Oil Spill

On April 29, the MODIS image on the Terra satellite captured a wide-view natural-color image of the oil slick (outlined in white) just off the Louisiana coast. The oil slick appears as dull gray interlocking comma shapes, one opaque and the other nearly transparent. Sunglint -- the mirror-like reflection of the sun off the water -- enhances the oil slicks visibility. The northwestern tip of the oil slick almost touches the Mississippi Delta.
Credit: NASA/Earth Observatory/Jesse Allen, using data provided courtesy of the University of Wisconsins Space Science and Engineering Center MODIS Direct Broadcast system.

source: http://www.nasa.gov/topics/earth/features/oil_spill_initial_feature.html