Our planet's core is 2.5 years younger than the crust, a new study found. Researchers calculated the crust's relative ages and compared it with the core's age estimates.

Apart from shedding new light on gravity's influence over time, the study also highlighted the dangers of taking a famous scientist's words at face value with nothing but prestige backing it up.

In the 1960s, theoretical physicist Richard Feynman predicted that because of time dilation, the Earth's core is younger than the crust. This theory was presented during one of his famous Caltech lectures.

Back then, Feynman suggested that the age difference was roughly a "day or two." Moving forward, physicists accepted the theory without actually checking the real figures behind the age difference.

According to general relativity, big stellar objects such as stars and planets are capable of warping the space-time's fabric. This capability leads to a gravitational pull that can slow down time.

This means that the objects found closest to the Earth's core has a stronger gravitational pull, which means it runs on a much slower clock compared to the ones found in the crust.

This suggested that the materials found in the planet's core are relatively younger. The question now is just how young is the Earth's core compared to its crust? This is where the new research comes in.

The research team included R E Mikkelsen and U I Uggerhøj from the Aarhus University and J Faye from the University of Copenhagen. In the new study, the trio looked into the math behind the theory to get to the actual figures.

They found that in the span of 4.5 billion years, the core's gravitational pull makes it about 2.5 years younger than the planet's surface. This figure didn't include the geological process.

Feynman could have made the error in estimates originally. But there is also a possibility that the transcription of his famous lecture somehow distorted "days" into "years."

"One should always be cautious and test even famous people's suggestions. I fell into the trap of not doing it, I must admit," said Uggerhøj.

The research was published in the European Journal of Physics on April 8.

Photo: Kevin Gill | Flickr