Earth’s Inner Core is Around 1.15 Billion Years Old…So?

Perhaps I just have fine-tuned glasses when I look at the earth history.  Here we see a planet that developed a liquid outer core and a solid core.  Interesting that according to this release, the inner core formed 1 to 1.3 billion years ago. This article suggests  balancing to develop and maintain both cores.

Here is a quote from socratic.org. “With the heavy inner core, the earth’s orbit and rotation will remain stable over the long term, giving us day and night and summer and winter. … These swirling convection currents result in the earth’s magnetic field which keeps us properly oriented for travel, and shields earth from deadly cosmic rays.”  It is vital for life.

I am sure that this had to be in place before the planet was ready for more complex lifeforms.    Intuitively, I would guess that this type of planet situation is very rare in the universe.