Velocity of the Earth's core
What is the core's approximate velocity?
You mean rotational rate? ever so slightly faster (I think its faster) than the rest of the earth.
Yes, that seems to be the case indeed, the solid inner core spins faster.
while we're on the topic of the earth's core, has anyone seen the movie the core? its good for a laugh! there is absolutely no regard for sciencentific evidence in that movie
Have heard about it. Newton would have pulled his hair out but the movie sort of underlines that the Inner core has a life of its own.
Tidal forces delux
I have a thought experiment for you. Suppose the earth had a 4 meter hollow sphere exactly in the center. What would the gravitational effects be if you placed a ball bearing in the center of this hollow sphere and dropped it? would it be weightless? Or would you be able to roll it "upside down" (relatively speaking) on the "ceiling." Or would it be pulled apart by tidal forces? hmmm?
in the centre of the Earth, all mass is divided equally around you. This means that the sum of all individual gravity vectors is zero. So there is no up or down, just no gravity and the ball bearing would behave exactly as in a spaceship. If you move it off centre a little but, the influence is minimum, changing the total sum only with an infinitemisal small amount.
The pressure in the centre of the Earth is tremendous of course, so it would be a bit hard to dig that hole and get a bearing inside.
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