Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
2002 November 12
Explanation: Dominating the top third of Africa is the largest band of dry land on Earth: the Sahara Desert. Stretching across the Sahara are vast plains of sand and gravel, seas of sand dunes, and barren rocky mountains. Only 10,000 years ago, however, grasses covered the region, then rich in mammals such as lions and elephants. Now only two percent of the Sahara are oases, patches of land where crops will grow and where nearly two million people live. Oases are usually centred on natural water springs. Pictured above is colourful and rocky land spanning about 50 kilometres near the Terkezi Oasis in Chad.
Authors & editors:
Jerry Bonnell (USRA)
NASA Technical Rep.: Jay Norris. Specific rights apply.
A service of: LHEA at NASA / GSFC
& NASA SEU Edu. Forum
& Michigan Tech. U.