**Ask a monkey a physics question thread**

[Eric]

Daily Mail says the earth's core is two and a half years younger than its crust. In the 1960s they estimated the difference was just a day or two. What are the cliff notes on the way they figured out the difference is 2.5 years?

[MadMojoMonkey]

Daily Mail says the earth's core is two and a half years younger than its crust. In the 1960s they estimated the difference was just a day or two. What are the cliff notes on the way they figured out the difference is 2.5 years?

:/
Tectonic plate movement means the crust of the Earth is constantly (albeit slowly) being dragged down into the core. Volcanic activity moves the molten core back to the crust where it cools and becomes new crust.

The Earth is ~3.5 billion years old and someone is saying there's a way to tell that parts of it are a couple years older or younger than the rest? I'm going to have to find the article you read and look for sources. Maybe there's some exciting geology that I am about to learn.