[meteorite-list] Molten Core? Solid Core? Rocky Core? Blue Cheese!?

[Meteorites USA]

OK,

A friend and I were watching a show on Discovery or NatGeo a couple 
months back. The program I think was about asteroids, and impacts, 
perhaps even "How the Earth Was Made" or another program. Don't really 
remember....

The point is during the show they said very matter-of-factly on three 
separate occasions that the Earth's core was made of three different 
materials. One scientist (or narrator I don't remember)  said Earth had 
a rocky core. Which we laughed at of course because we all know that the 
Earth's core is Solid iron right? Then another scientist confirmed our 
knowledge and stated what we already knew. The Earth core is made of 
SOLID iron. "Of course we said!" Now that's right... Then not 10 minutes 
more into the show another person stated that the Earth had a molten 
iron core.

To make matters even more confusing the show went on to say that the 
SOLID iron core was surrounded by molten iron with lighter "rocky" 
materials "floating" out beyond that OK... sounded good at the time, but....

My question is simple. Which is it? Molten? Solid Iron? or Solid iron 
surrounded by molten iron. And if it's the latter how is this possible? 
Wouldn't the solid iron core NOT be solid if it were sitting in the 
middle of a molten lake of iron? Does the core cool faster than the 
surrounding material, and if so how is this possible considering this 
the logic that says an object cools from the outside in.

Now, I'd like to stop there but I just read an interesting article on 
National Geographic's website titled "North Magnetic Pole Moving East 
Due to Core Flux" here:
http://news.nationalgeographic.com/news/2009/12/091224-north-pole-magnetic-russia-earth-core.html

At the end of the article it flatly states:

"...Wandering Pole -

Geologists think Earth has a magnetic field because the core is made up 
of a solid iron center surrounded by rapidly spinning liquid metal. This 
creates a "dynamo" that drives our magnetic field.

Scientists had long suspected that, since the molten core is constantly 
moving, changes in its magnetism might be affecting the surface location 
of magnetic north...."

I don't know about you, but this confuses me just a little bit...

Can anyone please clear this up for me? And perhaps the rest of the 
world? ;)

Regards,
Eric Wichman
Meteorites USA