Quite an understatement:
> The core is about 4,000 miles from the Earth's surface and, despite best efforts, scientists have so far been unable to reach it.
> The core is about 4,000 miles from the Earth's surface and, despite best efforts, scientists have so far been unable to reach it.
> Dr. Josh Keyes: The core is the size of Mars. You're talking about jump-starting a planet. This is a superheated hyper-fluid of molten iron and nickel at 9,000 degrees Fahrenheit. And the deepest we've ever been is... 7 miles, with a two-inch drill bit. Space is easy. It's empty. We're talking about millions of pounds of pressure per square inch. Even if we somehow came up with a brilliant plan to fix the core, we just can't get there.
> Dr Conrad Zimsky: ...But what if we could?
We know there is a core thousands of miles beneath our very feet, and we can only guess as to what exactly it is, a mystery beneath us our entire lives.