What effect/relation do inner core fires of planets (eg earth) have on their gravities?

Answer 1

Extremely little. The Gravity in Newtonian Physics is determined by the mass of the body which is not effected by the state of the matter only its net mass.

However in General Relativity not only the mass but the pressure is involved. So in General Relativity increased positive pressure does very slightly increase the gravity. But this added amount is usually very insignificant for most bodies due to the fact that these pressures are extremely small relative to the speed of light.

Answer 2

In that it requires an energy source to perform work, what is the energy source that performs the work of the force of gravity? If there is not an energy source, then the force of gravity is being created in all mass at all times. This concept, though, directly goes against the concept that energy (gravity) is unable to be created or destroyed.

Were our planet to have no internal heat energy, then it would have no gravitational field. When energy is contained within a mass, that mass must evidence that internal energy in some manner. How is the vast heat energy within our planet being evidenced?

Our planet must expend 0.00444 kg./sec of gravitational waves in order to maintain its gravitational field. Our sun expends 665 lbs./sec in order to keep the planets in place. Stephen Hawking, in "A Brief History of Time" mentions on page 92, para. 3, that gravitational energy carries away energy from the mass they originate from. Where is this energy coming from. Were you to go to http://timebones.blogspot.com and scroll down to "The Problem and Repair of Relativity", in the last half of that writing is, "An Experiment You Can Help With". This will present the question and answer and offer a solution.

Answer 3

Non really, their gravity is a function of their total mass. The molten cores however give rise to strong magnetic fields. Jules, Australia.

Answer 4

They are right, and it's not really fire, it's molten.