Age of the Earth

:For the "Age of Earth" as used in the game of Myst and its sequels: see Age of D'ni.

Related Topics:
Myst - Age of D'ni

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The age of the Earth is estimated to be 4.55 billion (4.55 × 109) years. This estimate represents a compromise between the oldest known terrestrial minerals – small crystals of zircon from the Jack Hills of Western Australia – and astronomers' and planetologists' estimates of the age of the solar system. The radiometric age dating evidence from the zircons confirms that the Earth is at least 4.404 billion years old. Comparing the mass and luminosity of the Sun to the multitudes of other stars, it appears that the solar system can not be much older than those rocks. Ca-Al-rich inclusions - the oldest known solid constituents within meteorites which are formed within the solar system - are 4.567 billion years old, giving an age for the solar system and an upper limit for the age of the Earth. It is assumed that the accretion of the Earth began soon after the formation of the Ca-Al-rich inclusions and the meteorites. Since the accretion time of the Earth is not exactly known yet and the predictions from different accretion models vary between several millions up to about one hundred million years, the exact age of the Earth is difficult to define. This article describes the modern dating methods used to arrive at the age of the Earth and outlines their history.

Related Topics:
Earth - Mineral - Zircon - Jack Hills - Western Australia - Solar system - Radiometric age dating - Sun - Ca-Al-rich inclusions - Meteorites

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