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July 22, 2011

Strange But True!

Q. If the moon can pull the mighty oceans, and if your body is mostly water, then why shouldn't the moon create tides within you as well?

A. In our educated society, not one person in a thousand could explain this if their lives depended on it, says Bob Berman in “Secrets of the Night Sky.” The problem is the confusion between gravitational and tidal effects: Our planet orbits the sun, not the moon, so the sun has the stronger pull on us. Yet the ocean tides primarily follow the movements of the moon; this is because gravity falls off rapidly with increasing distance, meaning the moon's pull on the side of the Earth facing it is stronger than its pull on the other side, 8,000 miles farther away. This difference is not what produces the tidal effect: it IS the tidal effect.


 
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