Oil from the Deepwater Horizon well remained visible on the surface of the Gulf of Mexico on June 25, 2010. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra captured this natural-color image the same day. The oil appears as interlocking curved tendrils varying in color from white to dark gray.
When the Sun is at the right angle, sunglint makes the oil visible. Oil smoothes the surface of the water, making it a better mirror of sunlight. Close to the precise location of the Sun’s reflection, oil is brighter than surrounding ocean water, and farther away from the Sun’s reflection, oil may look darker than oil-free water. The relative brightness of any spot, however, is not a perfect indicator of the oil slick’s location or amount. Not all oil appears brighter or darker than nearby water, and not all relatively bright or dark areas are necessarily oil-slicked. Please see the links below for more information.
NASA image by Jeff Schmaltz, MODIS Rapid Response Team. Caption by Michon Scott.