For once, "shadow of the atom" is not just a poetic metaphor for the nuclear age. The black dot at the center of this image is, literally, the shadow cast by a single atom of ytterbium, magnified 6500 times.
This is the difference between low kinetic energy (top) and high kinetic energy (bottom), as illustrated in the 1956 Disney book Our Friend the Atom. It may be useful in visualizing some of the ideas presented in my recent feature on space radiation.
From Fresh Photons, a fantastic blog chock full of science pictures.
Via David NgRead the rest