300 Foxes and a Donkey's Jawbone
Sheol, the underworld realm of the dead. A.k.a. the interior of the Earth. Hell is real. Get used to it.
The largest number of Hebrew uses of the phrase the foundations of the earth have been rendered from the Hebrew root yasad. It's here where we find the meaning which ties us directly to our Biblical theory of gravity.
When we hear people talk about judgement we may hear phrases like “...burning in hell for all eternity.” It's wrong and physically impossible. Hell is temporary.
The way we find all of the meaning which is contained in the phrase the foundations of the earth is to systematically examine all of the different Hebrew word combinations which have been translated this way.
There are some clues for us to be able to figure out the Earth's former size. This comes from the pillars of the Earth which are part of its internal structure.
It's very useful to know the volume of material in the Earth's crust and mantle, but before we move on it's also worthwhile to note that the Earth's crust and mantle have several Biblical synonyms.
With a few pieces of information we can take what we know about the Earth today and deduce what the Earth was like in the past. This is the alternative to using Uniformitarianism to assume that things were the same in the past.
If you're skeptical that there's really an underworld realm of the dead you should consider two things: 1. the deepest hole drilled is 12 km deep, 2. the Lehmann Discontinuity is approximately 220 km deep.
Thus hath the Lord GOD shewed unto me: and, behold, the Lord GOD called to contend by fire, and it devoured the great deep, and did eat up a part. (Amos 7:4) KJV
And the tongue is a fire, a world of iniquity. The tongue is so set among our members that it defiles the whole body, and sets on fire the course of nature; and it is set on fire by hell. (James 3:6) NKJV
The nice folk over at popular science (SciPop) just discovered remnants of the pillars of the earth.