unutrašnjosti ne može se dogoditi. Odsustvo magnetosfere omogućava česticama nabijenim solarnim vjetrom da nagrizaju vašu atmosferu prskanjem. Umjesto toga, na planeti poput Zemlje, veća masa dovela je do istopljene unutrašnjosti koja je zauzvrat stvorila magnetosferu koja je trajala milijardama godina, na Marsu je to trajalo neko vrijeme, ali sada je gotovo nestalo pa je i atmosfera gotovo uništena. Na Zemlji prisustvo atmosfere dovodi do svih vrsta hemijskih erozija i pojava. Takođe, istopljena unutrašnjost, zajedno sa specifičnostima hemijskog sastava i debljine kore, omogućava mehanizam koji se naziva tektonika ploča. Tektonika se ne može dogoditi na Veneri, jer kora nije toliko gusta (zbog različitog sastava), pa se stoga ne raspada u pločama, već se samo deformiše i savija u složenom ponašanju jedinstvenom za Veneru.

Takođe sudari sa planetesimalima mogu promijeniti buduću evoluciju sličnih planeta. Venera je vjerojatno bila vrlo slična Zemlji (slične mase, vrlo sličnog sastava i ne toliko različitih temperatura kao što bi se moglo pomisliti), ali njihovi su se putevi potpuno razišli jer su tektonike na Zemlji reciklirale litosferu, a na Veneri se ugljični dioksid zaglavio u efektu staklenika, i zato što je Zemlja imala sudar s drugom planetom koja nam ima naš Mjesec, koji je mehanički stabilizator, dok je slučajni sudar s Venerom (s različitim parametrima udara) doveo do izuzetno spore rotacije i dugih dana (ali bez mjeseci). Duži dani znače drugačiju izolaciju, a to drastično mijenja klimu planete. Na Marsu su dani slični Zemljinim, ali budući da je manji i atmosfera je nestala, mnoge stvari se vrlo razlikuju od Zemljine. Također, Mars nema tektonike (kora je deblja od Zemljine i kreće se poput monolitnog objekta), tako da je malo vulkana i oni rastu ogromni (dok na zemlji jedna vruća tačka generisana plašnom perjanicom buši nekoliko rupa na kori kao ploča se kreće na onome što se naziva vulkanski lanac), a postoje i stresne greške poput Valles Marinerisa (jedinstvene u Sunčevom sistemu) koje bi tektonski pokreti mogli opustiti.

Da biste vidjeli koliko različita može biti evolucija dva planetarna objekta tako što ćete ih učiniti različitom masom, pogledajte naš Mjesec. Ima isti kemijski sastav (zapravo je dio sa Zemlje), u osnovi je na istoj udaljenosti od Sunca kao i Zemlja, živi u istom međuplanetarnom okruženju (isto sunčevo zračenje, sunčev vjetar, brzine udara itd.) , i dalje je potpuno drugačije. Sve je to zbog mase! Mjesec ne može zadržati veliku atmosferu kao Zemlja jer ima manje gravitacijskog privlačenja. Ista temperatura za našu atmosferu tamo znači da čestice lako postižu brzinu izlaza i počinju izlaziti iz gravitacijskog izvora. Bez atmosfere i unutarnje vrućine, mjesecu nedostaje gotovo bilo koja vrsta erozije tokom milijardama godina evolucije. Procesi erozije na Zemlji učinili su da raznolikost geoloških formacija eksplodira u odnosu na one pronađene na Mjesecu. Čak i tada Mjesec ima svoje osobenosti i dinamičke karakteristike jedinstvene za njega.

Sad smo sve bliži pitanju satelita. Oni bi u stvari trebali izgledati gotovo isto, jer su izrađeni od vrlo sličnog materijala u izuzetno sličnim uvjetima. I zaista vjerujemo da su mjeseci prvotno bili vrlo slični (na primjer 4 galilejska mjeseca). Ali Io je blizu Jupitera i ostali su mjeseci u interakciji s njim na takav način da su geološki procesi potpuno drugačiji. Voda i hlapljivi sastojci brzo su isparili dok su se zagrevali plimnim silama sa Jupitera. Ove plimne sile nisu bile toliko jake u Europi, jer je ona dalje, tako da je otopila samo dio ledene kore stvarajući ledeni analog tektonike ploča koji je stvorio mnoštvo različitih formacija. Sateliti evoluiraju. Enceladus puca mlaznicama zbog plimnih interakcija i orbitalnih rezonancija s drugim mjesecima. Neki mjeseci poput Japeta imaju dvostruku obojenu površinu zbog materijala prskanog Enceladusom koji je sletio na jednu od njegovih strana. Neki mjeseci poput Tritona nemaju nikakve veze s drugim, jer su nastali u drugoj regiji Sunčevog sistema, a kasnije su zarobljeni gravitacijskim povlačenjem planete (u ovom slučaju Neptuna).

Kao što sam već spomenuo. Atmosfere (gustina, sastav i pritisak) u velikoj mjeri ovise o masi planete ili Mjeseca. Pogledajte ovaj grafikon:

Prikazuje brzinu molekula plina u odnosu na temperaturu plina. Za veće temperature molekuli gasa se brže kreću. Na planeti male mase brzina bijega je niža od one veće mase. Stoga planeta bliža Suncu (na višoj temperaturi) mora biti veće veličine ako želi sačuvati iste molekule plina u svojoj atmosferi kao i planeta koja je udaljenija (hladnija). Možete vidjeti zašto bi Zemljina atmosfera mogla zarobiti i zadržati vodu, kiseonik, ugljični dioksid, amonijak, metanski dušik i druge plinove, dok nije u stanju zarobiti vodik i helij (jer su lakši i tako se za iste temperature mogu kretati brzo kao potreban za bijeg sa Zemlje). U međuvremenu, Mjesec, koji ima istu toplinu koja dolazi sa Sunca kao i Zemlja, jer je manje masivan, ne može zadržati gotovo nijedan plin (možda malo ksenona). Titan je ogroman mjesec, tako da može zadržati mnogo plinovitih molekula poput dušika i kiseonika (oni zauzvrat čine pritisak dovoljno visokim da na površini zadrže i hlapljive materije poput metana). Ali zašto Ganimed nema istu atmosferu kao Titan ako su u osnovi iste veličine? Budući da je Ganimed bliži Suncu, veća temperatura znači da se molekuli brže kreću i tako lako izbjegavaju njegovu privlačnost.

Kao što vidite, složeni procesi atmosfere mjeseca ili planete sve mijenjaju (erozija, procesi recikliranja, hemijska korozija itd.), A zauzvrat ta raznolikost atmosfera dolazi iz različitih masa i udaljenosti do Sunca.

Mislim da je Sunčev sistem kaotičan sistem, dinamički, geološki, hemijski itd. Kaos znači da će se za malu razliku u početnim uslovima sistem razvijati eksponencijalno divergirajući različita stanja. Planete i mjeseci mogli su započeti kao slični objekti, ali istorija i kaotična dinamika sistema evoluirali su u potpuno drugačija okruženja. I ne samo to, već istina je da planete nisu započele jednake, već su se od početka jako razlikovale, pa zamislite koliko je daleko Venera da bi postala Titan ili Io da bi postala Zemlja.

Takođe postoje procesi i uslovi koji su posebno pogodni za divergenciju. Na primjer: Zemlja je vrlo dinamična, dok Mars, Venera, Merkur, Mjesec i drugi potpuno nisu. Zašto? jer na Zemlji voda može postojati u 3 različita stanja materije. Tečnu vodu, vodenu paru i led možemo pronaći u različitim regijama i godišnjim dobima. A to je zato što je Zemlja na prosječnoj temperaturi i u atmosferi je prisutan odgovarajući pritisak da to dozvoli. Zemljini uslovi su vrlo blizu trostruke tačke vode (gdje koegzistiraju sva tri stanja materije), zato na Zemlji imamo kružni tok vode, a rijeke i lednici nagrizaju krajolik, a oblaci regulišu klimu.

Mars, Venera, Merkur imaju temperaturu i pritisak da se to ne može dogoditi, ne samo na vodi već i na mnogim tamo prisutnim jedinjenjima. Znate li gdje se to može dogoditi? Na Plutonu! To je bilo vrlo iznenađujuće, Pluton pokazuje raznolikost terena i geoloških karakteristika koje premašuju sva očekivanja. Sada znamo da je to zato što je Pluton izuzetno dinamičan (kao Zemlja) i može se dogoditi puno erozije i geohemijskih procesa, ali to nije zbog vode (jer Pluton ima nizak pritisak i niske temperature), već dušika i Neon! Oba elementa imaju svoju trostruku tačku u rasponu od Plutona, pa se na ovoj patuljastoj planeti očekuju neonske rijeke, azotni lednici i izmaglica.

To je zaista zanimljivo pitanje. Kako su nevjerovatni zakoni prirode koji dopuštaju krajnju raznolikost čak i među braćom. Pitam se kako bi mogla biti planeta oko bilo koje druge zvijezde, naše pojednostavljene kategorije vrućih Jupitera, mini-Neptuna, super-terasa, itd ... su tako primitivne i restriktivne. Ono što nas čekaju u ovom složenom i raznolikom kosmosu izvan je našeg poimanja.


Sunčev sistem

Redoslijed poglavlja u Gr 8 Planet Earth and Beyond u CAPS je sljedeći:

Iako je ovo redoslijed u CAPS-u i način je na koji je ovdje naručen sadržaj u ovim radnim bilježnicama, predlažemo da prvo započnemo s poglavljem 3 o "Pogled u svemir", a zatim prelazimo na druga dva poglavlja. To konceptualno ima više smisla da prvo naučimo kako vidimo u svemir, a zatim nastavimo da gledamo objekte koji su posmatrani u našem Sunčevom sistemu i šire, koristeći razne teleskope.

Učenici 6. razreda obrađivali su materijale u vezi sa Sunčevim sistemom, a 7. razreda fokusirali su se na sistem Sunce, Zemlja i Mjesec. Učenici bi trebali biti upoznati sa činjenicom da je Sunce zvijezda smještena u središtu Sunčevog sistema i trebali bi razumjeti da planete kruže oko Sunca. Oni bi također trebali biti svjesni da postoje dvije vrste planeta: manji stjenoviti planeti i veći plinski divovi. U ovom poglavlju detaljnije je predstavljen Sunčev sistem i sažeto je fizičko objašnjenje za dvije vrste planeta. Uporedit će svojstva različitih planeta, informacije koje će zatim koristiti kako bi objasnili zašto je Zemlja trenutno jedina planeta pogodna za život u našem Sunčevom sistemu. Glavni ciljevi ovog poglavlja su osigurati da učenici razumiju sljedeće:

  • Sunce je zvijezda i proizvodi toplotu i svjetlost (energiju) nuklearnim reakcijama.
  • Sve planete, patuljaste planete i asteroidi kruže oko Sunca, a u svojim orbitama ih drži sila gravitacije.
  • Različite planete imaju različita uočena svojstva i karakteristike.
  • Zemlja se nalazi u posebnoj zoni oko Sunca, gdje je život moguć.

Odjeljak 1.1 pokriva svojstva Sunca, odjeljak 1.2 predstavlja sve ostale objekte u Sunčevom sustavu, a odjeljak 1.3 pokriva naše posebno mjesto u Sunčevom sistemu.

Konceptne mape: Mape koncepata u ovim radnim sveskama kreirane su u Siyavuli koristeći program otvorenog koda pod nazivom CMapTools. Program možete preuzeti s ove veze ako ga želite koristiti za izradu vlastitih konceptualnih mapa. [Link] http://cmap.ihmc.us/download/

Mislite li da je važno predavati astronomiju učenicima u školi? Pročitajte ovaj zanimljiv i informativan članak s detaljima o prednostima i primjenama astronomije. http://www.iau.org/public/themes/why_is_astronomy_important/

Građanska nauka nudi vam besplatnu, lako dostupnu i inspirativnu priliku da u učionicu unesete pravu nauku. Saznajte više o uključivanju stvarne nauke u vašu učionicu sa Zooniverse građanskim naučnim projektima na ZooTeach: [veza] http://www.zooteach.org/ .. ZooTeach je web stranica na kojoj nastavnici i nastavnici mogu dijeliti visokokvalitetne planove lekcija i resurse koji dopunjuju naučne projekte o građanima Zooniverse.

Jeste li znali da su ove radne bilježnice stvorene u Siyavuli uz doprinos mnogih saradnika i volontera? Samo se okrenite naprijed da vidite dugački spisak. Pročitajte više o Siyavuli na našoj web stranici: www.siyavula.com. Također se možete prijaviti na našoj stranici zajednice ako želite ostati u kontaktu i uključiti se u naše projekte.

Siyavula je takođe stvorio a raspon udžbenika za ostale razrede i predmete, a mi ćemo proizvoditi više. Ovi udžbenici i radne sveske jesu otvoreno licenciran i slobodno dostupan za vas da koristite, preuzimate, kopirate, prerađujete i distribuirate. Trenutno dostupni udžbenici Siyavula su:


P: Zašto su mnoge galaksije, naš Sunčev sistem i Saturnovi prstenovi svi ravni?

Fizičar: Ovo je možda najkraći odgovor do sada: & # 8220accretion & # 8220.

Priraštaj: stvaranje stvari ravnim milijardama godina.

Akrecija je proces gravitacionog kolabiranja materije iz oblaka prašine ili plina ili (obično) oboje. Prije razmišljanja o tome što veliki oblak plina radi kad naleti na sebe, vrijedi razmisliti o tome što se dogodi sa samo dvije nakupine prašine kad nalete jedan na drugog.

Većina sudara je neelastična, što znači da gube energiju i da su čestice & # 8217 putanje & # 8220 u prosjeku & # 8221. U najekstremnijem slučaju stvari će se držati zajedno.

U savršeno elastičnom sudaru objekti će se odbiti pod približno istim kutom u koji su došli. Većina sudara je neelastična, što znači da oni izgubiti energija i ugao između putanja objekata & # 8217 smanjuje se nakon sudara. U najekstremnijem neelastičnom slučaju čestice će se lijepiti. Za sitne čestice to je češće nego što mislite.

Stona sol, u nultoj gravitaciji, spontano se skuplja zbog elektrostatičkih sila (kliknite sliku za film).

Vremenom sudari oslobađaju energiju (kao toplotu i svetlost). Ovaj gubitak energije uzrokuje da se oblak fizički skuplja, jer gubitak energije znači da se komadići prašine i plina kreću sporije (a to znači da padaju u niže i niže orbite). Ali sudari također čine stvari & # 8220prosječnim & # 8221 njihovim putanjama. Dakle, dok veliki napuhani oblak može imati komadiće prašine i plina koji putuju u bilo kojem smjeru, tijekom nakupljanja oni se na kraju smjeste u istu, prosječnu, rotacijsku ravninu.

Svaki atom plina i prašina se kreće duž vlastite orbitalne petlje, povučen suradničkim gravitacijskim utjecajem svakog drugog atoma i trupa (tamo nema niti jedne točke odakle gravitacija potječe). Iako je put svake od njih prilično slučajan, uvijek postoji neto okretanje u nekom smjeru. Ideja je da bilo koji oblak u svemiru započne sa najmanje a malo malo okretanja. Ovo nije velika tvrdnja da sipate kavu u šalicu i barem će se malo komadića okretati. Ista turbulencija prirodno se pojavljuje na svim skalama šolja većim od kafe u svemiru (iako obično ne mnogo manjim). Dakle, u prosjeku će se bilo koji oblak okretati u nekom smjeru.

Stvari u oblaku i dalje će se sudarati dok svaki njegov dio ne napravi jednu od tri stvari: 1) pobjegne, 2) padne u centar ili 3) krene se protokom. Većina oblaka završi u centru. Na primjer, naše Sunce čini 99,86% materije u Sunčevom sistemu. Materijal koji se prestaje sudarati i ide s protokom tvori prsten. Sve što nije u ravni prstena mora biti u orbiti koja prolazi kroz njega, što znači da će i dalje udarati i gubiti energiju. Na kraju će se objekt & # 8220nepravilno kružiti & # 8221 naći u orbiti oko svega ostalog u prstenu ili će izgubiti dovoljno kinetičke energije da padne na planetu ili zvijezdu ispod. Usput, još uvijek postoje a puno od & # 8220 nepovezanog & # 8221 smeća u našem Sunčevom sustavu koji & # 8217 još čeka na & # 8220pridruživanje & # 8221 planeti.

Ti prstenovi su i sama prilično uzbudljiva mjesta. Unutar njih će se nalaziti & # 8220 nakupine & # 8221 veće gustoće koje se uvlače u okolni materijal. Na kraju se to pretvori u manje diskove za povećanje u većem disku. Naš Sunčev sistem formirao se kao disk sa svim planetima koji se formiraju unutar tog diska u & # 8220 ravni ekliptike & # 8221. Jedna od tih grudica postala je Jupiter, koji ima svoj vlastiti skup mjeseci koji su se takođe formirali na akrecijskom disku oko Jupitera. U stvari, Jupiterovi luni postavljeni su toliko poput ostatka Sunčevog sistema (koji se vrte u istoj ravni) da su pomogli ranim astronomima da prvo shvate čitav Sunčev sistem. Teško je vidjeti kako se planete kreću iz vida na površini jedne od tih planeta u pokretu (Zemlja), pa je lijepo imati jednostavan primjer u boksu kao što je Jupiter.

Planete uvijek leže u istoj ravni, & # 8220ekliptici & # 8221. Budući da se i Zemlja nalazi u ovoj ravni, ekliptika se pojavljuje kao traka na nebu gdje se mogu naći Sunce i sve planete. Slično tome, Jupiterovi mjeseci također leže u ravni.

Sve u svemu, te grudice dodaju element kaosa u priču. Planete i mjeseci ne kruže samo oko Sunca, već i međusobno komuniciraju. Ponekad to dovodi do strašnih stvari poput planeta koje utječu jedna na drugu i velikih eksplozija. Jedna od vodećih teorija stvaranja našeg Mjeseca je jedan takav utjecaj. Ali ove interakcije ponekad mogu praskati manje objekte u čudne orbite izvan ravni. Saznanje da se planete obično nalaze u istoj ravni znatno olakšava posao astronomima. Sa Zemlje se ekliptika pojavljuje kao tanka traka od koje nijedna druga planeta ne zaluta. Pluton je bio drugi pronađeni patuljasti planet (nakon Cerere) jer kruži u blizini ravni svih ostalih planeta i nalazi se unutar ovog pojasa. Patuljasta planeta Xena i njen mjesec Gabriel kruže u orbiti način izvan ekliptike, što je veliki dio zašto ih nisu pronašli do 2005. (nebo je ipak veliko mjesto). Službena imena Xene i Gabriela su & # 8220Eris & # 8221 i & # 8220Dysnomia & # 8221, ali podržavam originalne etikete otkrivača, jer su oni # 8217 neverovatni. Dakle, stvari mogu imati nesigurne orbite, ali to moraju učiniti način sranje tamo gdje ne nalete neizbježno na nešto drugo. Xena je obično otprilike dvostruko udaljenija od Plutona, što je definitivno način na koji sranje postoji.

Nisu sve tvari diskovi za akreciju. Da bi disk mogao stvoriti materiju o kojoj je riječ mora komunicirati. Plin i prašina to sjajno rade. Ali kad se jednom formiraju, zvijezde jedva da uopće stupaju u interakciju. Na primjer, kada (ne ako!) Galaksije Andromeda i Mliječni put udaraju jedna drugu, to & # 8217s stvarno malo je vjerojatno da će se ijedna zvijezda zaletjeti jedna u drugu (oni su # premali i međusobno udaljeni). Međutim, džinovski oblaci plina u svakom od njih trebali bi se zabiti i izazvati nalet stvaranja novih zvijezda. Za četiri milijarde godina nebo će biti posebno lijepo.


Globalno zagrijavanje 1-2-3

Pouka iz naše priče o dvije planete vodi direktno do podnaslova ovog poglavlja, u kojem kažem da je globalno zagrijavanje lako poput 1-2-3. Pod ovim mislim da se za sve argumente koje možete čuti u medijima, osnovna nauka o globalnom zagrijavanju može sažeti u tri jednostavne izjave, koje utjelovljuju dvije neosporne naučne činjenice i neizbježni zaključak koji iz njih slijedi:

  1. Činjenica: Ugljični dioksid je staklenički plin, pod kojim mislimo na plin koji zadržava toplinu i čini planetu (poput Zemlje ili Venere) toplijom nego što bi bila inače.
  2. Činjenica: Ljudska aktivnost, posebno upotreba fosilnih goriva 2 - pri čemu mislimo na ugljen, naftu i plin, a svi oni oslobađaju ugljični dioksid kada sagorijevaju - dodaje znatno više ovog plina koji zauzima toplotu u Zemljinu atmosferu.
  3. Neizbježan zaključak: Trebali bi očekujte porast koncentracije ugljičnog dioksida za zagrijavanje naše planete, a zagrijavanje postaje sve jače jer dodajemo više ugljičnog dioksida.

Primijetite neizbježnost zaključka: Sve dok su obje činjenice istinite - i pokazat ću vam zašto nema znanstvene sumnje ni u jednu od njih - tada zaista ne postoji način da se zaobiđe zaključak da treba očekivati ​​globalno zagrijavanje.

Naravno, saznanje da se očekuje globalno zagrijavanje ne govori nam koliko ćemo loše ili neposredno utjecati na to, a samo po sebi ostavlja mogućnost da drugi faktori (poput klimatskih povratnih informacija) ublaže ili čak suprotstave očekivano zagrijavanje, barem na nekim vremenskim skalama. O raspravi o tim pitanjima razgovarat ćemo u poglavlju 2. Prvo ćemo, međutim, svoju pažnju usmjeriti na dokaze koji podupiru naše dvije činjenice.


Zemaljske vs Jovian Planets

Pa, koja je razlika između zemaljskih i jovijskih planeta? Njihova glavna razlika je njihov sastav. Zemaljske planete prekrivene su čvrstim površinama, dok jovijske planete karakterišu plinovite površine. Ove zemaljske planete u našem Sunčevom sustavu su Merkur, Venera, Zemlja i Mars. Jovianske planete su Jupiter, Saturn, Uran i Neptun.

Teoretizira se da zemaljske planete imaju gusto, metalno jezgro (slično Zemljinom) koje je okruženo silikatnim materijalima. Jovianske planete su masivne planete sa jezgrima manje gustine. Njihova atmosfera može biti sastavljena od helija, vodonika, metana i amonijaka. Teoretizira se da ove planete imaju jezgro napravljeno od rastopljene stijene. Ugljičnog dioksida i azota ima u izobilju na zemaljskim planetama.


P: Zašto su potrebne hiljade godina da svjetlost pobjegne Suncu?

Fizičar: Originalna izjava često je nešto slično, & # 8220 Potrebno je desetine hiljada godina da foton dođe iz jezgre na površinu Sunca, ali samo osam minuta da stigne od Sunca do Zemlje & # 8221. Ovo je jedna od onih sjajnih činjenica koje kognoscenti vole razbacivati, poput & # 8220 Jeste li znali da koristimo samo 10% svog mozga? & # 8221. Nažalost, poput stvari sa 10%, iza ove činjenice stoje detalji koji je čine nešto manje zanimljivom i na kraju ili lažnom ili čak pogrešnom.

Foton nasumično vijuga van Sunca.

Izračun iza stava od više hiljada godina ide ovako:

-Foton pređe u prosjeku određenu udaljenost, d, prije nego što ga atom kratko apsorbira i oslobodi i rasipa u novom slučajnom smjeru.

-S obzirom na d i brzinu svjetlosti, c, možete odrediti prosječni vremenski korak i veličinu svemirskog koraka (koliko često foton & # 8220steps & # 8221 i koliko daleko & # 8220steps & # 8221 svaki put).

-Veličina Sunca izračunava se u smislu veličine koraka. Događa se iznenađujuće nezgodna matematika koja uključuje & # 8220Brownovo kretanje & # 8221 i vjerojatnosti. Konačno,

-Pronađeno je prosječno vrijeme potrebno za izlazak na površinu Sunca.

Matematika koja stoji iza toga slična je (identična) onoj koja stoji iza stvari poput Plinka ili rušenja kockara. Izračun je pomalo lukav (zbog čega se ponekad koristi i kao primjer), ali zaključak je da je fotonu potrebno između mnogo hiljada i mnogo miliona godina da pijano odluta na površinu Sunca. Ako umirete iz znatiželje, onda je jedan takav izračun uključen u sos za odgovor (posljednji dio ovog posta).

Međutim, ovaj rezultat pomalo zavarava. Prvo, jer donosi neke suptilne matematičke pretpostavke, i drugo, jer donosi neke masivne (lažne) fizičke pretpostavke. Unutar Sunca fotoni se kontinuirano razmjenjuju, dijele na mnogo, sakupljaju u jedno, rasipaju i uglavnom se ne čuvaju u komadu. Umjesto da o fotonima na Suncu razmišljate kao o loptama koje se odskaču između atoma sličnih kickeru, smatrajte fotone kao pretjeranu kafu, a atome kao šalice.

Možete razmišljati o unutrašnjosti Sunca ovako kako se gomila čaša prelijeva jedna u drugu u džinovskoj umjetničkoj stvari. Nema smisla razgovarati o tome koliko je vremena potrebno kavi u najsrednjoj šalici umjetnosti da izađe iz umjetnosti, ali ima smisla razgovarati o tome koliko vremena prije nego što pola izlazi, ili prije nego što barem nešto od toga izađe.

Nakon stvaranja u fuzijskom događaju u jezgri, prva stvar koju svježa serija fotona napravi je razbiti se na stotine fotona niže energije. Govoreći o tome koliko dugo traje foton bilo šta na Suncu više od oko jedne nanosekunde malo zavarava, jer je u to vrijeme gotovo svaki foton na Suncu razbijen i / ili kombiniran s drugim fotonima, ostavljajući ih pomiješane.

Prvi najsitniji djelić energije fotona generiranog u jezgri izlazi na površinu u roku od nekoliko minuta, a ponose ga tamo stvoreni fotoni. Statistika o hiljadama godina korisna je u tome što izražava kada se oko pola originalne energije fotona iscuri u svemir. Posljednja energija fotona nikada nije potpuno pušten u svemir (to je & # 8220 zadnja pasta za zube u cijevi & # 8221).

Slika kafe je odavde.

Odgovor Gravy: Samo zato što je zanimljivo vidjeti ga na barem jedan ili dva načina, barem jednom, ovdje je # matematika iza statistike slučajnih šetnji i & # 8220escapes & # 8221. Ovo nije najizravnija metoda, ali obavlja posao. Također, fotoni se ne ponašaju na ovaj način, tako da je ovo više izračun & # 8220 šta ako & # 8221.

Ako čestica pređe u prosjeku udaljenost Δx u slučajnom smjeru (50/50 lijevo / desno) svaki Δt vrijeme, tada je vjerovatnoća da je čestica P (x, t) na određenom mjestu u određeno vrijeme zadovoljava jednadžbu:

Ovaj posljednji skok, od diskretnog procesa do kontinuiranog procesa u kojem se račun može primijeniti, djeluje samo kada su Δx i Δt vrlo male. U ovom slučaju srednji slobodni put je Δx = d = 0,01m, što znači da je pri brzini svjetlosti Δt = d / c = 3 & # 21510 -11 s, i. Za foton koji započinje na x = 0 kada je t = 0, rješenje jednadžbe je:.

Dakle, želimo shvatiti vjerovatnoću da je do određenog vremena T čestica prešla dalje od -R & ltx & ltR, gdje je R radijus Sunca. Evo slatkog trika: zamislite da Sunce ide zauvijek, tako da se na R. ne dogodi ništa posebno (matematički teško)

Želimo znati kolika je vjerovatnoća putanje fotona uključujući x = R (ovo odgovara postizanju površine). Primijetite da ako put fotona pređe x = R, tada je u nekom trenutku morao biti na liniji X = R.

Veća krivulja zvona vjerovatnoća je pronalaska fotona na tom mjestu nakon nekog vremena t. Ružičasta regija je vjerovatnoća da će foton doći do x = R u bilo koje vrijeme do T.

Sada, budući da se pretpostavlja da foton ima ravnomjernu šansu da ide u bilo kojem smjeru, tada će polovina fotona koji dođu do x = R biti desno od njega, a polovina lijevo. So, the total probability of making it to x=R is double the probability of being on the far side of x=R. Just so that it looks fancy, let’s say the probability of escape after some time T is . The whole argument above is a description of why there’s a 𔄚” in front of . This can be expressed in terms of the error function, , as . That re-expression doesn’t change anything, but it does help get everybody on the same page.

We can now say that a photon (starting at the center of the Sun, moving at the speed of light, and scattering off of atoms on average every d distance, while hypothetically not being changed by those scatterings) is 50% likely to have escaped the Sun when , which happens when .

Plugging in meters, meters/second, and meters, you can solve for T and find that T = 1,100,000 years. However, there are different mean free distances in different parts of the Sun (due mostly to different densities), which makes that whole last calculation much more difficult (or you can just run a quick computer simulation). Different people will run through this calculation (or something similar) and get wildly different amounts of time because we may have been using different mean free distance. These folk seem to think the “true time”, taking into account what we know about densities in the Sun, should be somewhere in the 100 thousand year range. But again keep in mind that actual photons don’t behave this way.

If you’ve read this far, you may be interested in where there were errors in the big calculation. “Jumping to calculus” introduces a tiny, tiny error, but that decreases rapidly if Δx and Δt are small compared to the scale of the problem (e.g., Δt = 3吆 -11 seconds vs. T = 1.1 million years). Also, I’ve ignored the fact that 1) passing -R also means escaping the Sun, and 2) the Sun is a sphere and not a line segment. What I very, very subtly did was “project” the random movement of the photon onto the radial direction, and then only keep track of that direction (“radial” = “out from the center”). This has the effect of changing the equation. This new form can be approximated by varying d with x. One effect is a “bump” near x=0 that makes it hard to drift back to the exact center, but throughout the region where the photons spend most of their time the effect is mostly just a replacement of d by . I’ve also ignored the time spent being absorbed, which is the same as assuming that the Sun’s index of refraction is 1.

Overall the errors introduced are smaller than the errors introduced by the range in different quoted values of d (and the fact that it’s assumed to be constant). Still, it involves some cute math.


Exploring space: Why’s it so important?

Carol Beckles isn't buying into all the space exploration hype. She’s a single, middle-class mother of three living in a modest, cozy three-bedroom home in Atlanta’s suburbs. She foots the college bill of her oldest daughter Tiffany, who – like her mom – wishes she got more government help to pay for tuition.

“It’s definitely hard. From the time that I was a senior (in high school) I had to start figuring out how I was going to pay for this,” said Tiffany who sits close beside her mom.

A mere mention of taxpayers’ dollars going to NASA makes Carol cringe. “I don’t see the use. What are we going out there to do?” she asked. CNN commenters often share these sentiments one recently identified himself/herself as "waste of tax dollars."

It’s been asked since space exploration began in the late 1950s. Some people argue that some –- if not all –- funding for space exploration could be used to revitalize the economy, fix the education system, or solve undersea mysteries, among other Earth-related issues.

“We need to be researching the bottom of the oceans just as much,” said CNN’s space and science meteorologist Chad Myers. “There could be things at the bottom of the Earth that we don’t know about.”

According to a 2010 CNN/ORC poll, 50% of Americans agreed that the money spent for the space shuttle program - which ended last year - should be spent elsewhere. And in a 2009 Gallup poll, the percentage of Americans who believe the U.S. space program should be scrapped jumped four points: From 4% to 8% in an 11-year period (1998-2009).

The numbers reveal that some question the purpose of space exploration. NASA chief scientist Waleed Abdalati said the government’s financial contribution to NASA has been beneficial to humans and will continue to set breakthroughs in technology.

“By sending astronauts to space and trying to understand their biological responses to space environment, we’ve learned a lot about understanding human beings,” said Abdalati. “A lot of the instrumentation in an emergency room, for example, is traceable to investments by NASA to monitor and understand human health and performance in a space-related environment.”

Human benefits from space exploration

The birth of the space age has spurred on a plethora of new ideas and ground-breaking technologies that are used in day-to-day living.

Health: During the early Apollo missions, scientists needed precise images of the moon’s surface in order to land the first man on the moon. In the 1960s, NASA’s Jet Propulsion Laboratory created digital image processing, an innovative technology that uses computers to enhance images of the moon. In the medical field, scientists and researchers found that this technology could be used to enhance images of organs in humans. Today, digital image processing is used in Magnetic Resonance Imaging and CT scans.

Medicine: Before Dan Carter joined NASA in 1985, developing large amounts of protein crystal was a challenge. He and colleagues discovered that space-produced crystal could be used to make the atomic components of albumin(PDF), an essential human protein. They founded a called New Century Pharmaceuticals in 1997. Their findings helped lead to the development of a cancer drug combination approach and skin care products.

Information Technology: Captured by satellites, NASA’s Earth Observing System Data and Information System collects and archives information of the Earth’s atmosphere, oceans and vegetation on a daily basis. The massive amount of data accumulated has reached 4.5 petabytes. That’s equivalent to completely filling 90 million four-drawer file cabinets with paper, according to NASA’s 2010 “Spinoff” publication(PDF). To provide convenient access to the large data repositories, NASA partnered with Archivas Inc. to create a high-tech software program that can hold large amounts of information. Hospitals, cell-phone providers, businesses and organizations now use this same technology to store information.

Communications: Satellites play an instrumental role in how we communicate and navigate the world. In the 1960s companies including AT&T and RCA partnered with NASA and other space agencies to build and place satellites in the Earth’s orbit. Global positioning systems, television networks, radio stations and cell-phone carriers are all dependent on satellites to keep the world connected.

GPS in particular arose as a result of Sputnik, the Soviet satellite that launched in 1957. Changes in radio frequency helped U.S. scientists track where Sputnik was because of the Doppler effect - that is, a shift in the frequency of sound or light waves corresponds to a change in position. This principle led to a Navy navigation system called TRANSIT intended for submarines. GPS for continuous navigation was developed as a Defense Department initiative in the 1970s, leading to the launch of the first GPS satellite in 1978. The system was complete in 1995 (More about this from Time.com).

Environment: When the Saturn 1B launch stand (used in several Apollo missions) was disassembled, it was stored away in an open field. No one knew until years later that the launch stand was coated with a paint containing polychlorinated biphenyls (PCBs), a toxic chemical that was seeping into the Earth’s soil. Quinn and her colleagues created the Activated Metal Treatment System (AMTS), a paste-like solvent solution that extracts PCBs from paint without removing the paint itself. The innovative system has been redesigned since then to remove many forms of contamination and pesticides on land.

Transportation: The parachute shrouds that landed the Vikings on Mars have a fibrous material used in automobile tires. These state-of-the-art tires were originally developed by Goodyear Tire and Rubber Company. Now the tires, famously called radial tires, are manufactured in factories around the world. They are five times more durable than steel and have an expected tread life 10,000 miles greater than conventional tires.

Public safety: Those powerful rocket launchers that propel spacecrafts into deep space are now fighting fires. Rory Groonwald, chief engineer at Orbital Technologies Corporation, partnered with the U.S. Air Force Fire Rescue Research Group to design a similar high-pressured system that suppresses fires in seconds. The technology also reduces water usage because the extreme force creates fines water droplets as opposed to an excessive flow.

Memory foam: For anyone who gets a better night’s sleep from a foam mattress, NASA’s to thank. The administration originally developed the polyurethane-silicon plastic to reduce harsh impact when spacecrafts landed. Now the famed foam is used in everything from automobiles and airplanes to helmets and horseback saddles.

We also have advanced water filtration systems for astronauts as a result of the space program.

In 2012, NASA was allocated $18.7 billion(PDF) from the federal government (less than 1% of the entire U.S. budget) for further research and exploration. $3.8 billion of that will go specifically to space exploration. By comparison, the Department of Defense got $670 billion and another $69.8 billion went to education.

Even with a limited budget (the smallest budget of any major agency), President Obama emphasized at a 2010 conference at the Kennedy Space Center that space exploration has been key to America’s position as a world leader.

“For pennies on the dollar, the space program has improved our lives, advanced our society, strengthened our economy, and inspired generations of Americans,” he said.

If re-elected, he plans to pump an additional $6 billion in NASA’s budget over the next three years.

Carol does not know for sure if Tiffany’s post-secondary education in business administration will lead her to a job in the field. She does know though, that the opportunities for her will be greater if she stays in college, so she said she will continue to invest in her daughter's education.

In the same way, said Abdalati, society must continue to invest in space exploration.

“There’s value to making these investments. It’s very easy to look at the challenges we face financially as a nation and consider alternative investments, but if we don’t carve out a small fraction of the national budget to support exploration, we lose something tremendously important and, in fact, we step back as a society.”

CNN's Elizabeth Landau contributed to this report

Soundisključeno (448 Responses)

carol is an idiot, 10 billion spent each month for the wars since 03, nasa is minisucle compared to that.

Agree. I vote that we instead cut funding to educate everyone whose IQ is in the lower 20th percentile. Our need for more teachers would be lessened, and class teacher/student ratios would improve as well as the average score of all standardized tests. Also employment will go up as this lower 20th percentile would have to settle for minimum wage jobs. This would then also help deplete the number of jobs available to illegal immigrants. So much WIN here.

You still wouldn't save any taxpayer money because the Chicago teachers' union would demand that all that slashed funding be given to them instead. Afterall 3 months of vacation time and $75,000+ per year in pay is not enough for people who were too stupid to major in Engineering or something else serious.

@Greg. You can not be serious. My wife is a teacher and I take offense to your comments. I can tell you, they do not get 3 months off. Any vacation they get during the school year is used to prepare for the upcoming weeks and the 2 months they get in summer is often not all time off. Some of it is spent prepping the classroom for the following year.
There is nothing more important than teaching the children of this nation so they can grow up to want to become engineers or as you say "something else serious" (like more teachers in my opinion). It's obvious from your irrational argument that you fail to see the irony of your statement. It takes teachers to teach engineers. In other words, engineers aren't just born as such. They must grow up in an environment that fosters such a willingness to create and learn. An environment that every child deserves.

Greg, you are a moron. I taught for 9 years and now I own my own business. Teaching is much a much harder job than what I do now and I make more money and work when and how I want. Teachers deserve everything they want and unless you want to do what they do shut your mouth. Lets get back to the to the topic. I can tell that the woman in the article probably votes the same as Greg does haha! And just to be clear, exploration of space is the MOST important thing we do.

The key is the last sentence in the first paragraph: "Tiffany, who – like her mom – wishes she got more government help to pay for tuition." Nuff said.

I wish I had government help to get through school too. But I did what used to be known as the American thing and I busted my a s s to work my way through school. Now I have a well paying job and I resent those people who think I owe them higher taxes so they can coast through it all. Get off it and work your way through school. It takes more time and effort but guess what? It actually means more to you when you made it happen yourself.

thank you cheapseats, people need to learn how to work like the rest of us. (Im not really a crook, just a screenname) But you're right, people expect the government to give people money when all they do is sit on their butts and do nothing all day. They don't even look for jobs! They sit, watch TV and keep tabs on their mail box.

Ultimately, man must learn to live in space. At any time in the future, perhaps tomorrow, the Earth could become uninhabitable for man and every other organism on the planet. We think we have eons ahead of us, but there is also a theory that the conditions that make life possible may only exist in a tiny window of time. I cringe a little when I hear about 'space exploration'. Exploration is important, but the primary goal needs to be survival of life itself. We need to establish self-sufficient colonies in space as soon as possible. We are the first generation to possess the technology to make it possible. If we fail to do so, we may be condemning life on Earth to extinction.

mr osler got it correct
earth already got wiped out by an asteroid & after millions of years we finally have the technology to stop that but she doesnt think its important . whata loser she is.
all i did was go to fafsa.gov & got all my school paid for plus extra to live on, couldnt be simpler

everything on earth is wiped out every 100,000 years who says we are any different, we need to escape earth or some day we will be the fossil being dug up

100% Agree. The human species needs backup.

The idea that we're going to colonize space is laughable. It would be a thousand times easier for us to colonize the uninhabitable areas of Earth than it would be to colonize Venus, Mars, the Moon, or any other environment outside of our atmosphere. But you don't see permanent residents of Antartica, do you? Nor do you see floating airship cities, nor cities in the Gobi Desert.

It would be cheaper also to engineer methods to prevent extinction events here on Earth. There have been five mass extinction events in the last 500 million years, so they occur about once every 100 million years. None of the extinctions that life here has experienced would be sufficient to wipe humanity out. The only event in Earth's history that was cataclysmic enough to do that was when we collided with another planet (part of which is now our moon), but that was before life existed and is not replicable, because the planetary orbits are now too stable for such an interaction to occur.

Asteroid impacts, flood basalt events, gradual or even sudden environmental change: these are all problems that we can solve without having to blast off to our space colonies. The risk factors we have less ability to address, such as gamma ray bursts, are both incredibly unlikely, and flying off into space probably would not work anyway. If we're going to be hit by a gamma ray burst we better have taken off for another star system several million years ago, or it's going to hit those space ships as well.

The reality is, if humans can make it another million years, we've had a pretty good run. I think it's unlikely we'll get that far, but not because of a natural event. We're going to be the first species to cause our own extinction. Colonizing space is a great plan for 10-100 million years from now, but it is pointless until we prove that we as a species are capable of surviving indefinitely barring an unprecedented extinction event. Right now we can't even keep the Earth's climate stable, and you think we're going to get into a space ship with less than one ten billionth its volume for the next million years without screwing everything up? This Earth is literally one giant spaceship we're riding and if we cannot live in a sustainable manner here, there's no way we're going to be able to do so on a much smaller scale.

I'm not an environmentalist, either. But it is a simple fact that to survive in a space ship for hundreds of thousands to millions of years you'd need to approach 100% recovery and reuse of all matter in that ship. If we can't do that on Earth, where everything is orders of magnitude easier, there's no way we can do it in space.

These points aside, I fully support our space program. I do think that manned space operations are too expensive for the payoff, though. I think we can do the same sort of research for less money using robotic missions. I think the manned space program is just a relic of the Cold War it grants us prestige to say we're sending our citizens into space. But it doesn't result in much science (it took how many years before the ISS had a basic lab in it?).

The space program is a jobs program that has the benefit of doing science that can benefit humanity. Compare this to our defense program, which is a jobs program that creates weapons to kill people. Clearly, the former should receive as much funding as we can afford while the latter should receive as little as necessary to protect our country. As it stands the sums these departments receive are totally askew from what a rational person would assign them. But the funding is based on inertia rather than logic, so on it goes.

The rate at which the population of the world is growing and the rate at which we are going through easily found resources, a day will come when there is very little left for the bulk of the people on this planet. When that happens, the have-nots will destroy the have and there will be no colleges, so tuition will not matter. The time to act is before the crisis. Considering how hard it is to live in space and get anywhere interesting, we better focus on it or figure out how to stop consuming more than mother Earth can supply. Since most religions want us to make lots of babies, about the only hope is to figure out how to survive and thrive in space.

I believe Mankind are the problem. We need not seek to take our problem elsewhere. However, we will find resources to continue our downward spiral within our solar system. Corporations should realize this and contribute to a business of space exploration for profit. NASA should continue to be funded for the scientific advancements needed as corporations do not see long term profit from discovery. Our planet was seeded from space whether by design or accident. We have evolved and produced ous self destructive species which will obliterate itself eventually.

10M each month is a total watse.
Watch SciFi on TV and let the real world take care of families and children.
Wake Up and stop wasting our money on Nas-Car

Thank you for this wonderful insight. Please continue with your wonderful wisdom. Lets spend that 10,000,000 a month to feed kids and make them dependent on a handout every month, because inspiring them to become a scientist and engineer is to much of a hassle, and lets face it when did they REALLY come up with something useful with the sorcery they call math. I mean Steve Jobs must have been such the genius in helping advance the smaller processors and wonderful ways to connect to the mysterious on my magical device they call a MacBook Pro. Please in all seriousness log off. Unless you have something to contribute to the cause of advancing human life and inspiring people to push themselves to work harder, don't talk

She is not an idiot. She is a mom trying to keep her head above water that doesn't see the direct impact that NASA has had on her life. It is hard to see this when money is tight and you her a number like $18 Billion. So while I disagree with her I understand her perspective. Let's cut her a break.

actually, its not hard to see, and she deserves any criticism she gets here. anyone with an education past high school would be able to figure this out. it doesn't take a genius, or someone who is well off to understand simple facts, or use critical thinking skills.

Typical pedantic psychobabble. The benefits of the space program have impacted our daily lives, end of story. If she wants to complain about something else, try the money spent on war, or the one percenters, or whathaveya.

It is a shame that we can't ask Carol for a refund for the money spent by the government on her education. Obviously it was wasted upon her. And I thought that Georgia was one of the better states in terms of available scholarships for students. In Florida, they used some of the proceeds from the state lottery for student scholarships. They were available to anyone who had a decent high school GPA and scored well on the SATs. At least this is how it used to be when I got my bachelors degree 15 years ago.

Carol Beckles needs to understand that funding NASA *is* helping the economy. What, do you think that you just throw a few billion into a box and out pops a Mars lander? That money goes to fund jobs for highly educated and skilled scientists, engineers and technicians at NASA and their sub-contractors that develop the space vehicles, the special materials, and all the math behind the mission. You not only get new technologies that work their way into civilian use, you pay American workers to develop them.

Throwing money at welfare addicts or even paying for her kids college has a very low chance of immediate return. How many college students turn out to be worthless and do nothing? A lot. 95+% of welfare recipients will never contribute substantially to the US economy or to our society. They take a lot and return very little.

Funding NASA gives jobs to highly skilled American workers and provides near-term returns from R&D on robotics, material science, cosmology, biology, etc.

It's spelled "minuscule."
A little taxpayer-supported education could do you some good, too.

I like to think of NASA as a college for people that are already smart, but are willing to work hard to be even smarter, and get paid to learn about new discoveries. Then they share those discoveries with a bunch of dumber people that don't give a rat's furry butt about anything but themselves, and sometimes, not even that. Doing something stupid = not doing something smart.

Did you know that nearly 30% of students entering college need remedial instruction in English?

Then they should not be allowed into college. After they have reached achievemnt of a real High School grad at night school they can apply to college.

I think a better article would be Why are we not spending more on Space Exploration?

because it's a waste of $. Very, very little is learned that is applied to our society today. It's just the fantasies of little boys and the fiction of comics, books, and movies that makes it interesting. In these economic times it's a waste of $.

Stvarno? So you can just throw your Cell Phone, GPS, Color TV, Computer, Internet, LED bulbs, away? Clearly none of that is needed right?

Completely false. It's a shame, that you're simply too lazy to Google "economic benefits of the us space program".

That's unbelievably ignorant. Science and technology is what movies economies and innovation forward. We gave AIG more money for a bailout then we give nasa in four years.

Little boys, comic books, and movies. That is completely ignorant to the fact that we are one out of trillions of other planets, one out of hundreds of billions of other solar systems, and one out of billions of other galaxies. Space exploration in society involves those "fantasy-like ideas," but if you think like a realist, everything else out there is part of the universe we live in and it can provide our ever-curious minds of why us humans are here. Space exploration is really the next thing for humans to do. If your telling me we need to keep adding more and more to the Earth and expand our society and improve technology(which we obviously are), that is just completely selfish. I wouldn't mind if we turned around our society to live simpler, stress-free lives, where the only thing that matters is family, happiness, and spirituality.

Because we have more important things to do, like invade other countries.

Americans pay less than $10 a year per citizen to NASA. That means you could quit smoking (or give cut 2 packs), give up beer, or stop spending money on the NFL and solve all of our financial issues. Oh no – cant do that! I should not be paying 35% of my salary in taxes while rich people get breaks – that's the real issue.

Hey waste of money. really well then I suggest you throw away all of no stick pans, toss out all that Teflon oh throw away all your digital cams, throw away your iridium sunglasses, throw away your gps, throw away your cellphones, throw away your satellite tv forget about getting world news so fast. hmmm yeah real waste oh and forget about our cams in space the we use for surveillance to save our butts.

the earth will die for sure. the whole point of life is to keep life going

if the moon was once part of earth, every natural metal and no carbon based resource that can be found under the ground can be found on the moon. think of all that gold, silver, iron, uranium, all those resources. it could fix our economy.

Yes, we should give it all to the Defense Department to build more bombs so we can blow up more people. I feel safer already!

“Why are you giving Columbus all this money? Solve Hunger then go sailing!” — anonymous Spanish peasant, 1492.

You have bough into the Republican economy problem hook line and sinker. Look at the DOW !! I am willing to bet stores will have record sales come Christmas. More cars are being sold than any other time. The economy is doing just fine, no help from the Republicans. However to help Mitt get elected the prey on stupid people like you that rely on FOX new, Hannity, Beck and Limbaugh for News. Or should I say doom and gloom ever single day. But once Mitt is elected he will take credit for everything. That is until 4 or 8 years pass and everything falls back into the toilet again. If you say things are bad enough times morons like you will believe it. Things are getting better. Things are much much better than 4 years ago. Things will remind good for at least 4 years or until Mitt stars another War to bolster the economy, which he will. That is not speculation that is fact. Yo see the Republicans, Beck, Hannity, Limbaugh and Fox broadcast day after day scare tactics telling their listeners everything is bad. The reason they do this is so they can make more money because for some reason Bad news sells in this country, that is exactly why the Republicans, who actually created the bad new fail to report anything is getting better. Well until Mitt gets into office and then everything will be great, even if it is not. Just like religion they lie to you and because you respect them and they know they can get away with it. You respect and trust Religion and the Republicans because you have been brainwashed your whole life to do so. And your stupidity allows you to turn the tables 180 degrees and say everyone else is lying. We didn't go to the moon, man walked with dinosaurs, WMD's in Iraq. Toucher is ok as long as the USA is hiring other countries to do it for them and not doing it themselves. Letting people die in the streets because Obama care is an elitist, socialist concept, even the Christians who claim to be on the side of helping people are stand up against this. Bt they call themselves patriots. Explain to me how a "Patriot" can protest a soldiers funeral because it has something to do with people being gay ? Tell me how can Christians send entire families back to mexico and let our fruit and vegetable rot on the vine because they are illegal but have been working in the country for 20 + years. Republicans, Beck, Hannity and Limbaugh have screwed up this country so bad it is unbelievable. And then they turn around and blame it on the illegals, the gays and the people whom don't make enough money to eve pay taxes. NO the problem is the rick never having enough. The rich not giving back to there employees. The Republicans not working with the elected president on anything. Limbaugh, Beck, Hannity telling you day in and day out how bad things are and how bad our president is and you being so stupid you believe it. The NRA selling death in record numbers and then saying guns don't kill people, people kill people. 47000 Americans dies last year because of guns you the Republicans are ok with that, The NRA says we need more gun on the street to fight the problem, so they can make more money. And you, the Good Christian Republican believe them. The same Christens that saw how many pastors, bishops and clergy convicted of molesting your children and now it is the boy scouts turn to come clean after years of cover ups. Nope it is all the Democrats fault and Obama was behind it all. No he was not, you have been brainwashed on so many fronts you don't even know where or how to explain it. And it fear of looking weak you wont even try. You will just say with the standard message and vote yet another Republican into office and them blame all the screw up on the democrats. I am better off that I was four years ago. But in the next four years if I have to start carrying a gun just to protect myself, if I see one dirt road closed because the land was sold to some private rick guy to drill on. If I see one young man or woman going off to fight another war for nothing but a presidents ego. I will not be ok. But you will except it and call him great because he lowered your taxes $10 a year. THINK or at least try to think and try to question instead of listening and repeating what you hear mindlessly based on what religion says you should do. Or what Beck, Hannity or Limbaugh said. Disregard what scientists have spent there whole life researching and stick with the so called Fact man walked with dinosaurs, we didn't go to the moon and everything out side of our solar system was put there by the devil to test you. People and laugh at you, but that is because they are stupid. I am going to let you in on a secret. It is not them that are stupid. Religion, Guns, Fear of all sorts of things are what drives a Republican and that is no way to live a free life. I am sure None of the Republicans out there will remotely understand this but it is fact. Some republicans will look back years from now and think a little bit about these things. Some are so far gone they have lost any sort of personal or social responsibility.

You're probably sipping your triple-latte crappachino while typing this in your iPad at your "hip" (overused adjective, as you may know) coffeeshop and infesting the boards wirelessly, all thanks to NASA.

You couldn't possibly be MORE WRONG! Nearly EVER SINGLE bit of electronic convenience and gadgetry that YOU USE EVERY SINGLE DAY has been brought to you courtesy of the SPACE PROGRAM, you clueless fool! Without the Space Program you would NOT have: Microprocessors, digital computers, laptops, ipods, ipads, smart phones, CELL PHONES, Satellite phones, DIGITAL TV, dish TV, satellite communications, DVDs, GPS navigation, velcro, Digital imaging for ALL Medical scanning devices, ultrasound technology, laser angioplasty, pacemakers, ocular screening, flat screen TVs and Computer monitors, pagers, digital scanners, jump drives, 3D imaging, etc. and the list goes on and on and on.


Key Concepts and Summary

​The four giant planets have generally similar atmospheres, composed mostly of hydrogen and helium. Their atmospheres contain small quantities of methane and ammonia gas, both of which also condense to form clouds. Deeper (invisible) cloud layers consist of water and possibly ammonium hydrosulfide (Jupiter and Saturn) and hydrogen sulfide (Neptune). In the upper atmospheres, hydrocarbons and other trace compounds are produced by photochemistry. We do not know exactly what causes the colors in the clouds of Jupiter. Atmospheric motions on the giant planets are dominated by east-west circulation. Jupiter displays the most active cloud patterns, with Neptune second. Saturn is generally bland, in spite of its extremely high wind speeds, and Uranus is featureless (perhaps due to its lack of an internal heat source). Large storms (oval-shaped high-pressure systems such as the Great Red Spot on Jupiter and the Great Dark Spot on Neptune) can be found in some of the planet atmospheres.

For Further Exploration

​Articles​

Jupiter

​Aguirre, Edwin. “Hubble Zooms in on Jupiter’s New Red Spot.” Sky & amp teleskop (August 2006): 26.

Beatty, J. “Into the Giant.” Sky & amp teleskop (April 1996): 20. On the Galileo probe.

Beebe, R. “Queen of the Giant Storms.” Sky & amp teleskop (October 1990): 359. Excellent review of the Red Spot.

Johnson, T. “The Galileo Mission to Jupiter and Its Moons.” Scientific American (February 2000): 40. Results about Jupiter, Io, Ganymede, and Callisto.

Simon, A. “The Not-So-Great Red Spot.” Sky & amp teleskop (March 2016): 18. On how the huge storm on Jupiter is evolving with time.

Smith, B. “Voyage of the Century.” National Geographic (August 1990): 48. Beautiful summary of the Voyager mission to all four outer planets.

Stern, S. “Jupiter Up Close and Personal.” Astronomija (August 2007): 28. On the New Horizons mission flyby in February 2007.

Saturn

Gore, R. “The Riddle of the Rings.” National Geographic (July 1981): 3. Colorful report on the Voyager mission.

McEwen, A. “Cassini Unveils Saturn.” Astronomija (July 2006): 30. A report on the first two years of discoveries in the Saturn system.

Spilker, L. “Saturn Revolution.” Astronomija (October 2008): 34. On results from the Cassini mission.

Talcott, R. “Saturn’s Sweet Surprises.” Astronomija (June 2007): 52. On Cassini mission results.

Uranus and Neptune

​Cowling, T. “Big Blue: The Twin Worlds of Uranus and Neptune.” Astronomija (October 1990): 42. Nice, long review of the two planets.

Gore, R. “Neptune: Voyager’s Last Picture Show.” National Geographic (August 1990): 35.

Lunine, J. “Neptune at 150.” Sky & amp teleskop (September 1996): 38. Nice review.


Lyman Alpha has to do with recombination of electrons in hydrogen atoms (from n=2 to n=1). However, with chormospheric temperatures above 10,000, the electrons should be stripped away from the hydrogen atom. Can you explain why this is not so?

You are correct that Lyman Alpha is the n=2 to n=1 transition of the neutral hydrogen atom. One formation mechanism for Lyman Alpha is ionization and recombination. At the temperatures of the solar chromosphere, a substantial fraction of the hydrogen atoms have their electrons stripped away. Some of these electrons then recombine with hydrogen ions, and start to cascade down through the levels until they reach the ground level.

However, even at 20,000 degrees, not all of the hydrogen atoms are ionized. This is because the density is so low that collisions are not frequent enough to knock off the electrons from all the atoms faster than they can recombine. Thus, there is always a population of neutral hydrogen, which also contributes to the Lyman Alpha line.


Top 5 Reasons why Space Exploration is Important for the World


July 20th, 2009 was the 40th anniversary of Apollo 11’s historic flight to the moon, where astronauts Neil Armstrong and Buzz Aldrin became the first human beings to walk on the moon. 40 years ago, space flight inspired such awe that astronauts were hailed as heroes and celebrities by men, women, and children alike. 40 years later none of us, besides the most avid space fanatic, would likely to be able to name one astronaut in service today.

For recent Space News, check out our Space category.

Despite the tragedies of Space Shuttle Challenger, and later Columbia, where the world is shocked into being reminded of the inherit dangers of sitting on 1 million gallons of rocket fuel, or re-entering the earth’s atmosphere at 1,870 miles per hour. We all see space flight as mundane because the vast majority of space flights since Apollo 11, have been mostly conducting seemingly routine scientific experiments. Now don’t get me wrong, I believe in the importance of science in space, but these experiments don’t exactly inspire awe in the general population like, oh say, a manned mission to Mars would. We also don’t have the fever of beating those damned Ruskies because they might go to space and blow us all up, which we had during the height of the cold war when Apollo 11 touched down on the lunar Sea of Tranquility.

Watching some fantastic documentaries (such as Discovery’s When We Left Earth) celebrating the 40th anniversary this week, I got to thinking about the importance of continuing space exploration. I hear many people decry the importance of NASA and space flight. Most saying that it is a waste of time, and more importantly money. I disagree with such assessments. I often wonder if people threw out the same criticisms of our European ancestors, who dared to explore on wooden ships to discover “the new world.”

In my humble opinion, space exploration is important not only to humanity’s curiosity of the great beyond, but it is also important for the future of the earth and all of us living on it. So here I will count down “Houston style,” my top 5 reasons why space exploration is important for the world.

5. Promote Science Education – The Apollo missions inspired a whole generation of kids who wanted to grow up to be astronauts, rocket scientists, and engineers. We all know that science education has been slightly lacking in the United States as of late. Don’t you think that NASA’s return to the moon, or more importantly the much anticipated manned mission to Mars will again inspire a whole new generation to reach for the stars so to speak? I do.

4. NASA’s Environmental Research – You would think that the guys who burn a million pounds of rocket fuel wouldn’t be the most environmentally minded people in the world, or out of the world as it may be. However, most people don’t know that NASA does a lot of good environmental research while they are up there looking down at all of us. NASA has done a lot of work in studying air quality, climate change, alternative energy, and near earth objects which as we all know from the movies can destroy the earth any day now without warning, unless we have a group of oil drillers, a nuke, and Bruce Willis.

3. Eliminate Earth Over Population – The current earth population is almost 6.8 BILLION people. Arguably beyond the carrying capacity of the earth already. The big dream is space colonization. We need somewhere to put all these people, or we all might end up living in skyscrapers, see all animal’s habitats destroyed, and smog up the air beyond what is breathable (see: China).

2. Natural Resources – Related to over population, we are burning through the earth’s natural resources pretty quickly. Out in space there is virtually unlimited resources. It is all just a matter of collecting it and bringing it back, which granted will not be an easy task. Still… it is virtually unlimited natural resources! There will be no more excuses for hiking up prices on barrels of oil. (Although hopefully we will have moved far beyond oil by then).

1. Put Ourselves into Perspective – From space earth is really small. From space earth is really fragile. Sometimes I think it would be a good thing to put our place in the universe into perspective. I don’t go into your house light up a stogy, start pulling up your carpet, kick down your door, and then kill your cat. Yet, we as the human species have been doing that to our own home the earth for quite a while now. If we start seeing how small and fragile we are out there floating in space, maybe, just maybe we will not be so prone to abusing our one true home.

Blast Off! Here’s to the men and women who gave their lives to explore the great unknown. We cannot ignore the importance of space exploration, nor be complacent in it’s meaning to all of us. I hope space exploration can continue to inspire, educate, and provide for us in the next 40 years as it has the last 40 years.