[ Technical Notes > Melting the Inner Earth ]

Melting the Inner Earth

Today, the Earth’s density at any depth, z, is well known. Some values are given in column G of Table 110.¹ Based on those values, the mass, acceleration due to gravity, polar moment of inertia, and gravitational potential energy are calculated in columns H–K for successive spherical shells. The potential energy of a shell of mass m and radius r is

where G is the gravitational constant, g is the acceleration due to gravity at r, and M_i is the mass inside the shell.

Preflood values of density (column B) can be estimated at all depths by the formula

                         density = a + bz + cz² + dz³

where a = 2.840, b = 1.6362  × 10^-3, c = 5.4000  × 10^-8, and d = -1.1587  × 10^-1 1. These coefficients were selected to satisfy the following constraints: the flood did not appreciably change the mass of the Earth,² the preflood density at the Earth’s surface and center was what it is today (2.840 and 12.460 gm/cm³, respectively), pressure and, therefore, density increased smoothly with depth, and the polar moment of inertia allowed the Earth to rotate 360 times per year. (Endnote 35 on page 184 presents some of the evidence for a 360-day year before the flood.) Other functional relationships for preflood density vs. depth that satisfied these same constraints would not greatly alter the following conclusions.

As explained on pages 153–190, during the flood, mass shifts within the Earth generated internal friction, heating, and melting. Melting, especially near the center of the Earth where pressures (and thus frictional heating) were greatest, was followed by gravitational settling of the denser minerals and chemical elements. Rock that melted below the crossover depth contracted. [See “Magma Production and Movement” on page 156.] This produced further mass shifts (faulting), frictional heating, melting, and gravitational settling. Most of the potential energy lost by the Earth—the difference in the sums (highlighted in yellow) of columns F and K—was converted to heat by gravitational settling.³

          (2.489  × 10³⁹ – 2.460  × 10³⁹)  =  29.0  × 1036 ergs

Slippage began at the center of the Earth, as shown in “Forming the Core” on page 160. The potential energy lost by frictional melting eventually generated about 5 times more heat energy in the Earth’s growing core through gravitational settling.⁴ This created a diminishing ⁵ runaway situation: more slippage and melting produced more heating by gravitational settling, which then produced additional (but lesser amount of) slippage, melting etc.  Within months, most of the inner Earth melted. That melting, gravitational settling, and compression of magma in the outer core is shown by the sharp density discontinuity highlighted in red in Table 110 (column G) and by Earth’s extremely strong magnetic field.  [See “The Origin of Earth’s Powerful Magnetic Field” on page 180 for an explanation.]

All this heat, released within months⁶ inside Earth, could provide almost 3-billion years’ worth of the present heat flux at the Earth’s surface (1.0  × 10^2 8 ergs/year).

How does the heat released by gravitational settling (almost 29.0  × 10³⁶ ergs) compare with the heat needed to form Earth’s present-day core? It partly depends on the initial temperatures of the denser particles inside the Earth before they fell toward the Earth’s center to become the inner and outer core. However, before gravitational settling could begin, those temperatures would have been raised to near the local melting temperatures. Particles that melted after they fell added to the liquid outer core; denser particles that did not melt or that solidified under the great pressure near the Earth’s center formed the solid inner core.

Anderson gives the following estimates for the thermal properties of the inner and outer core. (The masses for inner and outer core are derived from Table 110.)

To form today’s inner core requires approximately

[5  × 10⁶ × (6,575 – 3,800)]  × 0.132  × 10²⁷ = 1.832  × 10³⁶ ergs

To form today’s outer core requires approximately

(4  × 10⁹ )   ×  (1.831  × 10 ²⁷ )  =  7.324  × 10³⁶ ergs

Therefore, the heat released by gravitational settling (almost 29.0  × 10³⁶ ergs) exceeded that needed to form the Earth’s inner and outer core (9.156  × 10³⁶ ergs). Temperatures quickly rose near the center of the Earth. Notice that the heat released by gravitational settling, if evenly distributed throughout the Earth, might melt the entire Earth, whose mass is 5.976  × 10²⁷ grams.

29.0  × 10³⁶  ergs   >   (~  4  × 10⁹ )  × (5.976  × 10²⁷ )  ergs

Table 110 allows two other important conclusions. Evolutionists claim that the Earth formed by meteoritic bombardment, sometimes called gravitational accretion. If so, the 2.489  × 10³⁹ ergs of potential energy lost by these meteoroids  (sum of column K)  would  become  heat  after impact with the growing Earth.  This is 86 times greater than the heat released by gravitational settling.  

 

It is also 104 times the heat needed to melt the entire Earth.

Even if the bombardment were spread over millions of years, the entire Earth should have melted, as experts have noted.⁸  Had this happened, we would not find heavy, nonreactive chemical elements, such as gold, at the Earth’s surface, nor would granite exist. [See “Molten Earth?” on page 87 and Endnote 23 on page 182.]

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