This discovery allows for a possible explanation of dark matter, as well as the possibility of creating engines with better than 100% efficiency (wtf?).
The problem: science journalists are not explaining this story very well. This story, for example, needs revision for coherence between sentences and between paragraphs, and makes a dog's breakfast of explaining the inverted Boltzmann distribution:
So here's the contest: pick some aspect of this amazing science story, and explain it better than the pros in FOUR HUNDRED WORDS OR LESS. Some aspects to explain might include:
1) why temperature can't just be defined as a linear measure of the energies of atoms in a substance, but should rather be seen as in some sense circular;
2) the inverted Boltzmann constant;
3) why a negative-temperature gas has a negative pressure;
4) how this discovery could yield engines with over 100% efficiency,
etc. Winners (to be decided by number of Yes votes) will receive adulation, respect, and little else, but hey, fun contest, right?