This satellite picture shows the size of the Gulf oil slick

Nasa provided a unique view of the Gulf oil spill with this photograph shot from an orbiting satellite.

As seen in this photograph taken on July 14 a silvery gray patch of oil spreads across the Gulf of Mexico about 80km southeast of the Mississippi River Delta.

The largest oil slick is located in the center of the image, but a few isolated ribbons of oil are visible to the east. The tan-colored waters around the river delta are full of sediment.

Southeast of the main oil patch, a very dark region may also be oil-covered. Oil smooths the water surface and changes the way it reflects light back to the satellite.

“Depending on the location of the oil, the angle of incoming sunlight, and the satellite viewing angle, oil-covered waters may appear much brighter or much darker than surrounding oil-free water,” said Rebecca Lindsey, of NASA's Earth Observatory.