Is the vortex in a stirred liquid swirling clockwise or counterclockwise?
It is possible that vortexes in the distant past were responsible for breaking the symmetry in nature to give us the handed life we see today, which has clear preferences for left- or right-handed molecular building blocks like sugars and amino acids. Vortexes in liquids clearly twist either one way or the other, as do screws, our hair, or snail shells. They can be related to each other like mirror images or left and right hands. This is called handedness (chirality). Vortexes are very complex structures, containing many regions with currents moving in completely different directions. For example, if a liquid is stirred in a cuvette, a dense circular current forms at the center while a loose spiral-shaped flow is present in the outer regions of the vortex. A research team headed by Takuzo Aida and Akihiko Tsuda has now synthesized a zinc porphyrin dendrimer that makes these individual local currents observable by spectroscopy. The highly branched zinc-containing molecules aggregate in
