Automoderated users, edit
3,552
edits
Changes
Jump to navigation
Jump to search
Line 14:
Line 14: − − ==Old Universe View== − − In the cosmological model of a billions of years old universe, it is theorized that the metallicity of certain astronomical objects may offer clues to those objects' ages. According to their [[Big Bang|Big Bang theory]], when the universe first formed, it consisted mostly of hydrogen with a sizable proportion of helium; only trace amounts of [[lithium]] and [[beryllium]] are believed to have been created, with no heavier elements forming. In this model, older stars will have lower metallicity than younger stars, as all other elements were created through stellar and supernova nucleosynthesis. In this model, stars classified as population III stars are the oldest known stars, followed by population II stars, and finally population I stars, which are the youngest.
→Old Universe View
'''Population III stars''' are essentially metal-free stars, although some have metals at the end of their lives. Population III stars were considered to be extremely massive and hot but have not been directly observed. Indirect evidence of their existence has been found through looking at [[General theory of relativity|gravitationally lensed]]<ref>http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2002ApJ...567..532H</ref>, and distant faint blue galaxies in the very distant universe<ref>http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2003ApJ...596..797F</ref>.
'''Population III stars''' are essentially metal-free stars, although some have metals at the end of their lives. Population III stars were considered to be extremely massive and hot but have not been directly observed. Indirect evidence of their existence has been found through looking at [[General theory of relativity|gravitationally lensed]]<ref>http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2002ApJ...567..532H</ref>, and distant faint blue galaxies in the very distant universe<ref>http://adsabs.harvard.edu/cgi-bin/nph-bib_query?bibcode=2003ApJ...596..797F</ref>.
[[Category:Astronomy]]
[[Category:Astronomy]]