What is Black dwarf?
[[File:Star Life Cycle Chart.jpg|thumb|Life cycle of stars. Black dwarf is in the lower right.]] A '''black dwarf''' is a kind of [[star]]. A black dwarf is made when a [[white dwarf]] star becomes too cold. When it is cold enough, it can no longer make large amounts of [[heat]] and [[light]]. The star will get darker and become black. Scientists are not certain if black dwarfs can exist because it takes longer than the [[age of the universe]] (13.8 billion years) for a white dwarf to become one. ==Formation== A white dwarf is made from a medium or small-sized star (any star less than nine or ten times the size of the [[sun]]) when it uses all of its fuel.<ref>{{Cite journal|last1=Hartmann|first1=D. H.|last2=Langer|first2=N.|last3=Woosley|first3=S. E.|last4=Fryer|first4=C. L.|last5=Heger|first5=A.|year=2003 |title=How massive single stars end their life |journal=The Astrophysical Journal|volume=591|issue=1|pages=288–300|language=en|doi=10.1086/375341|arxiv=astro-ph/0212469|bibcode=2003ApJ...591..288H|s2cid=59065632}}</ref> After the star uses its fuel, it is a very tight ball of [[Gas|gasses]]. Then, it gets colder and colder, until it stops making light and heat, when it becomes a black dwarf. Scientists are not sure how long this takes. Some think it takes 1,000,000 billion years, but others think it could be longer.<ref>{{Cite journal|last1=Laughlin|first1=Gregory|last2=Adams|first2=Fred C.|date=1997-01-18|title=A dying universe: The long-term fate and evolution of astrophysical objects|url=https://xxx.lanl.gov/abs/astro-ph/9701131v1|language=en}}{{Dead link|date=December 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> Scientists do not believe that black dwarf stars can exist right now because the universe is only 13.8 billion years old. ==References== {{Reflist}} {{-}} {{sci-stub}} [[Category:Types of stars]]