Earth's core is a billion years old

[Judi Lynn]

By Stephanie Pappas - Live Science Contributor an hour ago

The solidification of the inner core may have strengthened Earth's magnetic field.



(Image: © Shutterstock)
The solid inner core of Earth is a mere billion years old, new research finds.

Modern Earth is like a layer cake, with a solid outer crust, a hot, viscous mantle, a liquid outer core and a solid inner core. That solid inner core is growing slowly as the liquid iron in the core cools and crystallizes. This process helps power the churning motion of the liquid outer core, which in turn creates the magnetic field that surrounds Earth and helps protect the planet from harmful cosmic radiation.

In other words, the inner core is pretty important.

But not much is known about the history of this 1,500-mile-wide (2,442 kilometers) iron ball. Estimates of its age have ranged from half a billion years to more than 4 billion years, almost as old as 4.5-billion-year-old Earth itself. Now, researchers have squeezed a miniscule piece of iron between two diamonds and blasted it with lasers to arrive at a new estimate of 1 billion to 1.3 billion years old — a date range that coincides with a measurable strengthening of the Earth's magnetic field that happened around the same time.

"Earth is unique in our solar system in that it has a magnetic field, and that it's habitable," study author Jung-Fu Lin, a geoscientist at the University of Texas at Austin, told Live Science. "Eventually our results could be used to think about why other planets in our solar system don't have magnetic fields."

More:
https://www.livescience.com/earth-core-billion-years-old.html?utm_source=notification

[exboyfil]

1. The formation of a magnetic field could be a necessary condition for life

Of the four rocky planets, only the Earth has a substantial magnetic field. It is one of the elements in the rare earth hypothesis.

[cstanleytech]

2. I think its safer to say that a magnetic field make it easier for life rather than necessary

as I can imagine some scenarios where say a moon circling a gas giant could develop life if it has sufficient water provided of course its core is kept hot enough to keep the water deep down from freezing solid.

[exboyfil]

3. Interesting point

Then you still have the potential issue with the radiation given off by a gas giant. Here is a paper on the radiation belt from Jupiter.

https://www.astrobio.net/news-exclusive/hiding-from-jupiters-radiation/


I am in the rare earth camp especially when it comes to the development of multicellular life.

[cstanleytech]

4. That is why I mentioned the water as depending on the depth it may provide enough shielding.