Circular cloud formation over the Pacific
NASA’s TERRA satellite snapped an unusual formation over the Hawaiian archipelago last September the 3rd that was probably caused by air being heated over the dark lava of an island or a patch of warm ocean. As it rose, it formed clouds and light rain that cooled the air beneath the clouds causing a downdraft of air that spread out from the original clouds. As this cooler air encountered warmer air further away, it pushed it up causing its moisture to condense in turn forming the cloudy fairy ring.
These typed of nebulosity are known as open cell convective clouds, and result from temperature differentials causing patches of air to rise or fall. They can be circular or hexagonal, formed from the patterns of Rayleigh Bernard cells that form when fluids are heated form below. Closed cell ones retain the honeycomb hexagonal shape of the initial cells and are found in their centres, while open cell ones line the borders of the cell. The convective movement is also inversed, with warm air rising and condensing in the centre while sinking at the edges for closed cell formations and sinking in the centre while rising at the edges for open cell ones.
These clouds provide another example of the endless interactions mediated by the laws of physics that tie the sea, air and land together in the new interdisciplinary paradigm of Earth System Science that is being celebrated as the theme of this year’s Earth Science week.
Image credit: NASA
Have you seen these awesome thimble jellies (Linuche aquila) in the Jellies Experience?
Sometimes we import our jellies, and sometimes, well, we get lucky: these were grown from polyps that our clever aquarists discovered on rocks in our tropical exhibits.
The medusae (bell) of thimble jellies grow and harvest algae, called zooxanthellae, for sustenance. That’s brown coloration you see in the photos. In nature, these jellies collect in bunches at the surface. Their polyps live in long chitonous tubes, which is very different from the typical fixed jellyfish polyp.
But beware: Thimble jellies are also responsible for “sea bathers eruption” in tropical climes, such as the Caribbean. When the jellies spawn and their larvae form, they get stuck in skin or bathing suits, with unpleasant results!
Lava is rather fascinating as a fluid. Lava flow regimes range from extremely viscous creeping flows all the way to moderately turbulent channel flow. Lava itself also has a widely varying rheology, with its bulk properties like viscosity and its response to deformation changing strongly with temperature and composition. As lava cools, instabilities form in the fluid, causing the folding, coiling, branching, swirling, and fracturing associated with different types and classes of lava. (Image credit: E. Guddman, via Mirror)
In February 1935, a chimpanzee at London Zoo called Boo-Boo gave birth to a baby daughter. A couple of months later, a little blonde-haired girl was given a soft-toy replica of the zoo’s new arrival to mark her first birthday. This was Jane Goodall’s first recorded encounter with a chimp.