There are 100 reasons why Earth cannot be significantly hollow, but advanced beings can build hollow, even bigger?
We, or they, need a material millions of times stronger than rock to build a thin shell about the size of Jupiter. Because it is thin, and has vacuum inside, and it is 60,000 kilometers to the mass center, it has much less surface gravity than Earth. The surface gravity will increase when we add a thin veneer of earth material plus an atmosphere to the outside surface, which will behave much like Earth in most respects. How will it be different and can we fly space craft in the vacuum inside? Feel free to get off topic.
David Beierl2014-06-23T09:47:19Z
Dyson figured we'd eventually need so much space and energy that we'd rebuild as a hollow shell surrounding the sun (see Dyson Sphere). Check out Larry Niven's Known Space books, particularly Ringworld, for a much easier setup built as a strip with internal side walls to hold in atmosphere.
If there is even one hole in the shell, the atmosphere outside would fall through it to the interior, probably forming a small gas planet at its center. If it could be kept perfectly sealed, however, the inside of the shell would be gravitationally null throughout, making it zero gravity as well as vacuum.
No known or forseeable material could build this sort of structure. However, the way round this is some sort of dynamic support. For example the concept of a "statite", which is a spacecraft held up by a solar sail, so it hangs above its star rather than orbiting and objects on it feel gravity.
If it's vacuum inside and outside - why does it need to be so strong?
And, truly - an arch is one of the most stable structures there is - you could make this to be a gigantic arch, with each 'piece' the keystone for all the others. It would support itself.
But, why do you want to go inside? It'll be dark & spooky in there....
1 reason is enough. Ask any trained Geologist he will tell you. Why guys like you are dismissive of all the knowledge that is available at hand & go in search of something that you can't even define or articulate in a coherent, cogent manner as to what you seek? is it some kind of mental illness you suffer from? To me it appears to be a case of utter ignorance, of ignorance of your own level of ignorance. It is an incapacity to educate one self and that too in an age with a surfeit of information wherever one looks for it. It is a paradox of paucity & plenty side by side. You are men tally bankrupt.