We slept late this morning (out too late at a charity event last night), so I had to walk the dog alone. It was raining, and having seen the news stories about Hurricane Isabel, my mind wandered to the water cycle as one of the wonders of the universe. As we all learned in school:
- Energy from the sun heats the oceans (and lakes, rivers, etc.), causing water to evaporate.
- The resulting water vapor is pretty pure, because the other stuff in the sea doesn't evaporate nearly as much at the temperatures found on earth.
- The water vapor moves around the atmosphere, eventually to condense into clouds.
- Rain falls and collects as fresh water in aquafers, lakes, rivers, etc.
- All this reasonably-pure water is available for use in the various processes that we humans depend on, not least of which are our own bodily processes.
- "Used" water eventually makes its way back to the oceans, where the sun-driven process starts around again.
Of course this nifty arrangement arose, and continues, because of the laws of physics. Some folks believe God purposely designed it that way, others think it's just a series of coincidences, still others fall somewhere in between.
Regardless, if you've ever worked on cars (or in my case years ago, Navy nuclear reactors), you've just got to admire the way that this mechanism works, and on a planetary scale no less.
As I was getting soaked this morning, this was a very joyous thought.