How NASA finds oil.

Unfortunately, as NPR reveals, we’re not talking about the kind that’s still safely underground:

The NASA Earth Observatory explains that since ocean waters are never perfectly smooth, the sun’s reflection gets scattered off the surface in many directions. This yields a broad stripe of sunlight across the ocean in most satellite photographs.

But things change when you add oil to the water.

Diagrams and space photos (oo! a two-fer!) at the link.