Sea butterfly at different stages of wing beat. Photo: David Murphy.
In a remarkable example of convergent evolution, we show that the zooplanktonic sea butterfly Limacina helicina ‘flies’ underwater in the same way that very small insects fly in the air. Both sea butterflies and flying insects stroke their wings in a characteristic figure-of-eight pattern to produce lift, and both generate extra lift by peeling their wings apart at the beginning of the power stroke (the well-known Weis-Fogh ‘clap-and-fling’ mechanism). It is highly surprising to find a zooplankter ‘mimicking’ insect flight as almost all zooplankton swim in this intermediate Reynolds number range (Re=10–100) by using their appendages as paddles rather than wings. The sea butterfly is also unique in that it accomplishes its insect-like figure-of-eight wing stroke by extreme rotation of its body (what we call ‘hyper-pitching’), a paradigm that has implications for micro aerial vehicle (MAV) design. No other animal, to our knowledge, pitches to this extent under normal locomotion.
To make the discovery, Dr Murphy and his colleagues used a system they call tomographic particle image velocimetry: four high-speed cameras trained on a tiny volume of fluid, which is illuminated with laser beams and seeded with shiny particles to trace flow movements.
"Using our four cameras, we make a 3D measurement of the flow that the animal produces as it's swimming," he explained.
Joseph Kimble noticed this peculiarly-worded sign. I’m not sure of the jurisdiction but, to he honest, I would move elsewhere if I ran into a sign like this. The oddest sign ever? pic.twitter.com/6jBryKMiXQ— Joseph Kimble (@ProfJoeKimble) November 17, 2016
The Black Friday Mac Bundle 2.0 is one of the Boing Boing Store’s best-selling Mac bundles yet, and it’s about to come to an end. If you don’t get your copy now, here’s what you’ll be missing:This bundle comes packing 9 top-rated Mac apps in one package, at the hugely discounted price of just $23.99. […]
The Boing Boing Store’s Gift Guide is full of ideas for pretty much anyone in your life like hipster ice cub trays, Xbox controllers, Halo Boards, and even diamond necklaces. As always, all products in the Boing Boing Store come at great discounts, too. Shop by price bucket starting at under $20. Under $20:Bloxx Jumbo Ice Trays […]
Unlike traditional lighters, the SaberLight features an electronic plasma beam that’s both rechargeable and butane-free. This sleek lighter is even approved by TSA, so you’ll never be stuck buying lighters you’ll just have to throw away partially used. For some people, like me, this is a pretty big game-changer. The SaberLight’s beam is actually both hotter and cleaner […]