Scientists at Edinburgh University have discovered a ring-shaped air bubble forms as air moves through the bristles of dandelions, allowing the seeds to slowly descend to the ground.
Most of us never thought much of it when we'd blow on dandelions as children and watch the seeds dance in the wind. But scientists have only just cracked the secret behind the seeds' flight, which they say, has never been seen in nature before.
According to a study by researchers at the University of Edinburgh, in the UK, dandelion seeds can fly such long distances because rings of circulating air — called vortices — form just above their surface to lift them in the air.
For birds, aeroplanes and other seeds to fly, the vortices form in contact with their wings or wing-like surfaces.
But the dandelion seed's structure is full of open space. Instead, researchers were able to observe that the seed's filaments "radiate out from a central stalk like the spokes on a bicycle wheel, a feature that seems to be the key to their flight," according to a Nature journal editorial, published on Wednesday, alongside the study.
The discovery was made possible through the use of wind tunnels and laser technology to illuminate particles and visualise the flow of air around the seed.
"To discover that there were aerodynamic mechanisms that we didn't already know — despite the fact that we can fly things at Mach 9 — is always exciting," Richard Bomphrey, a comparative biomechanist at the Royal Veterinary College in Hatfield, UK, said.
The discovery could also impact future technology, according to Ignazio Maria Viola, a senior lecturer at the University of Edinburgh's Institute for Energy Systems.
"Nowadays we are designing smaller air vehicles or drones, because they fly in turbulence and they are very small, it happens very often that there are dynamics governed by some vortexes. So I am becoming more and more interested in how to fly exploiting vortexes instead of avoiding vortexes which is what traditional fluid mechanics does," he told the Associated Press news agency.
The scientists designed small silicon discs to imitate the dandelion's spokes with a range of openings. Those that best approximated dandelion seeds, which always have between 90 and 110 bristles, could maintain the detached vortex.