The core of the Earth has remained a mystery to researchers for quite some time, and for one simple reason, we can't drill down to the core to collect a sample.
Some of the most basic questions, such as 'how and when did the core form?' and the answers to those questions are currently being worked on by numerous seismologists and geodynamicists. In the new study, the researchers used seismic observations and geodynamic modeling with estimations of how iron alloys conduct themselves at high pressure and found that the Earth's inner core was growing faster on one side.
It should be noted that this study has its limitations, and the model that was created by the authors only works if it's if Earth's inner core consists "of one specific crystalline phase of iron", per Inverse. The created model allowed researchers to estimate that the Earth's inner core is between 500 million and 1.5 billion years old. Relatively speaking, that would make Earth's inner core quite young, as it would only be between a ninth and a third as old as Earth itself.
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