When I was a child, I worried about all the water running out of the rivers and into the oceans. First, I worried that the rivers would run out of water. Then, I worried that the oceans would fill up and flood over the land.

If you think about it, my worries were logical. How do the rivers keep running so long? (The Tigris and Euphrates rivers in the Middle East are even mentioned in the Garden of Eden). And, since all rivers flow into the oceans, why don't the oceans fill up and flood our land? "All streams flow into the sea, yet the sea is never full. To the place the streams come from,...