Wednesday, June 20, 2012

Where is the driest place on earth?

Antarctica!!! Parts of the continent have seen no rain for two million years.
A desert is technically defined as a place that receives less than ten inches of rain a year.
The Sahara gets just one inch of rain a year.

Antarctica’s average annual rainfall is about the same, but 2 percent of it, known as the Dry Valleys, is free of ice and snow and it never rains there at all.
The next-driest place in the world is the Atacama Desert in Chile. In some areas, no rain has fallen for four hundred years and its average annual rainfall is a tiny 0.004 inch. Taken as a whole, this makes it the world’s driest desert, 250 times as dry as the Sahara.
As well as the driest place on earth, Antarctica can also claim to be the wettest and the windiest. Seventy percent of the world’s fresh water is found there in the form of ice, and its wind speeds are the fastest ever recorded.
The unique conditions in the Dry Valleys of Antarctica are caused by so-called katabatic winds (from the Greek word for “going down”).
These occur when cold, dense air is pulled downhill simply by the force of gravity. The winds can reach speeds of 200 mph, evaporating all moisture—water, ice, and snow—in the process.
Though Antarctica is a desert, these completely dry parts of it are called, somewhat ironically, oases. They are so similar to conditions on Mars that NASA used them to test the Viking mission.

from "The General Book Of Ignorance"

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