(I was reading this article about advance 'aliens' living underground to avoid the Sun's radiation and which is why when manned machine search for lifeforms in other planets. It only see desolation on the surface.....If there are 'oceans' inside Earth (which I believe so) then where there Is water there is life......we might have another another civilisation on the other side......)
Are there ‘oceans’ hiding inside the Earth?
http://www.bbc.com/future/story/2014102 ... side-earth