MODIS / Terra satellite image, May 22, 2010.
Clouds and haze obscure the southeastern Gulf, but a small patch of what might be oil entrained in the Loop Current is visible. As we've said before, it is possible the Loop Current has a distinct color even without the presence of oil, so this is a low-confidence analysis and therefore is shown with a dashed orange line. Sure wish they'd send a vessel out there to do some sampling transects. Note the very broad area of sunglint covering the western half of this image. Look closely and you'll see a cluster of thin, bright, arcuate patches southwest of the Mississippi Delta; these are very thin oil slicks caused by persistent natural oil and gas seeps on the seafloor. I've seen a few of these seeps up close and personal from a research submarine, the Johnson Sea-Link II.
This radar image from Canada's RADARSAT-1 satellite (a real workhorse, still cranking after many years in orbit), also taken on May 22, shows detail of the main body of oil slick around the leaking well site and the Delta. Compare with the MODIS image above:
RADARSAT-1 image, May 22, 2010. Image courtesy CSTARS.
And this MODIS / Aqua image taken the next day, May 23, shows slick and sheen spread widely throughout the eastern Gulf, possibly covering as much as 18,670 square miles (48,356 km2) if we include both the high- and low-confidence areas:
MODIS / Aqua satellite image, May 23, 2010.