Via the crew of NASA's STS-65: They call them "glories" -- optical artifacts that are created when light is scattered backward by airborne water droplets. Although they look like rainbows, they're different in the way they form. Glories rely on a process known as diffraction, while rainbows are produced by refraction and reflection. Above, a glory is just visible against the backdrop of several stratocumulus eddies, or von karman vortices.
From "swag" to "on fleek," tweens explain the changing English language.