The river Nile is the longest river on the planet Earth. The river begins its journey at Lake Victoria in E. central Africa. It flows mostly north through the Sudan and Egypt to the Mediterranean Sea for a distance of 3470 miles. The black sediment brought down by the Nile to the Nile Delta at the Mediterranean Sea makes the land there incredibly fertile.

 The Nile  dictated the Egyptian way of life, particularly with agriculture. The Egyptian calendar was divided into three parts and all were regulated by the helical rising of the bright star Sirius. Helical rising means that the star rises above the eastern horizon the same time as the Sun. Sirius first rose helically at the time the Nile overflowed its banks.

 It  was the flooding of the Nile that enabled the Egyptians to survive, so it is easy to imagine why the Nile is so important in history. To the ancient Egyptians, the river Nile was the giver of life, and it was soon immersed in mystery and superstition. But not all mysteries of the Nile have ancient roots. Modern Geologists have some questions about he Nile’s past and why it does some of the things it does.

One of the many great mysteries of the Nile river may be solved with the discovery of an ancient river channel buried under layers of sand in the Sahara Desert in Africa.

The buried river channel was revealed in images taken by the Spaceborne Imaging Radar, known as SIR-C/X-SAR that flew twice on the Space Shuttle Endeavour in 1994.  The radar images were processed at NASA's Jet Propulsion Laboratory (JPL), Pasadena, CA, and the University of Texas at Dallas (UTD).

     One the curiosities of this river is called the Great Bend of the Nile While the river generally flows due north, in the Sudan, it makes a huge, looping bend that is really remarkable because the river is flowing through the Sahara Desert, the largest, driest desert on the face of the Earth. While it would be expected that the river would flow due north, Instead, it bends southwestwards and wanders through the Sahara for another 200 miles before resuming its northward course.

   At some time in the past though, the Nile flowed on a different course. Discovering the river channel shows us that probably sometime between 10,000 and 1,000,000 years ago, the Nile was forced to abandon its course and take up a new course to the south. This buried channel proves that this region has been geologically active. and shows us how this activity has altered the course of the river. Since the Nile is critically important to millions of people, it is vital to be able to predict what the river will do. By knowing the history of the river, it lends clues to the future.

Scientists have been studying the Nile for a long time but it was the tantalizing radar images of the area hidden beneath the sands of the Sahara that revealed new clues. Prior to this type of imaging, studies had been limited to what scientists could see from the ground , or from satellite images. Radar is far more efficient in getting information from sand covered areas because the radar waves are able to penetrate the sand.

SIR-C/X-SAR is a joint mission of the United States, German and Italian space agencies. JPL built and manages the SIR-C portion of the mission for NASA's Office of Mission to Planet Earth, a program to study the Earth's land, oceans, atmosphere and life as a total, integrated system.  More and more we are finding the radar data has applications to answer questions about the Earth.

Copyright © 1999 Kathy Miles and Charles F. Peters II