Science Forums 2

[Boerseun]

I suppose what Cold-co is saying with vertical and horizontal gravity, is the following:

Imagine there is a shaft going all the way to the center of the Earth.

You hop into an elevator going down the shaft.

For every kilometer you descend, there's a kilometer's worth of mass overhead, and one less kilometer's worth of mass between you and the Earth.

In other words, you will experience gravity from mass distributed all around you - below you, overhead, etc. And the further you go down, the "less" you will weigh as you are now being attracted upwards as well as downwards. You will always feel a positive pull towards the center, because there will always be more mass there, but the resultant gravitational pull you'll feel will become less and less until you reach the very center of the Earth, where there is as much mass in all directions - in which case you will be perfectly weightless.

And the question he is asking, is what would this do to the classic "iron-core under immense pressure" model? Isn't the seismic interface between the inner and outer core the area of densest pressure, rather than the center, and isn't the pressure gradient there responsible for the seismic interface, rather than composition?

Have I got that right, Cold-co?