Pluto -- The ninth and farthest planet from the Sun, is also by far the smallest, and composed mostly of ice. Its one moon, Charon, is unusually large in comparison, being about 1/3 the size of Pluto, and orbiting very closely.
More text on the back of this postcard. Who says that Pluto isn't really a planet anymore?
Visual Vacations Postcard series by Paul McGeehee