Radar image acquired on 2 May

In this radar image, acquired from Envisat's Advanced Synthetic Aperture Radar (ASAR) on 2 May 2010 03:45 UTC (Saturday night local time), the oil spill is visible due east of the Delta National Wildlife Refuge extending into the Gulf of Mexico. The white dots are oil rigs and ships. Radar is especially suited for detecting oil spills because it works day and night, can see through clouds (unlike optical sensors) and is particularly sensitive to the smoother water surface caused by the oil.