Picture of the Day: The Nile River Delta's Long-Stemmed Flower

While it's just a small percentage of Egypt's total land area, a huge chunk of the country's population is concentrated around the Nile Delta, as this photograph clearly shows. This image of lights was taken at night from an astronaut aboard the International Space Station on October 28, 2010, with a simple Nikon D3S digital camera outfitted with a 16mm lens.

"The Nile River and its delta look like a brilliant, long-stemmed flower in this photograph of the southeastern Mediterranean Sea," NASA pointed out. "The Cairo metropolitan area forms a particularly bright base of the flower. The smaller cities and towns within the Nile Delta tend to be hard to see amidst the dense agricultural vegetation during the day. However, these settles areas and the connecting roads between them become clearly visible at night. Likewise, urbanized regions and infrastructure along the Nile River becomes apparent."

The thin band of yellowish light seen arcing around the Earth near the top of the photograph is known as airglow, a band of light emission produced by the way solar radiation interacts with atmospheric molecules and atoms about 60 miles above the Earth's surface.

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Image: NASA.