Satellite imagery provides some answers
A thousand miles away an environmental group, SkyTruth, was watching the events unfold. SkyTruth uses satellite imagery to study and document environmental impacts on earth. Oil spreading across the sea surface leaves a sheen that changes the surface of the water, making it look different from surrounding water. This difference often can be detected in the images taken by satellites circling the earth. SkyTruth alerted scientists at Florida State University and the University of Miami about the possibility of a major spill. It began gathering satellite images from NASA’s MODIS website (which stands for Moderate Resolution Imaging Spectroradiometer) and other images made available through the University of Miami. It then used the images it collected to examine how far oil had traveled on the water’s surface, and estimate how much was actually leaking into the Gulf.