Theory is the set of fundamental principles of an art or a science, which provides a synthesized opinion, is a general notion, which can be refuted and reformulated.
A theory is the speculative part of a science, as opposed to practice. It is a system consisting of observations, ideas and axioms or postulates, constituting in its entirety a set that tries to explain certain phenomena. The explanation formed by a theory can be questioned in the future with the advancement of technology and the discovery of new concepts.
But we've never been to the planet's core. We haven't even come close. The central point of the Earth is over 6,000km down, and even the outermost part of the core is nearly 3,000 km below our feet.Aug 13, 2015
