× This page contains archived content and is no longer being updated. At the time of publication, it represented the best available science.

A massive oil slick in the Gulf of Mexico continued spreading on April 29, 2010, moving perilously close to shore, according to news reports. The U.S. Coast Guard attempted controlled burns on some of the oil to prevent its spread, but had to halt the process due to high winds. Meanwhile, the U.S. National Oceanic and Atmospheric Administration constructed a dome-and-pipe system to contain the spread of oil at the sea floor.

The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured a natural-color image of the oil slick just off the Louisiana coast. The top image shows a wide-area view, and the bottom image shows a close-up view of the oil slick (outlined in white in the top image). The oil slick appears as dull gray interlocking comma shapes, one opaque and the other nearly transparent. The northwestern tip of the oil slick almost touches the Mississippi Delta. Sunglint—the mirror-like reflection of the Sun off the water—enchances the oil slick’s visibility.

The oil slick resulted from an explosion that occurred on April 20, 2010, on the Deepwater Horizon rig. Two days after the explosion, the rig sank to the ocean floor, and a pipe connected to the well on the sea floor broke. Oil began leaking from the pipe, The New York Times reported. The following week, the U.S. Coast Guard discovered a new leak, and also found that five times as much oil was pouring from the well as initially assumed, according to Reuters.

Various methods of containing oil spills have been developed, including controlled burns, domes over the oil spill, and the use of remotely operated vehicles to manipulate equipment on the sea floor. The depth of this oil well—5,000 feet (1,500 meters) below the ocean surface—has complicated all proposed mitigation efforts. To protect wildlife along the shorelines of Louisiana, Mississippi, Alabama, and Florida, authorities were monitoring possible impacts of oil residue, and considering using cannons to scare birds away from affected areas and using shrimper boats to skim oil.

NASA Earth Observatory image created by Jesse Allen, using data provided courtesy of the University of Wisconsin’s Space Science and Engineering Center MODIS Direct Broadcast system. Caption by Michon Scott.