June 2, 2010
NASA photos show the spread of the spill from May 9 (U-shape)
to May 24 (before top kill)
(Michon Scott NASA’s Earth Observatory NASA Goddard Space Flight Center)
Effects of oil, water and sunlight on photo
Caption: When oil slicks are visible in satellite images, it is because they have changed how the water reflects light, either by making the Sun’s reflection brighter or by dampening the scattering of sunlight, which makes the oily area darker.
In coastal areas, however, similar changes in reflectivity can occur from differences in salinity (fresh versus salt water) and from naturally produced oils from plants.
Oil smoothes the ocean surface, making the Sun’s reflection brighter near the centerline of the path of the satellite, and reducing the scattering of sunlight in other places. As a result, the oil slick is brighter than the surrounding water in some places (image center) and darker than the surrounding water in others (image lower right). Bright white ribbons of oil streak across this sediment-laden water. Tendrils of oil extend to the north and east of the main body of the slick.