Let's remember that the first creation story imagines a universe made from water. On the second day, God creates a smooth dome, the raquia, to hold back some of the water; on the third day he rolls back the rest of the water to reveal dry land. Later, when He gets fed up with the creation and decides to flood it, all he does is open the gates of the heaven and allow the rolled back water to recover the previously revealed dry land ( נִבְקְעוּ֙ כָּֽל־מַעְיְנֹת֙ תְּהֹ֣ום רַבָּ֔ה וַאֲרֻבֹּ֥ת הַשָּׁמַ֖יִם נִפְתָּֽחוּ׃). So again: Where does all the water come from?
This sketch, which shows how the Bible views the universe, sums up the problem. (and remember that until rather late "Judaism" thought the sun went under the land every night, where among other things, it warmed up the Tiberian hot springs)
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