Bridget Grant, age 12, of Dotham, Ala., for her question:
WHERE IS THE WORLD'S LARGEST DESERT?
Largest desert area in the world is the Sahara. It is located in northern Africa and extends from the Atlantic Ocean eastward past the Red Sea to Iraq. The desert is about 1,000 miles wide and about 3,200 miles long. It's hard to believe, but the Sahara is almost as large in area as the United States.
Geographically distinct are the west Sahara, which is sometimes called the Sahara proper; the central Ahaggar Mountains and the Tibesti Massif, a plateau region; and the Libyan Desert in the east. The West Sahara is an area of rock strewn plains and sand deserts of varying elevations. The land is almost entirely without rainfall or surface water but possesses a number of underground rivers that flow from the Atlas and other mountains. Occasionally the waters of these rivers find their way to the surface and form naturally irrigated oases.
The soil in this region of the Sahara is fertile, and, where irrigation is possible, produces excellent crops. The central plateau region of the Sahara runs for approximately 1,000 miles in a northwest to southeast direction. The plateau itself varies in height from about 1,900 to 2,500 feet. Peaks in several mountain ranges that arise from the plateau are from about 6,000 to more than 11,200 feet high.
The Libyan Desert is considered the most arid part of the whole Sahara. Moisture is almost totally absent and very few oases exist. The land is characterized by sandy wastes and large dunes of sand 400 feet or more in height. The valley of the Nile River and the mountainous area of the Nubian Desert to the east are, geographically, a part of the Sahara, although the irrigation afforded by the Nile transforms the desert into fertile agricultural and throughout much of Egypt.
Politically, the Sahara lies largely in Morocco, Algeria, Tunisia, Libya, Egypt, Mauritania, Mali, Niger, Chad and Sudan.
The north Sahara has assumed economic importance with the discovery of extensive petroleum deposts in Algeria and Libya. The temperature range of the Sahara is extreme, ranging between freezing in the mountains to more than 130 degrees Fahrenheit in the west and central portions.
Except in the oases the desert is almost devoid of vegetation, although some stunted, thorny shrubs grow in the west Sahara. Artificial oases have been created by drilling water wells more than 3,280 feet deep. The chief trees of the oases are the date palm and a form of acacia.
Gazelle and antelope are found in many parts of the desert as are jackal, fox, badger and hyena. The Libyan Desert, however, virtually devoid of any form of animal or vegetable life.