ملف:Geologica time USGS.jpg

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حجم هذه المعاينة: 793 × 600 بكسل. البعد الآخر: 1٬000 × 756 بكسل.

الملف الأصلي ‏(1٬000 × 756 بكسل حجم الملف: 337 كيلوبايت، نوع MIME: image/jpeg)

مخطط دوامي لمقياس الزمن الجيولوجي.

خطأ في التعبير: عامل < غير متوقع.

English: {{Potd/{{{year}}}-{{{month}}}-{{{day}}} (en) }}

⧼Tpt-languages-legend⧽

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وصف قصير

⧼wm-license-information-description⧽Geologica time USGS.jpg	مخطط دوامي لمقياس الزمن الجيولوجي، يوضح العلاقات الزمنية والمكانية للأحداث التي وقعت خلال تاريخ الأرض English: A diagram of the geological time scale قالب:Eo Français : Diagramme montrant l'échelle des temps géologiques.
⧼wm-license-information-date⧽	2008 (Version 1.1)
⧼wm-license-information-source⧽	Graham, Joseph, Newman, William, and Stacy, John, 2008, The geologic time spiral—A path to the past (ver. 1.1): U.S. Geological Survey General Information Product 58, poster, 1 sheet. Available online at http://pubs.usgs.gov/gip/2008/58/
⧼wm-license-information-author⧽	United States Geological Survey
⧼wm-license-information-other-versions⧽	قالب:Derived from قالب:Derivative versions

Caption

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/.

ترخيص

This image is a work of a United States Geological Survey employee, taken or made during the course of the person's official duties. As a work of the United States Government, the image is in the public domain. For more information, see the USGS copyright policy.

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	زمن/تاريخ	صورة مصغرة	الأبعاد	مستخدم	تعليق
حالي	★ مراجعة معتمدة 00:19، 24 مارس 2009		1٬000 × 756 (337 كيلوبايت)	Shafei (نقاش \| مساهمات)

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