Friday, December 19, 2008

Did you Make the Connection

There are some 100,000 people who have had to evacuate their homes due to tidal flooding in the low lying islands of the Pacific this week. The tides have been exceptionally high.

The full moon last week was exceptionally bright.

The tides of course have been recognized since the time of Galileo as being caused by the gravitational attraction of the moon on the oceans. Gravitational force decreases as the square of the distance. The moon was bright because it was especially close to the earth, which in turn was why the tides were high. (Remember, orbits are not circular, and indeed are rather complicated when all the interactions of celestial bodies are taken into account.)

Of course, global warming will raise sea levels, and the tides are added to the sea level. So the abnormally high tides being experienced now are similar to the normal tides that the world will experience when more global warming has occurred and more ice has melted.

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