All this sounds interesting and kind of cool to think about. One thing you do have to take into consideration is the fact that everybody "knew" the earth was the center of the universe at one time, everybody "knew" the earth was flat, and there have been many things that many "knew" were true and later on have been proven wrong.

I'm not saying that this guy is right or wrong. All I'm saying is that it's possible...just not probable. We haven't even discovery our whole outer layer of the earth yet. We have found lost worlds and we haven't even mapped out the entire ocean floor.

There is, however, one thing that I don't understand about his theory. If this hollow earth theory is true...then where is all the magma coming from in volcanoes and when tectonic plates move apart???