Utente:Lo Scaligero/Sandbox: differenze tra le versioni
Contenuto cancellato Contenuto aggiunto
Riga 50:
=[[:en:Solar System|Solar System]]=
Il Sole è una [[Metallicità|stella di I popolazione]], ed è nato nelle fasi successive dell'evoluzione dell'[[Universo]]. Esso contiene più elementi pesanti dell'[[idrogeno]] e dell'[[elio]] ([[Metallicità|metalli]]) rispetto alle più vecchie stelle di popolazione II.<ref>{{cite journal |author=T. S. van Albada, Norman Baker |title=On the Two Oosterhoff Groups of Globular Clusters |journal=Astrophysical Journal |volume=185 |year=1973 |pages=477–498 |doi=10.1086/152434}}</ref>
▲Elements heavier than hydrogen and helium were formed in the [[solar core|cores]] of ancient and exploding stars, so the first generation of stars had to die before the universe could be enriched with these atoms. The oldest stars contain few metals, while stars born later have more. This high metallicity is thought to have been crucial to the Sun's developing a [[planetary system]], because planets form from accretion of metals.<ref> {{cite web |title=An Estimate of the Age Distribution of Terrestrial Planets in the Universe: Quantifying Metallicity as a Selection Effect |author=Charles H. Lineweaver |work=University of New South Wales |date=2001-03-09 |url=http://arxiv.org/abs/astro-ph/0012399 |accessdate=2006-07-23}}</ref>
[[Image:Heliospheric-current-sheet.gif|left|thumb|The [[heliospheric current sheet]].]]
|