“Impossible” dandelion flight described, in Nature News and ScienceDaily 17 October 2018, and Nature 17 October 2018, doi: 10.1038/s41586-018-0604-2.
Anyone who has tried to keep dandelions from taking over their gardens and lawns knows how efficiently these plants spread their flying seeds. Each dandelion seed is suspended under a parachute-like structure called a pappus, formed of between 90 and 110 fine bristles radiating out from a central stem.
A team of scientists at Edinburgh University have studied dandelion seeds flight in a vertical wind tunnel and found they fly “using a method researchers thought couldn’t work in the real world” – a detached vortex.
Many flying things, including birds, insects, seeds and aeroplanes use vortices (rings of circulating air) to help them fly, but these are attached to their wings or flying surfaces. As dandelion seeds fly a swirling mass of air (the vortex) forms above the pappus, but it is not attached to the any part of the seed. The vortex is formed by pressure differences between air moving through the spokes of the pappus and the air moving around the seed. Scientists had believed a detached vortex would be too unstable to be any use in controlled flight.
The researchers then carried out a series of tests with silicone models of varying structures, ranging from solid discs to bristly structures that were mostly open space, like the dandelion seeds. The models that were closest in structure to the dandelion seeds flew best. According to the Nature editorial, “If the number of openings in the discs was even 10% off of those in dandelion seeds, the vortex destabilized.”
The researchers concluding it was the porosity of the pappus, i.e. the amount of space for air to pass through the structure that made it stable. They wrote: “The porosity of the dandelion pappus appears to be tuned precisely to stabilize the vortex, while maximizing aerodynamic loading and minimizing material requirements.”
The Nature Editor commented: “It’s an example of how evolution can produce ingenious solutions to the most finicky problems, such as seed dispersal.” The researchers suggest this method of flying could be adapted for use in small flying drones used in remote sensing and pollution monitoring.
Editorial Comment: We can’t help thinking of a declaration by Jesus, “What is impossible with men is possible with God.” If human researchers and engineers do manage to design drones that use detached vortices to fly then let them acknowledge that the God and Creator Jesus Christ did it first, as well as giving human beings the intellect to study it, and the creativity to apply it.
However, as the experiments with silicone models showed, you have to get it right before it will work. Getting something to work straight away only happens with purposeful, creative design. Therefore, the statement that “evolution can produce ingenious solutions to the most finicky problems” is absurd nonsense. Chance random processes only destroy things while creative design makes things that work.
Evidence News vol. 18 No. 15
31 October 2018
Creation Research Australia
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