At the Edge of Space

Gr 9 Up—"At the edge of space, there are violent forces at work." Thus begins this NOVA episode about a lesser-known phenomenon called sprites: mysterious yet beautiful bursts of light that occur in the upper atmosphere during severe thunderstorms. The narration starts off with a definition and visual of what defines the upper atmosphere and the ionosphere, which resides 60 miles above Earth. Sprites are defined as high-altitude lightning that is 10 times more powerful than lightning in the lower atmosphere. Next discussed is how scientists use high-powered cameras (shooting as much as 10,000 frames per second) to capture images of sprites, how they are formed, and why they have such an unusual shape. It ends with an explanation of the role sprites play as part of the global electric circuit. This has stunning video and stills of the remarkable natural occurrence. The scientists' enthusiasm for their subject is infectious, and their passion shines through. Overall, a well-organized and visually appealing video that will be excellent for in-depth space units and for those interested in the subject.—Stephanie Farnlacher, Trace Crossings School, Hoover, AL