4.567 billion years (years based on the current present rotation rate) this of course was far different in the past.
http://en.wikipedia.org/wiki/Age_of_the_Earth
Based on extensive and detailed scientific evidence, geologists have determined the age of the Earth to be around 4.567 billion years (4.567×109 years). This age represents a compromise between the oldest-known terrestrial minerals small crystals of zircon from the Jack Hills of Western Australia and astronomers' and planetologists' determinations of the age of the solar system based in part on radiometric age dating of meteorite material and lunar samples.
The radiometric age dating evidence from the zircons further 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 cannot be much older than those rocks. Ca-Al-rich inclusions (inclusions rich in calcium and aluminium) 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 100 million years, the exact age of the Earth is difficult to define.
In the centuries preceding the scientific revolution, the age of the Earth was determined from the accounts of creation by religious authority. Today some religious groups continue to accept only theological accounts regarding the age of the earth, rejecting scientific evidence which contradicts their beliefs.
Like other radiometric methods, radiocarbon dating faces technical problems and operates under some questionable assumptions.
Whoops! Earth’s Oldest ‘Diamonds’ Actually Polishing Grit
LiveScience | 1/3/2014 | Becky Oskin
Posted on 1/3/2014 5:26:38 PM by aimhigh
https://www.freerepublic.com/focus/news/3108059/posts