Antimatter is powerful stuff, but is it a genuine mirror image of matter? The coldest antiprotons ever made take us a step closer to finding out.

The simplest antiatom, antihydrogen, is made of an antiproton and a positron, the electron's antimatter counterpart. If it is a mirror image of hydrogen, it should emit an identical spectrum of light. The way to test this is to create ultra-cold antihydrogen, allowing it to be trapped and studied. The hard part is cooling the antiprotons.

Read more at http://www.newscientist.com/article/mg20627664.800-frozen-antiprotons-bring-antimatter-within-reach.html.