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# New Calculations Suggest that Earth's Core is 2.5 Years Younger Than the Crust

May 26, 2016 03:17 AM EDT
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Researchers from Aarhus University in Denmark have calculated that Earth's core is actually 2.5 years younger than its surface, debunking previous claims that the core is "a day or two" younger than the surface.

Previously, scientists have widely accepted theoretical physicist Richard Feynman's claims in the 1960s stating that the center of the Earth is a day or two younger than its surface due to the curvature of space and time caused by gravity.

According to the report from Science Alert, Einstein's theory of general relativity states that the more massive an object, the more the fabric of space-time is 'warped' by its existence, creating a gravitational pull that in effect slows time in the object's general surrounding area.

Since then, Feynman's prediction has been cited in various scientific papers and even used as a material for university textbooks. However, according to the report from Gizmodo, no one bothered to check Feynman's calculation.

Due to this, Ulrik Uggerhøj from Aarhus University in Denmark tried to check the previously accepted calculation. Using back-of-the-envelope calculation and more elaborate analysis, researchers were able to determine that the center of the Earth was in fact two and half years younger than the surface.

Their calculations, elaborated in a paper published in the European Journal of Physics, involves solving the difference in gravitational potential or the measure of the work done by gravity in moving a mass from one location to another between Earth's center and surface.

New Scientists reported that plugging the differences into the equations of relativity yields a time dilation factor of around 3 x 10-10, which basically means that time moves slower in the center of the Earth compared to surface. Factoring the age of the Earth, about four billion years, the cumulative effect of the time dilution adds up to a difference around a year and a half. However, using a more accurate model of Earth's density resulted in difference of age around two and a half years.

Their calculations seem on the spot but it can't be really proven experimentally. Researchers also want to clarify that they did not intend to prove Feynman wrong. Instead, the researchers want their solution to be used for educational purposes, as an example in the classroom.