On May 25, 2010, the Deepwater Horizon oil spill in the Gulf of Mexico was perfectly positioned in the sunglint part of a photo-like image from the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Aqua satellite.
In the sunglint region—where the mirror-like reflection of the Sun gets blurred into a wide, bright strip—any differences in the texture of the water surface are enhanced. Oil smoothes the water, making it a better “mirror.” Oil-covered waters are very bright in this image, but, depending on the viewing conditions (time of day, satellite viewing angle, slick location), oil-covered water may look darker rather than brighter.
The slick appears large and sprawling, reaching out in numerous ribbons toward the tip of the Mississippi River Delta. Oil is visible in the marshes of Barataria Bay and barrier islands to the southwest. Although most of the oil is located near and to the west and northwest of the damaged well, one streamer of oil continues to stretch toward the southeast.
The relative brightness of the oil from place to place is not necessarily an indication of the amount of oil. Any oil located in the precise spot where the Sun's reflection would appear if the surface of the Gulf were perfectly smooth and calm is going to look very bright in these images. The cause of the dark patch of water in the middle of the slick just west of the well is not known, but it may indicate the use of skimmers, dispersants, or booms.