Especially interesting to Christians is how this relates to the Great Flood of Noah's day.  The fact of the matter is the utter impossibility of covering the entire earth, even 40 cubits above the highest mountain, with water from the sky above.  Can't be done … even with the so-called (and, unproven) canopy of "water vapor" that supposedly surrounded the earth in Noah's time.

However, the Bible says that the flood started like this; — "the same day were all the FOUNTAINS OF THE GREAT DEEP broken up, and the windows of heaven were opened."

If the "fountains of the great deep" refers to this massive underground ocean …. how did the author of Genesis know about that??

After decades of theorizing and searching, scientists are reporting that they've finally found a massive reservoir of water in the Earth's mantle — a reservoir so vast that could fill the Earth's oceans three times over. This discovery suggests that Earth's surface water actually came from within, as part of a "whole-Earth water cycle," rather than the prevailing theory of icy comets striking Earth billions of years ago.