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Stjerneobservatorium for Folket For hobbyastronomen: 40: Stjernekart + Slik finner du planetene 47: Reisetips: Berlins historiske observatorier 44. årgang 46: 75 år siden første norske kometoppdagelse Juni 2014 3 Kr. 69,– 52: Pangbilder fra måneformørkelsen 15. april s. 27: Itokawa, en sammenlimt asteroide Fallskjermhopper nær truffet av himmelstein Spektakulært norsk videoklipp sett av 4 millioner på tre dager side 16 s. 18: Observatorium på Sydpolen kan ha sett direkte bevis på Big Bang s. 24: Finnes det mørk materie i Melkeveien? s. 30: Hvordan starter supernovaeksplosjoner? Astronomiske nyheter: Solas nye nabostjerne er iskald Asteroiden som har ringer Jordlik og beboelig 12 svære galakser omringer Melkeveien Norsk Astronomisk Selskap vil utvide på Solobservatoriet og bygge: Stjerneobservatorium Interpress Norge Returuke: 28 for folket Side 12 ASTRONOMI Innhold Utgiver: Norsk Astronomisk Selskap Postboks 1029 Blindern, 0315 Oslo Org.nr. 987 629 533 ISSN 0802-7587 Abonnementsservice: Bli medlem / avslutte medlemskap / melde adresseforandring / gi beskjed om manglende blad: «Astronomi», c/o Ask Media AS, Postboks 130, 2261 Kirkenær Org.nr. 990 684 219 Tlf. 46 94 10 00 (kl. 09.00-15.00) Faks 62 94 87 05 e-post: [email protected] Girokonto: 7112.05.74951 Ask Media fører abonnements register for en rekke tidsskrifter. Vær vennlig å oppgi at henvendelsen gjelder bladet Astronomi. Vi gjør oppmerksom på at Ask Media kun fører medlemsregiste - ret for NAS og ikke har mulighet til å besvare astronomi-spørsmål. Henvendelser til Norsk Astronomisk Selskap: Se kontaktinfo side 55. Norsk Astronomisk Selskap Redaktør: bygger observatorium for folket Bidrag, artikler, bilder, annonser o.l.: «Astronomi», v/Trond Erik Hillestad, Riskeveien 10, 3157 Barkåker Tlf. 99 73 73 85 Fallskjermhopper nær Kan ha sett gravitasjonsbølger [email protected] truffet av himmelstein fra Big Bang Etter at Anders Helstrup hoppet Forskerne bak eksperimentet BICEP2 Layout: ut fra fly over Rena, filmet video- Foto: Anders kan ha fått et første glimt av den såkalte Eureka Design AS v/ Bendik Nerstad kameraet hans en stein som suste Helstrup inflasjonsfasen. Dette er en viktig – men Tlf. 46 94 12 70. www.eurekadesign.no forbi i stor fart. Kunne det være antatt – periode som inntraff i Universets Trond Erik Hillestad en meteoritt? 16 aller første sekund. 18 Trykk: Flisa Trykkeri, Boks 23, 2271 Flisa Tlf. 62 95 50 60. www.flisatrykkeri.no En todelt asteroide Mørk materie Asteroiden Itokawa har forskjellig tetthet i hver i sentrum av Melkeveien? Innholdet eller deler av innholdet ende! Trolig består den av to legemer som har Matematikerne har lenge ment at den mørke i tidsskriftet må ikke kopieres, kollidert og smeltet sammen. 27 materien må være der. Nå har astronomene mangfoldig gjøres eller på annen måte trolig klart å observere den. 24 be nyttes uten redaktørens tillatelse. Nyhetstjeneste: Drevet av Astrofysisk institutt og NAS: Medarbeidere i denne utgave: Utgivelser i 2014: www.astronomi.no Hans E.F. Amundsen, Tor E. Aslesen, Hans K. 1-14 13. feb. 4-14 10. juli Aspenberg, Conor Cunningham, Håkon Dahle, Arne 2-14 27. mars 5-14 18. sep. Fornøyd med bladet? Ros/ris sendes Danielsen, Tryggve Dyrvik, Øyvind Grøn, Anders 3-14 25. mai 6-14 20. nov. til [email protected] Helstrup, Per Erik Jorde, Henning Knutsen, Jostein NAS-veven: Riiser Kristiansen, Trond Larsen, Steinar Midtskogen, Startdatoer for løssalg hos Narvesen. På www.nas-veven.no Bernt Olsen, Robert B. Slobins, Mikkel Steine, NAS-medlemmer vil normalt få bladet kan du diskutere astro - Erik Sundheim i postkassen noen dager tidligere. nomi, utveksle erfa - ringer og møte like - sinnede. 2 Astronomi 3/14 Faste spalter 56 AstroGalleri Lesernes egne bilder 4 AstroNytt EKSTRASOLARE PLANETER Planet på størrelse med Jorda funnet i den beboelige sonen til en rød dvergstjerne . .7 Innsikt: GALAKSER Naboområdet til vår lokale Himmelmekanikkens galaktiske hop . 10 suverene regnemestre METEORITTER Det vakte forargelse i England da det mektige Kjempeasteroide traff Jorda imperiet tapte æren for å ha oppdaget plane - for 3,26 milliarder år siden . 6 ten Neptun. Professor Henning Knutsen bringer oss videre i historien om en av astro - nomiens største thrillere. Del 2 av 3. 34 PLANETER Ny «grøft» på Mars . 9 Foto: NASA/JPL 12 SMÅLEGEMER Solobservatoriet på Harestua huser flere Nytt liv Asteroide med ringer . 4 Hav under isen på Enceladus . 8 attraksjoner, som soltårnet på bildet. NAS i gamle Dvergplanet utenfor Plutos bane . 11 planlegger å oppføre et nytt observatorie - observatorier bygg med en avansert stjernekikkert. Verdensmetropolen Foto: Hans K. Aspenberg Berlin har en rekke STJERNER astronomiske Den største gule stjernen . 8 Uvanlig jetstrøm fra pulsar . 9 severdigheter En kald nabostjerne til Sola Kosmisk linse å by på. 47 er oppdaget . 11 viser galaksenes utvikling Foto: Tor E. Aslesen I astronomien finnes det mange forunder - 51 Filmomtaler lige sammenhenger. Målinger av hvordan Fiksjonsfilmer: The Tripods, et svart hull «spiser», viser oss hoved - 75 år siden norsk Looper, Dark Energy trekkene i en galakses livshistorie. 40 kometoppdagelse I 1939 oppdaget Olaf 55 Info Hassel en komet fra sitt Opplysninger om NAS . .55 hjem i Hokksund. Dette Om lokale astroforeninger . .54 Hvordan starter supernova - var den første offisielle eksplosjoner? norske kometoppdagelse. 46 55 Lederen har ordet En helt alminnelig dag ved teleskopet. Restene etter en supernova avslører at Men hva skjer? stjernen nær sagt kokte over. 30 Foto: Olaf Hassel (1898-1972). Fra bildearkiv hos Norsk Døvehistorisk Selskap 54 Møtekalender Møter og andre arrangmenter Forside: Bidrag til Astronomi: 52 Rapport Soltårnet på Harestua er et kjent lande - Artikler bør leveres tre måneder før utgivelse. Total måneformørkelse 15. april 2014 merke. Publisering i en bestemt utgave kan likevel Foto: Trond Erik Hillestad ikke garanteres. 42 Solsystemet Astronomi og Norsk Astronomisk Selskap Stjernekart, planeter Asteroiden Itokawa viser seg å bestå av to drives hovedsakelig på frivillig basis. Vi er og beskrivelse av stjernehimmelen forskjellige asteroider! Her fotografert av glade for bidrag til bladet, men med vår den japanske romsonden Hayabusa i 2005. begrensede økonomi kan vi dessverre ikke Foto: JAXA honorere artikler og bilder. Astronomi 3/14 3 AstroNYTT SMÅLEGEMER Asteroide med ringer F. Braga-Ribas og medarbeidere har Asteroider i dette området kalles kentau - Den 26. mars 2014 ble det annonsert oppdaget en dobbelt ring rundt kjem- rer. Chariklo er den største kjente ken - at på fotografier tatt 3. juni 2013 så man peasteroiden Chariklo. tauren med en diameter på 250 km. Den for første gang ringer rundt et annet er på grensen mellom å være en aste - legeme enn de fire største planetene i Asteroiden Chariklo ble oppdaget av roide eller en dvergplanet. Solsystemet. Ringene er henholdsvis 7 astronomen J.V. Scotti 15. februar 1997. Chariklo beveger seg i en elliptisk bane km og 3 km tykke, og det er en avstand Den går i bane rundt Sola mellom der avstanden fra Sola varierer mellom på 9 km mellom sentrene deres. Det er banene til Saturn og Uranus. 13,1 AE og 18,7 AE (AE: astronomiske bare 5 km mellom ytterkantene deres. enhet, dvs. Jordas gjennomsnittsavstand Ringene består i det minste delvis av fra Sola). ispartikler. Øyvind Grøn Kilde: http://www.eso.org/public/news/eso1410/ Illustrasjon av asteroiden Chariklos ringer sett fra dens overflate. Ill.: ESO/L. Calçada/Nick Risinger (skysurvey.org) 4 Astronomi 3/14 AstroNYTT Astronomi 3/14 5 AstroNYTT METEORITTER Kjempeasteroide traff Jorda for 3,26 milliarder år siden Geologiske undersøkelser i Sør- Afrika har ledet til den konklu- sjon at Jorda ble truffet av en asteroide med diameter på mellom 37 og 58 km. Asteroiden hadde dermed omtrent 3 til 6 ganger så stor diameter som den som traff Jorda for 65 millioner år siden og utryddet dinosaurene. Nedslaget var trolig bare ett av flere som inntraff for mellom 3 og 3,8 milliarder år siden. De utgjorde etterdønningene etter en kraftig kollisjonsperiode som kalles Det sene store bombardement, som i hovedsak tok slutt for 3,8 milliarder år siden. Jorda skulle også senere oppleve kollisjoner, men bare av en og annen etternøler. Geologene har lenge hatt mis - tanke om at rundt et dusin store asteroider traff Jorda for mellom 3,23 og 3,47 milliarder år siden. De nye undersøkelsene har altså tid - festet alderen til ett av disse til 3,26 milliarder år – og at det skyldtes en asteroide som var større enn for - skerne hadde forestilt seg. Den hadde hele 50 ganger større masse enn asteroiden som utryddet dino - saurene, og traff Jorda med en fart på 20 km/s. Tidspunktet og omfanget av kol - lisjonen er bestemt ved hjelp av geologiske undersøkelser av et felt i Sør-Afrika kalt Barberton-feltet. Dette inneholder noen av de eldste Øverst størrelsen av asteroiden som traff Jorda for 3,26 milliarder år siden, sammenliknet med asteroi - steinene på Jorda. Asteroiden traff den som utryddet dinosaurene for 65 millioner år siden. Nederst ser vi den resulterende kraterstørrelsen. ikke selve feltet, men det er funn Ill.: American Geophysical Union + USGS + Trond Erik Hillestad herfra som gjør at geologene mener å ha funnet bevis for et seks ganger mer langvarig enn det varmt og begynte å koke i en kort starten på det systemet av konti - nedslag, som trolig skjedde noen store jordskjelvet utenfor Japan i periode. Atmosfæren ble fylt av glø - nentalplater vi har i dag. tusen kilometer unna. 2011. Det ble også dannet tsuna - dende støv. Smeltet stein ble Øyvind Grøn Forskerne har konstruert en mier som i flere tusen meters slynget opp i jordbane og etter hvert modell for kollisjonsforløpet og dybde forplantet seg utover i ver - regnet det flytende stein som ble Kilde: http://news.agu.org/press- ettervirkningene. Kollisjonskrateret denshavene. avkjølt og størknet til dråpeform. release/scientists-reconstruct- hadde en utstrekning på 500 km. I tillegg ble det omgjort så mye Trolig sprakk de daværende ancient-impact-that-dwarfs-dino - Det oppsto voldsomme jordskjelv bevegelsesenergi til termisk energi kontinentalplatene opp, og den saur-extinction-blast/ med en halv times varighet, dvs.
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