User:Solipsist/MainPageTemp-22Jul
2üMainPageIntr}}
Today's featured articleA white dwarf is a stellar core remnant composed mostly of electron-degenerate matter, supported against its own gravity only by electron degeneracy pressure. A white dwarf is very dense: in an Earth sized volume, it contains a mass comparable to the Sun. What light it radiates is from its residual heat. White dwarfs are thought to be the final evolutionary state of stars whose mass is insufficient for them to become a neutron star or black hole. This includes more than 97% of the stars in the Milky Way. After the hydrogen-fusing period of such a main-sequence star ends, it will expand to a red giant and shed its outer layers, leaving behind a core which is the white dwarf. This, very hot when it forms, cools as it radiates its energy until its material begins to crystallize into a cold black dwarf. The oldest known white dwarfs still radiate at temperatures of a few thousand kelvins, which establishes an observational limit on the maximum possible age of the universe. (Full article...)
Recently featured:
Selected anniversaries Julia Gillard
|
In the news Vera Rubin Observatory
|
Wikipedia in other languages
You may read and edit articles in many different languages:
This Wikipedia is written in English. Many other Wikipedias are available; some of the largest are listed below.
-
1,000,000+ articles
-
250,000+ articles
-
50,000+ articles
Wikipedia's sister projects
Wikipedia is written by volunteer editors and hosted by the Wikimedia Foundation, a non-profit organization that also hosts a range of other volunteer projects:
-
Commons
Free media repository -
MediaWiki
Wiki software development -
Meta-Wiki
Wikimedia project coordination -
Wikibooks
Free textbooks and manuals -
Wikidata
Free knowledge base -
Wikinews
Free-content news -
Wikiquote
Collection of quotations -
Wikisource
Free-content library -
Wikispecies
Directory of species -
Wikiversity
Free learning tools -
Wikivoyage
Free travel guide -
Wiktionary
Dictionary and thesaurus