Hawaii’s Kilauea volcano (image left) with the long swirls of volcanic gases (top half of the image) wafting west from the volcano... Astronauts are trained to take oblique images of hard-to-see atmospheric haze by shooting obliquely to enhance visibility. The gas haze—termed vog, a combination of fog, smog and volcanic—is well known in Hawaii, and is defined as “a form of air pollution that results when sulfur dioxide and other gases … emitted by an erupting volcano react with oxygen and moisture in the presence of sunlight...."