This image was selected as picture of the day on Wikimedia Commons for 11 June 2009. It was captioned as follows: English: A diagram of the geological time scale Other languages: Bahasa Indonesia: Diagram skala waktu geologi yang berbentuk spiral Čeština: Schématické znázornění geologické časové škály Dansk: Diagram over Jordens geologiske tidsperioder Deutsch: Visuelle Darstellung der Erdzeitalter als Zeitspirale mit englischer Beschriftung (eine deutsche Version der Grafik ist derzeit nicht vorhanden) English: A diagram of the geological time scale Español: Diagrama de la escala de tiempo geológica Français : Diagramme de l'échelle des temps géologiques. Italiano: Diagramma della scala dei tempi geologici. Magyar: A geológiai időskála szemléltetése Nederlands: Engelstalige visuele presentatie van de geologische tijdschaal in de vorm van een spiraal Polski: Diagram przedstawiający skalę czasu geologicznego. Português: Um diagrama (em inglês) da escala de tempo geológico. Română: Diagramă a istoriei geologice a Pământului Slovenščina: Diagram geoloških dob (napisi v angleščini) Македонски: Приказ на геолошките периоди Русский: Геохронологическая шкала, изображённая в виде спирали Українська: Геохронологічна шкала, зображена у вигляді спіралі मराठी: विविध भूशास्त्रीय काळ दाखवणारे चित्र 한국어: 지질학적 연대표. 日本語： ら旋状の地質学年表 中文： 地质学时标图 中文（繁體）： 地質學時標圖 עברית : דיאגרמה של סקאלת זמן גיאולוגי

This image was selected as picture of the day on Vietnamese Wikipedia.

本文件是维基共享资源特色图片（特色图片），并被视为最好的图像之一。  本图像长宽比为4:3或5:4，适于用作桌面背景（请见图库）。  本文件是克罗地亚语维基百科特色图片（Slika tjedna），并被视为最好的图像之一。 如果你拥有相似质量的可采用适当著作权许可协议发布的图像，一定要上传、标记并推荐它。

Original source: http://pubs.usgs.gov/gip/2008/58/geotimespiral_text.pdf

The Earth is very old—4.5 billion years or more according to scientific estimates. Most of the evidence for an ancient Earth is contained in the rocks that form the Earth's crust. The rock layers themselves—like pages in a long and complicated history—record the events of the past, and buried within them are the remains of life—the plants and animals that evolved from organic structures that existed 3 billion years ago.

Also contained in rocks once molten are radioactive elements whose isotopes provide Earth with an atomic clock. Within these rocks, "parent" isotopes decay at a predictable rate to form "daughter" isotopes. By determining the relative amounts of parent and daughter isotopes, the age of these rocks can be calculated. Thus, the scientific evidence from rock layers, from fossils, and from the ages of rocks as measured by atomic clocks attests to a very old Earth.

See USGS Fact Sheet 2007-3015 at http://pubs.usgs.gov/fs/2007/3015/ for ages of geologic time periods. Ages in the spiral have been rounded from the age estimates in the Fact Sheet. B.Y., billion years; M.Y., million years. For more information, see the booklet on Geologic Time at http://pubs.usgs.gov/gip/geotime/.

本图片在美国属于公有领域，因为其只包含最初来自美国内政部下属机构美国地质调查局的材料。更多信息请参见USGS官方版权方针。 Bahasa Indonesia ∙ català ∙ čeština ∙ Deutsch ∙ eesti ∙ English ∙ español ∙ français ∙ galego ∙ italiano ∙ Nederlands ∙ português ∙ polski ∙ sicilianu ∙ suomi ∙ Tiếng Việt ∙ Türkçe ∙ български ∙ македонски ∙ русский ∙ മലയാളം ∙ 한국어 ∙ 日本語 ∙ 中文 ∙ 中文（简体） ∙ 中文（繁體） ∙ العربية ∙ فارسی ∙ +/−