[Dave Lammel]

Dave Lammel  asked the Naked Scientists:
   
Dear Naked Scientists,

Your 15 November podcast, "Producing Planets," mentioned that during the formation of Earth, heavier materials such as iron were drawn closer to the core by gravity, while lighter materials such as basalts floated nearer the surface.  

My question is, what would you speculate would be the material at the very centre of the core.  Since gravity would be pulling outward in all directions on the core, would not the very centre be filled with lighter material?  Would there be a gradation of material densities such as that occurring near the surface?  Could the precise centre even be gas?

Love your show.

Dave Lammel
San Rafael, California, USA

What do you think?

[JimBob]

A theoretical miasma -

Seriously, no one knows. It really cannot be a zero gravity point because all the forces of this galaxy, however small, are acting on it. It is most likely a super flux - a molten super fluid of unknown properties. It is likely not only iron, but is more likely similar to meteorite material; nickle-iron with a lot of other heavy elements included. But so hot it would be gaseous if it were not under such confining pressure.

[chrisrich]

Fun thing is even if we could dig down to find out is if that center is under considerable pressure imagine the cork we might be popping if we get down that far.  Anyone feel like deflating the earth?  Hopefully it won't fly around the solar system like a deflating balloon.

[LeeE]

Anyone feel like deflating the earth?  Hopefully it won't fly around the solar system like a deflating balloon.

Now that is a funny image []

[Nizzle]

I thought leprechauns with lots and lots of pots of gold

[Titanscape]

The spirits live their in dungeons and managing dungeons. I recall a story of a violent criminal who died and saw people he knew deep in the Earth, being pushed into the mantle. Changed his life.

[LeeE]

I recall a story of a violent criminal who died and saw people he knew deep in the Earth, being pushed into the mantle. Changed his life.

Death does tend to be a life changing occurrence.

[JimBob]

The post commenting on the physics of the original statement

A theoretical miasma -

(snip)

It really cannot be a zero gravity point because all the forces of this galaxy, however small, are acting on it.

posted by "fontwell" has been merged with a longer, already established, now found at

http://www.thenakedscientists.com/forum/index.php?topic=26472.msg304484#msg304484 This thread, "The center of the earth is not gravity free," is specifically focused on the topic fontwell posted. It has already been discussed at length. 

Please post follow up comments on this particular aspect to that merged thread.

[Titanscape]

Are there still 4 dimensions deep inside the planet?

[diverjohn]

What is at the centre of the Earth?
I asked that question last year, on the hunch that the most dense metals (gold and uranium) would be at the core in a molten state and under high pressure.
I thought that if you could bore a hole to the core (ignoring the obvious technical problems of doing so such as extreme heat and moving layers) and let the molten gold spew out and make oneself very wealthy.
I don't think the strength of the gravity is an issue, as the pressure of the weight of rock around the core would be the major factor to consider.
John

[diverjohn]

Another thought ...
if the heaviest / most dense metals are in the core, is there anything more heavy than uranium that may be there? Not thinking of the short-lived Actinides, but of something more exotic. physicists have pondered the existence of very large nuclei that are stable but not yet discovered, though I have doubts as to whether they'd survive a few billion years without decaying.