[One, Two, Middlesboogie]

Hmmm... thanks kleeng; good info there. I'd forgotten that mass (not size) dictates gravitational force.

Just had a new though re: possible things tht could cancel out the gravity. Niteowl mentions in her fic that it could be cancelled out by the same force that makes the Security Orbs hover.

But the problem with the points kleeng raised, as I see it, is that if it is so big, Oddworld will automatically have an iron (or similar dense metal) core, because of the weight of its mantle and lithosphere compressing the core. Even Jupiter, which is mostly liquid and gas, has a solid iron core.

However, this is assuming that it does indeed have a lithosphere and mantle. As Niteowl pointed out in her fic, "There did not seem to be a lot of seismic activity on this planet. The precarious architecture he'd [one of the characters] seen wouldn't have survived otherwise."

So, does Oddworld indeed have tectonic plates? Earth's interior is liquid (with the exception of the inner core, which would be liquid but is solid due to the weight of the other layers which compress it), and lithospheric plates float on top and move around continuously, but very slowly.
Could Oddworld's crust be one single piece? And its interior gaseous? If so, it would probably have a liquid core, because such a huge quantity of gas would be compressed.

But is it that huge? If we look at my diagram again, we can see that if diameter is the comparitive criterion, Oddworld is vast. But if it is 10 times bigger by volume or surface area, it is comparitively very small, and not vastly bigger than Earth.