re: some numbers .
Johannes blithered: "Would such a difference in surface pressure have any effect on the cavities within the planet, I do not know, but the idea is intriguing. "
No it is not "intriguing" - once again you fail to grasp what a grade schooler would see using common sense- (why am I surprised, you have proven yourself to be incompetent at doing simple calculations and when someone does them for you, as I have done, you ignore them).
get an education, and this goes for the idiot-non-savant BD... This "theory" is so amazingly beyond common sense that it isnt even laughable- just very sad