The linchpin to the molten core model of the earth is the current reigning theory of gravity. I stress the word 'theory' here because that is all it amounts to, and a poor example of one at that. Allow me to explain. According to modern scientific understanding, because of the gravitational pull on all matter which comprises the earth, the deeper one goes into the earth's crust, the greater the pressure due to the cumulative effect of more and more matter above the point of reference (much like deep sea diving). It is a fair assumption I suppose. As the pressure grows, so too does the temperature, which increases up to a point that the rocks and other minerals liquefy. As you progress even deeper, the pressures become so intense that the core itself becomes a super-heated, incredibly dense solid mass of metal (cue applause for the marvels of the modern scientific mind!)
Much like a religion gone terribly wrong, on the surface everything seems to work out nicely and everyone gets an 'S' for satisfactorily playing together. If, however, you dig a bit deeper, you find a debris field of discarded and annoying evidence which stubbornly will not fit into this utopia of modern scientific explanation. Shall we examine a few?
The Kola borehole — The deepest hole drilled into the crust of the earth is located at the Kola Peninsula in Murmansk Russia and extends down 12,262 meters (7.6 miles). Earth scientists had a very precise agenda of pressures, temperatures and rock compositions they expected to encounter with each new depth as they drilled. Instead, they found that they were wrong on nearly all accounts as the Kola borehole produced one surprise after another. It was so astonishing that one scientist commented 'Every time we drill a hole we find the unexpected. That's exciting, but disturbing.' And a science reporter remarked: 'Kola revealed how far from truth scientific theory can roam.'
Anomalous acceleration of Pioneer probes 10 & 11 — As Pioneer probes 10 & 11 near the outer reaches of opposite ends of our solar system, they are slowing down each at an equal, albeit unexpected rate. Scientists, upon examination of this startling evidence are forced to throw up their hands and confess ignorance of the underlying mechanism at work (a.k.a. gravity).
Ultra-short-period planets — WASP-18b is a planet roughly 10 times the mass of Jupiter which completes an orbit around its sun in less than one earth day. Due to the immense gravitational tidal forces exerted on WASP-18b from its close proximity to its sun, its orbit should have degraded until it collided with the star millions of years ago. This unexpected behaviour has astrophysicists and astronomers exclaiming "Perhaps we really are missing some key bit of physics!"
Precession of a pendulum during a solar eclipse — The Allais effect or the precession of the plane of oscillation of a pendulum during a solar eclipse is but one of many anomalous observations and readings made during solar eclipses which seem to somehow alter the otherwise 'normal' gravitational flux experienced by an observer on the surface of earth. A satisfactory explanation has yet to be offered by the scientific community.
Tamarack mine experiment — In an effort to measure the convergence of the earth's gravitational field, two 4,250 foot steel cables were lowered into a mine shaft, each having a weight on the end. Instead of converging, it was discovered the cables actually diverged from each other. The results of the experiment translated to the earth having a center of gravity some 4000 miles out in space! No matter how many times this experiment was repeated, each time taking great care to rule out interference by pesky variables, the results were markedly different from those obtained when applying mainstream models for gravitation.
Einstein's cosmic 'fudge factor', the Lambda Coefficient — Einstein's most accomplished work, his theory of general relativity, was so deficient in describing the effects of gravity by his own admission, that he introduced a 'fudge factor' or lambda coefficient into his equations to cause them to more accurately conform to observable reality. We still herald general relativity as the opus magnum of science when it comes to our collective ability to define the mechanics of gravity. Why then did Einstein refer to lambda as the 'biggest blunder' of his life?