They can, however, be just as awe-inspiring during their quieter moments, like when a simmering peak blows a lazy smoke ring into the sky. Over the last few days, Italy’s vertiginous Mount Etna ...

There are similarities between how volcanoes huff out these halos and how dolphins blow bubble rings or how smokers exhale smoke rings. And the volcanic versions are commonly called smoke rings ...

Smoke rings are being seen in a new light. Doughnut-shaped structures called vortex rings are sometimes seen swirling through fluids. Smokers can form them with their mouths, volcanoes can spit ...