Mainstream researchers have long attributed our sense of smell to a "lock and key" hypothesis. The idea is that every odor molecule that enters our nose has a specific shape that fits a specific receptor—like a key fits a lock—allowing us to detect, say, the acrid aroma of burnt coffee. But the hypothesis leaves some questions unanswered. For one, it doesn't explain, why we can detect tens of thousands of odors with only a few hundred smell receptors. It also doesn't explain why odor molecules with very similar shapes give us such different smells; the molecules that gives us the smell of vodka and rotten eggs are almost identical, for example.
Enter vibrations. Chemists have long known that atoms in a molecule vibrate at a particular frequency, depending on their overall molecular structure. Even molecules that differ by a single atom can vibrate quite differently. In the new study, neurobiologists Maribel Franco and Efthimios Skoulakis at the Alexander Fleming institute in Athens and biophysicist Luca Turin and colleagues at the Massachusetts Institute of Technology tested whether these vibrations could account for our wide range of smell.
— From Do Vibrating Molecules Give Us Our Sense of Smell? at Science magazine. You can also find articles at New Scientist and Nature. Thanks to Tania and everyone else who passed along one or more of the links!