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 Ng
Absolute zero is supposed to be the coldest cold — 0 Kelvin, the point where atoms stop moving.
But researchers at the University of Munich say it's possible to get colder than that, an idea they've demonstrated experimentally. But what does it mean to be colder than cold? Here's the scientists' totally unhelpful explanation:
another way to look at these negative temperatures is to consider them hotter than infinity, researchers added.
Cool. Thanks, guys. Luckily, journalist Charles Q. Choi makes this strange idea make a whole lot more sense. Read his explanation at LiveScience.